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SECTION III
NEUROSURGERY
CHAPTER XIII
EXPERIMENTAL
OBSERVATIONS ON PERIPHERAL NERVE REPAIR a
INTRODUCTION
In
no field of medicine, perhaps, is the interdependence of experimental
and clinical
work so clearly demonstrated as in peripheral nerve surgery.
Questions
which concern the structure, development, growth, degeneration, and
regeneration, after injury, of the peripheral nerves have engaged the
attention of observers for
more than a century, and there exists an extensive literature, dealing
with these and relative
problems, to which both the experimenter and the clinician have
contributed. A study of this
literature, while showing constant advance in knowledge, as concerns
all phases of the questions
involved, will reveal also wide and fundamental divergence of opinions
which have influenced
and retarded progress as regards structural interpretations and their
clinical applications.
The
nervous system consists of independent, anatomic units, the neurons,
related to each
other by contiguity and not by continuity. The peripheral nervous
system is, therefore, both on
anatomic and functional considerations, ia part of the central nervous
system, and in its surgical
treatment should be regarded as such. There are 31 pairs of spinal
nerves, quite symmetrically
arranged, which course singly or join to form plexuses and which
throughout the thoracic and
upper lumbar regions and for certain sacral nerves are connected with
the ganglia of the
sympathetic system through the white rami or preganglionic branches.
Considered structurally,
each spinal nerve consists of bundles of nerve fibers, certain of which
are processes of neurons,
known as neuraxes or axons, the cell bodies of which are situated in
the ventral gray of the
central nervous system or in the sympathetic ganglia and carry nerve
impulses from the central
nervous system to the periphery, and are thus known is efferent nerve
fibers, while other nerve
fibers are processes of neurons known as dendrites, the cell bodies of
which are found in the
spinal ganglia and conduct nerve impulses toward the central nervous
system and constitute the
neuraxes of afferent nerve fibers. The neuraxes and neuraxes dendrites,
forming the nerve fibers
of the spinal nerve, may been sheathed in a layer of myelin, known as
myelinated or medullated
nerve fibers, or they may be naked, and are then known as nonmyelinated
or nonmedullated
nerve fibers. Considered functionally, we recognize in each spinal
nerve nerve fibers belonging
to one of four
a Report
of the work of the Neurosurgical Laboratory, Department of Anatomy,
University of
Michigan, Ann Arborr, Mich. The following medical officers, on special
assignments,
collaborated in the experimental work for stated periods Lieut. Col.
Dean Lewis, Maj. J. F.
Corbitt, Maj. Byron Stookey, and Maj. T. Roberg. During the latter
portion of this investigation
technical laboratory assistance was made available through a grant
received from the committee
on research of the American Medical Association, for which
acknowledgment is here made.
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functional systems,
designating a functional system "as the sum of all the neurons in the
body which possesses certain physiological and anatomical characters in
common so that they may
react in a common mode." 1 The functional systems of the
spinal nerves are designated: 1,
Somatic efferent; 2.visceral efferent; 3,
somatic afferent; 4, visceral afferent. The nerve fiber
composition of a spinal nerve may be represented graphically as shown
in Figure 211.
FIG. 211.- Diagrammatic
cross section of the Spinal
cord, showing on the
right side the nerve roots and type nerve
fibers. A, Somatic efferent neuron; B, preganglionic neuron of the
visceral efferent system; C, postganglionic
neuron of the visceral efferent system ; D, somatic afferent neuron; D,
somatic afferent neuron with nonmedullated
processes, E, visceral afferent neuron (interoceptive impulses); PR.
G., preganglionic bundle or white ramus; PO.
G., postganglionic bundle or gray ramus; S Y. G., sympathetic ganglion
of the sympathetic chain
The
somatic efferent fibers (fig. 211-A) are the neuraxes of neurons the
cell bodies of
which are located in the ventral portion of the spinal gray. They leave
the cord through the
ventral roots and terminate in skeletal muscle in sublammellar end
plates or motor nerve
endings. The nerve fibers belonging to this functional system are
relatively large, myelinated
fibers.
The
visceral efferent fibers (figs. 211-B and C), or the sympathetic fibers
of the spinal
nerves, are neuraxes of sympathetic neurons, the cell bodies of which
are situated in the
sympathetic ganglia of the symipathetie trunks. They constitute the
postganglionic nerve fibers. They enter the spinal nerves through
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the gray rami
communicants, each spinal nerve having such connection with the
sympathetic
trunks. The sympathetic ganglion cells of the sympathetic trunks are in
synaptic relation with
the preganglionic neurons, the cell bodies of which are situated in the
visceral efferent column of
the spinal gray, their neuraxes leaving the spinal cord by way of the
ventral roots of the
successive thoracic and four upper lumbar nerves and by way of the
white rami, branches
reaching the sympathetic ganglia where they form synaptic relations
with the sympathetic nerve
cells, it being well known, through the fundamental experimental
researches of Langley, that
there are always two neurons concerned in carrying an impulse from the
central nervous system,
through the spinal nerves to involuntary muscle and glandular tissue.
The investigations of
Boeke make it probable that the visceral efferent fibers may play a
part in the innervation of
certain skeletal muscle fibers.
The
somatic afferent fibers (figs. 211-D and D') of the spinal nerves are
the dendritic
branches of sensory neurons, the cell bodies of which are situated in
the spinal ganglia and
convey impulses from the periphery to the central nervous system. A
certain per cent of these
nerve fibers are relatively large myelinated fibers, which have origin
in peripheral nerve endings.
both encapsuled and nonencapsuled. They are connected with the larger
and more complex
ganglion cells. A certain per cent of somatic afferent nerve fibers are
nonmyelinated (Ranson) or
are very fine myelinated fibers (Langley) which are connected with the
smaller and simpler
ganglion cells of the spinal ganglia. They are distributed in large
part to the skin but also to the
muscular branches.
The
visceral afferent fibers (fig. 211-E), strictly speaking, are not
primarily distributed to
the peripheral nerves of the body wall and extremities. but to the
thoracic and abdominal viscera
which they reach by way of the white rami. The cell bodies of these
fibers are in the spinal
ganglia. their neuraxes pass through the respective dorsal roots to the
dorsal column of the spinal
cord.
According
to function, the somatic afferent neurons are classified either as
exteroceptive
fibers, which carry impulses from sense organs and from the surface of
the body, or as
proprioceptive fibers, carrying impulses arising from within the body,
from joint, tendon, and
deep connective tissue and from muscular tissue, and also from the
semicircular apparatus of the
ears. The visceral afferent nerve fibers are said to carry
interoceptive nerve impulses. There is
no recognizable structural differentiation in afferent nerve fibers to
be correlated with the type of
impulses carried, though each group of afferent fibers is connected
with special receptors or
sensory nerve endings in the periphery and with distinctive neuron
paths in the central nervous
system. The cranial nerves, structurally considered, are very similar
to the spinal nerves. but
collectively considered contain additional functional systems having
restricted distribution and
specialized function; considerations which need not receive special
discussion here.
STRUCTURE OF A NERVE
The
efferent and afferent fibers of a nerve trunk are intermingled and run
together in
small bundles known as funiculi. A funiculus may approach a millimeter
in size. Each funiculus
is surrounded by a connective tissue sheath known as the perineurium,
composed of several
lamellae. of flattened collagenous
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connective tissue
bundles; anastomosing here and there, between these flattened
connective
bundles, spread out fibroblasts are found which, on the inner surface
of the perineurium, form a
fairly distinct layer. The writer has not been able to demonstrate the
fairly definite layer of
endothelioid cells described by Key and Retzius. A few wandering cells
and a few clasmatocytes
are found between the lamellae of the perineurium. Relatively few
elastic fibers, arranged in
network, are found in the perineurium. Flattened trabeculae of
collagenous connective tissue
pass from the perineural sheaths to the interior of the funiculi and
there is found a loose
connective tissue, consisting of fibrils and fine fibers of collagenous
connective tissue and a few
elastic fibrils, disposed as a network and found between the fibers or
small bundles of such, and
forming more or less distinct tubular sheaths for the fibers of the
funiculi. This constitutes the
endoneurium of the funiculus. In it are found a few fibroblasts and a
few clasmatocytes and
wandering cells. The spinal nerves generally consist of more than one
funiculus, and certain of
the larger ones have many funiculi. Surrounding the whole nerve trunk
and extending between
the funiculi, there is found an areolar connective tissue, continuous
with the surrounding Connective tissue, which is known as epineurium.
The name would suggest that this sheath is upon
the nerve. It should be understood that the epineurium extends between
and surrounds the
several funiculi of a nerve trunk; therefore. an epineurial stitch or
suture may pass through a
nerve trunk, conceivably between the funiculi. The epineurium consists
of looser and denser
areolar connective tissue with often, especially in the larger nerves,
an appreciable amount of
adipose tissue, disposed in small groups of fat cells or in scattered
cells. In the epineurium are
found the larger blood vessels and the lymph vessels of a nerve trunk,
also sensory nerve endings
for the nerve itself. The cells of the epineurium are largely of the
type of the fixed fibroblasts;
wandering cells and clasmatocytes are also found, but in variable
numbers: mast cells have be es
described. The details of the ultimate distribution of the blood and
lymph vessels of a nerve
trunk require further study and should be given special consideration
for each of the several
larger nerve trunks, subject to injury. The larger blood vessels, both
arteries and veins, course in
the epineurium. Terminal arterioles pass through the perineural sheaths
of the several funiculi
and break up into capillaries which course in the endoneurium, between
the nerve fibers,
forming long-meshed anastomoses. The capillaries of the funiculi are
relatively scanty. Definite
lymph vessels and lymph capillaries have not been shown to exist within
the funiculi and
perineural sheath. They have been demonstrated by injection in the
epineural sheath.
Special
interest was drawn to the funicular structure of peripheral nerves
through the
studies and publications of Stoffel 2 and his followers,
who claimed that the several peripheral
nerves presented a definite funicular morphology which extended
throughout the nerve trunk and
was fairly constant, so that definite sensory and motor paths could be
demarked in the internal
topography of the nerve. This laboratory was not especially concerned
with this problem.
realizing that during healing or regeneration of a cut nerve, in the
field of the scar, even with the
best of suture, the funicular pattern is to a large extent lot.
Extended researches bearing on this
problem were undertaken by Heinemann, 3
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Borchardt and Wyasmenski,4 Langley and Hashimoto, 5 Coinpton,6 Dustin,7 and Kunzel.8 These
observers have shown, either by careful dissections of macerated nerve
trunks, or by means of
carefully oriented serial sections of nerve trunks, that Stoffel 's
views can not be maintained. It
has been shown that an extensive anastomosis and exchange of nerve
fiber bundles exists
between funiculi and that the funicular pattern is not the same even at
relatively short intervals
and not necessarily alike in the same anatomic nerve in different
individuals. This question has
been well summarized by Stookey, 9 who has reviewed the
pertinent literature.
STRUCTURE OF NERVE FIBERS
Nerve fibers are either myelinated-medullated, or
nonmyelinated-non-medullated. A
myelinated nerve fiber consists of the neuraxis or axon, the myelin or
the medullary sheath, and
the neurolemma with its neurolemma nuclei or sheath cells. The neuraxis
is the direct
continuation of the respective nerve cell or neuron, the essential and
conducting part of a nerve
fiber, and passes uninterruptedly from the cell body to its
destination. It must be regarded as in
protoplasmic continuity with the cell body of the neuron, its trophic
center. The neuraxis is
devoid of any sheath in the immediate vicinity of the nerve cell and
very generally loses all
sheaths before termination. It consists of neurofibrils, continuous
with the neurofibrils of the cell
body of the peripheral neuron, embedded in a homogeneous neuroplasm. A
delicate, peripheral
protoplasmic sheath may be present, known as the axolemma, but this
difficult to establish
conclusively. The myelin sheath in the living and structurally
unaltered nerve fibers appears as a
homogeneous and structure less sheath which is interrupted from place
to place at stated
intervals, at the nodes or constrictions of Ranvier. These nodes occur
at regular intervals of a
length approximately one hundred times the diameter of the fiber. The
segment of a nerve
intervening between two nodes is known as an internodal segment. The
structure of the myelin
has not been fully determined, nor is it clear whether the myelin layer
is to be regarded as a part
of the neuron or iasispecial sheath quite distinct from the neuraxis.
The myelin sheath presents
quite distinctive structural appearances depending on the mode of
fixation and staining of the
nerve fibers. In segments of the same nerve, treated with different
reagents in fixation and
staining, quite dissimilar pictures of myelin structure may be
obtained. It would seem that from
the complex material which forms the myelin, largely made up of
lecithin, there separates out a
coagulable substance which under certain treatment forms a reticulum,
keratin-like in nature, and
known as the neurokeratin net, the arrangement of which varies with
different fixations. The
majority of the special structural characteristics described for myelin
are regarded as fixation
artifacts. It is stained black in osmic acid and is differentially
stainable by a variety of methods. It presents special manifestations
in degenerating nerves. In early stages of development of nerve
fibers or in early stages of regeneration of peripheral nerves, the
myelin seems to appear as a
continuous, delicate sheath, a differentiation of the peripheral part
of the neuraxis; in further
development the nodes of Ranvier appear. There is at hand evidence,
though not conclusive, to
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warrant considering the
myelin sheath as a part of the respective neuro. The suggestion that
the
myelin is in its histogenesis closely related to the neurolemma sheath
is not without its
supporters. In a comprehensive histologic and histopathologic study of
peripheral nerves by
Donikow,10 in which extended consideration is given to the
structure of the myelin sheath, the conclusion is reached that the
plasma cells of Schwann consist of a dense nuclear zone and a
looser meshwork which pervades the myelin sheath of the entire
internodal segment, in the
meshes of which is contained myelin substance. Not unlike this
conclusion is that of Nemiloff, 11 who regards the nuclei
of the neurolemma sheath as related to a protoplasmic reticulum which
pervades the myelin sheath. According to these observations, the myelin
sheath is not a part of
the neuron but an ensheathing structure. The neurolemma forms the
outermost layer of the
myelinated nerve fiber of peripheral nerves. It is very thin,
apparently homogeneous layer
closely applied to the myelin sheath. There is at hand evidence of a
delicate fibrillar structure of
the neurolemma sheath. The flattened, oval nuclei found lying on the
inner surface of the neurolemma sheath, one for each internodal
segment, are considered as part of the neurolemma
sheath and are known as neurolemma cells or sheath cells
Histogenetically, considered, they are
of ectodermal origin. It has not bees possible to obtain conclusive
evidence as to whether the
neurolemma forms a continuous sheath or is interrupted and cemented end
to end at the nodes of Ranvier. In degenerating nerve fibers the
neurolemma sheaths form a delicate tubular structure
which does not fragment with the neuraxis and myelin and the sheath
cells proliferate and
separate from its inner surface. The neurolemma sheath is absent from
nerve fibers of central
nervous system; it’s place is there very probably taken by the
neuroglia tissue. A nonmedullated
fiber consists of a neuraxis which is made up of neurofibrils and
neuroplasm with a delicate
outer protoplasmic layer or axolemma. They present nuclei at relatively
frequent intervals; nuclei
which have the appearance of neurolemma or sheath nuclei, although it
is difficult to
demonstrate clearly a definite neurolemma sheath. It is quite possible
that in the nonmedullated
fibers the sheath cells do not form a continuous neurolemma sheath.
DEVELOPMENT OF PERIPHERAL NERVE FIBERS
Since
histogenesis and experimental embryology of the nervous system has done
much to
clarify the problems of degeneration and regeneration of peripheral
nerves, a brief consideration
may here be given to the question of development of peripheral nerves.
It is now generally
believed that the nerve fibers of the entire nervous system are derived
from the neurosensory
ectoderm through the neuroblasts; the afferent fibers and the visceral
or sympathetic efferent
fibers largely from the neural crest, the anlage of the spinal and
indirectly of the sympathetic
ganglia; the somatic efferent fibers from the neural tube. The
"outgrowth theory" of nerve
developments first formulated by His 12 is now very
generally accepted. According to this theory
the neuraxis (and the dendrites) of a neuron are regarded as the
outgrowth from a single cell. the
neuroblast, no matter what the length of these processes. The growing
tip of the neuraxis shows
an expansion, known as the end-disc or the incremental
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cone; this is
thought to have ameboid properties. The theory of His does not admit of
demonstration in adult tissue, but admits of "near proof" in early
embryonic stages, especially in
tissues stained in differential neuron stains. Harrison's13 experimental observations of growing in
coagulated lymph ganglion cells from the spinal cord of amphibian
embryos, in which growing
and budding neuraxes could be observed under the microscope, very
substantially confirmed the
outgrowth theory of nerve development. Growing neuraxes of the ventral
and dorsal roots of
suitably early embryonic stages are from the beginning accompanied by
cellular elements which
are in very close apposition with the growing nerve fibers. These
cells, which were regarded as
of mesodermal origin by earlier observers, are now known to be of
ectodermal origin and are
variously thought of as contributing to the formation of sheath cells
or as participating in the
formation of the neuraxis itself. The constant presence of these sheath
cells in the early stages of
growing nerve roots led to the formulation of the " chain theory " of
peripheral nerve
development, according to which, in essential, each internodal segment
is thought to be derived
from a cell, the neurons thus constituting a colony of cells in chain,
or a syncytiun. With this
theory the names of Balfour, 14 Dohrn, 15 and
Bethe, 16, are especially associated. Modifications
and interpretation of these two theories of peripheral nerve origin and
growth are extant. Hensen 17 early contended for a primary connection between the
nerve cells and the muscular and other
tissues and thought that out of this primary syncytial net the nerve
fibers were developed. Held 18 has more recently amplified this view. Such questions are not
determined by a study of sections
alone, although such study has contributed largely to the solution of
the problem; experimental
embryology has been of material assistance. Harrison 19 was
able to ablate the neural crest in
very young amphibian embryos, thus removing the anlage of the dorsal
spinal ganglia without
injuring the ventral part of the spinal cord from which the ventral
root fibers have origin. It was
found on development of the ventral root fibers that these were devoid
of sheath cells. Further
experiments by the same observer and others, including limb
transplantation in young amphibian
embryos, which on attachment and outgrowth in new positions became
neurotized, indicate that
there does not exist a primary connection between nerve cells and the
peripheral tissues, a sine
qua non to nerve growth. Observations made and deductions drawn from
experimental
embryology bearing on peripheral nerve development have been summarized
as follows by
Streeter: 20 It was shown that no peripheral nerve fibers
would develop in an embryo from
which the nerve center had been removed, thus establishing the fact
that the ganglion cells are an
essential element of the fibers. It was shown that the sheath cells of
Schwann, upon the influence
of which in the formation of the fibers many histologists had placed
much emphasis, were not
essential to the growth of the nerve fiber, and that the axis cylinders
will develop and extend out
in the surrounding tissues in the normal way and reach their normal
length in specimens where
the sheath cells have been eliminated. It was shown by modifying the
environment of the
developing nerves that fibers will form in surroundings entirely
different from their natural path
and establish completely foreign connections." Histogenetic studies
have shown quite
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conclusively that the
neuraxis is a protoplasmic outgrowth from a single neuroblast. The
prevailing opinion is that the neurolemma sheath and its sheath nuclei
are of ectodermal origin,
derived directly or indirectly from the neuro-sensory ectoderm, as also
the capsule cells of spinal
and sympathetic ganglia. These neurolemma sheath cells, however, are
not to be regarded as
potential neuroblasts. There exists less certainty as to the
development of the myelin sheath. This
sheath seems a part of the neuraxis, which in its deposition is
influenced by the sheath cells.
Very careful studies of the histogenesis of the myelin are required
before the structure of the
myelin sheath and its relation to the neuraxis can be fully determined;
in such studies
experimental embryology must play its rǒle.
DEGENERATION AND REGENERATION OF
PERIPHERAL
NERVES
There
exists a very extensive literature dealing with the problem of
peripheral nerve
degeneration and regeneration, far too extensive to receive even
cursory review here; certain
main phases of the development may be noted and briefly considered,
since such treatment will
obviate repeated restatement in discussing the experimental work.
Arnemann, 21 as early as 1787,
recognized the fact that a severed nerve lost its conductivity, and
Cruikshank 22 and Haighton 23 believed themselves to have demonstrated experimentally regeneration of
a severed peripheral
nerve. However, it was not until 1852 that Waller 24 clearly demonstrated that the portion of a
nerve fiber separated from a "ganglion cell," when a nerve is severed,
undergoes degeneration
and is regenerated through down growth from the central part. Ranvier 25 and Vanlair 26 mate-rially extended our knowledge more
particularly as concerns the down growth of central fibers in
regeneration. Their views were controverted by Schiff, Erb, and
Wolberg, so that about 1890
there existed three main views concerning the mode of regeneration of
severed peripheral
nerves: 1, The view of Waller, that after degeneration of the
peripheral stump regeneration was
through downgrowth of neuraxes derived from the central stump; 2, that
after secondary
degeneration neuraxes developed in the peripheral stump which were
secondarily united to the
central fibers; 3, that the neuraxes of the peripheral stump did not
degenerate. In the few years
following 1890 there appeared a series of mono-graphic contributions
dealing with this problem: Bu ngner,27 Howell and Huber 28 Stroebe, 29 Huber. 30 Bűngner, in his
frequently
quoted communication, paid especial attention to sheath-cell
proliferation, and defined clearly
the nucleated protoplasmic strands, derived from the proliferating
sheath cells and designated by
him as "bandfasern," which appear during the second and third week
after injury, and were
interpreted by him as new nerve fibers or potential nerve fibers.
Stroebe, in his experimental
studies, believes himself to have shown the down growth of neuraxes
from the central stump.
Huber, using Stroebe's method of neuraxis staining in an experimental
study of bridging nerve
defects, believed he had demonstrated the downgrowth of central
neuraxes, the division of
neuraxes in regeneration and the incremental cone at the growing ends
of the neuraxes, the same
as found on the growing tips of neuraxes in development, and in neurons
grown in tissue
cultures. These observations were followed by studies of Galeoti and
Levi,31 Kennedy,32 and
Wieting, 33 each
1099
of whom favored the view
of peripheral autoregeneration in degenerated nerve. At about 1900
two main and opposing views as to the regeneration of degenerated nerve
were held: 1, What is
known as the monogenetic conception of nerve regeneration, according to
which regeneration of
a degenerated severed nerve is through downgrowth of neuraxes derived
from the neuraxes of
the nerve fibers of the central stump, at all times connected with
central nerve cells;2, a polygenetic conception, according
to which
regeneration is obtained through cells derived from both
the central and peripheral stump. The technical staining methods then
at the disposal of
observers were inadequate to admit of clear and differential staining
of neuraxes, leading often to
differences in the interpretation of observations made. Bethe 16 hoped to bring solution to the
problem through a series of especially devised experiments in which
downgrowth of central
fibers was thought to be obviated. Bethe believed he had demonstrated
new nerve fibers in a
distal stump completely separated from the central connection. The
experiments of Bethe
seemed conclusive, and received wide consideration; they were refuted
by the experimental
observations of Langley and Anderson,34 Lugaro,35 and others. Several lines of investigation in
correlated fields did much to bring solution to the problem: The
experimental embryonic
observations of Harrison and others contributed largely to the
confirmation of the neuron
doctrine and the outgrowth theory of nerve development, as above
stated; the histogenesis of
neurons was much more carefully studied; marked improvement in
technical histologic methods
was effected, especially as concerns the silver precipitation methods
of Golgi, Cajal,
Bielsehowski, and Ranson, and the intra vitam methylene blue method of
Ehrlich. A series of
experimental studies on nerve degenerations and regenerations was
undertaken, controlled by
careful histologic studies, in which the downgrowth of the neuraxis in
regeneration could be
followed step by step. This more recent literature includes
contributions by Perroncito, 36 Poscharissky, 37 Cajal, 38 Ranson, 39 Boeke, 40 41 Dustin, 42 Ingebrigsten,43 and others, in all of
which the modern silver precipitation methods for staining neuraxes
have been used to control
experimental results, the consensus of their work confirming the
monogenetic or downgrowth
theory of neuraxis development.
An
injury to a peripheral nerve, producing severance of continuity induced
be crush,
sharp instrument, bullet wound or laceration, calls forth a series of
structural changes in the
distal segment, known as secondary degeneration or Wallerian
degeneration, involving at about
the same time the entire distal stump. except for a narrow zone in the
immediate vicinity of the
wound, a zone of traumatic injury the width of which rarely exceeds 0.5
cm. These structural
changes are influenced by the presence or absence of the myelin and
will be described separately
for the two types of nerve fibers.
DEGENERATION OF MYELINATED NERVE FIBERS
For
a period of three to four days in dog and man, two to three days in the
rabbit and
guinea pig, the nerve fibers distal to the line of injury, except in
the zone of traumatism, show no
demonstrable structural change and respond to mechanical and electrical
stimulation. Structural
change is first demonstrable in the neurofibrils of the neuraxis; they
show varicosities and
hypertrophy and
1100
granular change
(Mönkeberg and Bethe),44 and in pyridine-silver
preparations,
irregularities of contour and staining (Ranson). 39 Beginning with the third or fourth day (man
and dog; second or third day, rabbit and guinea pig) changes in the
myelin sheaths in certain of
the myelinated fibers is noted, consisting of irregularly placed
enlargements and constrictions,
followed by fragmentation or segmentation of the myelin and soon after
of the neuraxis,
resulting in the formation of segments, found within the continuous
neurolemma sheath, known
as myelin ellipsoids, presenting rounded ends inclosed by a laver of
myelin and containing
fragments of the neuraxis. This fragmentation of the myelin sheath and
neuraxis is preceded or
accompanied by the hypertrophy of the protoplasm of the sheath cells,
their nuclei showing
richer chromatin content. These, in their growth, first compress the
myelin and neuraxis and, as
these fragment, hypertrophy to occupy the lumen of the neurolemma
sheath. These primary
changes in the myelin and neuraxis are followed by progressive
fragmentation of the myelin
ellipsoids, resulting in the formation of larger or smaller masses of
oval or spheric shape, many
still containing fragments of the neuraxis differentially stainable
with silver methods. This is
accompanied by growth of the protoplasm of the sheath cells and
proliferation of their nuclei in
part at least by mitosis (Büngner,27 Huber 45).
The hypertrophied protoplasm of the sheath cells
begins to surround the myelin remaining. By the end of the first week
after injury there are still
to be found some few myelinated fibers which do not show fragmentation
of the myelin;
however, the majority of them show evidence of degeneration but to a
variable degree. During
the second week after injury there is noted a growth of the sheath cell
protoplasm and a proliferation of their nuclei and a progressive
fragmentation of the myelin remains. The sheath cells
exert a phagocytic action on the myelin remains, so that during the
second and third weeks after
the injury the myelin globules become progressively less numerous and
smaller and the
protoplasm and nuclei of the sheath cells form distinct nucleated
syncytial bands, still containing
a variable number of myelin globules. The nucleated syncytial bands
were first fully described
by Bu ngner 27 as the "bandfasern" and, regarded as new
nerve fibers, they were designated as
"embryonic fibers" by Howell and Huber 28. These syncytial,
protoplasmic, nucleated bands,
developed through hypertrophv of the sheath cells, constitute a stage
in the degeneration of
peripheral nerve fibers which extends through weeks and months. They
represent an undif-ferentiated, perhaps embryonic, protoplasm, and are
of ectodermal origin. Büngner 27 and Bethe 16 and other adherents of the school of polygenetic nerve
regeneration, have described a delicate,
longitudinal striation within the proto-plasm of the "bandfasern,"
indicative of neurax is
development and of peripheral autoregeneration. Faint longitudinal
striation is now and again
seen in the"bandfasern" in silver preparations, but transition stages
between the syncytial
protoplasmic bands and developed neuraxes have not been demonstrated.
In considering
regeneration of nerves it will be noted that neuraxes appear in the
distal degenerated stump
before the "bandfasern" are fully developed. The question of the mode
of removal of the myelin
in degenerating nerve fibers has received extensive consideration; both
fixed and wandering
cells of the
1101
peripheral trunk and its
vessels have been brought in causal relation with this process.
Donikow, 10 using various fixing and staining methods, has made a
critical study of this question in
degenerating nerves of the rabbit and finds that with the beginning of
fragmentation of the
myelin, fat droplets are found in the protoplasm of the sheath cells
which are thought to pass to
the tissue lymph spaces of the endoneurium probably in colloidal
solution. The fourth day after
injury, fat droplets are found in the endoneural cells and by the end
of the first week in the
cellular elements of the perineurium.
DEGENERATION OF THE NONMYELINATED FIBERS
The
account here given is based on Ranson's 39 observations in
preparations stained with
pyridine-silver methods. Two types of nonmyelinated fibers are
recognized; such as degenerated
during the first week, thought to be afferent fibers; such as
degenerated during the second week,
thought to be visceral efferent fibers. Degeneration of the former
begins soon after injury, the neuraxis becoming granular and during the
second and third day showing alternate darker and
lighter segments, the former representing neuraxis remains, the latter
perhaps exudate. By the
fourth day the darker segments disintegrate and disappear, so that by
the end of the first week
after injury the degenerated fibers are difficult to see. A
proliferation of the sheath cells takes
place and fine, nucleated protoplasmic bands develop and are found,
usually, grouped in small
bundles. The more slowly degenerating non-myelinated fibers may present
uniform staining
nearly two weeks after injury and be mistaken for newly formed
neuraxes; their mode of
degeneration is the same as that of the more rapidly degenerating
nonmyelinated fibers. "We
have, therefore, as the terminal stage of the degeneration of the
non-medullated fibers, nucleated
protoplasmic bands which differ from similar bands formed from the
medullated fibers only in
size and in absence of myelin droplets." (Ranson.) 39
DEGENERATION OF NERVE ENDINGS
Tello 46 and Boeke 40 have used differential silver
staining methods in the study of motor
nerve endings in degeneration. The account of Boeke is here followed.
This investigator found
that changes are observed in the neuro fibrillar net of the end plate
during the first day after
injury in that these fibrils stain only lightly. This stage lasts only
a short time and is followed by
one in which the fibrils hypertrophy and agglutinate and stain more
deeply. This agglutination of
the neurofibrils proceeds until darkly staining irregular strands are
formed; these clump, run
together, fragment and form irregular stainable masses which ultimately
disappear. The
telolemma nuclei are said to disappear and the sole plate nuclei to
proliferate; the sole plate
hypertrophies. The degeneration of the neuromuscular and neurotendinous
and other pro-
prioceptive nerve endings awaits special study with the use of modern
differential neuraxis
staining methods. It can be stated that the neuraxes disappear
completely from the endings with
the degeneration of peripheral nerves.
1102
THE NEUROLEMMA SHEATH
The
ultimate fate of the neurolemma sheath of degenerating peripheral nerve
fibers has
not been conclusively determined. As has been stated, during the early
stages of degeneration,
while the protoplasm of the sheath cells shows hypertrophy and their
nuclei proliferation, the
neurolemma sheath as such appears to show no structural changes. In
cross or in longitudinal
sections of the peripheral stump of a degenerating nerve, one to three
months after the beginning
of degeneration, it seems possible to differentiate membranous sheaths,
surrounding the
nucleated syncytial bands, quite evident in regions where myelin
globules are still present,
though it is not possible to stain the neurolemma sheaths
differentially. In experimental
observations on degenerate nerves, extending 12 to 15 months after
injury to the nerve, what
appear as collapsed neurolemma sheaths, surrounding nucleated
protoplasmic bands are thought
to be present. According to the observations of Cajal, the neurolemma
sheaths are said to
disappear several weeks after the formation of the nucleated
protoplasmic bands, these bands
remaining surrounded by a fibrillar sheath of connective tissue origin,
the fibrillar sheath of
Retzius or of Henle. That a delicate sheath, either of ectodermal
origin, neuroleinma sheath, or
of mesodermal origin, the fibrillar sheath of Retzius or of Henle
surrounds the nucleated,
syncytial protoplasmic bands, the product of sheath cell proliferation,
months after the
degeneration of a peripheral nerve is under way, seems well
established.
DEGENERATION IN THE PERIPHERAL AND CENTRAL
ZONE OF TRAUTMATISM
There
are observed certain structural changes in the immediate vicinity of
the wound,
differing from the changes noted for secondary nerve degeneration,
involving both myelinated
and unmyelinated nerve fibers. In sections of an injured nerve trunk,
including that portion of
the distal stump adjacent to the wound, fixed in chrom-acetic-osmic
mixture, about 24 hours
after the injury it will be observed that the myelin sheaths of the
myelinated fibers do not stain black in osmic acid, as do the nerve
fibers more distal, but present a granular appearance and
indistinctive coloring. This appears to be the result of the traumatic
injury. The neurolemma
sheaths appear distended, leucocytes appear in appreciable numbers,
both between and, now and
again, within the neurolemma sheaths. These changes are noted near the
wound at a time when 1
cm. distal, the nerve fibers show no structural change nor alteration
in conductivity. In
preparations of the distal stump of the wound region stained after
differential neuraxis staining
methods, Perroncito,36 Cajal, 38, Ranson,39 and others have noted, both for myelinated and
nonmyelinated nerve, changes in the neuraxis regarded as an abortive
auto regeneration,
consisting of side branches terminating in bulbous ends. These may be
observed in certain
nonmedullated fibers by the end of the first day and may be quite
numerous; they do not show
much growth and the majority disappear within a few days. Certain of
the myelinated nerve
fibers show a similar phenomenon. The peripheral end of the central
stump of a divided or
injured nerve degenerates for a certain distance centrally; the
distance varying with the type of
injury, though it is usually not more than 0.5 cm.
1103
to 1 cm. The
degenerative changes noted here are essentially the same as described
for
peripheral secondary nerve degeneration. Kirk and Lewis 47 believe that there is present an early
hpertrophic reaction of the neurolemma sheaths adjacent to the line of
section, first noticed as an
increase in the protoplasm surrounding the sheath cell nuclei followed
by mitosis of these nuclei,
so that between the fourth and fifth day syncytial nucleated
protoplasmic bands have developed. Ranson 39 has described
certain changes in the nonmyelinated fibers of the central stump. An
early abortive regeneration analogous to that described for similar
fibers in the wound region of
the distal stump was noted the fine side branches terminating in
end-discs which develop only
slightly after their first appearance and disappear with the
cellulipetal degeneration of nonmyelinated fibers, which begins about
the third day after injury and extends about 2 cm.
centralward, degenerating as do the nonmyelinated fibers of the distal
stump. In preparations
stained in differential neuraxis stains, certain neuraxis phenomena are
observed in the
myelinated fibers of the distal end of the central stump which are
regarded as degenerative in
character. In certain of these myelinated fibers, 0.2 mm. to 0.5 mm.
from the wound, a zone of
reaction is found in which the neuraxis is greatly increased in
diameter, with neurofibrils staining more deeply and apparently
hypertrophied, with increase in neuroplasm; distal to this
zone of neuraxis reaction, in a respective fiber, the neuraxis
disintegrates. Very early branching
of the neuraxes in the immediate vicinity of the wound is noted. The
newly formed branches
may grow into the exudate of the wound, ending in small discs, or
remain within the old
neurolemma sheaths, where they become entangled and in further growth
often form quite
complex skeins. These phenomena appear to be abortive attempts at
regenerative and are rather
to be associated with degenerative processes.
REGENERATION OF
PERIPHERAL NERVES
The
process of regeneration of a peripheral nerve degenerated after injury,
is initiated
before the formation of the nucleated syncytial protoplasmic bands is
well under way; a topical
and timely separation of the two processes call not well be made since
they are concurrent; they
deserve separate discussion since they are independent. Certain of the
main phases in the
interpretation of the process of nerve regeneration were considered in
the brief review of the literature preceding this section and it was
noted that with the introduction of differential
neuraxis staining methods and their use in experimental studies of
nerve degeneration and
regeneration that the downgrowth or monogenetic theory of neuraxis
development has become
quite generally accepted. The studies of Perroncito,36 Cajal,38 Ranson,39 Boeke40, 41 Kirk and
Lewis,47 Dustin,42 Ingebritsen,43 and others. all of whom have used these special silver
methods to control the results of experimental observations, have been
especially helpful in
bringing clarity to this subject. Boeke, one of these more recent
workers, in an excellent study
expresses himself as follows: "I place myself without question as
adopting the viewpoint that as
in development of embryonic nerve fibers, the regenerating nerve fibers
arise exclusively
through outgrowth from divided nerves of the central stump, which enter
the peripheral path and
in
1104
this reach their
peripheral destination." While unanimity has not been reached in all
points there
is quite general agreement that the down-growing neuraxes, derived from
the central nerve
fibers, are a sine qua non of the regeneration of the peripheral
degenerated portion of a divided
or injured nerve. These
FIG. 212.- Microphotograph
of a
pyridine-silver preparation from a longitudinal section of the distal
end of the
central stump of the sciatic of a dog, 11 days after the operation of
cable-auto-nerve transplant, showing
division of down-growing central neuraxes
more modern observations
have extended but have confirmed fully conclusions reached by a
group of observers, using less satisfactory methods and working nearly
25 years ago. One
quotation may be permitted. Huber, 30 at the conclusion of
an extended study on the repair of
nerves after loss of substance
1105
expresses
himself as follows: “The regeneration of the peripheral end (which
always
degenerates so that only the old sheaths of Schwann containing band of
nucleated protoplasm,
developed from the hyperthro pied protoplasm and proliferated nuclei of
its fibers, are met
with) is the result of all out-growth of new axis cylinders from
undegenerated axes of the central
stump, the budding axes following paths of least resistance."
Evidences
of regeneration are noted in the distal end of the central stump of a
divided
nerve within the first day after injury (Perroncito36 and
others) in the form of fine branches
derived from central neuraxes, which grow into the exudate of the wound
or remain within the
neurolemma sheaths. These
FIG. 213.- From longitudinal
section of a
regenerating distal segment of a severed nerve several weeks after
operation. Note the single neuraxis deflected upon itself and
terminating in a prominent end-disc or incremental
cone. Pyridine-silver preparation
early branches of the
central neuraxes, very likely, in part degenerate again; at least there
is not
marked progress until toward the end of the first. week after injury,
evinced now by numerous
side branches and end divisions of central neuraxes, usually several
tenths of millimeters central
to the cut ends of the fibers. The central neuraxis of a myelinated
fiber may here give off
numerous new branches, the number estimated as high as 50 by Ranson, 39 clearly evident in
cross sections of suitable stages in which, in the crosscut
regenerating fibers of the central stump,
a variable though appreciable number of new neuraxes may be found
within one neurolemma
sheath, often found arranged in a circle surrounding the old neuraxis
of the respective fiber. These newly formed
1106
neuraxes grow toward the
periphery of the central stump, within the old neurolemma sheaths,
having a more or less parallel course, or for reasons not
satisfactorily explained may assume a
very complex coiled or spiral arrangement, forming longer or shorter
skeins which were first
clearly defined by
FIG. 214.- Taken from the
distal half of a
neurorna, 21 days after severance of the sciatic nerve of a dog;
pyridine-silver preparation. The figure presents a number of spiral
formations (Perroncito spirals), several end-discs or
incremental cones, the ends of down-growing neuraxes, crisscrossing of
down-growing neuraxes, typical of their
growth through embryonic connective tissue
Perroncito 36 and are often referred to as the spirals of Perroncito. On the ends of
the down-growing neuraxes smaller or larger end-discs or incremental
cones, similar to those found on
developing, embryonic nerve fibers are easily demonstrated. They often
are directed toward the
periphery but are also
1107
found directed
centralward and are conspicuous in the Perroncito spirals.The end-discs
on the
neuraxes are often many times the diameter of the respective neuraxis,
and it is conjectured that
their relative size is proportionate to the resistance met with by the
downgrowing neuraxis. The
nonmedullated fibers of the central stump begin regeneration about the
fourteenth day after
injury; these downgrowing neuraxes having small end-discs and arc often
found arranged in
small compact bundles. The downgrowing branches of the neuraxes of both
the myelinated and
the nonmyelinated nerve fibers of the central stump are first
nonmyelinated. The very marked
increase in the number of the central neuraxes was not appreciated
until these fine
nonmedullated nerve fibers were brought to view with silver staining,
the evidence contributing
largely to the substantiation of the theory of the downgrowth of
central neuraxes in the
regeneration of a peripheral degenerated nerve. From the beginning of
the time of budding and
downgrowth of central neuraxes, certain of them reach the exudate of
the central wound; their
number is appreciable toward the end of the first week after injury. As
the down-growing
neuraxes reach the exudate and the organizing embryonic connective
tissue of the wound region,
whether suture has taken place or not, the small bundles of
down-growing neuraxes lose their
regular arrangement and direction parallel to the long axis of the
nerve and assume an irregular
crisscross course and either as single fibers or small bundles of such
they course through the
wound region. Immediate suture of a severed nerve does not seem to
accentuate the rate of
downgrowth of the central neuraxes, nor is the forming scar tissue of
the wound region
negligible, even under the most favorable suture conditions, in
influencing the downgrowing
neuraxes and in dispersing them sufficiently to influence the funicular
structure. Now and again
central neuraxes may be traced through several divisions in the same or
successive sections
passing through the wound region. Neuraxes terminating in end-discs
within the organizing scar
tissue of the wound after suture or in the central stump when no suture
has taken place, are to be
observed in nearly every section in suitably stained sections of
requisite stages; they are found
extending in every direction. In cross and longitudinal serial sections
of the wound region,
including approximately one centimeter of the distal and central stumps
adjacent to the wound
and taken at intervals of three to five days during the first three
weeks after severance or injury
of the nerve, and prepared after the differential silver neuraxis
staining methods, a progressive
neurotization of the scar tissue maybe observed, proceeding from the
center to the periphery, and
easily demontrated in the region at a time when no neuraxes are found
in the more distal
segments of the degenerated nerve. There is noted a gradual decrease in
the number of neuraxes
as one passes from the more central to the more distal portion of the
wound. In cases of primary
suture of a severed nerve, new neuraxes of central origin are found in
the central end of the distal
segment of the divided nerve only a few days after they appear in the
wound region, at first in
small numbers and scattered here and there and then in progressively
larger numbers as time
advances. After the down-growing neuraxes have reached and penetrated
the central end of the
distal stump, the course of the majority of them becomes again quite
regular and parallel to the
long axis of
1108
the nerve. Under
favorable conditions new neuraxes may penetrate the central end of the
distal
stump before its nerves have reached the end stages of nerve
degeneration, evidenced by the
presence of nucleated syncytial bands developed from the hypertrophied
and proliferated sheath
cells. In their downgrowth into the central end of the distal stump
many of the down-growing
central neuraxes penetrate the neurolemma sheaths of the degenerating
peripheral fibers, others
are found in endoneural spaces between the nerve fibers, others pass
along the inner or outer
surface of the perineural sheath others again are found in the
epineurium. It is not unusual to
observe several new neuraxes within one neurolemma sheath of a
degenerating nerve fiber of the
distal stump and, in longitudinal sections of this region, neuraxes
with end
FIG. 215.- From a
longitudinal section of the
proximal zone of a neurorna on the sciatic of a dog, 31 days after
section; pyridine-silver preparation. The figure presents the central
down-growing neuraxes, in approximately
parallel arrangement, so long as the down-growing neuraxes are in the
main within the old neurolemma sheaths
and the dispersed and irregular arrangement of the neuraxes as found in
the scar tissue of the more distal zone of
the neuroma
discs are often noted
indicating the distal termination of a new neuraxis within the limits
of the
section. In cross or in longitudinal serial sections it can be readily
determined that neurotization
of the peripheral degenerated portion of a nerve progresses gradually
from the region of the
wound and suture toward the periphery and this at a rate which is
estimated at from 1 mm. to 2
mm. in 24 hours. The progressive neurotization is not only in the
distance of the penetration of
the downgrowing central neuraxes but also in the increase in the number
of neuraxes which
reach the distal stump; this number gradually decreasing toward the
periphery.
Attention
has been called to the very great increase in the number of the
neuraxes,
formed by division and budding in the distal end of the central stumps
1109
Only a
variable percentage of these reach the distal stump through the wound
region,
proportionately more, the more favorable and shorter the path. The
downgrowing central
neuraxes are diverted from their course toward the periphery in the
organizing scar tissue in
various ways. Certain of them are deflected centralward, ending in the
endoneural tissue of the
central stump. Others grow toward the edges of the wound and are lost
in the surrounding connective tissue, while others pass to the fibrous
layers of the peripheral stump outside of the
funiculi. In experimental work, it has been observed, that the more
successful the suture the
earlier do downgrowing neuraxes reach the distal stump and the greater
the number of
downgrowing neuraxes which penetrate it. In case a primary suture is
not made and the severed
nerve ends are not in close
FIG. 216.- From a
longitudinal section of a
neuroma on the sciatic of a dog, 31 days after nerve section;
pyridine-silver preparation. The figure makes evident the great
increase in the number of down-growing neuraxes as found in
the central zone of the neuroma, or proximal to the wound after
severance and suture
approximation, even
though there be not extensive separation, the down-growing central
neuraxes become dispersed and deflected in their course in the
organizing scar tissue forming the
central end of a cut nerve resulting in the formation of an amputation
neuroma, even in cases in
which the central down-growing neuraxes ultimately reach the distal
stump and bring about its
partial neurotization. The down-growing neuraxes of the central stump,
whether the branches of
myelinated or of nonmyelinated fibers, in the wound region and in the
distal stump are all at first
nonmyelinated fibers. Whether these down-growing neuraxes are preceded
or accompanied by
sheath cells derived from the central fibers has not been determined
conclusively. The modern
silver methods which give such clear differentiation of neuraxes and
terminal end-discs do not
1110
differentiate equally
clearly between cells derived from the ectodermal sheath cells and the
cells
derived from the mesodermal fibroblasts and both types of cells appear
to form syncytial
structures in the earlier stages of nerve repair. It is difficult to
conceive of the relatively large
end-discs of growing neuraxes, thought to have ameboid properties, as
coursing within the
nucleated protoplasmic bands. The same may be thought of the complex
spiral structures or the
numerous neuraxis buds growing from a single central neuraxis.
Experimental embryologic
evidence is at hand to show that neuraxes may grow without the presence
of sheath cells;
resulting in the formation of naked neuraxes
FIG. 217.- From a
longitudinal section of a
neuroma, removed-three-weeks after section of the sciatic of a dog;
pyridine-silver preparation. Note- the branching of neuraxes; the
crisscrossing of neuraxes; prominent spiral
formations and a number of typical though relatively large end-discs or
incremental cones denoting the distal ends of
downgrowing neuraxes
What appear to be
naked neuraxes are now and then followed for quite a long distance in
the connective tissue or between the muscle fibers and this some
distance from the wound. The
statement has been made that the nu-cleated syncytial protoplasmic
bands of the distal stump
exert a chemotactic influence on the downgrowing neuraxes, drawing them
toward the
neurolemma sheath of the peripheral stump and influencing their
downgrowth toward the
periphery. This has not been experimentally demonstrated. There are
often found several down-growing neuraxes in one neurolemma sheath of
the distal stump, but they are also found between
the nerve fibers of the funiculi and in the connective tissue outside
of the perineural sheaths. The relation of the
1111
down-growing neuraxes
found within the old neurolemma sheath to the nu-cleated syncytial
bands also found within the sheaths has been interpreted differently by
observers. They have
been regarded either as playing a passive r le or as
forming conduits for the down-growing
neuraxes. Ranson39 thinks that all the new axons lie in
protoplasmic bands and Boeke,40 as a
result of a study in which he made use of various technical methods,
reached the conclusion that
neurofibril strands are always intraprotoplasmic. Kirk and Lewis 47 believe that they have shown
that the nucleated, syncytial, protoplasmic bands constitute conduits
in the substance of which
the nonmedullated nerve fibers regenerating from the proximal stump
rapidly grow down, the
bands forming first, the fibers following along them though they state
that they do not wish to
imply "that the axis cylinders always and necessarily track along the
protoplasmic bands." The
prevailing opinion at the present time regarding the down-growing
neuraxes found in the
peripheral neurolemma sheaths is that they have an intraprotoplasmic
position. So far as has
been determined there is at hand no evidence to warrant the conclusion
that down-growing
neuraxes show any selectivity on reaching the peripheral stump. Thus
branches from the central
motor neurons may and do, no doubt, enter the sheath of degenerating
afferent or sensory nerve
fibers and vice versa; and that nonmedullated central fibers may enter
the sheaths of medullated
peripheral fibers and vice versa. It has long been known that central
motor fibers may grow into
distal sensory fibers, and vice versa. This has recently been confirmed
by Boeke.41 Functional
regeneration has not been attained although neuraxes are seen in the
periplheral segments and a
beginning in the formation of nerve terminations has been noted. It is
assumed that chance
brings as many down-growing central neuraxes of motor neuron origin to
degenerated peripheral
motor nerve fibers as of central fibers of other functional types and
so for other types of nerve
fibers. It has seemed to the writer that a simple mechanical
explanation is perhaps the correct
one. It may accordingly be assumed that developing neuraxes of the
central stump, which reach
degenerating homologous nerve fibers of the peripheral stump, develop
the functional activity
after the formation of the requisite nerve terminations; while
down-growing central neuraxes
which reach degenerating heterogeneous nerve fibers of the peripheral
stump ultimately
degenerate. The enormous increase in the number of central nerve
fibers, through division and
formation of side branches, permits many nerve fiber branches to go
astray and ultimately to
undergo degeneration by reason of want of functional activity and still
leave a sufficient number
to admit of structural and functional regeneration of a nerve going to
a given part. The
conclusion is, as a result of many experimental observations on nerve
repair, that there is
obtained at best only partial regeneration of the distal segment of a
peripheral divided or injured
nerve.
Huber,48 Tello,46 and Boeke40 have
studied
the regeneration of the motor and sensory
nerve ending in striated muscle tissue after experimental degeneration
of nerves, with the aid of
the intra vitam methylene blue method and certain silver precipitation
neuraxis stains. Experimental observations show that a muscle responds
to electrical stimulation of its nerve
which had previously been degenerated, so soon as newly formed motor
nerve endings can be
demonstrated in said muscle by suitable staining methods. Down-growing
neuraxes,
1112
now and then terminating
in end-discs can often be demonstrated in the interfascicular muscular
branches when stimulation of the motor branches fails to incite
muscular contraction.
Developing motor endings in regeneration have been demonstrated as
forming as the result of
the branching of end discs, or as branches of collaterals led to the
muscle fibers within the old
neurolemma sheaths or along syncytial strands of sheath cells and
perhaps along cells of
connective tissue origin. There may be formed more than one nerve
termination on a single fiber. Motor endings regenerate before sensory
endings; possibly explaining a voluntary control of a
muscle before there is synergic action of said muscle. Coarser or finer
nerve fibers are often
found within the capsule of neuromuscular and neurotendinous nerve
endings before the endings
show full development. Complete regeneration of the complex endings has
been observed.
THE MYELIN SHEATH AND NEUROLEMMA SHEATH OF
REGENERATING NERVE FIBERS
The
silver precipitation methods used as differential staining for
neuraxes, and used by
nearly all observers in the more recent studies of nerve degeneration
and regeneration are not
suitable methods for the study of the histogenesis of the myelin or
neurolemma sheath, so that
these more recent observation have on the whole not contributed
materially to the solution of this
question. As has been stated, all downgrowing neuraxes derived from the
central stump are at
first nonmyelinated. It seems quite clear that such of these fibers as
are destined to become
myelinated acquire their myelin sheath beginning with the proximal end,
and proceeding from here distalward. New myelinated nerve fibers can be
recognized first in the distal end of the
proximal segment of a divided nerve toward the end of the first month
after injury in the formof
very delicate and apparently continuous sheaths demonstrable in
chromatized tissue treated by
differential myelin staining, methods. The structural appearances
presented suggest the
differentiation of the myelin sheath as a peripheral layer of the
neuraxis, though this can not be
stated without reservation. Myelin sheath formation proceeds distalward
and does not involve all
of the nerve fibers at the same time. This process of myelinization
begins in the proximal stump
before functional connection of the nerve fibers with formation of
nerve terminations has been
effected.
The
neurolemma sheaths of regenerating nerve fibers appear to be new
formations,
developed from the sheath cells, which migrate with budding neuraxes or
are found in situ by the
down-growing neuraxes and derived through, sheath cell proliferation
during the process of
degeneration of the nerve. The detail of the development and formation
of the neurolemma
sheath of regenerating nerve fibers has not been definitely determined.
EXPERIMENTAL
OBSERVATIONS
The
experimental observations to be recorded and discussed in the following
pages deal
in a large measure with the question of bridging nerve defects
peripheral nerves, due to loss of
substance. These defects were bridged by nerve transplants or
otherwise. No experimental
observations on simple, primary, or secondary end-to-end suture of a
severed nerve were made.
The
1113
end-to-end suture of a
divided peripheral nerve, either as a primary or a secondary operation,
is a
recognized procedure in surgery, even though there may not be full
agreement as to technical
details of the operation. The differences of opinion as to the
technique of end-to-end suture of a
divided nerve were not such as seemed to warrant extended
experimentation at a time when
other questions seemed to be more pressing. The same can not be said
for operative procedure suggested and used for the repair of a divided
nerve after loss of substance. The various
methods which have been suggested to bridge the gap between the severed
ends of a peripheral
nerve in case there is loss of tissue to the extent that the severed
ends can not be brought
together without undue tension were reviewed by Huber 4 and
critically considered in the light
of experimental observations. Such operative procedures include the
formation of a nerve flap
from either the central or distal stump or both; operations of nerve
implantations; operations of
nerve crossing, either complete or incomplete; suture a distance;
tubular sutures and nerve
grafting or nerve transplantation. The value of the nerve flap in the
repair of peripheral nerves
was tested experimentally by Huber 30 and discredited and
shown to be of no value by Stookey 50 as a result of a critical review of all the reported
cases. Nerve implantation consists of the
insertion of the severed end of one nerve, either the central or distal
end or both, into the
interfunicular tissue of an adjacent nerve. By multiple or serial
implantation is meant where one
or several parallel nerves are injured, with loss of substance and are
then serially implanted (Hofmeister).51 Neither of these
operations can be approved since on implantation of the central
stump of a divided nerve into the interfunicular connective tissue of a
sound nerve there is not
furnished a suitable path for the downgrowth of central neuraxes; the
less so in serial
implantation. By nerve crossing is here meant the suture of the central
end, complete crossing, or
a flap from a normal nerve, incomplete nerve crossing, to the distal
end of another nerve. It has
been shown experimentally that complete and incomplete nerve crossing
are feasible and logical
procedures, whether made as a primary or a secondary operation. In
selecting this as the
operation of choice it needs to be decided whether other operative
procedure may not offer more
favorable end results when considering both of the nerves involved. It
should be understood that
in the operation of complete crossing, in forming the central flap, the
sound nerve is injured to
the extent of the flap and paralysis will ensue in the field of the cut
fibers, not relieved or only
partially relieved by the accidental downgrowth of central neuraxes
from the parent nerve. In
suture a distance a bundle of catgut strands has been used to bridge a
defect in a divided nerve
with loss of substance by Huber 30, with some success as
concerns neurotization of the distal
stump. However, other methods offer greater opportunity for bridging
nerve defects. Muscle and
tendon fibers, woolen, silk, and other fibers have been used for suture
a distance with
unfavorable results and need receive no further consideration here. The
operation of uniting the
separated ends of a divided nerve by means of a tube through the lumen
of which the central
neuraxes were thought to be directed to the distal stump-tubular nerve
suture-is an old operation
and has received more than incidental attention by surgeons even in
relatively recent years. A
variety of materials have been
1114
used, not all of which
have been tested experimentally. Of materials used at operation or in
experiments, mention is here made of decalcified bone tube, iodoform
gauze, epidermis of man,
magnesium tubes, hardened-gelatine tubes, rubber tubes and sheet rubber
wrapped to form a
tube, galalith tubes, hardened arteries and fresh arteries and veins,
fascia lata and other
connective tissue membranes, peritoneum, Cargile membrane, celloid in
tubes, arteries filled
with agar, as suggested by Edinger and extensively used for a brief
period in the German army.
Certain of these materials for tubular nerve suture were given
consideration in our experimental
work and will be discussed in connection with the experimental
observations. Other materials
used are really more of academic interest than of practical use and
their consideration need not
occupy space here. Nerve grafts or nerve transplants were given
extensive consideration in our
experimental work, new methods were devised which, judging from
experimental results, should
receive favorable consideration at the hands of surgeons in dealing
with the repair of injured
nerves after loss of substance. We have followed surgical usage and
have designated a nerve
segment from another nerve of the same individual as an
auto-nerve-trans-plant; a nerve segment
taken from another individual but of the same species as a homo-nerve
transplant; a nerve
segment taken from another individual but of a different species, a
hetero-nerve transplant.
The
literature dealing with both the clinical and the experimental phases
of the question
of repair of peripheral nerves after loss of substance is an extensive
one, too extensive to be
reviewed here. Certain of the contributions will be considered in
connection with the discussion
of the experimental observations. Many citations are given by Huber 49 and by Stookey 9, who
give critical reviews of clinical and experimental observations.
The
experimental observations to be discussed here will be considered under
the
following heads: a
Series
No. 1. Injection of absolute alcohol into a normal nerve, without
subsequent
cutting of the nerve; 12 experiments.
Series
No. 2. Injection of full-strength acetone into a normal nerve, without
subsequent
cutting of the nerve; 3 experiments.
Series
No. 3. Injection of absolute alcohol into the central end of a divided
nerve to
obviate the formation of an amputation neuroma; 37 experiments.
Series
No. 4. Amputation neuroma formation in aseptic wounds; 12experiments.
Series
No. 5. Auto-nerve transplants, including cable auto-nerve transplants;
17
experiments.
Series
No. 6. Homo-nerve transplants; 6 experiments.
Series
No. 7. Hetero-nerve transplants, mainly guinea pig's nerves to rabbits,
also nerves
of dogs to rabbits; 39 experiments.
Series
No. 8. Degenerated auto-nerve transplants; 3 experiments.
Series
No. 9. Degenerated homo-nerve transplants; 5 experiments.
Series
No. 10. Degenerated hetero-nerve transplants; 16 experiments.
a Brief preliminary reports have been given Of
these experimental observations before the Chicago Neurological
and Pathological Societies (Huber) and before the Chicago Surgical and
Neurological Societies (Huber), 53 Reports
of progress were given by Huber 54 on special detail before
the Neurosurgical School in New York City.
1115
Series
No. 11. Homo-nerve transplants which had been stored in sterile
vaseline at 3° C.;
8 experiments.
Series
No. 12. Homo-nerve transplants which had been stored in sterile liquid
petrolatum
at 3? C; 40 experiments.
Series
No. 13. Homo-nerve transplants which had been stored in 50 percent
alcohol at
room temperature; 19 experiments.
Series
No. 14. Hetero-nerve transplants, dog's nerve to rabbit; stored in
sterile liquid
petrolatum at 3° C.; 6 experiments.
Series
No. 15. Hetero-nerve transplant, dog's nerve to rabbit, stored in 50
percent alcohol;
3 experiments.
Series
No. 16. Auto-nerve transplants, wrapped in Cargile membrane;
14experiments.
Series
No. 17. Auto-nerve transplants, wrapped in auto-fascial sheaths of
fascia lata;
14experiments.
Series
No. 18. Auto-nerve transplants, wrapped in formalized arterial sheaths;
6
experiments.
Series
No. 19. Auto-nerve transplants, wrapped in auto-fat sheaths;
2experiments. Series No. 20. Tubular sutures with use of formalized
arteries; 13 experiments.
Series
No. 21. Tension sutures; resected nerve sutured under extreme tension,
with or
without wrapping in Cargile membrane or formalized arterial sheaths; 13
experiments.
All
of the operative work was carried out under strict asepsis and by
surgeons on special
detail for experimental nerve surgery. This work was very carefully
done, especially as pertains
to the technique of the operative work on the nerves. Special care was
exercised in placing
sutures so as to obtain accurate coaptation of the severed nerve ends,
to stay all hemorrhage, and
to obviate clot formation between the severed nerve ends. In
practically all of the experimental
operations healing of the wound was attained by primary intention; when
otherwise, notation is
made in the respective protocol. In the several series of experiments
undertaken the respective
animals were kept under observation for periods which varied in the
several experiments from
one day to about a year. Very few animals were lost as a result of
operation. There was
evidently great difference in resistance to disease. Now and again
epidemics would interfere
with the schedule of experiments, though not always with complete loss
of the experiment. At
fixed times the animals operated upon were killed and the operated
nerves exposed and gross
observations recorded. Functional tests were made in nearly all cases
in which return of function
was crucial to the experiment. After exposure of the nerve and the
making of the necessary
functional tests the operated nerve was removed for histologic study.
In cases in which the
operated animals died during the night, especially if this occurred in
an experiment in which
some time had elapsed since the initial operation, equally careful
exposure of the operated nerve
was made and a histologic study undertaken. In nearly all of the
experiments a segment of the
nerve central to the wound region, the wound region, and the portion of
the nerve distal to the
wound were removed for
1116
histologic study, and
sectioned serially in alternate longitudinal and crosscut series.
Considering
the primary purpose of these series of studies, namely the opportunity
of applying in practical
surgery the conclusions reached in the work of repair of peripheral
nerves, our attention was
especially directed toward the behavior of the central neuraxes in the
process of neurotization of the peripheral segment, the sine qua non of
peripheral nerve repair. It was necessary to
determine on a reasonably reliable differential neuraxis stain, one
that could be used in staining
en masse and permit of paraffin embedding to facilitate, so far as
possible, the making of serial
sections, so essential to the adequate study of the problem in
question. After brief trial of several methods the pyridine-silver
method of neuraxis staining (Ranson) was selected and the great
majority of the histologic sections made were stained after this
method. The essential steps of
the pyridine-silver method of neuraxis staining are as follows: 1.
Fixation of tissue in
ammoniated absolute alcohol for 2 to 3 days. The ammoniated alcohol is
prepared by adding 1
c. c. of strong ammonia water to 100 c. c. of absolute alcohol. A
relatively large quantity of the
fixative is essential. 2. Wash for about 2 minutes in distilled water.
3. Place for 24 hours in
pyridine. 4. Wash in distilled water for 24 hours, changing the water
frequently. 5. Place in 2 per
cent aqueous solution of nitrate of silver, in which the tissue remains
for 3 to 5 days, in the dark
and at a temperature of 32? C. to 35° C. 6.
Rinse in distilled water and place for 1 to 2 days in a
pyrogallic acid-formalin solution prepared by dissolving 4 gms. of
pyrogallic acid in 100 c. c. of
5 percent formalin. Keep in the dark and at a temperature of 32? C. to 35? C. 7. After washing in
distilled water for several minutes dehydrate in graded alcohol,
beginning with 80 percent
alcohol. The dehydration needs to be thoroughly done; several changes
of absolute alcohol are
required. 8. Clear in xylol and embed in paraffin. A necessary stay in
the warm oven even for 48
hours, to insure thorough penetration of the paraffin, does not
deleteriously affect the stain.
The
great bulk of the sections stained by the pyridine-silver method were
cut serially by
Huber's “water on the knife" method with the knife in the oblique
position and on the sliding
microtome. The sections as cut were arranged serially on the slide and
fixed to the slide by the
water-albumin fixation method and warmed to attain flattening of the
sections. After removal of the paraffin thorough dehydration and
clearing in xylol, the sections were mounted under
cover glass in damar. Attempts at contrast staining were made but not
generally used. In
successfully stained preparations after use of the pyridine-silver
method the nonmyelinated
neuraxes stain a nearly black or brown-black or dark brown color, which
usually contrasts quite
distinctly with the yellow-brown color of the connective tissue. The
neuraxes of myelinated
fibers of the central stump, especially of the larger nerve fibers, are
of a light brown or
yellowish-brown color. The Perroncito spirals and the incremental cones
or end-discs are very
clearly differentiated. The myelin sheaths are not differentially
stained. The nuclei of the
neurolemma sheaths and of the fibrous connective tissue cells and
fibroblasts of growing fibrous
tissue. may or may not be differentiated, usually not clearly nor
certainly enough to determine
definitely questions concerning their participation
1117
in the downgrowth of
central neuraxes. The Bielschowsky method and this method as modified
by Boeke in his studies of degeneration and regeneration of nerves, as
also Cajal's methods, were
used; but they did not give as reliable and constant results as the
pyridine-silver method. The
pyridine-silver method does not give as satisfactory results in cases
where the tissues are
removed several hours after death, though in certain of the experiments
in which the animal died
during the night, very successful staining of the neuraxes was
attained. It should be understood
that with all silver precipitation methods of neuraxis staining, as
with intra vitam methylene blue
method, positive results can be received with much greater assurance
than negative results. The
fact that no neuraxes are found stained in such preparations is not
proof positive of their non
existence. Certain of the operated nerves were fixed in formalin and
after chromatization stained
in differential myelinstains, in iron-lac-hematoxylin or double stained
in safranine and licht gr u n. In other cases the nerve was fixed in
chrom-acetic-osmic acid mixture and stained in
safranin and licht grün. The experiments in which these latter
histologic methods were used
in place of the pyridine-silver method are relatively few and mostly in
experiments of short
duration.
INJECTION
INTO LIVING UNCUT NERVE
SERIES NO. 1
INJECTION OF ABSOLUTE ALCOHOL INTO A LIVING
NERVE WITHOUT CUTTING THE NERVE
Schlösser 54, 55 introduced the use of alcohol injection
into a nerve trunk or the tissue
surrounding the nerve trunk for the relief of neuralgia or other
peripheral nerve irritations.
Brissaud, Sicard, and Tanon 56 record the use of alcohol
injection for facial spasms. Since then
the method has been extensively used in the operative relief for
neuralgic conditions.
Experimental observations on alcohol injection into a living nerve
trunk are first recorded by
Finkelnburgs 57 who, taking part in a general discussion on
the treatment of neuralgia, reports
briefly on experimental observations in which 0.6 c. c. to 1.5 c. c. of
60 per cent to 80 per cent
alcohol was injected into the sciatic of dogs after exposure of the
nerve or into the tissues
surrounding the nerve. A complete paralysis was produced on injecting
the nerve, lasting for
months, with complete degeneration of the nerve in the wound region and
the peripheral segment
of the nerve. A much more extended and careful study of the question
was undertaken by May.58 He injected the
infraorbital as a pure sensory nerve, the sciatic and anterior crural
as mixed
nerves, and also the Gasserian ganglion. General histologic methods, as
also Cajal's and
Bielschowsky's silver impregnation methods for neuraxis staining, were
used. The protocols of
the experiments made are given, as also figures illustrative of the
changes resulting in the nerve
on injection of alcohol. The following are certain of the conclusions
reached by May:58
1. Alcohol injected into the trunk of a
peripheral nerve produces more or less complete local necrosis of the
nerve at the point of injection.
1118
2. The change is not an ascending one;
the
nerve above the point of injection remains normal; the cells of
origin of the fibers flay show some degree of chromatolysis, but do not
exhibit signs of permanent injury.
3.
The conditions produced by such injection are more favorable to
regeneration than those resulting from
simple section without suture. The anatomical continuity of the nerve
trunk favors rapid regeneration, though this is
to some extent retarded by the fibrosis which occurs to a greater or
less extent in every ease of alcohol injection.
Harris 59, 60 and Patrick 61 have reported
extensive clinical observations, dealing, mainly
with the injection of the trigeminal ganglion for the relief of
trifacial neuralgia, an operation
experimentally studied by May. 58 The injection of a nerve
trunk with alcohol in causalgia was
first recommended by Sicarde 62 and has since received
consideration by a number of other
observers, who have used the method with success.
The
experimental observations in this series were undertaken with a primary
view of
gaining experimental data for comparison and correlation with the
experiments reported upon
under Series No. 3, dealing with the amputation neuroma. The histologic
findings in the several
experiments are of interest per se, especially as concerns the more
immediate effects of the
alcohol on the living nerve fibers. Our observations were made on the
sciatic nerve of the
rabbit. This nerve, in the rabbit, can be exposed from the popliteal
space to the sciatic notch with
very little bleeding. The exposed nerve was then freed from its bed at
about the middle of its
course and raised slightly on a blunt hook and injected through a fine
hypodermic needle
inserted if possible beneath the perineural sheath of the large
funiculus and into the epineural
sheath surrounding the smaller funiculi and in a direction nearly
parallel to the long axis of the
nerve. The injection of the alcohol was made slowly and with the nerve
exposed, so as to enable
the observer to follow the immediate result of the injection. The nerve
for the length of 1.5 cm.
to 2 cm. presents, after successful injection, a "milky white"
appearance. The few drops of
alcohol which might escape into the wound were taken up with cotton.
The wound was then
closed with deep catgut or silk stitches and the skin wound with
interrupted silk stitches.
PROTOCOLS
EXPERIMENT
No. 1.- Rabbit No. 24a. Large; full grown; 1 hour. March 12, 1918.4 p.
m., right sciatic
exposed and injected while in place, with absolute alcohol. Nerve not
cut. Wound closed. March 12, 5 p. m., wound
opened, one hour after alcohol injection A slight hemorrhage is found
at the point of injection. The part of the nerve
affected by the alcohol, a little over 1 cm. in length, presents a dull
white appearance. The sciatic removed and fixed
in neutral formalin. Bielsehowsky's differential staining method used.
Microscopic
findings.- In series of longitudinal sections, including
the field
of alcohol injection and the
nerve trunk adjacent, central and distal thereto, it may be observed
that in the nerve fibers found in the field of
alcohol injection the neuraxes are not interrupted and present the
staining reaction of normal neuraxes. The myelin
of many of the fibers presents a distinctly granular appearance; the
granules appear to have been derived from the
neurokeratin net. In other fibers the "Golgi funnels" are clearly
differentiated. The neurolemma sheaths in the
injected field are well maintained; of regular contour and found deeply
stained. Not as yet distinct structural changes
noted as the result of alcohol injection.
EXPERIMENT
No. 2.- Rabbit No. 40a; full grown; 3 hours. March 23, 1918, 11 a.
m., left sciatic exposed
and injected while in place with absolute alcohol. Nerve not cut. Wound
closed. March 23, 2 p. m., three hours after
alcohol injection. Wound opened and let
1119
sciatic exposed. The area of alcohol
injection recognized by tile dull white appearance presented by the
nerve trunk
in this region. This area extends along the length of the nerve trunk
for a distance a little over 1 cm. Calf muscles do
not contract when nerve is cut central to field of alcohol injection.
The nerve removed and fixed in neutral formalin. Bielschowsky's silver
stain used.
Microscopic
findings.- Of the several series of longitudinal
sections, in those
including the injected area, it
may be observed that the neuraxes of the nerve fibers found in the
alcohol injected area are as yet unfragmented and
show normal differential staining. In one small area a few segmented
neuraxes noted. The myelin sheaths present a
distinctly grani lar appearance; neurolemma sheaths have normal
appearance. The nerve fibers of this area
present structurally no distinct
departure from that presented by the normal fibers.
EXPERIMENT
No. 3.- Rabbit No. 61a; large; full grown; abscess on neck; 6 hours.
March 23, 1918, 11.20
a. m., the right sciatic exposed and injected while in place with
absolute alcohol. Nerve not cut. Wound closed.
March 23, 5.20 p. m., wound opened and sciatic exposed. Area of alcohol
injection easily recognized by its dull
white color. Muscles do not contract when nerve is cut central to field
of injection. Nerve fixed in neutral formalin.
Bielschowsky's silver staining method used.
Microscopic
findings.- In several series of
longitudinal sections including the area of alcohol injection, in
the immediate alcoholized field and especially in the larger internal
popliteal bundle, many of the nerve fibers are
found to contain fragmented neuraxes. These fragments of neuraxes are
of longer or shorter length; certain of the
fragments present a wavy course; others are coiled. Certain other
neuraxes present a granular disintegration. In the
external popliteal funiculus, fragmentation of neuraxes not so
distinct. The myelin of the nerve fibers presents a
granular appearance; the neurolemma sheaths are found well maintained.
EXPERIMENT
No. 4.- Rabbit No. 6a; large; full grown; 1 day. February 21, 1918,
right sciatic exposed
and injected while in place with absolute alcohol. Nerve not cut. Wound
closed. February 22, killed, 24 hours after
injection; wound opened and nerve exposed. Area of alcohol injection
recognized by dull white color of nerve in the
region of alcohol injections. Muscles do not contract on cutting
central sciatic. Nerve removed and fixed in neutral
formalin. Bielschowsky's silver staining method used.
Microscopic findings.-Several series of longitudinal
sections
made. In the series including the field of
alcohol injection numerous fragmented neuraxes are found. These
neuraxes fragments stain differentially in the
silver stain; they vary in length; many are distinctly coiled, like a
spiral spring; others present a wavy course; others
show alternate enlargements and constrictions. Many of the nerve fibers
more peripherally placed in the sections
do not show this neuraxis fragmentation. Presumably such fibers were
not affected by the alcohol. In the
affected nerve fibers the myelin presents a granular appearance; the
neurolemma sheaths do not show a distinct
structural change.
EXPERIMENT
No. 5.- Rabbit No. 6; large; full grown; 2 days. February 20, 1918,
left
sciatic exposed and
injected in place with absolute alcohol. Nerve not cut. Wound Whose.
February 22, killed, two days after alcohol
injection. On exposing the nerve the area of alcohol injection is
recognized by its dull white color. The nerve
removed and fixed in neutral formalin. Bielschowsky's silver staining
method used.
Microscopic findings.-Several
series
of longitudinal sections made. In such of the sections as include the
field of alcohol injection, the majority of the neuraxes are found
fragmented into longer and shorter segments, which
take the differential silver stain. Many of these neuraxis segments
appear to be breaking up into granules, which
granules are differentially stained .A certain number of nerve fibers
having unfragmented neuraxes are found here
and there in the sections. Nerve fibers with fragmented and
unfragmented neuraxes are often found in close
proximity. The myelin of the nerve fibers distinctly granular; the
neurolemma sheaths found of normal contour and
appear structurally well preserved. The sheath cells not clearly
differentiated.
EXPERIMENT No. 6.- Rabbit No. 7a; full grown;
3 days. February 22,1918, right sciatic exposed and
while in place injected with absolute alcohol. Nerve not cut. Wound
closed.
1120
February 25, killed. On exposing the
nerve
the field of alcohol injection recognized by the dull white color
assumed
by the nerve in this region. Nerve removed and fixed in neutral
formalin. Bielschowskv's silver staining method
used.
Microscopic
findings.-Several series of longitudinal sections made. In such as
include the field of alcohol
injection, it is observed that nearly all of the neuraxes of the nerve
fibers show a fragmentation. The majority of
these neuraxes segments are of relatively short length, many of which
appear to be breaking down into granules. In
certain of the nerve fibers neuraxes segments are no longer evident.
Here and there in the field, nerve fibers with
unbroken neuraxes are to be seen. The rayelin of the nerve fibers
presents a granular appearance; neurolemma
sheaths well maintained.
EXPERIMENT No. 7.- Rabbit No. 7;
full grown; 4 days. February 21, 1918, left sciatic exposed and while
in place
injected with absolute alcohol. Nerve not cut. Wound closed. February
25, killed. Wound nearly healed. On
exposing the sciatic, area of injection with absolute alcohol no longer
dull white color, but appears slightly
congested; has not the glistening appearance of normal nerve trunk.
Sciatic removed and fixed in neutral formalin. Bielschowsky's silver
staining method used.
Microscopic
findings.- Several series of longitudinal sections
made. In such as include the area of
alcohol
injection, the neuraxes of nearly all of the nerve fibers found broken
in segments
of very variable length; relatively few unfragmented neuraxes observed.
In many of the neurolemma sheaths, no
longer any fragments of neuraxes found; in others again the neuraxes
segments are quite long and of wavy or spiral
course. The myelin of the nerve fibers granular; neurolemma sheaths of
the great majority of the fibers seem well
preserved.
EXPERIMENT
No. 8.- Rabbit No. 61; large; full grown; abscess on back; 11 days.
March 12, 1918, left
sciatic exposed and while in place injected with absolute alcohol.
Nerve not cut. Wound closed. March 23, killed,
wound well healed. The area of alcohol injection not clearly defined.
For a short segment the nerve seems congested. Sciatic removed and
fixed in neutral formalin. Bielschowsky's silver staining method used.
Microscopic findings.-Three
series of
longitudinal sections made, of a little over 3 cm.of the nerve trunk
including area of alcohol injection. In such sections as include the
area of alcohol injection, the neurolemma sheaths
of the nerve fibers clearly made out; within the great majority of
these a granular detritus with only here and there a
fragment of neuranis remaining. In other neurolemma sheaths deeply
stained globular masses; the histogenesis of
which is not clearly made out. Evidence of in-wandering of leucocytes
is noted; though the stain used does not
clearly define these. In longitudinal sections of the nerve distal to
the field of alcohol injection, the microscopic field
is quite different. In such segments longer and shorter segments of
neuraxes are found, differentially stained. A few
fibers in which unbroken neuraxes are present are seen. The distal
nerve segment sectioned presents the appearance
of degenerating peripheral nerve fibers.
EXPERIMENT
No. 9.- Rabbit No. 26a; full grown; 62 days. March 19, 1918. Right
sciatic exposed and
while in place injected with absolute alcohol. Nerve not cut. Wound
closed. May 23, killed. Severe neurotrophic
changes right hind foot. On exposing the right sciatic the region of
alcohol injection is detected by reason of a slight
discoloration if nerve; in this region it does not present the white
glistening appearance of a normal nerve trunk. No
twitching nor contraction
of the
calf muscles is observed on cutting the nerve either central or distal
to field of
alcohol injection. Nerve removed and fixed in ammoniated alcohol for
pyridine-silver staining. Good silver
differentiation attained.
Microscopic
findings.- Several series of longitudinal sections made. In such
sections as include the nerve
just central to the place of injection, numerous smaller and larger
bundles of neuraxes, having in the main a
longitudinal course, but here and there exchanging fibers are found,
separated by long, spindle-shaped areas
containing granular detritus and large vesicular cells, mutually
compressed. In cross sections of the nerve in
approximately the middle of the field of alcohol injection, it may be
observed that the fibrous sheaths of the nerve
are thickened, and that the funicular structure of the nerve is lost.
Numerous neuraxes arranged in smaller and larger
groups are observed in cross sections. Areas of vesicular cells and
granular detritus are here and there evident; some
few neuraxes are found in such areas. In cross section of the nerve
trunk, approximately 2 cm. distal to the place of
alcohol
1121
injection,
the
funicular structure of the nerve is again observed, with new
down-growing neuraxes observed in all of the funisiculi.
EXPERIMENT
No. 10.- Rabbit No. 65; full grown; 66 days. M1arch 21, 1918, the right
seistic exposed and while in place injected with absolute alcohol.
Nerve not cut. Wound closed. May 25, killed; much emaciated; for three
weeks posterior extremities partially
paralyzed. Cause not ascertained. On exposing the right sciatic, in
what appears as the region of
alcohol injection the nerve trunk shows distinct spindle-shaped
enlargement; nerve is here
somewhat adherent to the surrounding connective tissue. No contraction
of calf muscles on
cutting nerve central or distal to place of alcohol injection was
observed .Nerve removed and
fixed in ammoniated alcohol for pyridine-silver staining. No wholly
success fill silver
differentiation of neuraxes attained.
Microscopic
findings.-Three series of longitudinal sections made, including the
field of
alcohol injection. In these series it can be observed that numerous
neuraxes growing from the
central portion of the nerve have reached the portion distal to the
field of alcohol injection. In
longitudinal sections including the region of the spindle-shaped
enlargement bundles of neuraxes
are found to cross and crisscross in all directions. These microscopic
fields give the impression
that many of the nerve fibers were torn at the time of alcohol
injection, the appearance being that
of neuraxes passing through a fibrinous wound region. Distal to this
spindle-shaped
enlargement, they have a more regular longitudinal course much as seen
in regenerating
peripheral stump. The differential staining in this series is not
wholly satisfactory; neuraxes in
sufficient numbers were found differentially stained so that their
course could be determined at
different levels.
EXPERIMENT
No. l1.- Rabbit No. 46a; full grown; 71 days. March 20, 1918, right
sciatic exposed and injected while in place with absolute alcohol.
Nerve not cut. Wound closed.
May 31, rabbit found (lead in the morning; severe neurotrophic changes
in the right hind foot.
On exposing the right sciatic in the region of alcohol injection, the
nerve trunk presents a
slightly smaller diameter and appears slightly congested; there is
further a light Yellow color.
The distal segment presents the appearance of a degenerated nerve.
Sciatic removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
silver staining attained.
Microscopic
findings.- Three series of longitudinal and one of cross sections
made. In series of longitudinal sections including the field of alcohol
injection, numerous larger and smaller bundles of neuraxes having in
the main a longitudinal course are to be observed; between these
bundles of neuraxes long spindle-shaped areas or columns composed of
granular detritus and mutually compressed vesicular cells occur. In the
series of cross sections made
through the field of alcohol injections, the main funiculi (internal
and external popliteal) are found demarked. Neuraxes arranged in
smaller or larger groups and seen in cross section are
found; these are separated by irregularly round or oval areas composed
of granular detritus and
vesicular cells. In the longitudinal sections made distal to the field
of alcohol injection the nerve
presents the appearance of a regenerating peripheral nerve.
EXPERIMENT
No. 12.- Rabbit No. 64; full grown; 137 days. March 21, 1918, right
sciatic exposed and while in place injected with absolute alcohol.
Nerve not cut. Wound closed.
August 5, killed. Rabbit in good condition; small neurotrophic ulcer on
right heel. In exposing
the sciatic, this in the middle of the thigh, the region of the alcohol
injection presents for a length
of about 1.5 cm. a somewhat smaller diameter than the nerve central and
distal thereto, and
presents the appearance of a normal nerve though the funicular
structure can not be made out
and is in this region moderately adherent to the underlying muscle. On
cutting the sciatic central
and then distal to the field of alcohol injection, after exposure of
the calf muscles, these muscles
were seen to contract and twitch. Sciatic removed and fixed in
ammoniated alcohol. Fair silver
differentiation attained.
Microscopic findings.- Series of
longitudinal and cross sections were made at successive levels. Nerve
fibers, certain of which are myelinated, can be traced from the central
nerve through the field of alcohol injection to the distal nerve. In
cross sections of the nerve through the field of alcohol injection, it
can be seen that the funicular structure of the nerve is lost in this
region. The neuraxes are found arranged in smaller and larger bundles,
separated by strands of
endoneural connective tissue, which is very materially increased in
this region.
1122
Very little remains of the old nerve fibers observed. The
nerve
distal to the field of alcohol
injections contains numerous both myelinated and nonmyelinated nerve
fibers. The muscle tissue was not studied in sections.
SUMMARY AND CONCLUSIONS
In
Experiment No. 1, in which the nerve was removed for study one hour
after the
injection of absolute alcohol, the gross changes observed in the nerve
in the field of injection
were more evident than the microscopic changes. In the region of the
spread of the alcohol, the
nerve is coagulated, appears "milky white" or "dull white" and there is
evidence of capillary
hemorrhage. Unfortunately the record of this case does not state
whether the nerve responded to
mechanical stimulation on being cut central to the region of alcohol
injection. There is only very
slight evidence of structural change in the region of alcohol injection
as seen under the
microscope when the nerve is removed soon after the injection; the
neuraxes of the nerve fibers
presenting, on the whole, a normal appearance and showing normal
staining reaction on silver
impregnation.
In
Experiments No. 2, No. 3, and No. 4, in which the nerve was removed for
study at a
progressively longer period after the injection of alcohol, beginning
with three hours after the
operation, the nerve did not respond to mechanical stimulus on being
sectioned central to the
field of injection, while the nerve distal to this field presented
normal structure and function. In
the field immediately influenced by the injected alcohol, there is
evident a fragmentation of
neuraxes and myelin sheaths of nerve fibers not comparable to that
observed in secondary
degeneration, in that the change is not accompanied by proliferation of
sheath cells and comes
on soon after injury. Not all of the nerve fibers of an injected nerve
trunk are equally affected. A
certain number of nerve fibers, the number varying in the several
experiments, appears not to be
affected by the alcohol. The number of nerve fibers not affected, it
would seem, is greater in case
the alcohol is injected into the surrounding tissue rather than into
the nerve trunk. Beginning
with the third day after the alcohol injection, the neuraxes fragments,
many of which may still
stain differentially, begin to show evidence of further breaking down
and, by the eleventh day
after alcohol injection, the neurolemma sheaths (the sheaths of Henle?)
are found filled with a
granular detritus in which neuraxis fragments may or may not be found.
The breaking down
nerve fibers in the region of alcohol injection do not present the
successive stages of secondary
nerve degeneration. leading to the formation of nucleated, syncytial,
protoplasmic bands, but
present a microscopic picture which resembles more that of a nerve
transplant removed some10
to 15 days after transplantation. The segment of the nerve peripheral
to the field of alcohol
injection, on the other hand, presents the histologic changes
characteristic of secondary nerve
degeneration, as also the region immediately central to the field of
alcohol injection.
In
a nerve removed approximately two months after alcohol injection,
Experiments No. 9
and No. 10, there is found abundant evidence of regeneration, although
this has not extended far
into the distal segment. In the region of alcohol injection, readily
recognized in section, remains
of the old nerve fibers are found in the form of granular detritus and
also there are found large
vesicular cells with relatively small nuclei, presumably with
phagocytic function,
1123
arranged in irregular
columns or spindle-shaped areas; these may be found within or between
old
neurolemma sheaths and endoneural connective tissue septa. In this
region there are found new
neuraxes grouped in smaller and larger bundles, traceable to the
central segment, having in the
main a longitudinal course but here and there exchanging neuraxes. The
new neuraxes did not
appear in the distal regions of the peripheral segment. In only one
experiment, No. 12, was the
animal kept for a period long enough to admit are generation of the
distal segment. In this
experiment the nerve was removed somewhat over four months after the
operation, at which
time there was functional evidence of nerve regeneration. The region of
alcohol injection is
recognized by the absence of funicular structure, which structure is
evident central and distal to
the region. Bundles of nerve fibers, both myelinated and
non-myelinated, are found in the
"wound" region, separated by relatively large areas of connective
tissue. These bundles have in
the main a longitudinal course but are serpentine as they wind through
the connective tissue. The
appearance of a wound region after severance and suture of a nerve
trunk with not especially
good approximation of ends is not unlike that of the region of alcohol
injection followed by
regeneration, except that this special area in and old alcohol injected
nerve extends over a longer
distance in the course of the nerve. Peripheral to the region of
alcohol injection the process of
regeneration is as after nerve section. The conditions resulting from
injection of alcohol into a
nerve trunk May "I speaks of as a "chemical section" of the nerve and
thinks that it is probable
that regeneration would follow more quickly than after mechanical
section. This, it would seem,
depends entirely on the thoroughness and extent of the alcohol
injection. If a number of point
injections are made extending over several centimeters of nerve the
resulting fibrosis would be
quite extensive.
So
far as can be determined there is no selective action as regards
afferent and efferent
nerves as a result of alcohol injection. In cases of causalgia in which
60 percent alcohol was
injected, it was thought by certain observers that motor functions
might persist even though
reaction of degeneration were present. It is difficult to explain such
selective action, except on
the possible ground that the larger myelinated motor nerve fibers are
more resistant to the
weaker solutions of alcohol than the smaller myelinated or
nonmyelinated fibers of the
exteroceptive pain and temperature functional systems. In cases of
causalgia treated by the
injection of alcohol into the respective nerve, ultimate regeneration
of the injected nerve may be
anticipated with reasonable assurance.
SERIES NO. 2
INJECTION OF FULL STRENGTH ACETONE INTO
LIVING NERVE WITHOUT CUTTING THE NERVE
In this series of three experiments full
strength acetone was injected into the sciatics of rabbits precisely as
was described for Series No. 1, except that acetone solution was used
instead of absolute alcohol.
PROTOCOLS
EXPERIMENT
No. 13.- Rabbit No. 32a; full grown; 65 days. March 19, 1918, right
sciatic exposed and
injected with about 0.5 c. c. of full strength acetone. Nerve not cut.
1124
Appearance of portion of nerve injected
resembles closely that obtained when absolute alcohol is injected; dull
white color. Wound closed. May 23, killed. Rabbit presents severe
neurotrophic changes right hind foot. On
exposing the right sciatic, increase of connective tissue about nerve
in region of acetone injection; when nerve is
dissected free, nerve trunk presents slight enlargement in this region.
Calf muscles exposed; atrophic. Muscles did
not contract on cutting nerve central and distal to field of acetone
injection. Sciatic removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
silver staining attained.
Microscopic findings.- Four series of longitudinal sections
were
cut taken at successive levels and including
the field of acetone injection and the nerve just proximal and distal
thereto. In the series of sections including the
nerve about 1.5 cm. proximal to the point of acetone injection,
practically normal nerve structure is observed, the
stained neuraxes, both myelinated and nonmyelinated, having a
longitudinal direction. Here and there "end discs,"
the distal ends of down-growing neuraxes, are encountered. In
longitudinal sections of the immediate field of
acetone injection, numerous neuraxes in the form of larger and smaller
bundles, having in the main a longitudinal
course, but here and there interchanging fibers, are encountered. These
bundles of neuraxes are separated by areas
and columns of vesicular cells with small nuclei as well as granular
detritus. Areas of crisscrossing of neuraxes are
here and there encountered. In more distally placed sections many
neuraxes are found growing distalward on the
inner surface of the perineural sheath; such neuraxes interlace and
have a plexus form of arrangement. In sections
placed distal to the field of injection, new nerve fibers are found in
large numbers, having again a longitudinal
course. The nerve trunk in this region presents the appearance of a
regenerating peripheral nerve after severance of
continuity.
EXPERIMENT No. 14.- Rabbit No. 35a; full
grown; 78 days. March 19, 1918, right sciatic exposed and
injected while in place with full strength acetone. Nerve not Cut.
Wound closed. June 5, rabbit found dead in the
morning. On exposing the right sciatic this is found nonadherent to the
surrounding connective tissue. In the middle
of the thigh. the region of acetone injection, the sciatic presents a
short segment having a light yellow color. The
nerve of this region is not thickened nor adherent. Sciatic removed and
fixed in ammoniated alcohol for pyridine-silver staining. Only in part
successful silver differentiation attained.
Microscopic
findings.- In the several series of longitudinal sections made,
sufficiently good silver
differentiation obtained to determine the fact that central
down-growing neuraxes, in large numbers, pass through the
field of acetone injection into the nerve trunk distal to this field.
In the field of acetone injection are observed areas
and columns of granular detritus and large vesicular cells, separating
bundles of neuraxes. At the point of injection,
distinct increase of endoneural and perineural connective tissue is
noted.
EXPERIMENT No. 15.- Rabbit No. 53a; nearly
full grown; 323 days. March 20, l918, right sciatic exposed
and injected while in place with full strength acetone. Nerve not cut,
wound closed. January 17, 1919, rabbit found
Lead in the morning; seemed in fairly good condition the day before,
though somewhat emaciated. On exposing the
right sciatic there is found no material increase in the connective
tissue surrounding the nerve; central portion of the
nerve adherent to underlying muscle. The main funiculi of the nerve
evident practically the entire length. A slight
increase in the diameter of the nerve is noted in the region of acetone
injection. The calf muscles presented normal
size and color; owing to death of animal could not be tested
functionally. Sciatic removed and fixed in ammoniated
alcohol or pyridine-silver staining. Good but faint differentiation
attained.
Microscopic findings.- In three
series
of longitudinal sections, numerous both myelinated and
nonmyelinated neuraxes, having in the main a longitudinal course, can
be traced through the field of acetone
injection. Scarcely any of the remains of the degenerated portions of
nerve fibers found. In cross sections of the
nerve, made just central to the place of acetone injection but in the
region affected by the acetone, the funicular
arrangement of the nerve trunk is found to be maintained. Within the
several funiculi there is found a distinct
increase of the endoneural connective tissue. So far as can be
determined from histologic findings, very complete
regeneration of the nerve distal to the place of acetone injection has
taken place. Pieces of calf muscle were not
removed for histologic study.
1125
CONCLUSIONS
So far as can be determined from the
limited number of experiments in which full strength acetone was
injected into the nerve instead of absolute alcohol as in Series No. 1,
this may be regarded as a safe procedure and
affects the nerve in the region of the injection very much as does
absolute alcohol. There is a "chemical section" of
the nerve and the operation is followed by loss of function in the
peripheral field of the respective nerve. In due time
regeneration, through the region immediately affected by the acetone,
takes place in a manner as after alcohol
injection.
INJECTION
INTO DIVIDED NERVE TO PREVENT AMPUTATION NEUROMA
SERIES NO. 3
INJECTION OF ABSOLUTE ALCOHOL INTO THE
CENTRAL END OF A DIVIDED NERVE TO OBVIATE THE FORMATION OF
AMPUTATION
NEUROMA
SERIES NO. 4
AMPUTATION NEUROMA FORMATION IN ASEPTIC WOUNDS
The
experimental observations here reported under Series No. 3 and No.4
were undertaken with a view of
studying the factors which cause and govern neuroma formation and if
possible to devise a safe and practical method
to prevent their formation, and to determine if possible the general
principle according to which methods suggested
to prevent neuroma formation might be judged critically on the basis of
experimental observations. There has been
abundant opportunity to study the neuroma formation in experimental
operations other than those recorded under
Series 4, since in many of the operations listed under other series,
nerves were cut and resected incidental to the
respective operation; this in experiments made on dogs as well as on
rabbits. The work here reported was
supplemented by further experiments, in which several of the methods
suggested for the prevention of neuroma
formation were tested experimentally. In these supplementary
experiments, made post bellum, the operative work
was done by Dean Lewis, in the animal laboratory of Rush Medical
College, in affiliation with the University of
Chicago, while the histologic study was under-taken by Huber at the
University of Michigan. Their joint work
formed the basis of a communication 03 dealing with the question of
amputation neuromas, their development and
their prevention, in which many of the experiments here listed under
Series No. 3 and No. 4 were given
consideration.
PROTOCOLS
EXPERIMENT
No. 16.- Rabbit No. 24; large; full grown; 11 days. March 1, 1918 left
sciatic exposed; large
nerve. Absolute alcohol injected in several point injections;
approximately 2.5 cm. of nerve well injected. Nerve cut
distal to field of injection and resected about 1 cm. Wound closed.
March 12, killed. Sciatic exposed. Distal end of
central sciatic stump surrounded by a small amount of pus. Nerve ends
in slight enlargement, having light yellow
color. Hemorrhage into nerve trunk, extending for a distance of about 3
cm. from end. Central stump removed and
fixed in neutral formalin. Tissue stained after the Bielschowsky silver
staining method.
1126
Microscopic findings.-In several series of longitudinal
sections,
of successive levels of the distal end of the
central sciatic stump, in the region affected by the injected alcohol
the neuraxes of the nerve fibers are found in the
form of short irregular segments. The myelin of the fibers is present
in the form of a granular detritus and smaller
and larger globules. The neurolemma sheaths appear well preserved. Here
and there irregularly formed cellula elements are found within the
neurolemma sheaths, the histogenesis of which is not clearly
determined.
EXPERIMENT No.
17.-Rabbit No. 40; full grown;
18 days. March 5, 1918, left sciatic exposed and
absolute alcohol injected; in the larger internal popliteal bundle
several point injections. Quite a little absolute
alcohol escaped into the wound. The nerve cut distal to the injection
and resected. The wound closed. March 23,
rabbit killed. Wound well healed. On exposing the sciatic no material
increase of connective tissue about nerve. Distal end of central
sciatic stump tapers to a fine point; slightly adherent to underlying
muscle. About 2.5 cm. of
end of central stump of light yellow color. Central sciatic stump
removed and fixed in neutral formalin for
Bielschowsky silver staining.
Microscopic findings.-In two series of longitudinal sections
of
successive levels of the distal end of the
central sciatic stump it may be clearly ascertained that both of the
main bundles of the sciatic were well injected, in
that in practically all of the nerve fibers only scattered neuraxis
fragments are to be found. The myelin remains
found in the form of granular detritus. The neurolemma sheaths present,
many showing spindle-shaped enlargement
at irregular intervals. Small nuclei of doubtful source found scattered
through the granular myelin detritus. The
fibrous tissue sheaths of the distal end of the central sciatic stump
thickened; fibrous tissue at the cut end of the
nerve.
EXPERIMENT No. 18.-Rabbit No. 14; full grown;
20 days. February 26, 1918, left sciatic exposed and
injected with absolute alcohol, making several point injections. Very
little alcohol escaped to wound. Nerve cut
distal to place of injection and resected 1 cm. Wound closed. March 18,
rabbit found dead in the morning. Wound
well healed. On exposing the sciatic, the distal end of the central
stump found tapering to a fine line adherent to the
underlying muscle. A small blood clot found surrounding the distal end
of the central sciatic stump. Central sciatic
removed and fixed in neutral formalin. Sections stained in iron
hematoxylin and picro-fuchsin.
Microscopic findings.-In the several series of longitudinal
sections made at successive levels, the structural
appearance presented is such that the sections would not be recognized
as sections of peripheral nerve tissue,
endoneural connective tissue strands and neurolemma sheaths being the
only portion of nerve structure recognized
within the funiculi of the larger internal popliteal bundle. Within
these sheaths, the neuraxes of the fibers have
completely disappeared. The myelin remains are found in the form of a
granular detritus or as inclusions in large
vesicular cells having very small nuclei. In the external popliteal
bundle, not so fully injected, certain normal fibers
are to be found; other fibers showing degeneration phenomena,
resembling those found in a peripheral nerve after
section, are observed. The perineural sheaths of both the internal and
external popliteal bundles present a structural
appearance which is not unlike that of a normal nerve.
EXPERIMENT No. 19.-Rabbit No. 28; small; half
grown; 21 days. March 1, 1918, left sciatic exposed and
injected with absolute alcohol; very successfully injected; hardly any
alcohol escaped. Nerve cut distal to injection
and resected. Wound closed. March 22, rabbit found dead in the morning;
seemed well nourished; wound well
healed. On exposing the left sciatic this found only slightly adherent
to the muscle bed. Distal end of central stump,
for about 1.5 cm. tapers to fine strand and is of light yellow color.
Distal end of central stump removed and fixed in
neutral formalin. Sections stained in iron hematoxylin and
picro-fuchsin.
Microscopic findings.-In several series of longitudinal
sections,
including the area of alcohol injection, the
perineural sheaths of time funiculi appear slightly thickened. Of the
old nerve fibers, the neurolemma sheaths only in
part present; areas in which they have disappeared. In such areas, and
within distended neuroleninia sheaths in
other parts, there are found large vesicular cells, mutually
compressed, having granular and globular inclusions. The
cells have small nuclei. In the most distal part of the central stump
such cells are less numerous, with a consequent
reduction in the size of the nerve.
1127
EXPERIMENT No. 20.- Rabbit No. 11; full
grown;
24 days. February 26, 1918, left sciatic exposed and
injected with absolute alcohol; cut distal to place of injection and
resected. Wound closed. March 22, rabbit found
dead in the morning; seemed well nourished; wound well healed. On
exposing the nerve this was found only slightly
adherent to the underlying muscle. Distal end of central stump presents
tapering end. The central stump removed and
fixed in neutral formalin. Sections stained in iron-hematoxylin and
picro-fuchsin.
Microscopic
findings.- In series of longitudinal sections of the distal end of
the central stump, including the
area injected with absolute alcohol and 2 cm. central, perineural
sheath found well maintained. In the injected
area, practically only the old neurolema sheaths observed; many of
these greatly distended, and here and there
small areas where these have disappeared. In such areas and within
certain of the neurolemma sheaths large
vesicular cells with small nuclei are observed. Both of the main
bundles equally involved.
EXPERIMENT No. 21.- Rabbit No. 1; large; full
grown; 36 days. February 18, 1918, left sciatic exposed
and raised from bed for several centimeters. Lifted on hook and
injected with absolute alcohol. Area well injected
presents a milky white appearance. Cut distal to injection and resected
5 mm. Wound closed. March 26, rabbit died
during morning; still warm when found. Very much emaciated. Abscesses
filled with "cheesy" pus in various parts
of body. The wound was well healed. On exposing the nerve it was found
that the external popliteal was not cut at
the operation and apparently was not injected. The internal popliteal
stump found with tapering end. Nerve fixed in
neutral formalin. Bielschowsky silver staining; good differentiation of
neuraxes.
Microscopic
findings.- From a study of several series of longitudinal sections,
it is evident
that the external popliteal was insufficiently injected in that a large
portion of this nerve bundle
seems not to have been affected by the alcohol; showing normal nerve
fibers. In the part of the
nerve affected by the alcohol the neuraxes and myelin sheaths have
disappeared and are replaced
by a granular detritus and large vesicular cells with protoplasmic
inclusions. Perineural sheaths
not materially thickened.
EXPERIMENT No. 22.- Rabbit No. 21; full grown;
36l days. February 28, 1918, left sciatic exposed and
injected with absolute alcohol; injected in two regions about 8 mm.
apart. Nerve cut distal to field of injection and
resected. Wound closed. April 5, rabbit found dead in the morning;
emaciated; wound well healed. On exposing the
nerve a discoloration about distal end of central stump noted (probably
due to hemorrhage). The distal end of the
central stump tapers to nearly a point anil presents a light yellow
color. About 1.5 cm. proximal to the distal end of
central stump nerve presents a normal appearance. Nerve removed and
fixed in neutral formalin. Sections stained in
iron-hematoxylin and piero- fuchsin.
Microscopic findings.- In three series of longitudinal
section:;
taken at successive levels, including about 3
cm. of the distal end of the central stump, the following observations
are permitted. Approximately 2 cm. central to
the place of injection normal nerve tissue is reached. Distal thereto
in progressive degree, neuraxes and myelin are
replaced by granular detritus, globules and phagocytic cells, in part
within neurolemma sheaths, in part in areas in
which the neuroleninna sheaths have disappeared, only strands of
endonicural connective tissue remaining.
Down-growing nerve fibers, in part With very thin myelin sheaths, can
be traced from the central undegenerated
portion into the degenerated area. These fibers are found singly or in
small bundles; present a very regular course,
with direction in the main parallel to the long axis of the nerve, and
reach to within 1 cm. of the distal end of the
central stump. Here and there strands of nucleated bands of syncytial
protoplasm are noted in the degenerated
portion of the nerve.
EXPERIMENT
No. 23.- Rabbit No. 2; large; full grown; 49 days. February 18,
1918,right sciatic exposed;
partly freed and injected with absolute alcohol; cut distal to
injection and resected 5 mm. Wound closed. March 18,
wound completely healed; hair growing over shaved area. April 8, found
dead in the morning. On exposing nerve it
was found that the external popliteal bundle was cut but not the
internal bundle. External popliteal presents slight
enlargement of distal end of central stump; end tapers to fine strand
and is of light yellow color. Nerve removed and
fixed in neutral formalin. Section stained in iron-hematoxylin.
1128
Microscopic findings.-Only the cut external popliteal nerve
sectioned. Evident from series of longitudinal
sections that this branch was only partly injected, since in it only a
small area in which neuraxes and invelin sheath
disintegration is observed. The remainder of the stump resembles in
structure closely amputation neurorna, with
proliferation of connective tissue and down-growing neuraxes. This
experiment can not be regarded as successful.
EXPERIMENT
No. 24.-Rabbit No. 43; half grown; 52 days. March 5, 1918, left sciatic
exposed and
injected with absolute alcohol; one injection. Quite a little alcohol
escaped to wound. Nerve cut and resected. Wound
closed. April 25, killed. Rabbit in good condition. On exposing nerve,
this presents normal appearance to about 2.5
cm. from distal end of the central stump. Distal end shows a slight
spindle-shaped enlargement central-ward, then
tapers to a fine strand. Streaks of yellow-white color, parallel to
long axis oh-served. The distal end of the central
stump removed and fixed in ammoniated alcohol for pyridine-silver
staining. Good differential silver staining
attained.
Microscopic findings.-In three series of longitudinal
sections,
taken at different levels ,it may be observed,
that in the distal part of the central stump to the extent of about 2
cm. the neuraxes and myelin and in part the
neurolemma sheaths of the nerves have been re-placed by granular and
globular detritus and vesicular cells, arranged
in columns or groups separated by strands of endoneural connective
tissue and neurolernma remains. Single
neuraxes or small groups of such, growing from the central
undegenerated portion of the nerve can be traced into
degenerated area. These neuraxes have a regular course, in the main
parallel to the long axis of the nerve. Neucleated
protoplasmic strands accompany these neuraxes. In the distal most part
of the central stump as vet no new neuraxes
are found; from this part also the granular detritus and vesicular
cells have disappeared.
EXPERIMENT No. 25.-Rabbit No. 22; full grown;
56 days. February 28, 1918.left sciatic exposed and
injected with absolute alcohol; well injected. Nerve cut distal to
field of injection and resected. Wound closed. April
25, killed. Rabbit in good condition; slight neurotrophic ulcer left
foot. Wound well healed. On exposing nerve it is
found that it presents a normal appearance to about 1.5 cm. from distal
end of the central stump, which presents only
very slight enlargement, is of yellow-white color, and tapers to fine
strand, which seems continuous with
surrounding connective tissue. Nerve removed and fixed in ammoniated
alcohol for pyridine-silver staining. Successful silver differentiation
attained.
Microscopic
findings.-In series of
longitudinal sections taken at successive levels it may be observed
that
numerous new neuraxes growing from the central undegenerated portion of
the nerve have grown distally into the
portion injected with absolute alcohol. These neuraxes course singly or
in small bundles, having in the main a
longitudinal course, the small bundles of neuraxes showing here and
there interchange of fibers. Between these
neuraxes are found columns or areas of granular detritus and vesicular
cells. The down-growing neuraxes have
practically reached the distal end of the central stump. There is
observed no tangling or crisscrossing of neuraxes as
seen in a neuroma, nor in the intergrowth of neuraxes and connective
tissue as observed at the end of a neuroma.
EXPERIMENT No. 26-Rabbit No. 41; large; full
grown; 58 days. March 5, 1918, left sciatic exposed and
internal and external popliteal bundles injected separately; the former
two injections; well injected. Nerve cut distal
to injection and resected Wound closed. May 3, rabbit found dead in the
morning. Neurotrophic changes left heel;
popliteal lymph gland enlarged. On exposing the nerve it is found that
the central stump tapers to fine strand, and
presents light-yellow color. About 2 cm. central to distal end of
central stump nerve presents normal appearance,
with funiculi distinct. Nerve remove and fixed in Flemming
chrom-osmic-acetic solution. Sections stained in
safranine and licht
grün.
Microscopic
findings.-In three series of longitudinal sections taken at
successive level sit may be observed,
beginning with the most distally placed series, that the neuraxes and
myelin of the nerve fibers of both of the main
funiculi have entirely disappeared, with fine strands of endoneural
connective tissue and neurolemma sheath remains
forming a very open meshed network, surrounding areas of granular and
globular detritus, through which are
scattered small round or oval nuclei. In the series of the next higher
level the same
1129
general structure is found for the
greater
part of the section. In the more central portion of the sections small
strands
of syncytial nucleated bands of protoplasm are observed, which become
more numerous in the centrally placed of
the three series. These nucleated proto-plasmic bands have grown into
the degenerated portion of the nerve from the
central undegenerated portion.
EXPERIMENT
No. 27.-Rabbit No. 38; nearly full grown; 63 days. March 5, 1918,left
sciatic exposed;
quite a little bleeding; controlled. Two injections of absolute alcohol
made; both bundles injected. Nerve cut and 5
mm. resected. Wound closed. May 13, rabbit found dead in the morning;
in fairly good condition. On exposing the
nerve, distal end of central stump found tapering to fine strand
slightly adherent to muscle bed. The distal end for a
distance of about 2 cm. presents a light-yellow color; central to this
nerve normal appearance. Nerve removed and
fixed in neutral formalin. Sections stained iniron-hematoxylin and
picro-fuchsin.
Microscopic
findings.-In several series of longitudinal sections taken at
successive levels, it is observed that
in the distal end of the central stump, in the area of the alcohol
injection, neuraxes and myelin of the nerve fibers
have entirely disappeared, fine strands of endoneural connective tissue
and remnants of neurolemma sheaths
remaining. This portion of the nerve consisting almost wholly of
granular and globular detritus, surrounded by the
perineural sheaths. More centralward in the series of sections,
nucleated protoplasmic bands growing distally from
the undegenerated central nerve are to be observed, to one side, near
the perineural sheath, these protoplasmic bands
extend distally to near the distal end of the central stump.
EXPERIMENT No. 28.-Rabbit No. 18; full grown;
65 days. February 27, 1918, left sciatic exposed; large
vein cut; clamped. Absolute alcohol injected and nerve cut just distal
to injected field and resected. Wound closed.
May 5, found dead in the morning. Protocol incomplete, simple
statement, " No neuroma."
EXPERIMENT
No. 29.-Rabbit No. 10; full grown; 71 days. February 26, 1918, left
sciatic exposed and
injected with absolute alcohol. Nerve cut distal to field of injection;
resected 1 cm. Wound closed. May 8, killed.
Rabbit not in good condition; emaciated;"fungus" ears. On exposing, the
left sciatic central stump is found ending in
fine tapering strand, not especially adherent to the muscle bed; of
light-yellow color. About 2 cm. central to distal
end nerve presents the appearance of normal nerve. The nerve removed
and fixed in ammoniated alcohol for
pyridine-silver staining. Very good differential silver staining
attained.
Microscopic findings.-From the microscopic appearances
presented
in the several series of longitudinal
sections taken at successive levels, it is evident that the injection
of alcohol was not wholly successful in this
experiment. Numerous neuraxes may be traced from the central portion of
the nerve, toward the end of the central
stump, numerous large end-discs found at various levels. Especially to
one side of the nerve, and about 2 mm. from
its distal end, numerous complex spirals of neuraxes are to be
observed. At the distal end of the central stump,
crossing and recrossing of neuraxes is noted, though there is not
observed that intergrowth of neuraxes and
connective tissue as is generally seen in a neuroma. In the entire
series of sections, few remains of myelin and
neuraxes of the old nerve fibers observed. The conclusion
seems
warranted that at the time of operation the nerve
trunk was partially injected with absolute alcohol, and that after section of the
nerve
a partial neuroma developed.
EXPERIMENT No. 30.- Rabbit No. 32; full grown;
80 days. March 4, 1918, left sciatic exposed. Several
injections of absolute alcohol made, spaced at intervals of about 5 mm.
Well injected. Nerve resected 1.3 cm. just
distal to field of injection. Wound closed. May 23, killed. Rabbit in
good condition; severe neurotrophic changes
left hind foot. On exposing left sciatic, this presents a normal
appearance to within 2 cm. of distal end of central
stump. The end presents first a slight enlargement, then tapers to a
fine strand only loosely adherent to the
surrounding connective tissue. Distal nerve segment completely
degenerated. Central sciatic removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
silver staining attained.
1130
Microscopic findings.- In three series of longitudinal
sections
and one series of cross sections approximately
3 cm. of the distal end of the central sciatic stump was sectioned. The
most centrally placed sections include a
portion of the normal nerve. Numerous downgrowing neuraxes may be
traced from this portion of the nerve into that
portion immediately influenced by the absolute alcohol. In this latter
portion areas and columns of globular and
granular detritus are found, coursing between which there may le
observed smaller and larger bundles of neuraxes,
which have in the main a regular course, with here and there
interchange of fibers. These down-growing neuraxes
may be traced to the distal end of the central stump, but present no
tangling or intertwining as observed in a
neuroma. The perineural sheath surrounds these down-growing neuraxes.
EXPERIMENT
No. 31.- Rabbit No. 26; full grown; 83 davs. March 1. 1918, left
sciatic
exposed and
injected with absolute alcohol. Well injected. Nerve cut distal to
field of injection and resected 8 mm. Wound
closed. May 23, killed. Rabbit in goon condition. On exposing the left
sciatic, this presents normal appearance to
within 2 cm. of distal end of central stump. Distal end of central
stump presents slight enlargement. then tapers to
fine strand, adherent to underlying muscles. Nerve removed and fixed in
ammoniated alcohol for pyridine-silver
staining. Good silver differentiation attained.
Microscopic
findings.- In two series of longitudinal sections in which
approximately 4 cm. of nerve is
sectioned, it is observed that numerous neuraxes growing distalward
from the central uninjured portion of the nerve
extend into the portion affected by the absolute alcohol. These
neuraxes are inclosed within the thickened perineural
and epineural sheaths and have in the main a longitudinal course,
except those found in close proximity to the
fibrinous sheaths; many of them cross and recross and intertwine oil
the inner surface of the perineural sheath. These
down-growing neuraxes can be traced to the attenuated end of the
central stump. The remains of the fibers affected
by the absolute alcohol found in areas of granular detritus,
interspersed with large vesicular cells and fat cells,
between which course the neuraxes.
EXPERIMENT
No. 32.-Rabbit No. 29; full grown; 83 days. March 1, 1918, left sciatic
exposed and
injected with absolute alcohol; well injected. Nerve cut distal to
field of injection and resected. Wound closed. May 23, rabbit found
dead in the morning. Left femur found broken; apparently some days
before death. On
exposing the sciatic, tissues about nerve found much congested and
containing extravasated blood, owing to fracture. The distal end of the
central sciatic found to taper to fine strand; relations not clear
owing to extravasated blood.
Nerve removed and fixed in ammoniated alcohol for pyridine-silver
staining. Good silver differentiation attained.
Microscopic
findings.-In two series of longitudinal sections including
approximately 4 cm. of the distal end
of the promixal stump), large number of down-growing neuraxes maybe
traced from the uninjured central portion
of the nerve to its distal end. These nueraxes are inclosed in the
thickened fibrous tissue sheaths of the nerve and
have in the main a regular course. Within the area injected with
absolute alcohol a few columns and areas of
granular detritus, certain large vesicular cells and many fat cells are
found. Such columns and areas are separated by
bundles of down-growing Neuraxis, a few of which cross such fields
either as single fibers or as small bundles of
such.
EXPERIMENT
No. 33.-Rabbit No. 17; nearly fully grown; 84 days. February 27, 1918.
left sciatic exposed
and injected with absolute alcohol. First injection not successful;
nerve slightly torn. Second attempt at a higher
level, was successful; well injected. Nerve cut and resected. Wound
closed. May 22, rabbit found dead in the
morning; seemed in good condition; severe neurotrophic changes left
hind foot. On exposing the left sciatic. the
distal end of the central stump is found to taper to fine strand;
adherent to the underlying muscle. Several delicate
nerve bundles appear to extend on the muscle bed for a distance of
about 1 cm. beyond the cut end of the nerve. No
evidence of a neuroma noted. Nerve removed and fixed in ammoniated
alcohol for pyridine-silver staining. Good
differential silver staining attained. A portion of the nerve removed
in this experiment was lost; the portion at hand
represents the most distal portion of the central stump for the length
of a little over 1 cm.
1131
Microscopic
findings.-In a series of
longitudinal sections, small bundles of fine neuraxes inclosed within
the thickened fibrous sheath are observed. These bundles of neuraxes
are found separated by areas of granular
detritus and fat cells.
EXPERIMENT
No. 34.- Rabbit No. 42; half grown; 84 days. March 5, 191S, left
sciatic
exposed and
injected with absolute alcohol; larger bundle in two stages; smaller
bundle, one injection. Well injected. Nerve cut
and resected 1 cm. Wound closed. May 29, rabbit found dead in the
morning. Protocol incomplete. Nerve
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Good silver differentiation attained.
Microscopic
findings.- In three series of longitudinal and cross sections in
which approximately 4 cm. of
nerve were cut, central neuraxes are found passing distalward through
the area injected by absolute alcohol, and
have reached the distal end of the central stump, and as scattered
neuraxes or as small bundles of such can be traced
into the connective tissue overlying the muscle bed for a distance of
about 1 cm. beyond the cut end of the nerve. In
the main these neuraxes have a very regular longitudinal course. Very
little detritus, the remains of the injured nerve
fibers found in the area injected with absolute alcohol.
EXPERIMENT
No. 35.- Rabbit No. 8; full grown; 90 days. February 23, 1918, left
sciatic exposed and
injected with absolute alcohol; well injected. Nerve cut just distal to
injection; resected 1 cm. Wound closed. May
23, killed. Rabbit very much emaciated; severe neurotrophic changes
foot, two-toes missing; large ulcer on heel. On
exposing the sciatic, this is found of normal appearance to about 1.5
cm. from end of central stump. End of stump
presents slight enlargement then tapers to a fine strand. The nerve
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Faint but differential neuraxis staining
attained.
Microscopic
findings.- In three series of longitudinal and one of cross
sections, taking in a little over 4 cm.
of the distal end of the nerve the following may be observed: Neuraxes
in large numbers can be traced from the
central practically uninjured portion of the nerve, through the area
affected by the alcohol to the distal end of the
central stump. In a series of cross sections, taken about 2 cm. above
the point of puncture for alcohol injection, the
funicular structure of the nerve is not lost; the perineural sheaths
are distinctly thickened. Within the funiculi,
numerous neuraxes seen in cross section, four to ten within one
neurolemma sheath. Not all of the funiculi found
equally affected. In the more distal portion of the nerve, in two
series of longitudinal sections, numerous neuraxes,
having in the main a longitudinal course, and arranged in larger or
smaller bundles, and separated by elongated areas
and columns of granular detritus, vesicular cells and fat cells, are to
be observed. inclosed within the thickened
fibrous sheaths.
EXPERIMENT
No. 36.- Rabbit No. 37; full grown; 93 days. March 5, 1918, left
sciatic
exposed and
injected with absolute alcohol; both bundles well injected. Nerve cut
about .5 cm. distal to place of injection and
resected 1 cm. A small amount of alcohol escaped to wound. Wound
closed. June 6, killed. Rabbit in fair condition;
neurotrophic ulcer on left heel. On exposing the sciatic nerve is found
to present normal appearance to near end of
distal stump which tapers to a fine strand. Nerve removed and fixed in
Flemming's chrom-osmic-acetic mixture.
Sections stained in safranine and licht grün.
Microscopic
findings.-In several series of cross and longitudinal sections made
from the distal 4 cm. of the
central stump the following observations are made: In the series of
longitudinal sections small bundles composed of
nucleated protoplasmic bands and fine myelinated nerve fibers may be
traced from the central normal portion of the
nerve to the end of the distal stump. Between these there are found
broader or narrower columns composed of, in the
main, large vesicular cells with small nuclei, having globular and
granular protoplasmic inclusions. These cells
would appear to have phagocytized the remains of the nerve fibers
affected by the absolute alcohol. The fibrous
sheaths of the distal end of the central stump are found materially
thickened. In the distal 1.5 cm. the funicular
structure of the nerve is lost.
EXPERIMENT
No. 37.- Rabbit No. 34; full grown; 94 days. March 4, 1918, the left
sciatic exposed and
injected with absolute alcohol; well injected. Nerve cut 5 mm. distal to place of injection and
resected 1 cm.
Wound closed. June 5, killed. Much emaciated; severe neurotrophic
ulcer, left heel. On exposing the left sciatic
nerve found normal to within1.5 cm. of end of the central stump;
presents slight enlargement, then tapers to fine
strand;
1132
adherent to the underlying muscle. Nerve
removed and fixed in neutral formalin. Sections stained in
iron-hematoxylin and picro-fuchsin. Tissue not well embedded, sections
torn.
Microscopic
findings.-In the sections remaining it can be determined that
nucleated protoplasmic bands
extend from the central undegenerated portion of the nerve to the
distal end of the central stump. These bands of
nucleated protoplasm regarded as nonmyelinated fibers. Between such
bands or bundles are found columns or long
spindle-shaped areas of large closely arranged vesicular cells with
globular or granular inclusions.
EXPERIMENT
No. 38.- Rabbit No. 39; small rabbit; not full grown; 95 days. March 5, 1918, left sciatic
exposed; free venous bleeding. Absolute alcohol injected; larger bundle
in several places; smaller bundle one
injection. Well injected. A small amount of alcohol escaped to wound.
Wound closed. June 8, rabbit found dead in
the morning. On exposing the left sciatic this presents a normal
appearance to within a short distance of the distal
end of the central stump, which tapers to a fine strand. Nerve removed
and fixed in ammoniated alcohol for pyridine-silver staining. Silver
differentiation is not successful.
Microscopic findings.-Several series of longitudinal
sections,
though not showing differentiation of
neuraxes, are sufficiently stained to admit of making the
interpretation that there was no neuroma formation; the
arrangement of the connective tissue warrants this conclusion.
EXPERIMENT
No. 39.-Rabbit No. 27; full grown; 97 days. March 1, 1918, left sciatic
exposed and
injected with absolute alcohol. On first attempt, movement of animal
prevents successful injection; on second trial
successful injection made. Nerve cut distal to injection and resected.
June 6, killed. Rabbit in good condition. On
exposing the left sciatic the nerve presents normal appearance to near
distal end of the central stump, which appears
to end in fine tapering strand. The relations of distal end of central
stump not clearly made out owing to presence of
dense cicatricial tissue at end of the fine tapering strand. Nerve
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Fairly good silver differentiation attained;
sheath nuclei as well as neuraxes stained.
Microscopic findings.-Several
series
of longitudinal sections made. In these it is possible to trace
numerous
neuraxes from the more centrally placed sections, through the field
affected by the alcohol injection to the distal end
of the central stump. At the distal end of the central stump the
neuraxes are found to cross and recross, especially
those found in close relation to the outer fibrous sheath. In the more
central portion the neuraxes present a more
regular longitudinal course. In this portion of the nerve, between
small bundles of neuraxes, large spindle-shaped
areas composed of vesicular cells and granular detritus are to be
found. In relation with the distal end of the central
stump there was noted at the time the nerve was removed a small
irregular mass about 5 mm. in diameter which
appeared to consist of dense fibrous tissue. In sections this mass was
found to contain a nucleus of osseous tissue
surrounded by dense fibrous tissue. In this fibrous layer, mainly to
one side, several small bundles of neuraxes were
found. A study of this series of sections suggests imperfect alcohol
injection, as a result partial neuroma formation,
with proliferation of fibrous tissue consequent to escape of alcohol
into the wound.
EXPERIMENT
No. 40.-Rabbit No. 15; full grown; 102 days. February 26, 1918, left
sciatic exposed and
injected with absolute alcohol; nerve cut distal to injection and
resected1 cm. Wound closed. June 4, killed. Animal
not in good condition; severe neurotrophic ulcer on left heel;
popliteal lymph gland greatly enlarged. On exposing
the left sciatic, the central stump found tapering to fine strand;
distal end of light-yellow color. Connective tissue in
proximal part of popliteal space quite dense. Central sciatic removed
and fixed in ammoniated alcohol for pyridine-silver staining. Good
silver differentiation attained; especially more central portion of
nerve.
Microscopic findings.-Two series
of
longitudinal sections, including the 2 cm. of the distal end of the
central stump, made. In the more distally placed series, within the
thickened fibrous sheath, a granular detritus and
vesicular cells occupy nearly the entire area. No down-growing neuraxes
appear to have reached this portion of the
central stump. In the more centrally placed series, numerous new
neuraxes are found; those more axially placed have
a regular course; those more peripherally placed crisscross on the
inner surface of the fibrous tissue but do not
present the intergrowth of fibrous tissue and neuraxes as noted at the
distal end of a neuroma.
1133
EXPERIMENT No. 41.-Rabbit No. 3; large;
full
grown; 108 days. February 18, 1918, left sciatic exposed
and injected with absolute alcohol. Nerve cut about 5 mm. distal to
place of injection; not resected. Wound closed.
June 6, killed. Left hind foot slight neurotrophic changes on heel. On
exposing the sciatic it is found that the external
popliteal was not cut, and probably not injected. Internal popliteal
central stump presents a tapering end. Some
delicate fine strands seem to extend beyond the cut end; on cutting of
these “fibers," no twitching of calf muscles
observed. The nerve removed and fixed in an ammoniated alcohol for
pyridine-silver staining. Good silver
differentiation attained.
Microscopic findings.-The noncut
and
noninjected external popliteal sectioned with the cut and injected
internal popliteal, cut together in series of longitudinal sections. In
the sections, the external popliteal presents the
appearance of a normal nerve; here and there a few degenerated fibers
are noted. In the distal end of central stump of
the internal popliteal, central down-growing neuraxes can be traced to
the distal end, having in the main a regular
longitudinal course, and separated into smaller and larger bundles by
long spindle-shaped areas, occupied by
granular detritus and large vesicular cells. A few neuraxes can be
traced into the connective tissue surrounding the
distal end of the central stump of the internal popliteal.
EXPERIMENT
No. 42.-Rabbit No. 25; half grown rabbit; 150 days. March 1, 1918, left
sciatic exposed and
injected with absolute alcohol. Well injected; practically no alcohol
escaped to
the wound. Sciatic
cut 5 mm. distal
to place of injection and resected 1 cm. Wound closed. July 30, killed.
Rabbit not in good condition. On exposing
the left sciatic the central stump is found to end in a fine tapering
strand. No bulb. No nerve fibers could be traced
beyond the cut end of the nerve. Central sciatic removed and fixed in
ammoniated alcohol for pyridine-silver
staining. Good differential silver staining attained. During embedding
the end of the central sciatic stump became
bent, so that it was not possible to cut longitudinal sections
including the entire length of the piece.
Microscopic findings.-It is
evident on
study of the entire series, that down-growing neuraxes coming from
the central uninjected portion of the nerve, have passed through the
area injected with absolute alcohol and have
reached the distal end of the central sciatic stump. These neuraxes
have in the main a longitudinal course. Toward
the distal end some crisscrossing of neuraxes is observed; not to the
extent found in a neuroma, and such
crisscrossing of neuraxes as is observed occurs within the fibrous
tissue sheath and mainly on its inner surface.
EXPERIMENT
No. 43.-Rabbit No. 23; nearly full grown; 157 days. March 1, 1918,left
sciatic exposed and
injected with absolute alcohol. Well injected. A small quantity of
alcohol escaped to the wound. Nerve cut just
distal to place of injection and resected. Wound closed. August 5,
killed. Rabbit in good condition; foot missing;
stump completely healed. On exposing the sciatic the central stump is
found to end in fine tapering strand from the
distal end of which a fine filament can be traced toward the distal
sciatic stump, but does not reach it. Calf and foot
flexor muscles completely degenerated. Central sciatic removed and
fixed in ammoniated alcohol for pyridine-silver
staining. Not wholly successful differentiation attained; patchy.
Microscopic findings.-In fairly
complete series of longitudinal sections, taking in the distal 2 cm. of
the
central sciatic stump, it may be observed that numerous neuraxes, both
myelinated and nonmyelinated, grow distal
through the field of alcohol injection to the extreme distal end of the
central stump. Here the connective tissue sheath
of the nerve is found very materially thickened, the connective tissue
extending into the interior of the nerve end and
separating the nerves into small intertwining bundles. More centrally
the neuraxes have a more regular longitudinal
course, except those found in close relation to the fibrous tissue
sheath, which course along the inner surface without
definite arrangement. The structural appearances presented are not
those of a neuroma.
The
following eight experiments are briefly listed but not numbered:
Rabbit No. 30. Small rabbit;
full grown; 1
day. March 1, 1918, left sciatic exposed; injected with absolute
alcohol; cut; resected. Wound closed. March 2, found dead in the
morning. On opening wound, evidence of
hemorrhage along line of incision. Portion of
1134
sciatic injected with
alcohol of soft
consistence; no gross hemorrhage into nerve. Tissue not sectioned.
Rabbit No. 45. Full grown; 7 days. March 5,
1918, left sciatic exposed; injected with absolute alcohol;
large bundle in three stages. Nerve cut and resected. Wound closed.
March 12, found dead. Reported too late to use
tissue for microscopic study.
Rabbit
No. 44. Nearly full grown; 8 days. March 5, 1918, left sciatic exposed;
absolute alcohol injected. A
small amount escaped to wound. Nerve cut and resected. Wound closed.
March 13, a second operation attempted on
right sciatic. Rabbit did not recover from second operation. Left
sciatic wound found well healed. The distal end of
the central sciatic stump found loosely adherent to the underlying
muscle and presenting a slightly tapering end.
Central sciatic removed and fixed in neutral formalin. Tissue lost in
washing after fixation.
Rabbit
No. 49. Half grown; 9 days. March 6, 1918, left sciatic exposed;
injected with absolute alcohol.
Nerve cut and resected. Wound closed. March 15, found dead in the
morning. Reported too late to be used for
microscopic study. Central end of sciatic found slightly tapering.
Rabbit
No. 31. Half grown; 10 days. March 4, 1918, left sciatic exposed and
injected with absolute alcohol.
Nerve cut and resected. Wound closed. March 14, found dead in the
morning. Must have been dead many hours.
Wound well healed. Central sciatic stump found slightly tapering.
Tissue not studied microscopically.
Rabbit No. 36. Full grown; 11 days.
March 5,
1918, left sciatic exposed and injected with absolute
alcohol. Nerve cut and resected. Wound closed. March 16, found dead in
the morning. Rabbit dead many hours.
Tissue not used for study. Central sciatic stump found slightly
tapering.
Rabbit
No. 19. Full grown; 93 days. February 27, left sciatic exposed and
injected with absolute alcohol.
Nerve cut and resected. Wound closed. June 1, rabbit found dead in the
morning. Severe neurotrophic changes of
left hind foot; secondary injection. On exposing the sciatic this is
found to taper to fine strand. No neuroma. The
tissue not studied.
Rabbit
No. 30- Full grown; 98 days. February 28, 1918, left sciatic exposed
and absolute alcohol injected.
Wound closed. June 6, rabbit found dead in the morning. Reported too
late to be of use in study of the tissue. On
exposing the nerve this is found to taper to a fine strand. No neuroma.
EXPERIMENT
No. 44.- Rabbit No. 28a; small; half grown; 9 days. March 13,
1918,right
sciatic exposed;
cut and resected 1.2 cm. Wound closed. March 22, rabbit found dead in
the morning. Wound
'well healed.
On
exposing the sciatic, a small swelling on the distal end of central
sciatic stump noted. Beginning of neuroma. Central
sciatic stump removed and fixed in neutral formalin. Sections stained
in iron-hematoxylin and picro-fuchsin.
Microscopic
findings.-In longitudinal sections of the distal end of the central
stump early stages of
amputation neuroma formation noted, evidenced structurally by
fragmentation of the myelin to the extent of about 8
mm. of the distal end of the central nerve fibers; proliferation of the
sheath cells in this region; proliferation of the
connective tissue.
EXPERIMENT
No. 45.- Rabbit No. 12; full grown; 25 days. February 26, 1918, left
sciatic exposed; cut
and resected. Wound closed. March 23, killed. Wound healed. On exposing
nerve a distinct bulb on distal end of
the central sciatic stump found. Removed and fixed in ammoniated
alcohol for pyridine-silver staining. Tissue
misplaced; not sectioned.
EXPERIMENT
No. 46a.- Rabbit No. 16; small rabbit; not full grown; 28 days.
February
26, 1918, left
sciatic exposed; cut and resected. Wound closed. March 26, killed.
Rabbit in good condition. On exposing the left
sciatic distinct bulb found on central end of the distal stump. A
delicate filament, having the appearance of a small
nerve, traced a short distance beyond the distal end of the nerve bulb.
Bulb removed and fixed in neutral formalin for
silver staining. Bielschowsky silver method used.
Microscopic
findings.-In longitudinal section it is noted that the neuraxes
were not differentially stained,
but that the fibrous tissue is very clearly differentiated. This
enables
1135
the observation that in a neuroma the
endoneural connective tissue as well as the perineural sheaths show
distinct
proliferation.
EXPERIMENT
No. 46b.-Rabbit No. 4; full grown; 34 days. February 19, 1918, left
sciatic exposed; cut
and resected. Wound closed. March 26, killed. Wound well healed. On
exposing the left sciatic a long spindle-shaped enlargement is found on
the distal end of the central sciatic stump, from which is seen to pass
a fine nerve
bundle, lost in the connective tissue a short distance distal to the
bulb. Central sciatic and bulb removed and fixed in
neutral formalin for Bielschowskv's silver staining method.
Microscopic
findings.-In longitudinal sections of the distal end of the central
stump amputation neuroma
evidenced structurally; branching of down-growing neuraxes, many ending
in terminal disks; neuraxes with irregular
serrated borders; neuraxes showing spiral arrangement are observed;
endoneural connective tissue proliferated.
EXPERIMENT
No. 47.- Rabbit No. 47; full grown; 35 days. March 6, 1918, left
sciatic
exposed; cut and
resected 2 cm. Wound closed. April 10, rabbit found dead in the
morning; severe neurotrophic changes of heel;
wound well healed. Nerve not exposed until about 18 hours after death.
Central sciatic stump found to end in distal
spindle-shaped bulb. Central sciatic and bulb removed and fixed in
neutral formalin. Sections stained in iron-hematoxylin and
picro-fuchsin.
Microscopic findings.- In a series of longitudinal sections
of the
distal end of the central sciatic stump,
neuraxes conning from the distal end of the bulbous enlargement can be
traced into the connective tissue distal, in
the form of small myelinated fibers, either singly or in small bundles.
These have a very irregular course in the
connective tissue and extend for a distance of about 3 mm. beyond the
end of the bulb. A distinct mass of
connective tissue, blending the internal and external popliteal bundles
and extending through the bulb region
centralward, is found to contain many small bundles of nerve fibers.
There is found a distinct increase in the
thickness of the connective tissue sheaths in the bulb region, and also
of the endoneural connective tissue.
EXPERIMENT
No. 48.- Rabbit No. 22a; full grown; 44 days. March 13, 1918, right
sciatic exposed; cut
and resected 1.5 cm. Wound closed. April 25, killed. Wound well healed.
On exposing the right sciatic its central
stump found to end in a long spindle-shaped bulb adhering to the
underlying muscle. Nerve and bulb removed and
fixed in ammoniated alcohol for pyridine-silver
staining. Very good differential silver staining attained.
Microscopic
findings.-In a removal of the distal end of this nerve there was
removed with it a portion of
underlying fascia and muscle; in the serial longitudinal sections these
tissues are included
in normal
relation. In
study of the series of sections it is found that down-growing neuraxes
have grown distally beyond the limits of the
bulbous enlargement, and after passing a tangled irregular course in
the connective tissue penetrate the underlying
fascia, and in smaller and larger bundles extend distally between
muscle fibers in quite regular longitudinal course
for a distance of at least 1 cm., the distal limits of the section.
Certain of these neuraxes are found to end abruptly in
terminal discs, these often showing branching, so that two or three
discs are found at the distal end of one neuraxis. Within the bulbous
enlargement marked increase in number of neuraxes is noted.
EXPERIMENT No. 49.- Rabbit
No. 10a; full
grown; 57 days. March 12, 1918, right sciatic exposed; cut
and resected 1.8 cm. Wound closed. May 8, killed. Rabbit much
emaciated; "fungus" ears. On exposing the right
sciatic its central stump is found to end in a distinct bulbous
enlargement, from the distal end of which several fine
nerve bundles, spreading out fan-shaped, can be traced for a short
distance on the fascia overlying the muscle. Nerve
and bulb removed and fixed in ammoniated alcohol for pyridine-silver
staining. Good differential silver staining
attained.
Microscopic
findings.-In a series of longitudinal sections neuroma structure is
evidenced by the great
increase in the number of down-growing neuraxes, and their irregular
crisscross course at the level of nerve section.
Numerous small bundles of neuraxes traced into the connective tissue
distal to the bulbous enlargement; these are
lost in the connective tissue.
EXPERIMENT
No. 50.- Rabbit No. 17a; nearly full grown; 71 days. March 12, 1918,
right sciatic exposed;
cut without lifting from bed; resected 1.5 cm. Wound closed. May
1136
22, rabbit found dead in the morning. On
exposing the right sciatic its central stump found to end in a distinct
bulbous enlargement, not adherent to the underlying fascia and muscle.
Nerve and bulb removed and fixed in
ammoniated alcohol for pyridine-silver staining. Only fair differential
silver staining attained.
Microscopic
findings.- In section, sufficient neuraxes staining found to
determine neuromastructure; few
neuraxes have grow in distally beyond the limits of the neuroma.
EXPERIMENT
No. 51.- Rabbit No. 60; full grown; 79 days. March 12, 1918, left
sciatic exposed; nerve cut
and resected 0.6 cm. Not resected. Wound closed. May 31, rabbit found
dead in the morning; severe neurotrophic
changes in left hind foot. On exposing the left sciatic, no distinct
bulbous end noted on distal end of central stump, in
place of bulb a long spindle-shaped enlargement from the distal end of
which several fine nerve bundles can be
traced to the central end of the distal sciatic stump, which end is
slightly enlarged. Sciatic removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good silver
differentiation attained.
Microscopic
findings.- In several series of longitudinal sections including the
central and distal resected
nerve ends and the intervening connective tissue, it can be observed
that when structurally considered there is
present a well-developed amputation neuroma. Many neuraxes spirals arc found, with evidence of
great
increase in
the number of neuraxes. In the region representing the central cut end
of the nerve, neuraxes in smaller and larger
bundles intertwine with bundles of fibrous tissue; certain of the
neuraxes bundles extend distally in the connective
tissue, and may be traced to the central end of the distal stump;
others can be traced to the underlying muscle,
between muscle fibers of which they course.
EXPERIMENT
No. 52.- Rabbit No. 34a; full grown; 84 days. March 13, 1918, right
sciatic exposed; cut
and resected 1.3 cm. Wound closed. June 6, killed. Severe neurotrophic
changes right foot. On exposing the right
sciatic, its distal end is found to end in a distinct, long,
spindle-shaped bull), from the distal end of which several
small nerve bundles can be traced to the central end of the distal
sciatic stump. The central bulb and these nerve
strands not adherent to the underlying muscle. No contraction of the
calf muscle observed on cutting nerve central
and then distal to place of sciatic resection. Sciatic removed and
fixed in ammoniated alcohol for pyridine-silver
staining. Silver differentiation good for the more centrally placed
series of sections; for more distal series,
incomplete.
Microscopic findings.- In longitudinal sections of the
central
bulb region amputation neuroma evidenced
structurally from the distal end of which many small bundles of
neuraxes can be traced into the connective tissue
intervening between the resected nerve ends. In cross sections of this
connective tissue area numerous small bundles
of neuraxes, cut in cross, oblique or, for a distance, in longitudinal
section, are found separated by connective tissue.
In longitudinal sections of the central end of the distal sciatic stump
the silver differentiation not wholly successful, sufficient neuraxes staining observed to warrant the conclusion
that
certain of the central neuraxes have reached the
distal sciatic stump through the connective tissue intervening
between the resected nerve ends.
EXPERIMENT No. 53.- Rabbit
No. 46; full grown;
85 clays. .March 6, 1918, left sciatic exposed; cut and
resected 2 cm. Wound closed. May 31, rabbit found dead in the morning;
slight neurotrophic changes in the left
foot. On exposing the left sciatic very distinct bulbous ends on both
the main branches noted; these bulbs taper
distalward into fine nerve strands which can be traced a short distance
beyond the nerve bulbs. Central sciatic and
bulbous enlargement fixed in ammoniated alcohol for pyridine-silver
staining. Good differential silver staining
attained.
Microscopic findings.- In a series of longitudinal sections
of the
central bulbous enlargement amputation
neuroma evidenced structurally; many spirals of neuraxes found,
numerous branching neuraxes and terminal end-discs noted. Relatively
few neuraxes can be traced into the connective tissue distal to the
bulb.
EXPERIMENT
No. 54.-Rabbit No. 15a; large; full grown; 87 days. March 13,
1918,right sciatic exposed;
cut and resected 1.5 cm. Wound closed. June 8, killed. Severe
neurotrophic changes of right foot. On exposing the
right sciatic distinct bulbous enlargement on distal end of central
sciatic stump found. A fine strand of nerve fibers
can he traced from the distal end of the central bulb to the central
end of the distal sciatic stump.
1137
Sciatic removed and fixed in ammoniated
alcohol for pyridine silver staining. Good silver differentiation
attained.
Microscopic
findings.- In sections a large amputation neuroma
evidenced
structurally; in this noted spirals
of neuraxes, end-discs, crisscrossing of neuraxes, especially at its
distal end. Relatively few neuraxes can be traced
to the connective tissue distal to the neuroma. The distal sciatic
degenerated; no evidence of regeneration.
EXPERIMENT
No. 55.- Rabbit No. 35; full grown; 93 days. March 4, 1918, left
sciatic
exposed; cut and
resected 1 cm. Wound closed. June 5, rabbit found dead in the morning.
On exposing the left sciatic the distal end of
the central stump presents a well-formed, relatively large bulbous end.
Several fine nerve strands traced a distance
beyond the bulb; lost in the connective tissue. Sciatic removed and
fixed in ammoniated alcohol for pyridine-silver
staining. Unfortunately tissue lost; not sectioned.
EXPERIMENT
No. 56.- Rabbit No. 25a; half grown; 129 days. March 20, 1918, right
sciatic exposed; cut
and resected 1.2 cm. Ends of cut sciatic placed in alignment, and
muscles sutured over them. Wound closed. July
30, killed. Rabbit not in good condition. On exposing the right sciatic
the central stump is found to end in a long
spindle shaped bulbous end, the distal end of which reaches the central
end of the distal sciatic stump; the nerve
bundles uniting the resected nerve ends is adherent to the underlying
muscle. The distal sciatic stump presents a
spindle-shaped enlargement nearly as large as that found on the central
sciatic stump. Sciatic nerve removed and
fixed in ammoniated alcohol for pyridine-silver staining. Only partial
differential staining attained.
Microscopic findings.- In series of longitudinal sections,
well-developed amputation neuroma evidenced
structurally, from the distal end of which larger and smaller bundles
of neuraxes can be traced to and through the
connective tissue intervening between the resected nerve ends. In the
central end of the distal sciatic stump relatively
large numbers of neuraxes observed in such portions of the series of
sections in which the silver differentiation is
sufficiently good to determine them.
EXPERIMENT
No. 57.- Rabbit No. 13; full grown; 160 days. February 26, 1918, left
sciatic exposed; cut
and resected 1 cm. Wound closed. August 5, killed. Much emaciated; left
foot missing; healed over. On exposing
the left sciatic a distinct bulbous end on the distal end of the
central sciatic stump noted, from the distal end of which
fine nerve strands can be traced toward the central end of the distal
sciatic stump, but do not appear to reach it. Calf
muscles found atrophic. Central sciatic and bulb fixed in ammoniated
alcohol for pyridine-silver staining; distal
internal popliteal fixed in neutral formalin. Only fair differential
silver staining attained.
Microscopic
findings.- Well-developed amputation neuroma evidenced
structurally,
from the distal end of
which only a few neuraxes can be traced into the connective tissue
distal to the neuroma. The nerve fibers of the
distal internal popliteal found completely degenerated; relatively few
nuclei observed; neurolemma sheaths found
thickened and collapsed.
EXPERIMENT No. 58.- Rabbit No. 58;
full grown;
179 days. March 12, 1918, left; sciatic exposed and cut
high in thigh; the cut ends retracted so as to be separated 8 mm. Wound
closed. September 8, killed. Rabbit in fairly
good condition; somewhat emaciated; “fungus" ears. On exposing the left
sciatic there is observed a spindle-shaped
enlargement in the central sciatic stump, the distal end of which
continues to the central end of the distal, sciatic
stump, the intervening bundle being of nearly the same size as the
sciatic. The distal sciatic presents the appearance
of a normal nerve. The distal end of the central bulb, as also the
intervening nerve bundle, presents a light red color
as though more vascular than the remainder of the nerve. The sciatic and a segment of the
internal
popliteal and
posterior tibial fixed in neutral formalin. Sections stained in
iron-hematoxylin and picro-fuchsin.
Microscopic
findings.- In longitudinal sections of the central bulb it is seen
that numerous nerve fibers, both
myelinated and nonmyelinated, pass from the distal end of the bulb into
the connective tissue. Of these, those
coming from the more axial portion of the bulb have in the main a
longitudinal direction, while those which come
from the more peripheral portion of the bulb present a very irregular
course. In the central end of the distal stump
and
1138
at levels to the middle of the leg in
the
posterior tibial, in cross sections, numerous myelinated nerve fibers
are to be
seen.
EXPERIMENT
No. 59.- Rabbit No. 57; full grown; 180 days. March 12, 1918. left
sciatic exposed and cut
high in thigh; ends retracted so as to be separated 6 mm. Muscle,
stitched over cut nerve ends. Wound closed. September 9, rabbit found
dead in the morning; left foot missing; stump healed. On exposing the
sciatic a nerve
bundle of a diameter nearly as large as the sciatic extends from a
central sciatic bulb to the distal sciatic stump. The
distal sciatic presents the appearance of a normal nerve. Sciatic
removed and fixed in neutral formalin. Sections
stained in iron-hematoxylin and picro-fuchsin; safranine and
licht-grün.
Microscopic
findings.- In longitudinal sections of the central bulb region
numerous nerve fibers arranged
in small bundles can, be traced from the distal end of the central bulb
into the connective tissue distal to the bulb. In
cross sections of the nerve bundle intervening between the resected
nerve ends, it is observed that the nerve fibers
are arranged in numerous small funiculi, having no definite Perineural
sheaths and separated by intervening
connective tissue. In the distal sciatic stump, in both cross and
longitudinal sections, numerous myelinated fibers are
observed among fibers not yet regenerated.
EXPERIMENT No. 60.- Rabbit No. 51; full
grown-; 10 months. March 11, 1918, left sciatic exposed,
cut high in thigh; ends retracted 7 mm. Wound closed. January 9, 1919,
rabbit seemed normal 4 p. in.; found dead
9 p. m.; still warm. Toes of left foot found missing; healed. On
exposing the left sciatic, except for slight central
enlargement and loss of the funicular structure in the region of the
nerve section, sciatic nerve presented the
appearance of a normal nerve. Calf muscles and foot exteriors seemed
fully regenerated. Sciatic removed and fixed
in ammoniated alcohol for pyridine-silver staining. Faint but
differential silver staining attained.
Microscopic
findings.-In longitudinal sections of the bulbous enlargement on
the central sciatic stump the
neuroma structure evidenced by the crisscrossing of the neuraxes and
loss of the funicular structure of the nerve. In
cross sections of the tissue intervening between the resected nerve
ends, numerous small Funiculi of both myelinated
and non-myelinated nerve fibers, separated by bands of fibrous tissue
are observed. In a series of longitudinal
sections embracing the central end of the distal stump, both myelinated
and nonmyelinated nerve fibers, with regular
order of direction arc found in the connective tissue over the end of
the distal stump and can be traced into the distal
nerve in which they assume a definite longitudinal course.
EXPERIMENT No. 61.-Rabbit No. 53;
nearly full
grown; 11 mouths. March 11. 1911.left sciatic exposed
and cut; ends retracted 5 mm. Wound closed. January 17, 1918, rabbit
found dead in the morning; somewhat
emaciated. On exposing the left sciatic the nerve is observed to
present two spindle-shaped enlargements about 2
cm. apart, in the region of the nerve section. These are found united
by a nerve bundle of about the same size as the
sciatic. In the region of the two enlargements
and the
intervening bundle the nerve adherent to the underlying muscle. Calf
and extensor foot muscle seem regenerated; presenting normal size and
color. The animal was found dead too long
after death to make tissue of much value for special differential
neuraxes staining. Fixed in ammoniated alcohol for
pyridine-silver staining. Imperfect differentiation attained.
Microscopic
findings.-Sufficient silver differentiation of neuraxes obtained to
determine in several series of
longitudinal sections that both myelinated and nonmyelinated nerve;
coming from the central bulb, passing through
the intervening connective tissue, have reached the distal sciatic.
EXPERIMENT No. 62.-Rabbit No. 55; large; full
grown; 1 year. March 11, 1918, left sciatic exposed and
cut high in thigh, end retracted 8 mm. Very little bleeding. Muscle
stitched over nerve. Wound closed. March 11,
1919, killed. Active, in good condition: left foot missing; healed. On
exposing the left sciatic two slight, spindle-shaped swellings are
observed about 1 cm. apart, the distance bridged by a nerve bundle
nearly the size of the
sciatic; this in the region of nerve section. In this region nerve is
adherent to the underlying muscle. On exposing
calf and foot extensor muscles, these present a normal appearance
cutting nerve near sciatic notch, vigorous
contractions of calf and foot extensor muscles noted; the same on
cutting nerve in
the popliteal
space. Sciatic fixed in ammoniated alcohol
1139
for pyridine-silver staining; portions
of
calf muscles stained in gold chloride. Very good silver,
differentiation
attained.
Microscopic
findings.-In longitudinal sections of the central bulb numerous
myelinated and nonmyelinated
nerve fibers are seen to cross and recross in the distal end of the
central bulb and enter the connective tissue
intervening between the resected nerve ends. In cross sections of the
field a large number of small nerve funiculi,
without special fibrous sheaths but separated by bands of fibrous
tissue, can be observed. In longitudinal sections of
the distal end of the central sciatic small nerve bundles with very
sinuous course can be traced from the connective
tissue into the distal sciatic in which the neuraxes assume a regular
longitudinal course. Cross and longitudinal
sections of the distal sciatic at several levels present an appearance
which resembles closely that of a normal nerve.
Differentiation of nerve and endings in the muscle not successful.
EXPERIMENT No. 63.- Rabbit No. 56; full
grown; 1 year. March 11, 1918, left sciatic exposed; cut high in thigh;
cut ends retracted 8 mm. Very little bleeding.
Muscle stitched over nerve. Wound closed. March 11, 1919, killed.
Rabbit in good condition. On exposing the
sciatic the two resected ends found united, without appreciable
enlargement of the central or distal resected ends.
Calf and foot extensor muscles present normal appearance and contract
vigorously when nerve is cut central and
distal to the region of section. Sciatic removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good
differential silver staining attained.
Microscopic findings.-In series of cross and longitudinal
sections, including the field of operation and the
nerve distal, it can be observed that numerous neuraxes coming from the
distal end of the central bulbous
enlargement pass through the connective tissue intervening between the
resected nerve ends and enter the distal
sciatic, in which they are found in large numbers in all of the
funiculi. In cross section of the connective tissue found
between the resected nerve ends the neuraxes, both myelinated and
nonmyelinated, are found in the form, numerous
small nerve funiculi, separated by bands of connective tissue.
For
more than a century consideration has been given to the swellings which
form on the distal end of the
proximal stump of a completely or partially severed nerve and known as
neuroma or neuromata. The literature
dealing with the structure of neuroma is quite extensive and the
surgical literature dealing with the operative means
for the prevention of neuroma formation covers a period of many years.
The histologic description of neuroma,
presented by various writers, differs widely, especially for the period
preceding the introduction of specific neuraxis
stains. It is not thought necessary to review here at length this
extensive literature; certain of the more pertinent
references will be given incidental consideration.
The operations reported upon under Series No.
4 were made under strictly aseptic precautions and with as
little bleeding as possible, hemorrhage and suppuration having been
looked upon as important causative factors in
neuroma formation. The structural changes observed in the distal end of
the proximal stump of a divided nerve,
severed by means of a sharp instrument placed in an aseptic wound, are,
during the first few days after the operation,
precisely the structural changes observed in the distal end of the
proximal stump of a severed nerve, immediately
sutured under aseptic conditions. For a distance of from5 mm. to 1 cm.
from the cut surface, both myelinated and
nonmyelinated nerve fibers show degenerative changes accompanied by
proliferation of sheath cells, comparable in
every way to the degenerative changes noted in the peripheral stump.
The abortive regenerative changes, considered
in the general introduction, may also be observed. The connective
tissue of the nerve trunk early shows reaction to
the injury, evidenced by cell proliferation
1140
in the region of the cut
surface and exudate covering it, so that the cut end of the nerve is
early
covered by a connective tissue cap which becomes continuous with the
epineurium of the nerve
and less with the surrounding tissue. This connective tissue cap occurs
quite regularly in
neuromas. It is found organiz-
FIG. 218.- A longitudinal
section of a typical
neuroma removed from the sciatic of a dog 31 days after section;
pyridine-silver preparation. The relations of the epineurium and the
connective tissue cap found on the end of the
neuroma are clearly seen. Note the regular arrangement of the nerve
fibers and neuraxes in the upper half of the
figure and the crisscrossing and otherwise irregular arrangement of the
neuraxes as evident in the lower half of the
figure
ing when the central neuraxes show the
early
evidences of regeneration and downgrowth. These evidences of
regeneration, as concerns the neuraxes, are best seen and studied in
silver preparations, and consist of end and side
branches of neuraxes often found terminating in end- discs, very much
as observed in regeneration of a severed
nerve and subsequent suture. There is distinct
1141
FIG. 219.- Longitudinal
section of an atypical
neuroma from the sciatic of a dog, 18 days after section:
pyridine-silver preparation. The general structure of the neuroma is
clearly evident. The atypical form was due to pressure
consequent to scar tissue formation
1142
evidence of sheath cell
proliferation, but their relation to the budding and growing neuraxes
is
not quite clear in silver preparations nor can they be definitely
differentiated from the
proliferating connective tissue cells. During the second week after
resection of the nerve,
neuraxis budding and down-growth is clearly demonstrable. The
down-growing neuraxes
approach the region of neuroma formation with fairly regular and
approximately parallel course;
as they approach the region of the fibrous cap, single neuraxes or
small bundles of such begin to
intertwine; many are deflected from their course, even to the extent of
turning centralward, and
many terminal end-discs are observed. There is fairly distinct
interlacement of organizing
connective tissue bundles. Very characteristic of the earlier stages of
neuroma formation are
peculiar spiral complexes, first described by Perroncito, and formed of
a single relatively large
neuraxis or several neuraxes in axial position, about which are wound
in spiral form a variable
number of neuraxes and their branches, many ending in end-discs and all
found within a
neurolemma sheath. These Perroncito spirals may be scattered singly
here and there or be found
in larger or smaller groups. As such a spiral grows in diameter it
would seem that the old
neurolemma sheath disappears so that the spirals come to lie in the
endoneural connective tissue.
The connective tissue of a neuroma is deserving of consideration. It is
composed of loosely
woven, wavy, connective tissue bundles, is quite cellular and
differentiates quite slowly into a
compact tissue. One gains the impression that the growing neuraxes, as
they reach the region of
the connective tissue cap and the sides of the growing neuroma, for
sometime stimulate
connective tissue to growth. The formation of the central budding and
growing neuraxes and the
connective tissue of the neuroma progress simultaneously and there
develops an intergrowth of
connective tissue and neuraxes which characterize the terminal part of
the neuroma. A neuroma
is to be regarded as a thwarted attempt at regeneration of the nerve,
the down-growing neuraxes
being blocked by scar tissue. In many instances a well developed
neuroma has formed in a
strictly aseptic wound by the end of the third or the beginning of the
fourth week after operation.
As time progresses, in many instances, neuraxes singly or in small
bundles, penetrate the cap
over the end of the neuroma and penetrate the surrounding connective
tissue, pass into
intermuscular septa and may penetrate adjacent muscle and course
between muscle fibers. In
course of time, the down-growing neuraxes may reach the central end of
the distal stump and
bring about at least partial neurotization of the distal segment. The
importance of the
participation of growing and budding central neuraxes in neuroma
formation, is clearly seen in
pyridine-silver preparations of suitable stages. Cone 34 has
stressed the fact that three-fourths of
each painful bulb consists of nerve fibers and we are led to think that
their proliferation against
resistance is a cause of pain. All neuroma in the earlier stages of
development consist, to a large
extent, of nerve fibers or of neuraxes and in all neuromata there is to
be noted proliferation of
neuraxes against resistance. This fact led us to feel that any measure
employed with a view of
preventing neuroma formation, in order to attain success, must be
directed primarily toward the
neuraxes and not the connective tissue of the severed nerve end. Huber
and Lewis 33 tested
experimentally
1143
several methods
recommended in clinical surgery and directed more particularly toward
the
connective tissue at the end of the severed nerve, such as "swing door
operation" and “crush and
tie," and under most favorable conditions of asepsis, neuroma formation
was accentuated rather
than obviated. In the experiments in which absolute alcohol was
injected in the nerve, the
procedure was directed toward the neuraxes and it was hoped distinct
delay in neuraxis downgrowth would be attained. It may be stated that
the escape of a few drops of alcohol, an
accomplishment more likely to occur while injecting a nerve the size of
that of the sciatic of
rabbit, than the larger nerves of the extremities of man, is not to be
regarded as of serious
consequence, since the records show that the escape of absolute alcohol
into the wound was not
followed
FIG. 220.- Spiral formations
of Neuraxis from
neuroma shown in Figure 219. The figure presents a number of end-discs,
certain of which are the terminations of neuraxes participating in the
spiral structures
by excessive scar tissue
formation. One can not agree, therefore, with Corner 65 who
states that "injection of alcohol,
quinine, and urea should not be used, as about three or four fifths of
an
injection flows out of a nerve into the surrounding tissue, causing
later large formation of scar
tissue round the nerve and subsequent strangulation."
The
procedure employed in the experiments listed under Series No. 3 was to
inject the
central stump of a resected nerve approximately 1.5 cm. from the cut
surface with absolute
alcohol, through a hypodermic needle, inserting the needle very
obliquely and centralward.
Enough alcohol was slowly injected to give the nerve in the region of
the injection and for a
distance of approximately 2 cm. a milk white appearance or the
appearance of cooked white of egg. If alcohol escaped into the wound,
this was taken up with sterile cotton
1144
and the wound closed. At
the end of stated periods the operated nerves were removed and
studied macroscopically and microscopically as detailed in the
protocols of the several
experiments of Series No. 3.
SUMMARY
From
a study of the protocols of the series it may be noted that as a
consequence of
alcohol injection there ensues a fragmentation of the neuraxes and a
granular breaking down of
the myelin sheaths, and a destruction of the sheath cells in the region
of the alcohol injection
while the fibrous tissue sheath and the endoneural connective tissue
are not affected to the extent
of losing their fibrillar structure. These changes affect a region of
approximately 2 cm. in the
nerves experimented with, namely, the sciatic of rabbits. There is then
in the distal portion of the
proximal stump thus treated no neuraxis regeneration nor fibrous tissue
proliferation of the tissue
under consideration. By the end of the third week and the beginning of
the fourth week, the fragments of the old neuraxes have disappeared as
also much of the myelin detritus. The old
neurolemma sheaths seem to persist, and large vesicular cells, many
with relatively small nuclei,
and having lipoid granules and globules in their protoplasm, the
histogenesis of which it is
difficult to determine in the pyridine-silver preparations, make their
appearance. They are wholly
unlike the hypertrophied sheath cells of degenerating nerves. A
resected nerve without alcohol
injection, or with "swing door" or "crush and tie" operation after
resection, shows by the end of
the first month after operation a well-developed neuroma. Beginning
with the fifth or sixth week
after operation, a down-growth of central neuraxes into the region
affected by the alcohol begins
to be noted. The down-growing neuraxes, as observed in pyridine-silver
preparations, in
longitudinal section present a fairly regular course in the main
parallel to the long axis of the
nerve. They appear to course, in part at least, within old neurolemma
sheath remains (or sheath
of Henle) and gradually reach the distal end of the proximal stump by
the end of the second or
the middle of the third month after operation. The down-growing
neuraxes are accompanied by
sheath cells, it is thought derived from central sheath cells. Even in
nerve ends seen four to five
months after resection and injection of alcohol there is no evidence of
neuroma formation,
although central neuraxes. both myelinated and nonmyelinated, have
passed through the injected
portion of the nerve to the extreme distal end of the proximal segment.
The connective tissue
sheaths of this region are distinctly thickened and the endoneural
tissue increased so that the
nerve fibers found in the distal end are seen in small interlacing and
intertwining bundles,
separated by connective tissue. In none of the nerves studied in this
series was there any distinct
evidence of neuromas formation except in cases in which alcohol
injection was not successful. As a result of observations on
experiments of Series No. 3 and No. 4.evidence at hand warrants
the statement that a neuroma indicates an attempt at nerve regeneration
which is thwarted by the
formation of scar tissue found at the end of the neuroma; that they
form in aseptic wounds and
their formation is in no sense dependent on the presence of blood clot
or infection resulting in
suppuration. We believe ourselves to have demonstrated that absolute
1145
alcohol injected into
the nerve, 2 cm. to 2.5 cm. from its cut surface in several point
injections
arranged so as to involve all parts of the nerve trunk, is a procedure
which is successful in
preventing neuroma formation.
NERVE TRANSPLANTS
The
great majority of the experimental observations listed in the following
series deal
with cases in which, owing to loss of nerve substance at the time of
injury, the severed nerve
ends were separated to such extents that they could not be brought
together for suture. The
question of bridging defects in nerve resulting from loss of substance
at the time of injury is one
that has received consideration for a time nearly coincident with that
of the use of suture in uniting severed nerves. It is not proposed to
enter on a general discussion of the methods used or
suggested for the purpose of bridging nerve defects nor to consider
critically the extensive
literature bearing on this question; incidentally, certain pertinent
references will be considered.
Certain of the methods suggested as of service in bridging nerve
defects which have received
general recognition, such as suture a distance, tubular suture, nerve
implantation and nerve flaps,
were tested experimentally by Huber 30 several decades ago
and discarded as not justified on
experimental grounds. A few of these methods, such as the operation of
nerve flap made from
the central or distal stump, or from both stumps are still in use by
surgeons. A critical review of
all of the cases in which the operation of nerve flap was used to
bridge a nerve defect was made
by Stookey 50, who found that in
not a single case was there conclusive evidence of
regeneration. There has been a revival of the operation of nerve
implantation, in case of loss of
nerve substance in peripheral nerves, as a result of the advocacy of
this method by Hofmeister 51,
but there is no warrant for this method if properly done. It is only
when nerve fibers are cut in
the sound nerve at the seat of implantation, in which case the
operation becomes one of nerve
crossing, that there is any justification for attempting the method.
Consideration is given to
tubular suture in Series No. 20.
The
use of a segment of nerve to bridge a defect due to loss of substance
in a nerve has
long been advocated, by both the experimenter and the clinician. This
procedure was first tried
experimentally by Philipeaux and Vulpian 66 and was first
used by Albert 67 in human surgery. A
segment of nerve used to bridge a defect in a peripheral nerve, taken
from another nerve from
the same individual, is designated an autogenous transplant or graft-an
auto-nerve trans-plant; a
segment of nerve taken from another individual but of the same species
is known as a
homogenous transplant or graft-a homo-nerve transplant; a nerve segment
taken from another
individual but of a different species is called a heterogenous
transplant or graft-a hetero-nerve
transplant. Having in mind the practical application in human surgery,
various types of nerve
transplants were tested experimentally, such as normal or degenerated
nerves; fresh and preserved or stored in aseptic state; as single
nerves or a bundle of nerves, the latter known as
"cable-nerve transplant" or "multi-nerve transplant"; and wrapped or
unwrapped in protecting
membrane or sheath. These series constitute a very comprehensive
experimental study of the
question of nerve transplant.
1146
SERIES NO. 5
AUTO-NERVE TRANSPLANTS, INCLUDING
CABLE-AUTO-NERVE TRANSPLANTS
General
surgical experience regarding the question of tissue graft or
transplants, and the
favor with which autogenous tissue grafts arc regarded, made it
imperative that auto-nerve
transplants be given special consideration, even though it was
recognized that in using an
autogenous nerve transplant a normal functioning nerve was of necessity
resected to the extent
necessary to bridge the existing defect, with consequent loss of
function in the nerve resected
throughout its entire field of distribution. Consideration should be
given the fact that a nerve
transplant should have a cross-section area approximately that of the
nerve to be repaired, in
order to admit of ready downgrowth of central neuraxes. The mere
question of determining the
relative value of an auto-nerve transplant as over against other types
of nerve transplants did not
appear to have sufficient value, since it could hardly be regarded as
good surgery to resect one
major nerve of an extremity to repair another even though an auto-nerve
transplant should on
experimentation prove to have special merit. In our endeavor to make
auto-nerve transplants of
practical use in surgery, the operation here known as cable-auto-nerve
transplant was developed
and tested experimentally. This operation consists in using several
segments of a nerve which
could be resected without serious inconvenience as a result of loss of
function. Certain cutaneous
nerves were selected for this purpose and a sufficient number of
segments placed side by side so
that their combined cross-section area approximated that of the nerve
to be repaired. These
operations were made with great care, especially those in which cable
transplants were made. It
is so essential to obtain good end-to-end approximation in nerve suture
and it was our special
endeavor to obtain this. In valuating these and other experiments in
the light of possible
application to human surgery. it is recognized that a direct transfer
of results is not permissible.
The aseptic wounds in normal tissue and the nerve resected by means of
sharp instruments
present a condition not found in a severed nerve torn or crushed by
high explosive or otherwise,
perhaps wound infected, and perhaps not seen until months after injury
with abundant formation
of scar tissue. It was felt, however, that certain general deductions
could be made and certain
general principles formulated. In suturing the nerve transplants very
fine silk threads, waxed
with sterile wax, were used. It is essential and necessary to have good
approximation of the cut
surface. This is more readily attained with waxed silk sutures passed
through the nerve transplant
and the resected ends of the nerve than when catgut is used. Stookey 68 and Elsberg 69 have
described special technical methods, recommended for use in
cable-auto-nerve transplants in
human surgery. This operation is not an easy one and is very time
consuming. It generally
necessitates the making of a second wound, which even though it is
quite superficial, is of
necessity of some length. It is suggested that for purpose of
cable-auto-nerve transplant the
internal saphenous nerve, the anterior femoral cutaneous, and the sural
nerve from the lower
extremity and the cutaneous branch of the musculocutaneous (lateral
antibrachial cutaneous)
1147
and dorsal antibrachial
cutaneous from the upper extremity are, of the larger cutaneous nerves,
available.
The
protocols of experiments under Series No. 5, auto-nerve transplants and
cable-auto-nerve transplants follow:
PROTOCOLS
EXPERIMENT
NO. 64.- Dog No. 6; large; full grown; somewhat emaciated; 119 days.
April 11, 1918, left
sciatic exposed for a distance of 6 cm. Incision made through skin and
muscle; free bleeding. Superficial radial of
right forearm exposed and freed of connective tissue. Using No. 60
linen thread and fine, straight, round needles,
two sutures passed through nerve about 3 cm. apart. Radial cut with
scissors 2 mm. proximal and distal to suture
lines and nerve segment transferred to sciatic wound. One needle and
suture passed through sciatic centrally and
sciatic cut 2 mm. distal to suture line; central suture tied. Distal
suture passed through sciatic and the nerve cut 2
mm. proximal; distal suture tied. Only fair central and distal
approximation of nerve ends attained. Radial segment
has much smaller diameter than the sciatic nerve. Wounds closed. August
8, killed. Dog much emaciated, has not
been well for several days. Left hind foot, small neurotrophic ulcer of
heel; does not stand on ball of foot. Sear
tissue found in line of sciatic wound; extends to deeper tissues. Left
sciatic found surrounded by dense fibrous tissue.
On dissecting free, a large central bulb noted. A small nerve bundle
can be traced from this to distal sciatic stump.
Distal sciatic presents the appearance of a partially regenerated
nerve. Calf muscles exposed and sciatic and the
transplant freed from the bed. On slowly cutting with scissors, sciatic
central to the transplant, distinct twitching of
calf muscles noted; same when sciatic is cut distal to the transplant.
Sciatic and transplant and internal and external
popliteal branches removed and fixed in ammoniated alcohol for
pyridine-silver staining. After silver staining this
material was by accident overheated in oven; section series
unsatisfactory.
Microscopic findings.-In very broken and irregular sections,
sufficient evidence of down-growth of
neuraxes from the central bulb to warrant the conclusion that neuraxes
coming from the central bulbous enlargement
had grown through and outside of transplant to the distal sciatic
stump. Details could not be determined.
EXPERIMENT
NO. 65.-Dog No. 7; large; full grown; well fed; 120 days. April 12,
1918, left superficial
radial exposed and freed from connective tissue. Two silk sutures
passed 2.8 cm. apart and nerve cut central and
distal to sutured lines with sharp razor blade. Right sciatic exposed
and freed. Sciatic resected distal and proximal
to suture line and sutures tied. Good approximation of nerve ends
attained. Wound not quite dry; wounds closed.
August 10, killed. Dog emaciated, but seems in good condition. Walks
well; uses right hind foot quite normally;
standing on ball of foot. On exposing the right sciatic a relatively
large bulbous enlargement is found on the distal
end of the central sciatic stump. A small bundle of nerves leads from
this to the distal stump, the central end of
which is not materially enlarged. Central sciatic bulb and the
transplant not especially adherent to underlying
muscle. Calf muscles exposed. After completely freeing the sciatic from
notch to popliteal space, on slowly cutting
the nerve central to the transplant distinct twitching and contraction
of the calf muscles noted. Sciatic and transplant,
external and internal popliteal and pieces of calf muscles and extensor
leg muscles removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
silver staining attained.
Microscopic findinqs.-Large oval, central bulb evidenced
structurally, from the distal end of which
numerous down-growing neuraxes can be traced to the central end of the
transplant and also into the connective
tissue surrounding the central wound. In cross sections of the
transplant its funicular structure is found retained, with
the fibrous sheath thickened. Numerous neuraxis found in each of the
funiculi of the transplant, also in small bundles
in the connective tissue surrounding the transplant. In successive
cross and longitudinal series of sections, these
neuraxes can be traced to and through the distal wound into the distal
sciatic branches; in the internal popliteal
nearly to the level of the heel; in the external popliteal to the
region of the head of the fibula. In sections of the calf
muscles new neuraxes are found
1148
in the larger and smaller muscular
branches,
and as single nerve fibers, between and on the muscle fibers. Here and
there quite well developed motor nerve endings were noted.
EXPERIMENT
No. 66.- Dog No. 3; small dog; full grown; 132 days. March 8, 1918,
left
sciatic cut, high
up; wound closed. March 27, left sciatic exposed, nineteen days after
section. Difficult to find central stump; much
bleeding; muscles somewhat torn. Ends of cut sciatic stumps resected.
Right ulnar exposed and a segment
transplanted to the resected sciatic. Ulnar segment somewhat short;
central suture gave way; difficult to suture again.
One central and distal catgut suture used. Not good approximation
attained; transplant ultimately 1.5 cm. in length.
Wounds closed. August 6, killed. Dog in good condition; not materially
emaciated. Uses left hind leg well; now and
then steps on dorsun of foot; small ulcer on dorsum of foot. On
exposing left sciatic large bulbous enlargement is
found on central sciatic stump; from this a small bundle of nerves
leads to distal sciatic stump. Distal sciatic,
especially internal popliteal branch presents the appearance of a regenerated nerve. Central bulb and
region
of
transplant surrounded by quite dense fibrous tissue; adherent to
underlying muscle. After exposing calf muscles and
freeing the sciatic from bed on slowly cutting sciatic central to
transplant, feeble twitching of calf muscles noted.
Muscle not fully recovered, pale red color, streaked with yellow white.
Sciatic nerve and transplant, internal
popliteal and portions of calf muscles
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Fair
differential silver staining attained.
Microscopic findings.-From the distal end of a long
spindle-shaped bulbous enlargement, down-growing
neuraxes may be traced through a long fibrous union, extending several
millimeters, to the central end of the
transplant. In cross sections of the transplant, about 1 cm. distal to
the central wound, the funicular structure of the
ulnar can only be partially made out; there is observed material
increase of its fibrous sheaths. New neuraxes are
observed within the funiculi of the transplant and also in the
surrounding connective tissue, especially to one side.
These new neuraxes can be traced in sections, to the distal wound and
through it to the distal internal popliteal, the
external popliteal not having been united to the transplant at the
distal wound. In sections of the calf muscles, new
neuraxes are noted in the muscular branches entering the several calf
muscles, and in many of the inter- fascicular
nerve branches.
EXPERIMENT
No. 67.- Dog No. 8; large dog; full grown; 282 days. August 12,
1918,the
left superficial
radial exposed and freed from connective tissue. The right sciatic
exposed by cutting through muscle; good direction
of incision; free bleeding. Sutures passed through radial branch, 3 cm.
apart before cutting the same, and
transplanted to the resected right sciatic; good approximation
attained. Muscle stitched over sciatic and transplant
and the wounds closed. May 21, 1919, killed. Dog in good condition.
Uses right foot well, though has slight limp in
walking. On exposing right sciatic this is found embedded in loose
connective tissue, interspersed with small fat
globules. Large central bulbous enlargement noted, which extends in a
fine nerve strand to the distal sciatic. In the
region of the transplant diameter not quite half that of the sciatic.
Calf and plantar muscles exposed. After freeing
sciatic and the transplant from the bed, on slowly cutting the nerve with
scissors,
central to the transplant, distinct
contraction of the calf and interossei muscles observed. On cutting the
internal popliteal distal to the transplant the
same observation noted. Sciatic transplant and the internal popliteal
and several interossei muscles removed and
fixed in ammoniated alcohol for pyridine-silver staining. Good
differential silver staining attained.
Microscopic
findings.- Long spindle-shaped central bulb evidenced
structurally, from the distal end of
which numerous neuraxes pass into the transplant and into the
connective tissue surrounding it. In cross sections
taken about 1.5 cm. distal to the central wound, it may be observed
that the funicular structure of the transplant is
still retained, surrounded by a distinct though not dense layer of
fibrous tissue. Numerous new neuraxes are found
within the surrounding connective tissue. In sections these new
neuraxes may be traced to and through the distal
wound into the distal popliteals. In the posterior tibial, both
myelinated and nonmyelinated fibers may be traced to
the level of the heel. In sections of several interossei muscles new
neuraxes are to be observed in the muscular
branches and here an there motor end organs are noted. Regeneration of
distal popliteal to foot muscles, through the
transplant.
1149
EXPERIMENT NO. 68.- Dog No. 2; medium
size;
full grown; 439 days. March 7, 1918, left sciatic exposed
and cut high in thigh. March 26, 19 days later, severe neurotrophic
changes left foot; foot in part missing. Left sciatic
exposed; large central bulb note. Central and distal sciatic stump
resected. A segment of the right ulna of 2 cm.
length transplanted. One central and distal No. 000 catgut suture used.
Distal external popliteal resected for another
operation; transplant sutured distally only to internal popliteal
branch. Wounds closed. June 12, left foot completely
healed; dog in good condition. May 20,1919, killed. Dog in good
condition; very active. Left foot to metacarpals
missing. On exposing left sciatic this is found surrounded by loose
connective tissue. Large bulb on central sciatic
stump; this continuous distally with a nerve bundle about the size of
ulnar traced to distal internal popliteal; external
popliteal attached loosely to internal popliteal; no organic union.
Calf muscle fully exposed; these have the
appearance of normal muscle tissue. After completely freeing the
sciatic from its bed, on slowly cutting the nerve
with scissors central to the transplant, distinct contraction of the
calf muscles observed. Sciatic and transplant
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Fairly good silver differentiation attained.
Microscopic findings.-Very large bulbous
enlargement on central
sciatic stump evidenced structurally,
from the distal end of which numerous new neuraxes can be traced
distally through a wide, central, fibrous wound,
into the transplant and into the connective tissue surrounding the
same. In cross sections of the transplant, about 1
cm. distal to the central wound, one large funiculus of the
transplanted nerve segment clearly outlined by perineural
sheath. Within this numerous myelinated and nonmyelinated nerve fibers,
separated into small bundles by
endoneural connective tissue, are observed. In the connective tissue
surrounding the transplant numerous small
bundles of nerves are found. These neuraxes can be traced
through the
distal wound
into the distal
internal popliteal,
in which they are present in all of its funiculi, both as myelinated
and nonmyelinated nerve fibers. Regeneration to
lower level of popliteal space (the extent of nerve removed).
EXPERIMENT
No. 69.-Dog No. 1; medium size; full grown; 81 days. May 16, 1918,
right sciatic exposed
and freed. Left ulnar exposed. Two segments of the left ulnar of
approximately 3 cm. length transplanted to the
resected right sciatic. Each ulnar segment sutured centrally and
distally, separately to resected sciatic ends. Waxed,
fine, silk thread sutures used; good approximation of the nerve ends
attained. Wounds closed. August 5, killed. Dog
in good condition; slight foot-drop right hind leg; very little
neurotrophic change right hind foot. On exposing the
right sciatic, transplants found well in place; no distinct central
bulb. Transplant surrounded by loose connective
tissue, not adherent to underlying muscle. Calf muscles exposed. After freeing transplant from
bed on
slowly
cutting nerve central to the transplant, no contraction of calf muscles
observed. Sciatic removed and fixed in
ammoniated alcohol for pyridine-silver staining. Silver differentiation
only partially successful.
Microscopic
findings.-In longitudinal sections through the central wound a
central bulbous enlargement is
clearly made out structurally, from the distal end of which numerous
neuraxes traced into the transplant. In cross
sections of the transplant the two ulnar segments clearly made out,
each retaining its funicular structure. The two
nerves are found surrounded by a common fibrous tissue sheath. Within
the transplants new neuraxes found about
equally distributed. The down-growing neuraxes can be traced into the
distal wound and through this into the distal
sciatic in which they may be traced in lessening numbers, approximately
3 cm. distal to the distal wound.
EXPERIMENT
No. 70.-Dog No. 4; large dog; full grown; 152 days. March 8,1918, left
sciatic exposed and
cut high in thigh. Wound closed. April 15, slight neurotrophic changes
left heel; left sciatic again exposed, 38 days
after section. Large neuroma on central sciatic sump; central end of
distal sciatic only slightly enlarged. Central bulb
removed and distal sciatic stump resected
5 mm. Two superficial radial branches, having parallel course, exposed
and freed from connective tissue, brought together and clamped with
artery forceps. Two No. 110 silk thread sutures
formed 4 cm. apart and nerve cut with safety razor blade 2 mm. beyond
sutures. The two nerve segments transferred
to sciatic wound and sutured to resected sciatic ends; good
approximation attained. Diameter of the two radial
branches
1150
not as great as the resected sciatic.
Muscle
stitched over nerve and transplant and wounds closed. April 23,
superficial sciatic wound open to the extent 2.5 cm.; deeper wound
seemed healed; no infection. August 7, killed. Dog very much
emanciated; has not been feeding well for several days; left foot in
part missing; nearly healed. Had
had very severe neurotroplic changes of the foot. On exposing the left
sciatic, contiguous muscles found to have
yellow red color and much reduced in size. Large central sciatic bulb
noted .A small nerve bundle extends from
this to the distal sciatic stump. No material increase of fibrous
tissue about the nerve. Calf muscles exposed; these
appear very atrophic and not of normal color. After freeing nerve and
slowly cutting the same central to the
transplant no distinct contractions of calf muscles noted. Sciatic and
transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. In part good silver
differentiation attained; not uniformly stained.
Microscopic findings.-Large central bulbous enlargement
evidenced
structurally, from the distal end of
which numerous neuraxes can be traced to the central ends of the
transplanted nerve segments and the connective
tissue surrounding the same. In cross sections of the transplant, about
1.5 cm. distal to the central Wound, both of the
transplanted nerve segments clearly made out, with the funicular
structure retained. The transplanted nerve
segments surrounded by a common, fairly dense, fibrous sheath, which
extends between the nerves. Within the
funilculi of the transplant many new neuraxes observed; there appear to
be more of these in one nerve than in the
other, though this can not be definitely determined since the silver
differentiation is not uniform. In the connective
tissue surrounding the transplant many small bundles of nerve fibers
encountered; this mainly to one side. New
neuraxes in large numbers may be traced to and through the distal wound
into the distal popliteal stump, for a
distance of about 4 cm., the extent of the nerve removed for sections.
EXPERIMENT No. 71.-Dog No. 15; large, black
bound; full grown; 376 days. May 8, 1918, superficial
radial exposed and freed from connective tissue cut to segments about 4
cm. length, placed side by side and
clamped at each end with artery forceps. Thus suspended, two fine, silk
sutures passed through the two nerve
segments 2.2 cm. apart, cut beyond suture lines and transplanted to the
resected left sciatic, in suturing only the
internal popliteal bundle used, external popliteal disregarded. Fairly
good approximation of nerve end attained. Wounds closed. May 20, 1919,
killed. Dog in very good condition; still favors the left hind foot; no
distinct foot or
toe drop note. Shape and size of bulb in part due to large bulbous end
on external popliteal.
From the
distal end of
the bulb there may be traced a nerve bundle to the internal popliteal.
Calf muscles and foot muscles exposed. After
freeing sciatic and the transplant from the bed, on slowly cutting with
scissors central to the transplant, good
contraction of calf muscles noted; foot muscles contraction feeble and
uncertain. External popliteal cut, but not
included in the sutures, is distally found closely united to internal
popliteal. Cutting of external popliteal near head of
fibula calls forth good contraction of leg flexors. Sciatic and
transplant and two interossei muscles removed an fixed
in ammoniated alcohol for pyridine-silver staining Good differential
silver staining attained.
Microscopic findings.-Very large bulbous end on central
sciatic
evidenced structurally. In longitudinal
sections of this bulb, the unabsorbed central suture observed.
Down-growing neuraxes, crisscrossing in every
direction, reach the distal part of the bulb and can be traced to
central ends of the transplants and the surrounding
connective tissue. In cross sections of the transplant at two levels,
near central and distal wounds, only one nerve
bundle is clearly demarked. Whether there exists an error of record and
only one nerve bundle was transplanted and
not two as recorded, or whether one of the bundles pulled free
centrally and disappeared, can not now1 be
determined. The single nerve present is surrounded by a dense, felted
layer of fibrous tissue. Within its funiculi
numerous, both myelinated and nonmyelinated, neuraxes found; largely
arranged in small bundles separated by
endoneural connective tissue. In the connective tissue surrounding the
transplant in centrally and distally placed
cross sections, many small bundles of nerve fibers found. Neuraxes
found within and without the transplant may be
traced through the distal wound to the distal popliteal, in which in
successive levels they are observed in cross and
longitudinal sections to the level of the heel. In sections of
interossei muscles new neuraxes are observed in the small
interfascicular nerve branches and in one instance in a neuromuscular
spindle.
1151
Complete distal regeneration of the
internal
popliteal and branches, through the transplant, attained.
EXPERIMENT
No. 72.- Dog No. 14; relatively large dog; full grown; 91 days. May 2,
1918, left sciatic
exposed and freed. Two branches of the cutaneous radial exposed and
freed from connective tissue. Two segments
of the larger nerve of 2.5 cm. length transplanted to the resected
internal popliteal branch of sciatic; one central and
distal silk suture and one segment of the smaller nerve of 2.5 length
transplanted to the resected external popliteal;
one central and distal silk suture; good central and distal
approximation attained in all three segments of cutaneous
nerves used as transplants. Muscles stitched over nerve and transplant
and wounds closed. May 14, severe
neurotrophic changes left foot; possible infection of foot. Sciatic and
forearm wounds healed. August 2, found dead
in the morning; had not been eating well for several days; very much
emaciated; still neurotrophic changes of foot.
On exposing the left sciatic indistinct central bulb noted. Several
bundles of nerves lead from this to the distal
sciatic; can not determine definitely whether these nerve bundles are
within the transplanted nerve segments. Distal
sciatic does not present the appearance of normal nerve. Sciatic and
internal popliteal removed and fixed in
ammoniate alcohol for pyridine-silver staining. Silver differentiation only
partially successful.
Microscopic
findings.- In longitudinal sections of the central wound, scarcely
any evidence of central bulb
noted oil microscopic inspection, under the microscope crisscrossing of
central neuraxes as they pass to transplant is
noted. In cross sections of the transplant, the three transplanted
nerve segments quite clearly made out; found
surrounded by a common fibrous tissue sheath. Within the three
transplanted nerve segments the funicular
arrangement quite clearly retained. In each of these funiculi are found
new neuraxes, quite evenly distributed. Very
few neuraxes found in the connective tissue outside of the funiculi.
The new neuraxes may be traced into the distal
stump in which they are found in good numbers 3 mi. beyond the distal
wound, the extent of the nerve sectioned.
EXPERIMENT No. 73.- Dog. No. 9; large; full
grown; 323 days. June 29, 1918, right sciatic exposed and
freed from bed. Two branches of the left cutaneous radial exposed and
freed from connective tissue. Three segments
of these nerves having a length of 2 cm. each sutured separately
between the resected ends of the sciatic, using three
No. 00 catgut sutures softened for a short time in sterile distilled
-water. Only fair approximation of the nerve ends
attained. Dry field obtained by use of adrenalin. Wounds closed. May
18, 1919, killed. Dog in good condition;
walks well; severe skin disease; nails on two inner toes long and
curved so as to form complete circle. On exposing
the right sciatic no material increase of connective tissue about the
nerve noted; quite large central bulb, with
1ransplant well in place. Calf muscles exposed; sciatic a transplant
freed the entire length. On slowly cutting with
scissors the nerve central to the transplant, good contraction of calf
and flexor leg muscles noted. Foot muscles
exposed, on cutting posterior tibial near heel, good contraction of the
plantar interossei muscles observed. Sciatic,
transplant, posterior tibial, pieces rf calf and interossei muscles
removed and fixed in an ammoniated alcohol for
pyridine-silver staining. Good silver differentiation attained.
Microscopic findings- In longitudinal
sections of central wound region a large central bulb evidenced
structurally from the distal end of which numerous neuraxes extend to
the central end of the transplant. in cross
section of the transplant at two levels, near central and distal
wounds, only two of the transplanted nerves made out,
both of these have retained their funicular structure. The fate of the
third nerve segment can only be conjectured; it
is thought that it pulled free centrally and completely degenerated.
Within the funiculi of the two nerve segments
present there are found numerous new neuraxes. In the more centrally,
placed cross sections numerous small nerve
bundles are found in the connective tissue surrounding the
transplant;
scarcely any of
the extra
funicular nerve
bundles are found in the cross sections of the lower level. New
neuraxes were traced in the distal internal popliteal,
the level of the heel, and in sections of the interossei muscles into
the smaller interfascicular muscular branches;
motor and sensory muscle nerve endings were observed in sections of the
interossei muscles. Complete peripheral
regeneration attained, so far as distribution of peripheral motor
branches is concerned.
1152
EXPERIMENT No. 74. Dog No. 12;
large; full
grown; 11 days. April 26, 1918, left sciatic exposed and freed. Two
superficial cutaneous radial branches exposed and freed from connective
tissue. Free venous oozing in the
wound; after freeing nerves they were bathed in partly clotted blood
for about fifteen minutes. Four segments were
made of the cutaneos radial branches, placed side by side, and clamped
together at the ends with artery forceps. A
single silk thread suture passed centrally and distally through the
four nerve segments 2.5
FIG. 221.-Cross
section through the middle of
a cable-auto-nerve transplant, Experiment No. 74, 11 days
after operation; pyridine-silver preparation. Note the new epineural
sheath, seemingly uniting the four separate nerve
segments into one compact nerve with many funiculi. The funicular
structure of each nerve segment is well
maintained
cm. apart, and the nerve segments were
cut
beyond the sutures and the sutures tied, the forming a complete bundle.
This bundle of nerve was transferred to sciatic wound and fixed between
the resected ends of the sciatic by suturing
the same to the underlying muscles. The resected nerve ends and the
bundle of four nerve segments were united by
one central and distal epineural suture. Only fair approximation of
nerve ends attained. Muscle stitched over nerve
and transplant. Wound closed. Oozing in radial wound not full
1153
controlled. Closed. May 7, killed.
Forearm
wound open; superficial sciatic wound open to the extent of 3 cm.; deep
wound healed. Left sciatic exposed; transplants found well in place;
surrounded by newly forming connective tissue.
A small amount of sanguineous exudate surrounds nerve and transplants.
Sciatic and the transplants removed and
fixed in ammoniated alcohol for pyridine-silver staining. Very good
differential silver staining attained.
Microscopic
findings.-In longitudinal sections of the central wound, taking in
I cm. each of central end of
transplant and distal end of proximal stump; early stages of the
downgrowth of central neuraxes very beautifully
shown; the ends of the down-growing central neuraxes have reached the
fibrous wound, which the more advanced
are in the act of penetrating. Many of the central neuraxes terminate
in relatively large end-discs, others show
division, others still early stages of spiral formation. As yet no new
neuraxes can be traced to the central end of the
transplant. In cross sections of the transplant the four
FIG. 222.- Cross section
through the middle of
a cable-auto-nerve transplant, Experiment No. 75, 26 days after the
operation; pyridine-silver preparation. The funicular structure of the
four segments of the nerve used is well
maintained. Newly formed epineural tissue has united the nerve segments
so as to form a single nerve trunk
segments of nerve transplanted can be
clearly
made out, with the funicular structure of each stained and perineural
sheaths not thickened. The four nerves surrounded by a com-mon
connective tissue layer, forming a new epineural
sheath common to the four nerves. In both cross and longitudinal
sections of the transplant the neuraxes of the
transplanted nerves appear fragmented into irregular segments, still
staining differentially in silver. Sheath nuclei
only here and there noted; not well stained in silver. Distal sciatic
in early stages of degeneration.
EXPERIMENT
No. 75.- Dog No. 10; large dog; full grown; 26 days. April 24, 1918,the
left sciatic exposed
and freed. Two cutaneous radial branches exposed and freed from
connective tissue. These nerves cut into four
segments of a little over 4 cm. length, placed side by side in two
groups and together clamped at the ends with artery
forceps. Two fine silk thread sutures passed 2 cm. apart in each group
of two nerves, and the nerves cut a little
beyond the suture. These segments of the cutaneous radial, with sutures
in place, were transferred to the sciatic
wound, and each pair sutured separately to resected ends of
1154
the sciatic. Good approximation of nerve
ends
attained. Muscle stitched over nerve and transplant; wound closed.
May 20, dog died during the afternoon; nerve removed about two hours
after death; left hind foot, severe
neurotrotphic changes, slightly infected; sciatic wound well healed;
forearm wound partly opened. On exposing the
left sciatic no evidence of infection is noted; transplant found well
in place and firmly united to resected nerve ends. Quite distinct
bulbous enlargement on central sciatic noted; central end of distal
stump not materially enlarged. The
four transplanted nerve segments surrounded by newly formed connective
tissue so as to form one bundle. Sciatic
and transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining. Very good silver differential
attained.
Microscopic
findings.-In longitudinal sections through the central wound and
about 1 cm. each of sciatic
and transplants, the central bulbous enlargement is seen to include the
central wound and central sutures. Numerous
neuraxes coming from the central sciatic can he traced through the
central wound, in which they are found to
crisscross in all directions
FIG. 223.- Longitudinal
section through the
central wound region, cable-auto-nerve transplant, Experiment No..75 20
days after operation; pyridine-silver preparation . The central end is
found directed toward the left. The actual
wound region found between the central and distal loops of the
respective sutures is clearly seen in the figure
tions, into the central ends of th
transplanted nerve segment. In cross section of the transplant, 1 cm.
distal to the
central wound, the four nerve segments transplanted can be clearly made
out, each retaining its funicular structure,
and are surrounded by a common fibrous tissue sheath serving as an
epineural sheath, the whole transplant
presenting the appearance of a relatively large nerve trunk with 10
larger and smaller funiculi; in about equal
distribution there are found large numbers of new neuraxes, many found
to be within old neurolemma sheaths, others
in the endoneural tissue between these sheaths. Very few neuraxes
observed in the connective tissue surrounding the
several transplanted nerve segments. In longitudinal sections of the
distal wound and adjacent nerve trunk it may be
observed that certain of the down-growing neuraxes have reached the distal wound
(transplant
only 2 cm. in length),
having thus nearly reached the central end of the distal sciatic. In
this series of sections there was obtained very
successful differential staining of neuraxes. Very often when this is
the case the cellular elements of the tissue are
not clearly stained; therefore this series of sections is not
satisfactory for determining the behavior of the sheath cells
of the transplanted nerve segments.
1155
FIG. 224.- From a
longitudinal section of the
central wound region in cable-auto-nerve transplant, Experiment No.
75, 26 days after operation; pyridine-silver preparation. The figure
illustrates clearly the course of the central
neuraxes in passing through the sear tissue of the central wound. The
funicular structure of the central stump is lost
as the down-growing neuraxes pass through the wound
1156
EXPERIMENT No. 76.- Dog No. 11; large
log;
full grown; 109 days. April 25, 1918 left sciatic exposed
and freed. The cutaneous radial branches exposed and freed from
connective tissue. Quite a little venous oozing in
the radial wound, so that the isolated cutaneous radial branches were
bathed in partly clotted blood for 15 to 20
minutes. The cutaneous radial branches cut into segments of about 4 cm.
lengths and placed side by side and
together clamped at each end with an artery forceps. Two fine silk
thread sutures passed 2.5 cm. apart, and nerves
cut 2 mm. beyond the sutures. The sutures were then tied loosely and
cut short, thus forming a compact nerve bundle
of 2.5 cm. length, consisting of four segments of cutaneous radial.
This bundle was transplanted to the resected
left sciatic, and sutured centrally and distally by means of two fine
silk thread epineural stitches. Fairly good
approximation of cut nerve ends attained. Muscle stitch
FIG. 225.- From a
cross section of a
cable-auto-nerve transplant, Experiment No. 75, 26 days after
operation;
pyridine- silver preparation. The figure presents a portion of one of
the larger funiculi of a transplanted nerve seen to
seen in Figure 222. The black dots represent cross sections of a single
neuraxis or small bundles of such which grew
through the central wound and into the neurolemma sheaths of the
transplanted nerves
over nerve and transplant and wound
closed.
Forearm wound open a long time; not well protected; in part dry;
bleeding not fully controlled. Wound closed. Both wounds healed well.
August 12, killed. Slight foot- and toe-drop
of left hind foot; walks quite well. On exposing the left sciatic no
material increase of connective tissue about nerve
and transplant is found. Quite distinct bulbous enlargement of the
central sciatic is noted; slightly adherent to
underlying muscle. From distal end of the central bulb several small
nerve bundles can be traced to the distal sciatic
stump, which presents the appearance of a regenerated nerve of nearly
normal size. On exposing the calf muscles,
these appear of nearly normal size and color and manifest quite
rhythmic twitching. After freeing sciatic and
transplant from bed, on slowly cutting sciatic with scissors, central
to the transplant, distinct contractions of the calf
muscles observed; the same on cutting distal to transplant. The sciatic
1157
FIG. 226.- From a
longitudinal section of the
central third of a cable-auto-nerve transplant, Experiment No. 75, 24
days after operation. The figure presents a portion of one of the
larger funiculi as seen in longitudinal section. Note
the regular course of down-growing neuraxes, indicating that they are
extending distally within the neurolemma
sheaths of the transplanted nerves. (Compare with fig. 224)
1158
and transplant, internal and external
popliteal and posterior tibial, portions of calf and leg flexor muscles
removed
and fixed in ammoniated alcohol for pyridine-silver staining. In part
very good differential silver staining attained.
Microscopic findings.- In
longitudinal
sections of the central wound and adjacent nerve ends, central bulbous
end is
seen to include central wound and sutures and an area of small cell
infiltration near one of the central sutures. Many
new neuraxes can be traced from the central sciatic through the central
wound into the central end of the transplant;
others in the form of small nerve funiculi, having very tortuous
course, are traced distally in the connective tissue
outside of the transplant. In cross sections of the transplant, made
about 1.5 cm. distal to the central wound, the four
transplanted nerve segments with their respective funiculi can be
clearly made out, and are found surrounded by a
common fibrous tissue sheath, consisting of quite densely felted
fibrous tissue. Numerous new neuraxes are found in
each of the funiculi of the several transplanted nerve segments, also
in the form of small nerve bundles in the
connective tissue surrounding the nerve transplants. Neuraxes in large
numbers can, in sections of successive levels,
be traced through the transplanted nerve segments and distal wound into
the distal sciatic stump. In cross sections of
the internal popliteal at the lower level of the popliteal space,
numerous new neuraxes are found in all of the several funiculi. In alternate cross and longitudinal
sections of the distal internal popliteal, posterior tibial, and
internal
plantar new neuraxes were observed, these becoming progressively less
numerous distalward, so that in the internal
plantar only a few scattered neuraxes were found in an otherwise
degenerated nerve. In sections of the calf muscles,
numerous new neuraxes are found in the larger and smaller intramuscular
nerve branches and as single nerve fibers
on and between muscle fibers; here and there motor nerve endings are to
be seen. Regeneration of the distal sciatic
through a cable autonerve transplant attained. Partial regeneration of
the distal nerve to the level of the internal
plantar.
EXPERIMENT
No. 77.- Dog No. 5; medium size; full grown; 152 days. March 8,1918,
left sciatic exposed
and cut quite high in thigh; nerve ends retracted 8 mm. Wound closed.
April 16, left sciatic exposed, 39 days after
section. Dog in good condition; only slight limp noted. Large bulb
found on the central sciatic stump, from which
extends a fine nerve thread, which appears to reach the distal sciatic
stump, which presents slight central
enlargement; central and distal
sciatic stumps resected; end 3 cm. apart. Two branches of the cutaneous
radial
exposed and freed of connective tissue, and cut in segments about 4.5
cm. long; placed side by side and clamped at
each end with an artery forceps. Two No. 110 linen thread sutures
passed through the four nerve segments 3 cm.
apart. Nerves cut beyond suture lines and sutures tied loosely so as to
form compact bundle. The same suture used to
unite this nerve bundle to the ends of the resected sciatic; one extra
epineural stitch central and distal; fairly good
approximation of cut nerve ends attained. The four nerves together are
only about two-thirds the diameter of the
resected sciatic. Dry field; muscle stitched over nerve and transplant;
wounds closed. Wounds healed well. August 7,
killed. Dog emaciated; skin diseases; toe-drop on left hind foot; small
ulcer on dorsum of foot. On exposing the left
sciatic, there is noted an increase of connective tissue about nerve
and transplant, especially in region of central and
distal wound. No distinct central bulb observed and central end of
distal sciatic only slightly enlarged. The four
transplanted nerve segments surrounded by a common connective
tissue
sheath so as to form one nerve bundle about
two-thirds as large as the distal sciatic. After exposing the calf
muscles and freeing the sciatic and the transplant
from its bed, on slowly cutting the sciatic with scissors, central to
the transplant, indistinct, feeble twitching of calf
muscles observed; this observed somewhat
more clearly on cutting internal popliteal distal to the transplant.
Calf
muscles do not present normal color; pale red with narrow, light yellow
streaks. Sciatic and the transplant with
internal and external popliteal and portions of calf muscles removed
and fixed in ammoniated alcohol for pyridine-silver staining. Good
differential silver staining attained.
Microscopic
findings.- In longitudinal sections of the central wound and the
adjacent nerve ends, the central
bulbous enlargement is found to embrace the central wound and central
sutures. Numerous new neuraxes coming
from the central stump can be traced through the central wound, in
which they are seen to crisscross in all directions
into the central ends of
1159
the transplanted nerve segments. Many
neuraxes are seen to pass distally in the connective tissue surrounding
the
transplanted nerve segments. In cross sections of the transplant, the
four nerve segments transplanted are seen clearly
demarked; each retaining its funicula structure. They arc found
surrounded by a common connective tissue
sheath which serves as an epineural sheath. Numerous new neuraxes found
in each of the funiculi of the four
transplanted nerve segments. In the surrounding connective tissue,
especially to one side, some 15 to 20 small nerve
bundles are to be observed. New neuraxes can be traced in successive
sections through the distal wound into the
distal sciatic in which they are found in large numbers in all of the
several funiculi. In sections of the calf muscles,
new neuraxes are to be observed in the larger and smaller intramuscular
nerve branches, and as single nerve fibers
between and on the muscle fibers; a few motor nerve endings observed.
Only partial regeneration of nerves in the
calf muscles attained.
FIG. 227.- Cross
section of
cable-auto-nerve
transplant, Experiment No. 77, 152 days after operation;
pyridine-silver
preparation. The four nerve segments used as a nerve bridge in this
operation are clearly made out nearly four
months after the operation
EXPERIMENT No. 78.- Dog No. 9; large
dog; full
grown; 389 days. April 24, 1918,left sciatic exposed and
resected; quite free bleeding from the central stump; small artery
ligatured. Two branches of the right superficial
radial exposed and freed from connective tissue; cut into segments
about 4 cm. long, placed side by side, and
clamped at each end with an artery forceps. Two fine silk thread
sutures passed through the four nerve segments 2
cm. apart and nerve cut beyond sutures. The sutures tied loosely, so as
to form one compact bundle. This bundle
transferred to sciatic wound and with one continuous suture each of the
four nerve segments was sutured separately,
centrally and distally, to the resected nerve ends; fine vessel silk
was used for this suture. Muscle stitched over nerve
and transplant; wounds closed. May 18, 1919, killed. Dog not in good
condition, severe skin disease, active; walks
well. Nails on two of the toes very long and curved. On exposing the
left sciatic quite a large bulb found on the
central sciatic; no distinct enlargement of central end of distal
sciatic; transplant found well in place. Distal sciatic
presents the appearance of a normal nerve. Calf muscles exposed; these
have the appearance of normal muscle. After
freeing sciatic from the bed, on slowly cutting nerve with scissors,
central to
transplant, calf
muscles found to
contract well, even though this functional test was made nearly forty
minutes after the dog was killed. Contraction of
the foot muscles not so clearly made out; they had not been exposed.
Sciatic and transplant, distal popliteal and
portions of interossei muscles removed, fixed in ammoniated alcohol for
pyridine-silver staining. Good silver
differentiation attained.
1160
Microscopic findings.- In longitudinal sections of the
central
wound and adjacent nerve ends, the central
bulbous enlargement is found to include the central nerve wound and
central sutures. Numerous neuraxes can be
traced from the central sciatic through the central wound, in which they crisscross
in all directions into the central end of the transplant. In cross
sections of the
transplant, though more than one year after operation, the four
transplanted nerve segments can be clearly demarked,
each with distinctive funicular structure. These four nerves are
surrounded by a common fibrous tissue sheath which
serves as an epineural sheath. Numerous neuraxes, many of which are
myelinated, pass through the transplant to the
distal sciatic; these are found about equally distributed through the
several funiculi of the four transplanted nerve
segments. Only very few neuraxes, in the form of several small nerve
bundles, are found in the surrounding
connective tissue. In longitudinal sections of the distal wound and
adjacent nerve ends, there is also observed a
crisscrossing of neuraxes; the neuraxes having here a very irregular
course. In sections of the popliteal branches of
the sciatic, to the level of the posterior tibial at the heel, new
neuraxes in large numbers are to be observed.
Unfortunately the pieces of interossei muscles removed at post mortem
were lost in process of staining and can not
be reported upon. In so far as Microscopic evidence of nerves is
concerned, nearly complete regeneration of distal
branches of the sciatic was obtained.
EXPERIMENT No. 79.- Dog No. 13; large dog;
full grown; 385 days. April 30, 1918, left sciatic exposed;
resected. Two cutaneous radial branches exposed and freed from
connective tissue. Each branch cut centrally and
distally and pinned out, side by side, on piece of smooth wood, which
had been sterilized with the instruments. With
the nerves thus pinned out, sutures were passed so as to form two
bundles of nerves, each with two nerve segments
with sutures at each end; nerve bundles of 2.5 cm. length. Each of the
two bundles, each composed of two nerve
segments, was sutured separately between the resected nerve ends. One
bundle was cut longer than the other, so that
when they were sutured in place, one of the bundles presented a wavy
course. Fairly good central and distal
approximation of the nerve ends attained. Muscles stitched over nerve and the
transplant; wounds closed.
May 20,
1919, killed. Dog in very good condition; well fed and active; still
seems to favor left hind leg a little; small ulcer on
dorsum of the foot; two nails on this foot of large and irregular form.
On exposing the left sciatic a distinct bulbous
enlargement on central sciatic is found, from the distal end of which
several nerve bundles are seen to pass to the
distal sciatic stump. Distal sciatic and the popliteal branches present
the appearance of normal nerves. Calf and leg
flexor muscles fully exposed; after freeing sciatic and transplant from
bed, on slowly cutting sciatic central to the
transplant, vigorous contractions of the calf and leg flexor muscles
observed. Cutting of the posterior tibial at heel
does not call forth distinct contraction of the interossei muscles.
Sciatic and the trans- plant, internal and external
popliteal branches, portions of calf and interossei muscles removed and
fixed in ammoniated alcohol for pyridine-silver staining. Good
differential silver staining attained.
Microscopic
findings.-In longitudinal sections of the central wound and the
adjacent nerve ends, it is quite
clearly to be made out that good approximation of the severed ends was
not obtained at the time of operation. Down-growing neuraxes coming
from the central stump, on reaching the central wound, present a
felt-work arrangement,
crisscrossing in all directions; many can be traced into the connective
tissue surrounding the transplants. In cross
sections of the transplant, about 1 cm. distal to the central wound,
the field is made up of large numbers of small
nerve funiculi separated by fibrous tissue and three quite distinct
funiculi, surrounded by perineural sheath. The
latter appear to be the only funiculi surviving out of about ten as
found in other experiments in which four segments
of the cutaneous radial nerves were transplanted. Numerous neuraxes may
be traced through the distal wound into
the distal sciatic, in which they are found in sections taken at
successive levels to the posterior tibial at the level of
the heel. In both cross and longitudinal sections, made of pieces taken
from the interossei muscles, new neuraxes
may be observed in the intramuscular nerve branches, and nerve endings
in at least one neuromuscular spindle. No
fully formed motor endings were observed; however, this may be due to
imperfect silver differentiation.
Regeneration of the distal popliteal to the level of the interossei
muscles attained.
1161
EXPERIMENT
No. 80.-Rabbit No. 2a; large; full grown; 21 days. March 18, 1918, left
and right sciatic
exposed. A segment of the right sciatic having a length of 1.5 cm.
trans-planted to the resected left sciatic. One
through-and-through Chinese silk suture placed centrally and distally;
wounds closed. April 8, rabbit found dead in
the morning. Wounds well healed. On exposing the left sciatic
transplant is found well in place. Distinct bulb on
distal end of central sciatic stump noted. Sciatic and the transplant
removed and fixed in neutral formalin. Sections
stained in iron-hematoxylin and picro-fuchsin.
Microscopic
findings.-In longitudinal sections taken from the transplanted
nerve
segment, numerous small
round cells, found mostly in the looser connective tissue outside of
the perineural sheath, observed. In the
transplanted nerve fibers, the myelin is found in the form of irregular
globules, separated by a granular detritus.
Neuraxis remains not clearly made out. No distinct proliferation of
sheath cells can be observed in such broken-down fibers. The picture is
not that of a Wallerian degeneration. Strands of what appear to be
syncytial protoplasmic
bands, with short, rod-shaped nuclei, are noted. These bands resemble
those found in a peripheral nerve trunk after
section. Small bundles of such protoplasmic bands are separated by
areas having neurolemma sheaths in which
myelin remains are found.
In
all of the experiments of auto-nerve transplants, kept for a time
sufficiently long to
admit of nerve regeneration, the results obtained were very
satisfactory. In five of these
experiments (No. 64 to No. 68), only one small nerve was used to bridge
a defect in a resected
sciatic, in three (No. 69 to No.71), two segments of ulnar or
superficial radial nerves were used
to bridge such a defect, and in two experiments (No. 72 and No. 73)
three pieces taken from the
cutaneous radial were sutured between the resected ends. In all of the
several experiments there
was noted a nerve bulb on the distal end of the central sciatic stump,
in general the more
prominent the less adequately the nerve defect was bridged. On the
whole there appeared to be
little difference in the results attained in a primary operation in
which the nerve transplant was
sutured in place at the time of resection of the sciatic or in a
secondary operation (No. 66 and
No. 88) in which the sciatic was resected, the wound closed to be
reopened some weeks later,
and a nerve transplant made. A study of the protocols of the respective
experiment will show that
the central neuraxes were found to grow through the transplant, and to
a variable extent in the
connective tissue surrounding the nerve transplanted, to reach the
distal segment of the resected
nerve. It is not the purpose to discuss at this time the relative
merits of the auto-nerve
transplants. This will be undertaken after considering the observations
considered in Series No. 6
and No. 7. A somewhat further consideration may here be given to the
six experiments (No.
74to No. 79) in which four segments of the radial cutaneous nerves were
used to bridge a defect
in sciatic nerves the result of resection. This operation we have
designated a "cable-auto-nerve
transplant" or a multiple nerve transplant. The radial cutaneous
branches of the dog are relatively
small nerves consisting of three or four major funiculi and presenting
the form of a flattened oval
in cross section. Four segments of these nerves arranged in parallel
bundles were sutured singly
or in pairs or as one bundle between the resected ends of the sciatic,
by both central and distal
sutures. In the dog killed 11days after the operation (No. 74), before
regeneration could have
taken place, attention is called to the fact that on exposing the
nerve, the four nerve segments
transplanted were found united in one compact bundle, having the
appearance of a single nerve
trunk, by newly formed connective tissue. This
1162
newly formed connective
tissue forming an epineural sheath surrounding and enclosing the four
segments of nerve transplanted, giving in cross section the appearance
of a nerve trunk with
many funiculi. A little study of the cross section reveals the fact
that each of the four nerve
segments has in reality maintained its own identity, each showing its
respective funiculi
surrounded by perineural sheaths. In this experiment there is distinct
evidence of an active
downgrowth of central neuraxes, which have reached the central wound
region but have not as
yet penetrated the transplants. In the experiment (No. 75),which
terminated 26 days after the
operation, the transplanted nerve segments were found united in one
compact bundle by a newly
formed epineural sheath. However, in each nerve segment there can
easily be determined the
several funiculi, each surrounded by a distinct perineural sheath. The
transplanted nerve
segments were found firmly united to the central and distal stumps of
the resected nerve. The
nerve segment removed for study included the distal end of the central
stump to the extent of
about 2 cm., the transplant, and some3 cm. of the distal sciatic. This
segment was divided into
pieces so as to admit of longitudinal sections of the central and
distal wound regions and
contiguous transplant and sciatic segments and cross sections of the
middle of the transplant.
Nearly complete serial sections of the several pieces were made after
the tissue had been stained
by the pyridine-silver method. In the series of longitudinal sections
of the central wound region,
central neuraxes may be traced in large numbers through the central
wound and into the central
part of the nerve transplant. The picture presented is very much that
of a section through the
wound region after primary suture, except that in the cable
auto-transplant the approximation of
nerve ends is not so good; there is much more crisscrossing of the
down-growing neuraxes. The
cross-section series is very instructive. In the sections, taken from
about the middle of the
transplant, new neuraxes are found in all of the funiculi of the
several transplanted nerve
segments and in approximately equal distribution. Many of the
neurolemma sheaths of the
transplanted nerve fibers contain more than one neuraxis, others only
one, and again others none.
Very few neuraxes are found in the connective tissue outside of the
funiculi. In the longitudinal
sections, including the distal wound, it may be noted that the
down-growing neuraxes in
lessening number have penetrated the transplant to the region of the
distal wound. The distal
sciatic presents the picture of a degenerated nerve, the majority of
the neurolemma sheaths
containing syncytial strands.
In
the remaining four of the cable auto-nerve transplants (No. 76 to
No.79) ranging in
length of observation from nearly 4 months to a little over12 months,
even in those of long
duration, could there be made out readily the four segments of nerve
transplanted each with its
several funiculi showing conclusively that the severed nerve segments
formed definite paths
along which the down-growing central neuraxes proceeded to reach the
distal segment. In each
of these four experiments was there a return of motor function as
tested on the exposed muscles.
This is corroborated by the presence of new motor endings in the calf
muscles of certain
experiments and even in the foot muscles of other experiments. The
morphologic evidence of
regeneration through several nerve segments as used in the operation of
auto-nerve transplants, it seems, is
conclusive. It is here shown that it is possible to use several
segments of a
relatively small cutaneous nerve to bridge a defect in a major nerve,
such as the sciatic, thus
making available in human surgery the operation of auto-nerve
transplant.
SERIES NO. 6
HOMO-NERVE TRANSPLANTS
Under
Series No. 6 are presented observations on six experiments, all but one
on the
sciatic nerve of the rabbit, in which the sciatic was resected in one
animal and a segment of
requisite length removed from the sciatic of another animal used as a
nerve bridge. The
operation of homo-nerve transplant in human surgery has limited
opportunity for application
since it is to a large extent chance that would make available normal,
fresh human nerve tissue to
be used for purpose of transplant. As a secondary operation, where the
operation of nerve repair
may be timed, nerves from amputations may be made use of. We present an
extended series of
observations on the use of stored homo-nerve transplant which will be
considered under a
separate heading; in this series only operations in which fresh
homo-nerve transplants were used
are included.
PROTOCOLS
EXPERIMENT
NO. 81.- Rabbit No. 1l a; full-grown rabbit; 8 days. March 14, 1918,
right sciatic exposed
and resected to the extent of 1 cm. A segment taken from the right
sciatic of another rabbit, of 1.2 cm. length, used
as a transplant. One central and distal Chinese silk suture placed.
Fairly good approximation of nerve ends attained.
Wounds closed. March 22, rabbit found dead in the morning. Sciatic
wound healed. On exposing the sciatic,
transplant found in place and united to the resected nerve ends.
Sutures still show clearly. No distinct central bulb
observed. Sciatic and transplant removed and fixed in neutral formalin.
Sections stained in iron-hematoxylin and
picro-fuchsin.
Microscopic
findings.-In series of longitudinal sections of the transplant, the
myelin fthe transplanted
nerve fibers seen to be fragmented in many of the fibers. The
neurokeratinnet is clearly made out even in the
fragments of myelin. Neurolemma sheaths very distinct. Sheath cells
evident but do not manifest proliferation.
EXPERIMENT No. 82.- Rabbit No. la; large
rabbit; full grown; 8 days. March 18,1918, the right sciatic
exposed and resected 1.3 cm. The right sciatic of another rabbit
exposed and a segment of 1.5 cm. length
transplanted. One central and distal Chinese silk suture placed. Good
approximation attained; a little clotted blood
between nerve ends in distal wound. Wound closed. March 26, rabbit
found dead in the morning. On exposing the
right sciatic it is found that the central suture had given away a
little; distal suture good. Sciatic and the transplant
removed and fixed in neutral formalin for Bielschowsky silver staining.
Microscopic
findings.-In a series of longitudinal sections of the transplant it
is found that the epineural
sheath has been invaded by numerous small round cells. In the
transplanted nerve fibers the neuraxes are found to be
fragmented; these fragments, differentially stained, are either bent
upon themselves, are coiled, or have a wavy
course. The myelin is not clearly defined; appears granular. The
neurolemma sheaths intact and appear thickened. Sheath nuclei not differentiated.
EXPERIMENT
No. 83.- Dog No. 36a; medium size; full grown; 17 days. June 4, 1918,
right sciatic exposed
and internal popliteal freed, and resected. A segment of 3 cm. length
taken from the right internal popliteal of
another dog, under the anesthetic at the same time, used as a
transplant. One central and distal fine silk thread suture
placed; very good approximation. The uncut external popliteal funilculi
lies at the side of the operated internal popliteal
1164
Clean field; wound closed. June 21,
dog found dead in the morning; very slight neurotrophic changes right
hind foot. Wound well healed. On exposing the right sciatic the
transplant is found well in place; appears as if
slightly swollen; united to the resected nerve ends, though distally
the wound had separated a little. No distinct
central bulb noted. Sciatic and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining.
Very good silver differentiation for the central segment attained.
Microscopic
findings.- In longitudinal sections of the central wound and the
adjacent nerve ends, central
wound is clearly demarked by the presence of the central suture; good
fibrous union. Only indistinct central bulb
evidenced structurally. Numerous downgrowing neuraxes of- the central
stump, end, often after branching, in large
end-discs at the point of the fibrous union. Others have penetrated the
fibrous tissue of this region and are found in
the central end of the transplant in which they may be traced distally,
becoming gradually less numerous, for a
distance of nearly 1.5 cm. Now and again more than one neuraxis may be
observed in old neurolemma sheath of the
transplant. In cross section of the transplant about 1 cm. distal to
the central wound relatively few neuraxes are to be
found, scattered fairly evenly through the several funiculi of the
transplanted nerve. In the distal popliteal stump
early nerve degeneration stages observed. No new neuraxes traced to the
distal nerve.
EXPERIMENT No. 84.- Rabbit No 62; full grown;
23 days. March 21, 1918, right sciatic exposed and
resected 1.2 cm. Right sciatic of another rabbit exposed, while nerve
was being exposed rabbit died under anesthetic;
operation completed and nerve used in transplant. One central and one
distal Chinese silk suture placed; fair
approximation. Wound closed. April 13, killed. Caudal half of rabbit
paralyzed; cause not determined. Sciatic wound
well healed. On exposing nerve, transplant was found well in place;
slightly adherent to muscle bed. Central and
distal sutures clearly made out; no distinct central bulb. Sciatic and
transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. Very good silver differentiation
attained.
Microscopic
findings.-In longitudinal sections through the central
wound region and
adjacent nerve ends,
numerous down-growing neuraxes, crisscrossing through the fibrous
wound, can be traced into the central end of the
transplant. In cross sections of the transplant, about its middle,
the funicular arrangement of the transplanted nerve
segment is found well retained. The fibrous sheaths of the funiculi
found thickened, within them and between the
funiculi are found numerous small round cells. Within the funiculi
numerous down- growing neuraxes are to be seen.
In many instances four to six or eight new neuraxes found in one old
neurolemma sheath. Certain of these down-growing neuraxes have reached
the distal wound and can be traced to the distal sciatic in which they
extend for a
distance of about 1 cm.
EXPERIMENT NO.
85.- Rabbit No. 8a; full grown; 68 days. March 16, 1918, right
sciatic exposed and resected a little over 1 cm. A segment of
equal
length taken from the right sciatic of another rabbit used as
transplant.
One central and distal Chinese silk suture placed; good approximation.
Wound closed. May 23, killed. Severe
neurotrophic change right foot; rabbit in good condition. On exposing
the right sciatic, transplant is found well in
place; sutures clearly seen. Small spindle-shaped central bulb. After
exposing the calf muscles and freeing nerve
from bed, no contraction of muscles observed on cutting nerve central
to the transplant. Calf muscles appear atrophic
and of yellow-red color. Sciatic and the transplant removed and fixed
in ammoniated alcohol for pyridine-silver
staining. Good silver differentiation attained.
Microscopic
findings.-In longitudinal sections of the central wound and the
adjacent nerve ends, it may be
observed that numerous neuraxes pass from the central stump through the
central wound to the central end of the
transplant. In cross sections of the transplant it is to be observed
that its fibrous sheaths are materially thickened and
that its funicular structure is not fully maintained. Numerous new
neuraxes are observed both within the funiculi of
the transplant and especially to one side in the surrounding connective
tissue. In sections taken at successive levels,
the down-growing neuraxes may be traced into and through the distal
wound into the distal sciatic in which they are
found in good number 2 cm. beyond the distal found; the extent of the
sections.
1165
EXPERIMENT No. 86.-Rabbit
No. 27a; full
grown; 83 days. March 15, 1918, right sciatic exposed and
resected about 1 cm. A segment of equal length taken from the right
sciatic of another rabbit and used as transplant.
One central and distal Chinese silk suture placed. The muscle stitched
over the nerve and transplant and the wound
closed. June 6, killed. Wound well healed; rabbit in good condition. On
exposing the right sciatic transplant was
found well in place, with nerve sutures still evident. Small central
bulb observed. Transplant of smaller diameter
than resected nerve and slightly adherent to the underlying muscle.
After freeing nerve from bed and exposing the
calf muscles, on slowly cutting central sciatic no contraction of calf
muscles noted. Sciatic and the transplant and the
internal popliteal removed and fixed in ammoniated alcohol for pyridine
silver staining. Fairly good silver
differentiation attained.
Microscopic findings.-In longitudinal sections of the
central
wound, the central suture appears in the
sections, clearly indicating the region of the central wound. Numerous
down-growing neuraxes coming from the
central stump penetrate the central end of the transplant. In cross
sections of the transplant the funicular structure is
clearly demarked. In the funiculi numerous new neuraxes, evenly
distributed, are to be observed. Several groups of
small nerve bundles are found in the connective tissue surrounding the
transplant. In successive series of sections
these neuraxes can be traced into the distal sciatic stump in which
they are present in large numbers to the extent of
the sections, 2 cm. beyond the distal wound.
The
experiments in which fresh homo-nerve transplants were used, though
relatively few
in number and of relatively short duration, nevertheless show
conclusively the feasibility of
using fresh homo-nerve transplants to bridge a nerve defect. In the
last three of the experiments
listed (No. 84 to No. 86), ranging in duration from a little over one
month to nearly three
months, the down-growing central neuraxes were traceable through the
transplant and a variable
distance into the distal sciatic stump. As seen best in cross sections
of the transplant, the down-growing neuraxes are found within the
neurolemma sheath of the transplanted fibers, in the
endoneural tissue between the nerve fibers and in the connective tissue
surrounding the
perineural sheaths of the funiculi of the transplant. In Experiment No.
83, in which the sciatic of
a dog was operated upon and the experiment terminated at the end of
approximately three weeks,
the series of longitudinal sections of the central wound region
presents a typical picture of
regeneration from the central nerve stump with many branching central
neuraxes and many
down-growing neurax esterminating at various levels in end-discs. These
down-growing
neuraxes are traceable through the wound region and into the central
end of the transplant. No
neuraxes are found in the distal wound region; the distal sciatic
presenting a typical picture of a
degenerated peripheral nerve of about three weeks standing.
SERIES NO. 7
HETERO-NERVE TRANSPLANTS
There
can be no question that should hetero-nerve transplants prove to be a
feasible
operation it would become the operation of choice in cases in which a
nerve bridge was found
necessary. Therefore, it seemed to us worth while to reinvestigate the
merits of a hetero-nerve
transplant. In the majority of the experiments of this series (No. 87
to No. 125) one or two sciatic
nerves, taken from the guinea pig, were used to bridge defects in the
sciatic of rabbits, the result
of resection. In a few experiments a nerve taken from a dog was used
1166
to bridge a resected
sciatic of a rabbit. The operated animals were killed at stated
intervals,
ranging in the several experiments from three days to nearly a year.
Only fresh nerves were used
for purposes of transplants. While one animal was under an anesthetic
having one of the sciatic
nerves exposed, resected, and sutures placed, a guinea pig (or dog) was
placed under anesthesia, the region of the operation shaved and made
aseptic, so that at the proper time the desired nerve
could be exposed, a segment of requisite length taken and transferred
to the host and sutured in
place. In a number of instances two sciatics of a guinea pig were used
to bring the diameter of
the transplant to approximate that of the nerve to be bridged. Especial
care was taken to suture the transplant to the resected nerve ends with
as good end-to-end approximation as was possible
so as to make the conditions favorable for regeneration.
PROTOCOLS
EXPERIMENT
No. 87.- Rabbit No. 73; old; large rabbit; 3 days. April 22, 1918, left
sciatic exposed;
resected about 1 cm. The two sciatics of a half-grown guinea pig
exposed, exsected and placed side by side and
clamped at ends with artery forceps. Two fine silk threads passed a
little over 1 cm. apart through both nerves, and
nerves cut beyond sutures. The two nerves together used as a transplant
and sutured to the resected ends of the
sciatic. Wound closed. April 25, killed. Superficial wound found
healed; deep wound easily separated. On exposing
the sciatic it was observed that one of the nerves used as a trans-
plant had separated from the central stump; the
other from the distal stump; the respective ends lying free in the
wound. The sciatic and the transplanted nerves
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Good silver differentiation of central sciatic
stump attained.
Microscopic
findings.-In sections it is evident that the ends of the
transplanted nerve segment were not well
sutured to the resected ends. In longitudinal sections of the distal
end of the central sciatic stump, many of the central
neuraxes present distinctly swollen ends, many of irregular shape; no
distinct fibrillar differentiation is made out. No
clear evidence of the downgrowth of central neuraxes is observed.
Transplanted nerve segments and the distal sciatic
not clearly differentiated in this series.
EXPERIMENT No. 88.- Rabbit No. 73a; old; large
rabbit; 3 days. April 22, 1918, right sciatic exposed and
resected about 1 cm. Both of the sciatics of a half-grown guinea pig
exsected and together used as transplant. One
central and distal silk thread suture used. Wound closed. April 25,
killed. Superficial wound found healed; deep
wound easily separated. On exposing nerve, transplanted nerve segments
found well in place. Sciatic and transplants
removed and fixed in Flemming's chromo-osmic-acetic mixture. Sections
stained in safranine and licht grün.
Microscopic
findings.- In longitudinal sections of the central and
distal wound
regions, it is evident that
there was good end-to-end approximation of the ends-of the transplanted
nerve segments and the resected sciatic.
Central and distal wound region consists of a loose fibrocellular
tissue. In cross section of the transplanted nerve
segments, the funicular structure of the respective nerves well
maintained. The two nerves found surrounded by a
common layer of exudate with beginning fibrous tissue formation.
Evidence of in wandering of leucocytes; these
found between the nerve fibers. Very little fragmentation of the myelin
of the transplanted nerve fibers observed;
their sheath cells only indistinctly stained. In the distal sciatic
beginning fragmentation of the myelin and the
beginning of proliferation of the sheath cells noted; here and there a
mitotic figure in these.
EXPERIMENT No. 89.- Rabbit No. 74; full grown;
5 days. April 22, 1918, the left sciatic exposed and
resected 1.3 cm. The two sciatics of a half-grown guinea pig together
used as a transplant. One central and distal silk
suture placed. Wound closed. April 27, killed. Superficial wound
healed; deeper wound not fully united. On
exposing nerve, transplants found well in place, though only one of the
nerves is clearly made out; not adherent
1167
to the underlying muscle. Nerve and
transplant surrounded by sanguineous exudate. Sciatic and transplant
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Fairly good silver differentiation in the
central stump attained.
Microscopic
findings.-In longitudinal sections of the central wound region,
beginning stages of the down
growth of central neuraxes noted. Certain of these have reached the
central wound region. Not good alignment of
central end of the transplants and distal end of sciatic found. Silver
staining not satisfactory for detail study of
transplant. Distal sciatic beginning degeneration of peripheral fibers
made out.
EXPERIMENT
No. 90.- Rabbit No. 74a; full grown; 3 days. April 22, 1918, the right
sciatic exposed and
resected 1.5 cm. The two sciatics of a half-grown guinea pig used as a
transplant. One central and distal silk suture
placed. On suturing distally one nerve was twisted over other; half
spiral turn. Wound closed. April 25, killed.
Superficial wound healed; deep wound not completely healed. On exposing
sciatic it is found that the external
popliteal bundle was not cut, the transplant found sutured to internal
popliteal; transplants well in place, easily
demarked by presence of sutures. Internal popliteal and the transplant
removal and fixed in Flemming's chromo-osmic-acetic mixture. Sections
stained in safranine and licht grün.
Microscopic findings.- In longitudinal sections of central
and
distal wound regions, it may be observed that
the ends of the transplanted nerves are bent over hook-shaped; thus not
found in alignment with the resected nerve
ends. In longitudinal sections of the distal end of the central stump,
for a distance of about 8 mm., fragmentation of
myelin of central fibers and proliferation of the sheath cells noted.
In cross sections of the transplant, the funicular
structure of the two nerves is well maintained, with exudate and newly
forming fibrous tissue inclosing the two
nerves. The perineural sheaths of the funiculi not thickened. Beginning
of in wandering of cells through the
perineural sheaths observed. Only in a few of the larger funiculi, and
in these in the more peripherally placed fibers,
is fragmentation of the myelin noted. The great majority of the nerve
fibers of the transplanted nerves show as vet no
distinct fragmentation of the myelin and no proliferation of sheath
cells. In the distal sciatic the peripheral nerve
fibers show fragmentation of myelin and proliferation of sheath cells.
EXPERIMENT
No. 91.-Rabbit No. 69; large; full grown; 9 days. April 18, 1918, left
sciatic exposed and
resected 1.2 cm. The two sciatics of a half-grown guinea pig together
used as a transplant. One central and one distal
suture placed; good approximation. Wound closed. April 27, killed.
Superficial wound healed; deep wound healing.
On exposing the left sciatic transplant found well in place, surrounded
by exudate and newly forming connective
tissue, which unites the two nerves in one bundle. The transplant
appears congested, giving it a pink-red color.
Sciatic and the transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining. Good silver
differentiation attained.
Microscopic
findings.-In a series of longitudinal sections of the central wound
region, numerous neuraxes
growing from the neuraxes of the central sciatic can be traced to the central wound region, which they
have
invaded.
Certain of the neuraxes are seen to branch others to terminate in
end-discs; the beginning of spiral formation seems
evident. Fine naked neuraxes found in the fibrocellular central wound.
In the transplant, especially near the central
wound, the neuraxes of the transplanted nerve, found in the form of
long segments, having a regular course. Further
distalward shorter neuraxis segments are found. Distal sciatic presents
early stages of degeneration.
EXPERIMENT
No. 92.-Rabbit No. 69a; large; full grown; 9 days. April 18, 1918,right
sciatic exposed and
resected 1.2 cm. The two sciatics of a half-grown guinea pig together
used as a transplant. One central and distal silk
suture placed; good approximation. Wound closed. April 27, killed.
Superficial wound healed; deeper wound
healing. On exposing the right sciatic the transplants found well in
place and surrounded by newly forming
connective tissue. Sciatic and the transplant removed and fixed in
Flemming's chromo-osmic-acetic mixture.
Sections stained in safranine and licht grün.
Microscopic
findings.-Transplant found well
united to the resected nerve ends. In cross sections of the
transplant, through its middle region, the two nerves transplanted
clearly made out, each showing typical funicular
structure. The two nerves united by a
1168
thick, common fibrous tissue sheath, in
which
are seen numerous small round cells; these also in large numbers
between the two nerves. Wandering cells have invaded certain of the
nerve funictuli. In certain of the funiculi the
nerve fibers more peripherally placed show fragmentation of the myelin,
not distinctly evident in the more centrally
placed fibers. Not all of the funiculi react in the same way. Certain
of the sheath nuclei of the transplanted nerve
fibers are found to stain deeply; others more faintly. No proliferation
of these cells is noted. In the distal end of the
central sciatic stump and in the distal sciatic there is observed a
distinct increase in the number of the sheath cell
nuclei; here and there mitotic division is noted. Fragmentation of the
myelin, which varies in degree in different
nerve fibers, is observed in the distal sciatic.
EXPERIMENT
No. 93.- Rabbit No. 67; large; full grown; 9 days. April 18, 1918, left
sciatic exposed and
resected 1.4 cm. The-two sciatics of a nearly grown guinea pig used as
transplants. One central and distal suture
placed; centrally good approximation, distally"fair." Wound closed.
April 27, killed. Wound healed. On exposing the
left sciatic, transplants found well in place; surrounded by newly
formed connective tissue and adherent to the
underlying muscle. Sciatic and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining. For
central portion of nerve good silver differentiation attained.
Microscopic
findings.-In longitudinal sections of the central wound region
down-growing
neuraxes in relatively small number are found to have reached the
central wound region;
branching of these neuraxes is observed. In longitudinal sections of
the transplanted nerves, the
neuraxes of the nerve fibers are found fragmented into longer or
shorter segments, staining
differentially in the silver. A distinct layer of fibrous tissue
surrounds the transplant his tissue
incloses many small cells. Distal sciatic shows early stages of nerve
degeneration.
EXPERIMENT
No. 94.- Rabbit No. 67a; large; full grown; 9 days. April 18, 1918,
right
sciatic exposed and resected 1.5 cm. The two sciatics of a nearly grown
guinea pig used as
transplant. One central and distal silk suture placed. Clean, dry
wound. Wound closed. April 27,
killed. Wound healed. On exposing the right sciatic, transplant found
well in place; surrounded
by exudate and newly formed fibrous tissue, not adherent to under-lying
muscle. A dead space
nearly surrounds transplant; in this a small amount of sanguineous
exudate. Sciatic and
transplant removed and fixed in Flemming's chrom-osmic-acetic mixture.
Sections stained in
safranine and licht grün.
Microscopic
findings.-In longitudinal sections of the central and distal wound
regions,
the ends of the transplants are found united to the resected nerve ends
by means of fibro- cellular tissue. The wound regions surrounded by
numerous small cells; these have penetrated
the distal end of the central sciatic stump for a distance of about 2
mm. In cross sections of the
transplant the two nerves clearly demarked, with funicular structure
well maintained. These
nerves as seen in cross sections present an appearance which resembles
closely that of normal
nerves. At the periphery of the funiculi, beginning breaking down of
the myelin is noted. In
wandered cells are found here and there between the nerve fibers; not
to equal extent in all of the
funiculi. The distal sciatic presents early stages of nerve
degeneration, with great increase in the
number of the sheath cells, and fragmentation of the myelin.
EXPERIMENT
No. 95.- Rabbit No. 71; large; full grown: 15 days. April 19, 1918,
left
sciatic exposed and resected 1.4 cm. The two sciatics of a nearly grown
guinea pig used as
transplants. One central and distal No. 110 linen thread suture placed;
only "fair" central and
distal approximation of the nerve ends attained. Wound closed. May 4,
killed. Rabbit not well;
emaciated; wound well healed. On exposing the left sciatic, transplant
found well in place;
seems of smaller diameter than when used; not adherent to muscle.
Distinct central sciatic bulb
noted. Sciatic and transplant removed and fixed in ammoniated alcohol
for pyridine-silver
staining. For central portion of nerve fair silver differentiation
attained.
Microscopic
findings.- In longitudinal sections of the central wound region a
distinct
central bulb evidenced structurally, from the distal end of which a few
down-growing central
neuraxes have reached and penetrated the central wound region; numerous
bulbous end-discs on
such neuraxes noted. Within the transplant the old neuraxes found in
short segments still
showing the differential silver staining. The distal sciatic presents
early stages of degeneration.
1169
EXPERIMENT No. 96.- Rabbit
No. 71a; large;
full grown; 15 days. April 19, 1918, right sciatic exposed
and resected 1.2 cm. The two sciatics of a half-grown guinea pig used
as transplants. One central and distal No. 110
linen thread suture placed; good central approximation, "fair'" distal.
Wound closed. May 4, killed. Rabbit not well;
emaciated; wound was healed. On exposing the right sciatic transplant
is found well in place and of dull white color.
The two nerves are held together by scant connective tissue. Well
developed central bulb noted. Sciatic and
transplant removed and fixed in Flemming's chrom-osmic-acetic mixture.
Sections stained in safranine and licht grün.
Microscopic
findings.- Transplant found well united to resected nerve ends;
fibrous unio In cross
sections of the transplant, the two nerves transplanted are clearly
demarked with funicular structure well retained.
The two nerves found surrounded by common connective tissue sheath
infiltrated with small round cells; found in
large numbers between the two nerves. Here and there cells which have
penetrated the perineural sheaths are found
between the nerve fibers. It may be observed that the peripheral fibers
of the funiculi have their myelin and neuraxes
more fragmented than those more centrally placed. Wandering cells found
within certain of the neurolemma
sheaths.
In the distal sciatic the nerve fibers found in early stages of
degeneration.
EXPERIMENT
No. 97.- Rabbit No.
88; large; full grown; 42 days. August 20, 1918, the left sciatic
exposed; internal popliteal bundle freed; resected 2.8
cm. A segment of equal length taken from the left sciatic of a
full-grown guinea pig used as transplant. One central
and distal suture of waxed fine silk thread used; good approximation.
Wound closed. October 1, rabbit found dead in
the morning; neurotrophic ulcer left heel. On exposing the left
sciatic, it was found that the transplant remained
united to the central sciatic stump, the suture showing, but had pulled
free from the distal stump; its end lying free in
the wound; the portion of the transplant remaining having a
yellow-white color. Large bulbous end on central sciatic
stump noted. Central sciatic and remains of transplant removed and
fixed in neutral formalin. Sections stained in
iron-hematoxylin and picro-fuchin; safranine and licht grün.
Microscopic
findings.-In cross sections of the remains of the transplant the
funicular structure of the nerve
found well maintained; the perineural sheaths invaded by small round
cells. Within the perineural sheaths, large and
in fact multinucleated masses of protoplasm, indefinitely bounded, are to be seen. In
the
nerve fibers, the
neurolemma sheaths found containing globular masses, varying in size.
This more particularly in the perineural
fibers of the funiculi. The more centrally placed fibers found better
preserved; certain ones still showing the
neurokeratin net of the myelin.
EXPERIMENT No. 98.- Rabbit No. 88a; large;
full grown; 33 days. August 29, 1918, right sciatic exposed;
internal popliteal freed; resected 2.4 cm. The right sciatic of a
full-grown guinea pig used as transplant. One central
and distal waxed, fine silk-thread suture placed; good approximation.
Wound closed. October 1, rabbit found dead in
the morning; neurotrophic ulcer on right heel. On exposing the right
sciatic, transplant was found well in place; no
material increase of connective tissue. Transplant is of dull white
color. No distinct bulb on the central sciatic stump
noted. Sciatic and transplant removed and fixed in ammoniated alcohol
for pyridine-silver staining. For central part
of nerve good silver differentiation attained; for distal nerve not so
good.
Microscopic
findings.- In longitudinal sections of the central wound region a
long spindle-shaped bulb
evidenced structurally, including the central end of the transplanted
nerve segment. Down-growing neuraxes coming
from the central nerve are found to enter several of the funiculi of
the transplant in which they can be traced several
millimeters. In cross sections of the transplant taken about 1 cm.
distal to the central wound, the funicular structure
of the transplanted nerve is found well preserved, with the fibrous
sheaths of the funiculi thickened. The old
neuraxes of the transplanted nerve fibers evident within many of the
neurolemma sheaths. No new neuraxes made
out at this level. In longitudinal sections of the transplant, nearly
all of the myelinated nerve fibers show remains of
the neuraxes, as short segments of spiral form or looped, showing the
characteristic silver reaction. The nerves of the
distal popliteal found degenerated.
1170
EXPERIMENT No. 99.-Rabbit No. 70; full
grown;
34 days. April 19, 1918, left sciatic exposed and
resected 1.2 cm. The two sciatics of a half-grown guinea pig used as
transplants. One central and distal silk thread
suture placed. Good central approximation attained; distal not good; an
additional epineural stitch improves
somewhat. Wound closed. May23, killed. Wound well healed; beginning
neurotrophic ulcer on the left heel. On
exposing the left sciatic, transplant is found well in place,
surrounded by fibrous tissue and found adherent to
underlying muscle. Sciatic and the transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining.
Very good differential silver staining attained.
Microscopic
findings.- A large distinct central bulb evidenced structurally,
from the distal end of which
numerous neuraxes can be traced distally. Certain of the neuraxes can
be traced into the central end of the
transplanted nerves; others pass to the connective tissue surrounding
the transplanted nerves or found between them.
In cross sections of the middle of the transplant the two nerves are
clearly made out. The two nerves are found
surrounded by a common fibrous tissue sheath. At this level no new or
down-growing neuraxes made out within the
perineural sheaths of the nerve funiculi. In many of the nerve fibers
fragments of the old neuraxes may be seen. In
the fibrous tissue surrounding the transplanted nerves, mainly to one
side, there are to be found numerous neuraxes,
singly or in small bundles, separated by fibrous tissue. In
longitudinal sections of the distal wound region it is
evident certain of the down-growing neuraxes have reached this region
and may here be traced into the central end
of the distal popliteal. These new neuraxes appear to reach this level
mainly by way of the connective tissue found
surrounding the transplant.
EXPERIMENT NO. 100.- Rabbit
No. 70a; full
grown; 34 days. April 19, 1918, right sciatic exposed and
resected 1.4 cm. The two sciatics of a half-grown guinea pig used as a
transplant. One central and distal silk suture
placed. After suture, the two nerve segments transplanted found twisted
one spiral turn; the central and distal
approximation "fair."Wound closed. May 23, killed. Wound appeared well
healed. On removing skin over wound
area, a small focus of suppuration found in wound line; does not appear
to extend to deeper wound. On exposing
sciatic, tissue about nerve presents no evidence of infection. The
transplant found well in place, surrounded by
connective tissue and adherent to underlying muscle. No distinct
bulbous enlargement of central sciatic noted.
Sciatic and trans-plant removed and fixed in Flemming's
chrom-osmic-acetic mixture. Sections stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
Microscopic findings.-In longitudinal sections including the
central and distal wounds, the transplant
appears well united to resected nerve ends; fibrous tissue union. An
indistinct central bulbous enlargement is found,
from the distal end of which down-growing neuraxes in the form of
nonmyelinated nerve fibers may be observed;
these approach the central ends of the transplanted nerve segments. In
cross sections of the transplant, the funicular
arrangement of the transplanted nerves found well retained; surrounded
by a common fibrous sheath, showing much
round cell infiltration. The nerve fibers of the transplant appear to
be appreciably enlarged, with neurolemma sheath
distinct. Within these sheaths here and there globular remains of
myelin. Phagocytic cells found within the
neurolemma sheaths. The nerve fibers of the distal popliteal found
degenerated.
EXPERIMENT
NO. 101.- Rabbit No. 66; full grown; 50 days. April 17, 1918, left
sciatic exposed and
resected 1.3 cm. The two sciatics of a half-grown guinea pig used as a
transplant. One central and distal No. 110
linen-thread suture placed. Fairly good approximation attained. Wound
closed. June 6, killed. Rabbit good condition;
no distinct neurotrophic changes of left hind foot. On exposing the
left sciatic, transplants found well in place;
surrounded by a common fibrous sheath; adherent to underlying muscle. A
distinct bulbous enlargement on the
central sciatic stump noted. Calf muscles fully exposed; these appear
degenerated. On cutting nerve central to
transplant, no contraction of calf muscles noted. Nerve and transplant
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Very good differential silver staining
attained.
Microscopic
findings.-In longitudinal sections of the central wound region, a
long
spindle-shaped central bulb is recognized; line of union with central
end of transplants clearly
recognized by presence in the sections of central sutures. Numerous
down-growing central
neuraxes can be traced to the central end of the transplant, within
which they are traced
distalward for
1171
a distance of nearly 1 cm. Certain of
these
neuraxes are found in the remains of the old neurolemma sheaths, found
in the detritus derived from the transplanted nerve fibers. In cross
sections of the transplant, taken about 1 cm. distal
to the central wound, new neuraxes are to be observed within several of
the funiculi of the transplanted nerve
segments, even in the most necrotic portions. In longitudinal sections
of the distal wound region, a few of the down-growing neuraxis can be
traced from the distal end of the transplant into the distal wound and
from this a few
scattered neuraxes to the central end of the distal internal popliteal.
EXPERIMENT
NO. 102.- Rabbit No. 66a; full grown; 50 days. April 17, 1918, right
sciatic exposed and
resected 1.5 cm. The two sciatics of a half-grown guinea pig used as
transplants. One central and distal No. 110
linen-thread suture placed; fairly good approximation. Wound closed.
June 6, killed. Rabbit in good condition;
scarcely any neurotrophic changes in right hind foot. On exposing the
right sciatic, transplant found well in place;
surrounded by connective tissue; only moderately adherent to the
underlying muscle. Relatively dense fibrous tissue
surrounds distal wound. Distinct bulbous enlargement noted on central
sciatic stump. Calf muscles exposed; these
have the appearance of degenerated muscle; do not contract on cutting
nerve central to the transplant. Sciatic and
transplant removed and fixed in Flemming's chromo-osmic-acetic mixture.
Sections stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
Microscopic findings.-In longitudinal sections of the
central
wound region a very large central bull is
evidenced structurally, from the distal end of which numerous young
nerve fibers, the majority of which are as yet
nonmyelinated, are found to extend to the central end of the
transplant, in which larger and smaller syncytial masses,
irregular multinucleated giant cells, occupy the regions of the
transplanted nerve fibers. In cross sections of the
transplant the two nerve segments are recognized by their funicular
arrangement and are surrounded by a common
connective-tissue sheath. Within the perineural sheaths of the several
funiculi, masses of large vesicular cells and
irregular masses of syncytial protoplasm and granular detritus occupy
the greater part of the cross-section area of
each funiculus. In the fibrous tissue surrounding the transplanted
nerve segments, especially to one side, there is
observed an area in which some fifteen small funiculi of nerve fibers
arc to be found. No new nerve fibers were
traced to the distal sciatic. The nerves of the distal sciatic found
degenerated.
EXPERIMENT
No. 103.-Rabbit No. 68; large; full grown; 61 days. April 18, 1918,
left
sciatic exposed and
resected 1.4 cm. The two sciatics of a nearly-grown guinea pig used as
transplants. One central and distal No. 110
linen-thread suture placed; good approximation. Wound closed. June 18,
rabbit found dead in the morning; severe
neuro-trophic changes left hind foot. On exposing the left sciatic a
large bulbous enlargement on the central sciatic
stump is noted, from the distal end of which a fine strand, not quite
the size of one of the sciatics used as transplant,
leads to the distal sciatic stump. Sciatic and transplant removed and
fixed in ammoniated alcohol for pyridine-silver
staining. Only in part good silver differentiation attained.
Microscopic
findings.-In longitudinal sections of the
central wound region a large spindle-shaped bulbous enlargement of end
of central sciatic is evidenced structurally,
from the distal end of which down-growing neuraxes may be traced to the
central end of the transplant and the
connective tissue surrounding the transplant. III cross sections
distant about 1 cm. from central wound, the funicular
structure of one of the transplanted nerves can be made out, with
epineural sheaths thickened. Within the fibrous
sheath areas of granular detritus and faintly outlined vesicular cells
are noted. This mass occupies nearly the entire
cross area of each funiculus. No down-growing neuraxes recognized in
this detritus nor at this level in the
surrounding fibrous tissue. The distal popliteal found completely
degenerated.
EXPERIMENT
No. 104.-Rabbit No. 68a; large; full grown; 61 days. April 18,
1918, right sciatic exposed
and resected 1.5 cm. The two sciatics of a nearly-grown guinea pig used
as transplants. One central and distal No.
110 linen-thread suture placed; good approximation. Wound closed. June
18, rabbit found dead in the morning; very
severe neuro-trophic changes right heel. On exposing the right sciatic,
transplant found well in place; the two nerves
distinctly evident; of dull white color. No distinct central sciatic
bulb
1172
noted. Sciatic and transplant removed
and
fixed in ammoniated alcohol for pyridine-silver staining. Not well
differentiated- not well embedded; sections torn.
Microscopic
findings.-From well-developed central bulbous enlargement
down-growing neuraxes can be
traced in part into the central end of the transplant, the majority to
the side of the transplant into the surrounding
connective tissue. The remainder of the series of sections, especially
those of the transplant, so badly torn, owing to
faulty embedding, the resulting sections could not be used for critical
study. The nerves of the distal sciatic stump
found completely degenerated.
EXPERIMENT
No. 105.- Rabbit No. 96; full grown; 69 days. September 6, 1918, left
sciatic exposed and
the internal popliteal freed and resected 2.5 cm. A segment of equal
length taken from the left sciatic of a large
guinea pig used as transplant. One central and distal waxed fine
silk-thread suture placed; good approximation.
Slight hemorrhage from central sciatic stump, not fully controlled.
Wound closed. November 15, rabbit found dead
in the morning; not well for several days; slight neurotrophic changes
left heel. On exposing the left sciatic, the
external popliteal found in close approximation to operated internal
popliteal. Transplant found well in place and
easily recognized by reason of its yellow-white color. Small
spindle-shaped bulbous end central internal popliteal.
Internal popliteal and transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining, Only in part
good silver staining attained; sections torn.
Microscopic findings.-In longitudinal sections of the
central
wound region certain down-growing neuraxes
are found to enter the central end of the transplant; the majority are
seen to pass to the side of the transplant into the
surrounding connective tissue. In cross sections of the transplant it
is seen that the funicular structure of the
transplanted nerve is well retained, with epineural sheath thickened.
In many of the old nerve fibers of the transplant
remnants of the old neuraxes seen, both in cross and longitudinal
sections. The neurolemma sheaths seem thickened
and contain granular detritus. No new neuraxes traced to the distal
wound. The nerves of the distal popliteal found
degenerated.
EXPERIMENT
No. 106.- Rabbit No. 96a; full grown; 69 days. September 6, 1918, right
sciatic exposed,
internal popliteal freed; resected 2.5 cm. A segment of equal length
taken from the right sciatic of a large full-grown
guinea pig used as transplant. One central and distal waxed fine
silk-thread suture placed; good approximation.
Wound closed. November 15, rabbit found dead in the morning; not well
for several days; severe neurotrophic
changes right heel. On exposing the right sciatic, the central internal
popliteal is found to end in a large bull to which
the central end of the transplant is adherent. The transplant had
pulled free from the distal popliteal; the distal suture
is found in the free distal end of the transplant. Central and distal
internal popliteal and the transplant removed and
fixed in neutral formalin. The sections
stained in
iron-hematoxylin and picro-fuchsin; safranine and
licht-grün.
Microscopic findings.-In longitudinal sections of the
central
wound region, active downgrowth of small
myelinated and nonmyelinated neuraxes pass to the side of the
transplant and are lost in the surrounding connective
tissue. In cross sections of the transplant, just distal to central
wound, it is observed that the funicular structure of the
nerve is well retained; with each funiculus surrounded by a perineural
sheath. The nerve fibers within the perineural
sheaths of larger diameter; remnants of neuraxes noted. Under low
magnification the cross sections of the
transplanted nerve resemble closely in general structure a normal
nerve. The nerve fibers of the distal popliteal
completely degenerated.
EXPERIMENT No. 107.- Rabbit No. 89; full
grown; 87 days. August 30, 1918, left sciatic exposed; internal
popliteal freed; resected 3 cm. A segment of equal length, taken from
the left sciatic of a large, full-grown guinea
pig, used as a transplant. One central and distal waxed, fine silk
thread suture placed; good approximation. Wound
closed November 26, rabbit found dead in the morning; much emaciated,
on left heel neurotrophic ulcer. On
exposing the left sciatic the transplant is found well in place,
demarked by its light yellow color; no material increase
of connective tissue about it. Distinct bulbous enlargement on central
internal popliteal. Internal popliteal removed
and fixed in neutral formalin. Sections stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
Microscopic
findings.-In longitudinal sections of the central wound region,
from the large central bulb,
there may be traced many small myelinated and nonmyelinated nerve
1173
fibers to the central end of the nerve
transplant. In cross and longitudinal sections of the transplanted
nerve segment,
it may be observed that the perineural sheath of the nerve is not
materially thickened. Within this sheath large areas
in which are found closely arranged large vesicular cells, with
globular and granular inclusions, not Clearly defined. Other areas in
which similar cells and granular detritus are found in what appear to
be distended neurolemma
sheaths. Within the perineural sheath, mainly to one side, many small
funiculi of nerve fibers may be observed. No
new nerve fibers traced to and through the distal wound. The nerve
fibers of the distal popliteal stump found
completely degenerated.
EXPERIMENT
No. 108.-Rabbit No. 89a; full grown; 87 days. August 30, 1918, right
sciatic exposed;
internal popliteal freed and resected 3 cm. A segment of equal length,
taken from the right sciatic of a large, full-grown guinea pig, used as
transplant. One central and distal waxed, fine silk thread suture
placed; good
approximation. Wound closed. November 26, rabbit found dead in the
morning; much emaciated; severe neutrophic
ulcer right heel. On exposing the right sciatic, transplant is found
well in place; no material increase of connective
tissue and only moderately adherent to underlying muscle. Distinct
central bulbous enlargement found. Internal
popliteal and transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining. Good silver
differentiation attained.
Microscopic findings.-In longitudinal sections of the
central
wound region, and series of sections at
successive levels, the transplant is clearly demarked by reason of its
jet-black staining. Down-growing central
neuraxes can be seen to penetrate the central end of the transplant, in
which they can be traced distally until the jet
black, nontransparent colorations reached; here they are lost to view.
Certain of the central neuraxes pass to the side
of the transplant, coursing distalward in the surrounding connective
tissue. In cross sections of the transplant, the
perineural sheaths are not found materially thickened. Within the
sheaths the remains of the transplanted nerves so
deeply stained-jet black-that no structural details can be determined,
and it can not be ascertained whether central
neuraxes have reached this level. fn longitudinal sections of the
distal wound region, a few neuraxes can be traced
from the distal end of the transplant to the distal wound; others
appear to reach the wound region from the
surrounding connective tissue. Certain few neuraxes have reached the
central end of the distal popliteal in which
they have grown for a distance approximating 1 cm.
EXPERIMENT
No. 109.-Rabbit No. 93; full grown; 96 days. September 4, 1918, left
sciatic exposed;
internal popliteal bundle freed; resected 2.5 cm. A segment of equal
length, taken from the left sciatic of a full-grown guinea pig, used as
a transplant. One central and distal waxed, fine silk thread suture
placed; good
approximation. Wound closed. December 10, killed. Rabbit moribund;
breathing when killed; much emaciated,
severe neurotrophic ulcer left heel. On exposing the left sciatic, the
external
popliteal is found closely adherent to
operated internal popliteal; dissected free without cutting perineural
sheath. Large spindle-shaped bulb on internal
popliteal noted. The transplant is found well in place, but of small
size; only about one-half the size as when used.
Transplant presents several short stretches of yellow-white color. Calf
muscles exposed; these are atrophic and of
yellow-red color and do not contract nor show twitching on cutting
nerve. Internal popliteal and the transplant
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Fair silver differentiation attained.
Microscopic
findings.- In longitudinal sections of the central wound region, a
distinct central bulbous
enlargement is evidenced structurally, this included the central end of
the transplant, recognized as a granular mass
of detritus and faintly stained vesicular cells. Central neuraxes may
be traced mainly to the side of this mass into the
connective tissue surrounding the transplant. In cross sections of the
transplant, about its mid region, a very material
thickening of its
fibrous sheath
is noted. Within this fibrous sheath there are found numerous small
bundles of
neuraxes, separated by bands of fibrous tissue. The necrotic remains of
the transplanted nerve found to one side. In
longitudinal sections of the distal wound region, certain neuraxes
coming from the distal end of the transplant, more
numerous from the connective tissue surrounding the transplant, can be
traced through the distal wound into the
distal popliteal nerve, in which they are found, scattered through the
several fulliculi to the lower level of the
popliteal space.
1174
EXPERIMENT NO. 110.- Rabbit No. 93a;
full
grown; 96 days. September 4, 1918, right sciatic exposed;
internal popliteal freed; resected 2.2 emu . A segment of equal length,
taken from the right sciatic of a full-grown
guinea pig, used as a transplant. One central and distal waxed, fine
silk thread suture passed; good approximation. Wound closed. December
10, killed. Moribund; just breathing; much emaciated; severe
neurotrophic ulcer right
heel. On exposing the right sciatic, the external popliteal found free.
Transplanted nerve segment found well in
place, of small diameter, and shows several short stretch of
yellow-white color. Large central bulb noted. Calf
muscles exposed; these are atrophic and of pale yellow-red color. No
contraction or twitching of muscles observed
on cutting the nerve. Internal popliteal and transplant removed and
fixed in ammoniated alcohol for pyridine-silver
staining. Only in part good differential silver staining attained.
Microscopic
findings.-In longitudinal sections of the central wound region, a
distinct central bulb evidenced
structurally from the distal end of which down-growing neuraxes maybe
traced to the central end of the transplant
and to the connective tissue by the side of the transplant. The series
of cross sections of the transplant, torn and
found not well differentiated. To one side there may be made out the
necrotic remains of the transplanted nerves,
occupying about one-half of the cross section area of the transplant,
the remaining half consists largely of dense
fibrous tissue in which small bundles of neuraxes are observed this
portion of the section is fragmented, so that
relations are difficult to make out. In longitudinal sections of the
distal wound region, new neuraxes in small
numbers are seen to pass through the distal wound and to enter the
central end of the distal popliteal, in which they
extend for a distance of about 1 cm. beyond the distal wound.
EXPERIMENT No. 111.-Rabbit No. 87; not quite
full grown; 99 days. August 28,1918, left sciatic
exposed; internal popliteal bundle freed; resected 2.8 cm. A segment of
equal length taken from the left sciatic of a
large, full-grown guinea pig, used as transplant. One central and
distal waxed, fine silk thread suture placed; good
approximation. Wound closed. December 6, rabbit found dead in the
morning; mulch emaciated; severe neuro-trophic ulcer left heel; an
encapsuled, sausage-shaped, cold abscess over left tendo Achillis. On
exposing the left
sciatic, external popliteal found free. Transplant found well in place,
throughout of light yellow color, which clearly
demarks it; small diameter. Large spindle-shaped central bulb. Calf
muscles are atrophic and present the appearance
of degenerated muscle. Internal popliteal and transplant removed and
fixed in ammoniated alcohol for pyridine-silver staining. Fairly good
silver differentiation attained.
Microscopic
findings.-In longitudinal sections of the central wound region, a
large central bulb is
recognized structurally, in the distal end of this a necrotic area,
stained jet-black, interpreted as the central end of the
transplant, by the side of this area numerous neuraxes grow distalward.
In cross sections of the transplant in its mid
region, the perineural sheath found materially thickened; to one side
and within the fibrous sheath, a deeply stained
black mass is found occupying about one-half of the cross area of the
transplant and representing the necrotic
remains of the transplanted nerves. To the other side, also within the
fibrous sheath, there are found small groups of
neuraxes, separated by strands of fibrous tissue; a few new neuraxes
are to be observed in the region of the distal
wound. These may be traced to the distal popliteal in which they are
followed to the lower level of the popliteal
space; the remainder of the distal popliteal found completely
degenerated.
EXPERIMENT No. 112.-Rabbit
No. 87a; not quite
full grown; 99 days. August 28,1918, right sciatic
exposed; internal popliteal freed; resected 2.0 cm. A segment of equal
length taken from the right sciatic of a full-grown guinea pig, used as
transplant. One central and distal waxed, fine silk thread suture
placed; good
approximation. Wound closed. December 6, found dead in the morning;
much emaciated; severe neurotrophic ulcer
right heel. On exposing the right sciatic, external popliteal bundle
found free. The transplant found well in place, of
light yellow color; On it or in it there may be traced a fine nerve
bundle. Large spindle-shaped central bulb noted.
Both central and distal sutures clearly evident. Calf muscles atrophic.
The internal popliteal and the transplant
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Fair silver differentiation attained.
1175
Microscopic findings.- In longitudinal sections of the
central
wound region, a large central bulb evidenced
structurally, from the distal end of which new neuraxes may be traced
to the central end of the transplant. In cross
sections of the transplant, the perineural sheath found very materially
thickened and blended with the surrounding
connective tissue. Within this connective tissue sheath small bundles
of neuraxes, separated by strands of fibrous
tissue, arc to be found; certain small funiculi of nerve fibers seen in
the surrounding connective tissue. New neuraxes
in relatively small numbers found in the region of the distal wound,
and in the distal internal popliteal just distal. In
the posterior tibial continuation only degenerated nerve fibers found.
EXPERIMENT No. 113.-Rabbit No. 92; large;
full grown; 104 days. September 3. 1918, left sciatic
exposed; internal popliteal freed and resected 2.2 cm. A segment of
equal length taken from the left sciatic of a full-grown guinea pig,
used as transplant; good approximation. Wound closed. December 17,
killed. Rabbit much
emaciated; snuffles; neurotrophic ulcer on left heel. On exposing the
left sciatic, external popliteal found only
loosely adherent to the operated internal popliteal. On internal
popliteal large central bulb is noted. Transplant found
well in place, distal two-thirds of light yellow color, with several
glistening white streaks. Central end of distal
popliteal found distinctly enlarged. Calf muscles found atrophic, do
not respond on cutting nerve centrally. Internal
popliteal and the transplant removed and fixed in ammoniated alcohol
for pyridine-silver staining. Imperfect silver
differentiation attained.
Microscopic
findings.-In series of longitudinal and cross sections taken at
successive levels, the transplant
clearly demarked by reason of its jet-black, nontransparent staining.
The neuraxes of the central stump not clearly
differentiated and for the remainder of the series not differentiated.
EXPERIMENT No. 114.-Rabbit No. 92a; large;
full grown; 104 days. September 3, 1918, right sciatic
exposed and internal popliteal freed; resected 2.0 cm. A segment of
equal length taken from the right sciatic of a
full-grown guinea pig, used as a transplant. One central and distal
waxed, silk thread suture placed; central
approximation good; distal suture pulled out; an epineural stitch made.
Wound closed. December 17, killed. Rabbit
much emaciated; snuffles; neurotrophic ulcer on right heel. On exposing
right sciatic, external popliteal bound only
loosely to operated internal popliteal. The internal popliteal presents
a large central bull. The transplant found well in
place; of small diameter and in the main of light yellow color. Several
small bundles of nerve appear to run on or in
the trans- plant to reach the distal popliteal. Calf muscles atrophic;
do not respond on cutting the nerve centrally.
Internal popliteal and transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. Imperfect
silver differentiation attained; sections light yellow color, with
neuraxes not differentiated.
Microscopic
findings.-The results of this experiment can not be clearly
determined from study of sections.
In cross sections of the transplant, small areas, which are quite
certainly small funiculi of nerve fibers, found in the
fibrous tissue to one side of the transplant; the region of the nerve
fibers of the transplant only necrotic tissue made
out. No ne1uraxesdifferentiated in the distal popliteal.
EXPERIMENT No. 115.-Rabbit
No. 91; large;
full grown; 191 days. September 2, 191s,left sciatic
exposed; internal popliteal freed; resected 2.6 cm. A segment of equal
length take from a large full-grown guinea
pig, 12 minutes after it stopped breathing, used as trans-plant. One
central and distal waxed, fine silk thread suture
passed; good approximation. Wound closed. March 12, 1919, killed.
Rabbit in good condition; slightly emaciated;
old neurotrophic ulcer on left heel nearly healed. A large, encapsuled,
cold abscess found over tendo Achillis; this
does not involve deeper tissues. On exposing the left sciatic the
external popliteal found free; cutting of the nerve
does not cause contraction of the muscles supplied by it. The operated
internal popliteal bundle presents a large
central bulb; transplant found well in place but of small diameter.
Calf muscles found atrophic and do not respond on
cutting nerve central to the transplant. Internal popliteal removed and
fixed in ammoniated alcohol for pyridine-silver staining. Fairly good
silver differentiation attained.
Microscopic
findings.-In longitudinal sections of the central wound region,
long spindle-shaped bulb
evidenced structurally from the distal end of which numerous
down-growing
1176
neuraxes are found to enter the central
end
of the transplant. In cross sections of the transplant the fibrous
tissue
sheaths of the nerves transplanted are found materially thickened.
Numerous new neuraxes are found within the
transplant, in the form of very small bundles separated by fibrous
tissue. Only relatively few nerve fibers or neuraxes
found in the surrounding fibrous tissue. Within the transplant only
here and there necrotic remains of the
transplanted nerve fibers found. Down-growing neuraxes traced to the
distal wound and into the distal popliteal, in
which they are found in good numbers at the lower level of the
popliteal, the extent of the sections cut. The calf
muscles were not studied in this experiment.
EXPERIMENT
No. 116.- Rabbit No. 91a; large; fill grown; 191 days. September
2,1918,
right sciatic
exposed; internal popliteal freed; resected 3 cm. A segment of equal
length taken from the right sciatic of a large
guinea pig, which had stopped breathing 45 minutes previous, was used
as transplant. One central and distal waxed,
fine silk thread suture placed; good approximation. Wound closed. March
12, 1919, killed. Rabbit in good condition;
old neurotrophic ulcer on right heel nearly healed. On exposing right
sciatic, external popliteal found free. Large
central bulb noted on the operated internal popliteal. Transplant found
well in place, of good size, and presenting the
appearance of a small nerve bundle. The distal internal popliteal
presents the appearance of a normal nerve. External
popliteal cut and resected and internal popliteal freed from bed. Calf
muscles exposed. On slowly cutting with
scissors operated nerve central to the transplant, vigorous contraction
of the calf muscles observed; same on cutting
distal to the transplant. The internal popliteal and transplant removed
and fixed in ammoniated alcohol for pyridine-silver staining; portions
of the calf muscles removed for gold chloride staining. Fair
differential silver staining
attained.
Microscopic
findings.- In longitudinal sections of the central wound region
numerous neuraxes are observed
to extend from the distal end of a large central bulb to the central
end of the transplant. In cross sections of the
transplant, in its mid region, the fibrous tissue sheaths of the nerve
transplanted are found very materially thickened.
Within the fibrous tissue sheaths numerous new neuraxes are found in
the form of small bundles, separated by
connective tissue. In the distal end of the central bulb and at several
levels in the transplant areas of granular detritus,
vesicular cells with globular and granular inclusions are to be found;
remains of the transplanted nerves. New
neuraxes traced to and through the distal wound into the central end of
the distal popliteal. In gold chloride stained
pieces of calf muscles numerous new neuraxes are found in the larger
nerve bundles of the muscle and followed into
the smaller interfascicular branches, but motor end plates were not
found differentiated; teased muscle fibers
presented normal appearance.
EXPERIMENT
No. 117.- Rabbit No. 90; full grown; 194 days. August 30, 1918, left
sciatic exposed;
internal popliteal freed; resected 2.5 cm. A segment of equal length,
taken from the left sciatic of a large guinea pig,
which had stopped breathing 12 minutes previously, used as a
transplant. One central and distal waxed, fine silk
thread suture placed; centrally good approximation; distally "fair."
Wound closed. March 12, 1919, killed. Rabbit in
good condition; severe neurotrophic ulcer left heel, which appears to
be healing. On exposing the left sciatic,
external popliteal found free. Operated internal popliteal presents a
large central bulb. Transplant in place as a fine
strand extending from central bulb to the distal popliteal. Distal
popliteal does not appear degenerated. On exposing
the calf muscles these are found atrophic and of light yellow-red
color. External popliteal removed and internal
popliteal and transplant freed from bed. On slowly cutting with
scissors nerve central to the transplant feeble to
distinct contraction of the calf muscles observed. Internal popliteal
and transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. Good differential silver staining
attained; sections somewhat torn.
Microscopic
findings.- In longitudinal sections of the central wound region
including the central end of the
transplant numerous new neuraxes can be traced from the central bulb
into the transplant and into the surrounding
tissue. In cross sections of the transplant the transplanted nerve
segment is recognized by its distinctly thickened
fibrous sheaths, within which numerous new neuraxes may be seen.
Scarcely any necrotic remains of the
transplanted nerve observed. In the fibrous tissue surrounding the
transplanted nerve segment there are to be seen
many small funiculi of nerve fibers. Down-growing neuraxes can be
traced through
1177
the central wound into the central end
of the
distal popliteal, in which they are found in relatively large numbers
in
its several funiculi.
EXPERIMENT
No. 118.- Rabbit No. 90a; full grown; 194 days. August 30, 1918, right
sciatic exposed;
the internal popliteal freed; resected 2.3 cm. A segment of equal l
length taken from the right sciatic of a full grown
guinea pig, which stopped breathing 32 minutes previous, used as
transplant. One central and distal waxed, fine silk
thread suture placed; good approximation. Wound closed. March 12, 1919,
killed. Rabbit in good condition; severe
neurotrophic ulcer right heel. On exposing the right sciatic external
popliteal found free. The operated internal
popliteal presents a large central bulb. The transplant found in place;
its distal half of light brown color. Calf muscles
atrophic. Cutting of nerve central to transplant causes no contraction
of the calf muscles. Internal popliteal and
transplant removed and fixed in ammoniated alcohol for pyridine-silver
staining. Very good silver differentiation
attained.
Microscopic
findings.- In longitudinal sections of the central wound region,
including the central end of the
transplant, numerous neuraxes can be traced from the central bulb to
the central end of the transplant and
surrounding connective tissue. In the distal end of the central bulb,
the neuraxes are found to cross and intercross
central wound region. In cross sections of the transplant, about 1 cm.
distal to central wound, the perineural sheaths
of the transplanted nerve segments evident and not materially
thickened; within these sheaths numerous neuraxes are
observed. Outside of the perineural sheaths an area of connective
tissue is observed in which there are found
numerous small funiculi of nerve fibers. Down- growing neuraxes can be
traced through the transplant and from the
surrounding connective tissue to the distal wound and through this to
the distal popliteal stump in which, in the
several funiculi, they are found in relatively large numbers.
EXPERIMENT
No. 119.- Rabbit No. 95; full grown; 277 days. September 6, 1918, the
left sciatic
exposed; internal popliteal freed; resected 2.7 cm. A segment of equal
length taken from the left sciatic of a full-grown guinea pig, used as
a transplant. One central and distal waxed, fine silk thread suture
placed; central
approximation good; distal approximation, nerve ends not in good
alignment. Wound closed. June 10, 1919, rabbit
found dead in the morning; very much emaciated; severe neurotrophic
ulcer left heel. On exposing the left sciatic the
operated internal popliteal is found to end in a large central bulb,
from the distal end of which no transplant nor
nerve bundles can be traced to the distal popliteal, the central end of
which ends free and presents an S-shaped
curve.
It would appear that the central suture gave way soon after the
operation and that the transplanted nerve segment had
completely disappeared. Calf muscles found atrophic and distal internal
popliteal completely degenerated. Central
bulb and distal internal popliteal removed and fixed in ammoniated
alcohol for pyridine-silver staining. Fairly good
silver staining attained.
Microscopic
findings.- In longitudinal sections of the central bulb this is
found to include the central end
of the transplant, consisting of necrotic detritus. Active down-growth
of central neuraxes is evident; these are lost in
the surrounding connective tissue In the distal popliteal the nerve
fibers found completely degenerated.
EXPERIMENT
No. 120.-Rabbit No. 95a; full grown; 277 days. September 6, 1918, p
right sciatic
exposed; internal popliteal freed; resected 2.5 cm. A segment of equal
length taken from the sciatic of a large, full-grown guinea pig, used
as transplant. One central and distal waxed fine silk thread suture
placed; very good
approximation. Wound closed. June 10, 1919, rabbit found dead in the
morning; very much emaciated; severe
neurotrophic ulcer right heel. On exposing the right sciatic, the
operated internal popliteal found to end in a large
spindle-shaped bulb; the transplant well in place and of good size.
Conditions of calf muscles not recorded. Internal
popliteal and transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining. Fair silver
differentiation attained.
Microscopic
findings.-In longitudinal sections of the central wound region a
large
central bulb, with
characteristic structure of neuroma, including spiral neuraxes,
evidenced structurally. In distal end of bulb, the
necrotic remains of the central end of the transplant are found.
Numerous down-growing neuraxes pass by the side of
this necrotic area and extend distalward in the connective tissue. In
the several successive series of sections the
greater part of the transplanted nerve fibers, or the remains of the
same, stained jet-
1178
black in the silver. In cross sections
of the
transplant taken from its mild region small fuiniculi of nerve fibers
are
found in the connective tissue surrounding the transplant. In the
region of the distal wound and in sections of the
central end of the distal popliteal only a few neuraxes are to be
observed; the greater part of the distal popliteal
showing degenerated nerve fibers.
EXPERIMENT
NO. 121.- Rabbit No. 94; large Belgian hare; 358 days. September 5,
1918, left sciatic
exposed; internal popliteal freed; resected 2.5 cm. A segment of equal
length taken from the left sciatic of a large
guinea pig and used as transplant. One central and distal waxed fine
silk thread suture passed. Centrally "fair"
approximation attained; distally good alignment, but cut nerve ends not
quite end to end. Wound closed. August 28,
1919, rabbit in good condition; still large neurotrophic ulcer left
heel; appears to be healing; spreads toes of left hind
foot when held up by ears. On exposing the left sciatic external
popliteal is found in close apposition to the operated
internal popliteal; adherent to it. Large spindle-shaped central bulb
on the operated internal popliteal. Transplant
found well in place and presents the appearance of a normal nerve. Calf
muscles exposed and external popliteal cut
at the level of head of fibula; internal popliteal and transplant
freed. On slowly cutting with scissors, central sciatic,
good contraction of calf muscles and less vigorous contraction of the
plantar foot muscles observed. Calf
muscles
found of nearly normal size and of pale red color streaked with yellow.
The internal popliteal and transplant,
portions of calf and foot muscles removed and fixed in ammoniated
alcohol for pyridine-silver staining. Quite good
differential silver staining attained.
Microscopic
findings.-In longitudinal sections of the central wound
region,
from the distal end of the large
central bulb, certain down-growing neuraxes can be traced into the
central end of the nerve transplant, the majority
into the connective tissue surrounding the transplant. In the
connective tissue the small bundles of nerve fibers
present a very serpentine course. In cross sections of the transplant,
taken about 1 cm. distal to the central wound,
numerous small funiculi of nerve fibers are found in the connective
tissue surrounding the transplant, outside of the
perineural sheaths. Within the transplant crosscut neuraxes,
differentially stained, are found in good numbers,
separated by strands of connective tissue. Only small remnants of the
necrotic remains of the transplanted nerve
fibers found within the transplant. Down-growing neuraxes can be traced
to and through the distal wound, into the
distal popliteal, in which they are found in good numbers in all of the
funiculi. In sections of the calf muscles new
neuraxes are found in the larger and smaller intramuscular nerve
branches and as single fibers between and on the
muscle fibers.
EXPERIMENT
No. 122.- Rabbit No. 94a; large Belgian hare; 358 days. September 5,
1918, right sciatic
exposed; internal popliteal freed; resected 2.5 cm. A segment of equal
length taken from the right sciatic of a large,
full-grown guinea pig, used as transplant. One central and distal waxed
silk thread suture placed; good
approximation. Wound closed August 28, 1919, killed. Rabbit in very
good condition; still large neurotrophic ulcer
right heel, which appears to be healing. On exposing the right sciatic,
the external popliteal is found free. A long
spindle-shaped bulb found on the central internal popliteal. Transplant
found well in place, of small diameter but
presents the appearance of a normal nerve. Distal popliteal; looks like
a normal nerve. Calf muscles exposed; very
nearly of normal size and of pale red color streaked with light yellow.
After cutting and resecting external popliteal
and freeing the operated internal popliteal from bed, on slowly cutting
nerve with scissors, central to the transplant,
distinct but feeble contractions in the calf muscles noted; foot
muscles uncertain. Functional test 20 minutes after the
animal was killed. Internal popliteal and transplant and portions of
calf muscles removed and fixed in ammoniated
alcohol for pyridine-silver staining.
Microscopic
findings.-Only in part good silver differentiation attained; in
part fine granular silver deposit in
sections. In longitudinal sections of the central wound region large
numbers of down-growing neuraxes can be traced
from the distal end of the central bulb to the central end of the
transplant and the connective tissue surrounding the
transplant; the latter in the form of numerous small funiculi, very
much coiled and twisted; those entering the
transplant follow a more regular longitudinal course after having
passed the central
1179
wound region. In cross sections of the
transplant, about 1 cm. distal to the central wound, it may be observed
that
new neuraxes are found both within and without the perineural sheaths
of the nerve segment transplanted. New
neuraxes can be traced through the distal wound into the distal
popliteal, in which they arc found in good numbers in
all of the fulliculi. In the sections made from the calf muscles
neuraxes are found in the larger fasictilar nerve
bundles and here and there as single nerve fibers on the muscle fibers.
The muscle fibers so far as can be determined
in silver stained preparations appear to present normal structure; here
and there areas or columns of fat cells within
the muscle.
EXPERIMENT
NO. 123.- Rabbit No. 78a; large; full grown; 7 days. June 3, 1918,
right
sciatic exposed;
fascial plane not readily found, consequence muscle torn; sciatic
resected 2.5 cm. A segment of equal length taken
from the right external popliteal of a full-grown dog; nerve resected
two hours previous; nerve segment lying in the
wound used as transplant. One central and distal waxed fine silk thread
suture placed; good approximation.
Ultimately dry field; wound closed. June 10, rabbit found dead in the
morning; superficial wound healed; deep
wound congested. In deep wound near distal suture a small hematoma in
the connective tissue. Transplant found
well in place; united to the resected nerve ends; central and distal
sutures distinct. Sciatic and the transplant removed
and fixed in ammoniated alcohol for pyridine-silver staining. Faint but
differential silver staining attained.
Microscopic findings.- Transplant united to central sciatic
only
at one border; for the remainder of the cross
section separated by an appreciable distance. Distally good fibrous
union obtained. In longitudinal sections of the
transplant the neuraxes of the transplanted nerve fibers found
fragmented into relatively long segments, having a
wavy or spiral course, and stained differentially in the silver stain.
The neurolemma sheaths seem well maintained,
the perineural sheaths not appreciably thickened. In the distal end of
the central sciatic stump early stages of the
downgrowth of the central neuraxes evident. The nerve fibers of the
distal sciatic present early stages of
degeneration.
EXPERIMENT
No. 124.- Rabbit No. 75a; full grown, 13 days. May 10, 1918, right
sciatic exposed and
resected 2.5 cm. A segment of equal length, taken from the left
internal popliteal of a dog, used as transplant. One
central and distal silk-thread suture placed; good approximation.
Muscle stitched over nerve. Wound closed. May
23, rabbit found dead in the morning; "snuffles;" wound well healed. On
exposing the right sciatic, transplant found
well in place; appears of slightly greater diameter than when used;
found well united to the resected nerve ends.
Transplant surrounded by newly formed connective tissue. Sciatic and
the transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
neuraxis staining attained.
Microscopic
findings.-In longitudinal sections of the central and distal wound
regions, ends of transplant
found well united to the resected nerve ends. In longitudinal sections
of the transplanted nerve segment, the neuraxes
of the old nerve fibers are found segmented into longer and shorter
segments, staining differentially in the silver
stain; the neurolemma sheaths found well preserved; no distinct
evidence of the proliferation of the sheath cells. Structural evidence
of the beginning of a central bulb, from the distal end of which many
down-growing neuraxes,
terminating in bulbous end-discs, can be traced through the central
wound for a short distance into the central end of
the transplant. In certain of the neurolemma sheaths, near the central
wound, remnants of old neuraxes and down-grown new neuraxes are to be
found side by side. The fibers of the distal sciatic found in process
of degeneration;
many nucleated syncytial protoplasmic bands are seen, with
proliferation of sheath cells.
EXPERIMENT
No. 125.- Rabbit No. 76a; large; full grown; 52 days. May 17,
1918,right
sciatic exposed
and resected 2 cm. A segment of equal length, taken from the left ulnar
of a dog, used as a transplant. One central
and distal silk-thread suture passed; good approximation. Wound closed.
July 8, rabbit found dead in the morning;
wound well healed. On exposing the right sciatic, transplant was found
to be well in place, firmly united to the
resected sciatic stumps; adherent to the underlying muscle. Transplant
of yellow-white color but seems of good
consistency. No well-marked central bulb noted. Sciatic and transplant
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Good differential silver staining attained.
1180
Microscopic findings.-In the successive series of
longitudinal
and cross sections, the transplanted nerve
segment is clearly demarked by reason of a jet-black nontransparent
coloring, the connective tissue sheaths being
stained a yellow-brown color. Within the transplant, here and there
fragments of neuraxes are found within the
neurolemma sheaths. In cross sections of the transplant, wherever the
dark coloring admits of the observation, in
nearly every neurolemma sheath there may be observed the cut end of the
old neuraxis. In longitudinal sections of
the central wound region, clown-growing neuraxes, traced from the
distal end of the central bulb, may be seen
passing by the side of the nerve transplant into the surrounding
connective tissue, and in longitudinal sections of the
transplant, new neuraxes are found in the fibrous tissue between the
funiculi. No new neuraxes are found in the
region of the distal wound. The nerve fibers of the distal sciatic are
found completely degenerated.
It
is evident from a study of the protocols of the experiments on
hetero-nerve transplant,
that on the face of the results attained the statement iswarranted that
a hetero-nerve transplant
may be used to bridge a nerve defect with probability of success, to
the extent that certain of the
down-growing central neuraxes will penetrate the central end of the
transplant and through it
reach the distal segment. In all of the experiments of this series,
kept for more than three months
(No. 109 to No. 122) after the operation, the down-growing neuraxes
derived from the distal end
of the central stump could be traced into the central end of the
transplant, to the distal wound
region, and thence to the distal sciatic stump. There seems no question
that a certain number of
down-growing neuraxes, the number varying in the different experiments,
reach the distal sciatic
segment through the hetero-nerve transplant. Having established this
general conclusion, the
protocols of the experiments of long duration may be studied more
critically, and it will be found
that in nearly every record of microscopic findings it is noted that
the down-growing neuraxes
derived from the central stump not only penetrate the central end of
the trans-plant but at the
central wound region pass into the connective tissue surrounding the
transplant and in close
contiguity to it reach the distal wound and, perchance, enter the
distal sciatic stump. These extrafunicular nerve
bundles are most easily determined in cross sections of the transplant
and
surrounding connective tissue. In such sections, the funicular
structure of the nerve transplanted
is usually readily made out, even months after the operation, and the
perineural sheaths
surrounding the funiculi are evident. In properly stained sections,
with neuraxis differentiation,
extra funicular nerve fibers, singly or in small bundles, are easily
determined. Such
extrafunicular fiber bundles usually have an irregular serpentine
course, as though winding their
way through the interstices of the connective tissue. It may also be
noted that these
extrafunicular nerve fiber bundles are on the whole much more numerous
than is the case when
auto- or homo-nerve transplants are used, and mav include a relatively
large per cent of the
central nerve fibers reaching the distal wound and the distal nerve
segment. It can also be shown
that the rate of regeneration appears much slower when a hetero-nerve
transplant is used than
when using an auto- or homo-nerve transplant. Further, that the results
are not so satisfactory,
taking as an index the number of neuraxes which reach the distal stump
through the hetero-nerve
transplant, as when auto-or homo-nerve transplants are used. However,
the hetero-nerve
transplant does not become necrotic as is stated by certain observers.
If properly sutured to the
resected
1181
nerve ends, the ends of
the hetero-nerve transplant quickly form fibrous union with the
resected
nerve ends and become surrounded by newly formed connective tissue. In
experiments
terminated from six to twelve months after the operation, there is
usually present a prominent
central nerve bulb which includes the central wound region. In the
region of the transplant the
nerve bundle has the appearance of a living nerve, though of smaller
diameter than when the
nerve was transplanted. The hetero-nerve transplant has not
disappeared, since months after the
transplant was placed its funicular structure can be made out.
In
the earlier stages of experimental operative work on nerve bridging
nospecial
consideration was given to the relative value of auto-, homo-, and
hetero-nerve transplants; the
need of making such differentiation was not recognized. As early as
1869, Philippeaux and
Fulpian used a lingual nerve to bridge the resected hypoglossal nerve
of dogs; auto-nerve
transplant. These experiments were followed by others in which auto-,
homo-, and hetero-nerve
transplants were used, generally with indifferent or unfavorable
results. Huber, in 1895, reported
on a series of 26 experiments of nerve transplantation. Of this number
in 10 of the experiments
the animals were kept for a period of four months or more before the
operated nerve was tested
functionally and the nerve removed for examination. In five of these,
all hetero-nerve transplants
(cat's sciatic to resected ulnar of dog), the results were very
satisfactory; in four others the down-growing central neuraxes had
passed the region of the transplant and entered the distal nerve
segment. With the microscopic methods available then, such precise
neuraxis differentiation
could not be had as now and it was not determined whether all of the
down-growing neuraxes
passed to the distal stump through the funiculi of the transplant or
extra-funicular in the
surrounding connective tissue. In an unsigned statement, found in the
"Medical Supplement,
Daily Review of Foreign Press," London, October 1, 1918, giving a
review of the treatment of
gun-shot injuries of nerves in Germany to the middle of 1917, the
following statement appears:
When a gap between the two divided nerve ends
can not be obliterated, the unsettled question as to the
regeneration of nerves has to be taken into consideration. The dominant
view before the war was that regeneration in
the peripheral segment was due entirely to the down growth of
axis-cylinders from the proximal segment. But this
theory does not seem to receive much confirmation. The regeneration of
potential nerve fibers in the still separated
distal segment, as described by Ballance and Purves Stewart, has found
supporters, the potential nerve fibers
becoming linked up with axis cylinders in the proximal segment when the
two ends are brought
together * * *.
The second view that the distal segment regenerates so far affords
encouragement to the method of
inserting into the gap a nerve graft, which shall serve, as it were, to
prolong the peripheral segment to meet the
proximal end. Then the axis cylinders in the proximal segment, without
growing out more than is seen incase of
nerve end bulb, can become connected by a series of links with the
potentially regenerated nerve fibers, and then
these become fully developed. This nerve grafting to fill gaps gains
support from animal experimentation and
appears to be the plan which should be adopted in surgery.
The
experimental observations on nerve transplantation furnish the most
conclusive
evidence for the monogenetic ol downgrowth theory of nerve
regeneration. In none of the
experiments recorded under Series No. 5, No. 6,and No. 7 is there found
any evidence in support
of auto-regeneration of the
1182
peripheral stump. In
suitably stained pyridine-silver preparations of a nerve bridged by a
nerve
transplant and removed for study at the right time, in a serial order
at progressive stated
intervals, it can be seen that the budding central neuraxes grow to the
region of the central
wound and step for step into the transplant, through the transplant
into and through the distal
wound and into the distal segment, and in this progressively until the
end organs are reached. As
a result of the observations accumulated in this series of experiments,
there is found abundant
warrant for stating that the nerve bridge or nerve transplant offers a
suitable path for down-growing central neuraxes and that regeneration
of the distal segment after nerve bridging is only
through down-growing central neuraxes.
In
more recent experimental observations and in the more modern surgical
work more
precise recognition has been given to the relative merits of the
auto-, homo-, and hetero-nerve
transplants as with other tissue grafts. As a result of experimental
observations, Forssman 70 and
a little later Morzbacher,71 whose results were confirmed by
Segale,72 were the first to suggest
that there were important differences between homo- and hetero-nerve
transplants. As a result of
their observations it was concluded that in auto- and homo-nerve
transplants the transplanted
nerves survived and were capable of undergoing degenerative changes
while a hetero-nerve
transplant was subject to a necrobiotic process owing to the fact that
it did not survive in the
host. On the other hand, Maccabruni 73 working in the
laboratory of Golgi, found that there was
little difference in the behavior of auto-, homo-, or heterogenous
nerve segments transplanted
into connective tissue or intermuscular septa, the axial portion of
each becoming necrotic while
the more peripheral portions, subject to better nutrition, presented
the phenomena of nerve
degeneration, even proliferation of sheath cells. Ingebrigtsen has
considered this question in a
number of contributions. In the account of 1915, 74 the
following
statement appears: "In the
problem of transplantation of nerves the question of the fate and
survival and multiplication of
the cells of Schwann is of importance. The solution of this point,
which is the only reliable sign
of the survival of the transplanted piece, gives the key to the problem
and will influence the
procedure of surgeons in cases of nerve defects. If the grafts die and
become necrotic they are no
more suitable for bridges than strands of catgut." Writing in 1916,
Ingebrigtsen 75 states that
Wallerian degeneration occurs in auto- and homo-nerve transplants in
the same manner as in the
peripheral end of a cut nerve, except that the various changes take
place somewhat slowly, while
in hetero-transplants there is no Wallerian degeneration and no
proliferation of sheath cells and
12 to 15 days after transplantation the nerve becomes necrotic and on
histologic examination of
the later stages no new neuraxes were found in the heterogenous
transplant. After more extended
study and in a comprehensive monograph (1918) 43 Ingebrigtsen had broadened his viewpoint, as
may be noticed from the following quotation which is presented in this
quite literal translation:
And we come then to the conclusion that
the
cells of the sheath of Schwann of the auto-and homo-nerve transplants
are without biological significance whatever for the regeneration of
the new neuro-fibrils of the transplant, which
grow into the transplant from the central stump whether the transplant
is living or dead.
1183
In
the extended series of operations on nerve transplants, included in
Series No. 5, No. 6,
and No. 7, auto-, homo-, and lietero-nerve transplants, primary
consideration was given to the
downgrowth of central neuraxes in regeneration and their relation to
the transplanted nerve
fibers, and for this purpose the pyridine-silver neuraxis
differentiation method was largely used. This method is not suitable
for a detailed study of the myelin fragmentation nor the behavior of
the sheath cells of the transplanted nerves. The evidence at hand
warrants the conclusion that
none of the transplanted nerve fibers, whether of auto-, homo-, or
heterogenous source, undergo
typical Wallerian degeneration, if sheath cell proliferation is to be
considered a sine qua non of
Wallerian degeneration. Further, the conviction has been gained that
the sheath cells of the
transplant play a very subsidiary and a negligible r ole as concerns
regeneration through a
nerve transplant. (Series No. I1, No. 12,and No. 13 seem to demonstrate
this conclusively.) That there is a (difference in the behavior of
auto-and homo-nerve transplants on the one hand,
and hetero-nerve transplant on the other there can be no question.
However, one can not accept
the statement that heteroplastic nerve transplants become necrotic.
Months after such a transplant
has been placed, can its funicular structure be determined, with
funiculi surrounded by perineural
sheaths? That regeneration may take place through a hetero-nerve
transplant the earlier
observations of Huber (1895) 30 may serve to show, as also certain of
the experiments of longer
duration of Series No. 7. In preparations made from this series the
neuraxes were differentially
stained by the pyridine-silver method and in successful preparations
stained by this method there
is no difficulty in determining neuraxes. The results obtained as
regards regeneration of the
peripheral segment are not nearly so favorable on use of the
heterogenous transplant as when
auto- and homo-nerve transplants are used. However, this would seem to
be due not so much to a
difference in the mode of fragmentation of the myelin and a want of
sheath cell proliferation but
to a relatively retarded and at times imperfect phagocytosis of the
products of myelin
fragmentation, leaving the neurolemma tubes less suitable for neuraxis
downgrowth than when
homo- or auto-nerve transplants are used. The answer to the question of
chemotactic or want of
chemotactic action of the products of nerve degeneration and sheath
cell proliferation can not
now be given, since sufficient, and conclusive experimental evidence is
not now at hand. Conditions being approximately equal as concerns
operation, relative size of nerve and sutures,
the extrafunicular nerve fibers coming from the central stump and
passing into the connective
tissue surrounding the transplant are much more numerous when
heterogenous transplants are
used than with autogenous or homogenous transplants. This is
interpreted as an index that the
latter are more favorable than the former for downgrowth of neuraxes.
Thus, while the
regeneration of the distal segment of a resected nerve can be obtained
through a heterogenous
nerve bridge in experimental work, the outcome is less certain and less
satisfactory and it
requires a longer time than when auto-or homo-nerve transplants are
used. Thus, hetero-nerve
transplantation is not recommended as an operation in the repair of
human nerves after loss of
nerve substance.
1184
DEGENERATED
NERVE TRANSPLANTS
SERIES NO. 8, NO. 9, AND NO.
10
DEGENERATED AUTO-, HOMO-, AND
HETERO-NERVE
TRANSPLANTS
In
Series No. 8, No. 9, and No. 10, including degnerated auto-, homo-,and
hetero-nerve
transplants, the nerve segment selected for the transplant was taken
from a nerve which had been
caused to undergo Wallerian degeneration as a result of nerve section
some weeks before the
nerve segment was used as a nerve bridge. This series of experiments
was undertaken to test a
number of hypotheses relative to nerve transplants. It was conjectured
that since a transplanted
nerve segment degenerates after transplantation, the process of
regeneration through a nerve
transplant might be facilitated by using a nerve segment already
degenerated to the extent of
presentingthe nucleated syncytial strands (" band fasern ") in the
neurolemina sheaths. In a
measure one may regard the nucleated syncytial strands, the product of
sheath cell proliferation,
as less differentiated protoplasm than developed sheath cells,
conceivably a protoplasm more
favorable to downgrowth of central neuraxes. Especially was it
conjectured that a degenerated
hetero-nerve transplant might for this reason prove more satisfactory
than a hetero-nerve
transplant taken from a normal nerve. It was further felt, consequent
to the suggestion of certain
observers who have regarded degenerating nerve fibers and proliferating
sheath cells as capable
of exerting a chemotactic in-fluence on down-growing neuraxes in nerve
regeneration, a
degenerated nerve transplant might serve to attract, from the beginning
of transplantation, central
neuraxes in early stages of regeneration. None of these suppositions
were well founded. These
three series of experiments are jointly presented and considered. The
protocols of experiments
126 to 149 (Series No. 8, No. 9,and No. 10) are as follows:
PROTOCOLS
EXPERIMENT
No. 126.- Dog No. 1; medium size; full grown; 133 clays. March
25,1918, right ulnar exposed and resected 1.2 cm. As a transplant, used
1.2 cm. of the distal
segment of the left sciatic of the same clog, cut March 7, 18 days
previous. One central and one
distal Chinese silk suture placed; good approximation. Quite a little
bleeding, which was not
folly controlled. Fascia stitched over the nerve and transplant. Wound
closed. August 5, killed.
Dog in good condition. On exposing the ulnar, the transplant was found
well in place; easily
demarked, since central and distal sutures are still clearly evident.
Transplant has diameter
slightly larger than ulnar. Ulnar distal to transplant presents the
appearance of normal nerve.
Forearm muscles supplied by ulnar do not contract when ulnar is cut
central to the transplant.
Ulnar and the transplant and distal ulnar removed and fixed in
ammoniated alcohol. Only in part
good differential staining attained. Tissues not well embedded,
sections torn.
Microscopic
findings.- In longitudinal sections of the central wound region,
distinct
central bulb evidenced structurally, from the distal end of which
down-growing neuraxes can be
traced to the transplant. In cross sections of the transplant, the
funicular structure of the
degenerated nerve segment transplanted, is in part retained. New
neuraxes observed in the
funiculi, in which they are arranged in small bundles separated by
fibrous tissue; also in the
connective tissue surrounding the transplant; especially to one side.
In longitudinal sections of
the distal wound region, new neuraxes can be traced to the distal ulnar
and in this, in good
numbers to the level of the elbow; the extent of the distal ulnar
segment sectioned.
1185
EXPERIMENT No. 127.- Dog No. 3; medium
size;
full grown; 134 days. March 27,1918, right ulnar
exposed and resected 1.5 Cm. A segment of equal length, taken from the
external popliteal bundle of the left sciatic
of the same dog, cut March 8,18 days previously, used as transplant.
One central and distal Chinese silk suture
placed; fair approximation attained. Free venous bleeding, not fully
controlled. Fascia stitched over nerve; wound
closed. August 8, killed. Dog in very good condition. On exposing the
right ulnar, a large bulb is observed on end of
central ulnar stump, from which a small nerve bundle lead to the distal
ulnar segment. On cutting ulnar central to the
transplant, no distinct contraction of the forearm muscles supplied by
the ulnar is observed. 1lnar and transplant and
segment of distal ulnar removed and fixed in ammoniated alcohol for
pyridine-silver staining. Not entirely
successful silver differentiation attained.
Microscopic findings.- In alternate longitudinal and cross
sections, new neuraxes call be traced from the
central ulnar stump to the distal ulnar. In the cross sections taken
from the middle of the transplant, the funicular
structure of the transplanted nerve segment not clearly made out. Small
funiculi of nerve fibers are observed. Their
relation to the transplanted nerve segment is uncertain.
EXPERIMENT
No. 128.- Dog No. 2; medium size; full grown; 420 days. March 26,1918,
right ulnar
exposed and resected to the extent of 1.5 cm. A segment of equal length
taken from the left external popliteal of the
same dog, the left sciatic of which was cut March7, 19 days previous,
used as a transplant. One central and distal
Chinese silk suture placed; good approximation. Fascia stitched over
nerve; wound closed. May 20, 1919, killed. Dog in good condition. On
exposing the right ulnar, distinct central ulnar bulb is found, from
the distal end of which
a well-formed bundle of nerves, of slightly smaller diameter than the
ulnar, leads to the distal ulnar stump, the
central end of which is only slightly enlarged. In the region of the
transplant nerve firmly adherent to the
surrounding tissue, the distal ulnar has the appearance of a normal
nerve. After exposing the forearm muscles, and
freeing the ulnar from its bed, on slowly cutting the ulnar central to
the transplant, distinct and vigorous contraction
of the forearm muscles supplied by the ulnar. Ulnar and transplant
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Good differential silver staining attained.
Microscopic findings.-In series of alternate
longitudinal and
cross sections, through transplant and distal
ulnar, neuraxes coming from the central ulnar can be traced through the
transplant into the distal ulnar. In cross
section of the transplant, taken at its middle, it may be clearly seen
that the connective tissue of the transplant is very
materially increased; this blending with the perineural sheaths.
Certain of the down-growing neuraxes, both
myelinated and nonmyelinated, appear within a large funiculus of the
transplanted nerve segment. Others are found
in small bundles in the connective tissue outside of the transplant. In
the distal ulnar, cut in cross sections 2 cm.
below the elbow, both myelinated and nonmyelinated neuraxes are found
scattered through all of the funicili, in
large numbers.
EXPERIMENT
No. 129.- Dog No. 36; medium size; full grown; 17 days. June 4, 1918,
left sciatic exposed;
internal popliteal bundle freed and resected 3 cm. A segment of equal
length, taken from the left internal popliteal of
dog No. 24, the sciatic of which was cut May 18, 17 days previous, used
as a transplant. One central and distal
waxed, fine silk thread suture placed; very good central and distal
approximation attained. Wound closed. June 21,
dog found dead in the morning; no neurotrophic changes of left hind
foot. On exposing the left sciatic, transplant is
found well in place, and appears of slightly larger diameter than when
transplanted; no distant central bulb observed.
The internal popliteal and the transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good
differential silver staining attained.
Microscopic findings.- In longitudinal sections of the
central and
distal wound regions, transplant found well
united to resected nerve ends with only narrow fibrous tissue union
intervening. Scarcely any evidence of central
bulb noted. In the distal end of the central stump, active outgrowth of
central neuraxes observed. These have reached
the scar tissue of the central wound, which many have penetrated and
which they traverse by crisscrossing in all
directions. Many end-discs and evidence of branching of neuraxes seen.
A certain few of the central neuraxes have
passed through the central wound into the central end of
1186
the nerve transplant. These are much
more
nunerous near the central wound than a little more distally, but can be
traced to nearly the middle of the transplant. Within the transplant
there arc observed the thickened neurolemma
sheaths of the degenerated, transplanted nerve fibers, and remnants of
myelin. The distal internal popliteal is found
in early stage of degeneration.
EXPERIMENT
No. 130.-Dog No. 7; large; full grown; 36 days. July 5, 1918,
left sciatic exposed; internal popliteal bundle freed; resected 4 cm. A
segment of equal length, taken from the left
internal popliteal of dog No. 28, the sciatic of which was cut 28 days
previously, used as a transplant. One central
and distal waxed, fine silk thread suture placed; very good
approximation attained. Wound closed. August 10, killed.
Dog seemed well, though emaciated; no neurotrophic changes left hind
foot; wound well healed. On exposing the
left sciatic, the external popliteal bundle found free; the transplant
in the internal popliteal well in place, and clearly
demarked by its light yellow color; no material increase of connective
tissue about the transplant. No distinct central
bulb noted. The internal popliteal removed and fixed in neutral
formalin. Sections stained in iron-hematoxylin and
piero-fuchsin; safranine and light-grün.
Microscopic
findings.-In longitudinal sections of the central and distal wound
regions, transplant found well
united to the resected nerve ends; fibrous tissue union at the wounds.
In the sections from the central wound region,
new nerve fibers, in part with fine myelin sheaths, can be traced from
the central stump, through the central wound
into the transplant. In cross and longitudinal sections of the
transplant, the neurolemma sheaths found give the
impression of being thickened. Many of these sheaths contain large
vesicular cells, having globular, myelin remains
in their protoplasm; further, granular detritus; not many sheath nuclei
evident. The distal nerve presents degeneration
phenomena.
EXPERIMENT
No. 131.- Dog No. 5a; large; full grown; 37 days. July 3, 1918, the
right sciatic exposed;
internal popliteal freed; resected 3.4 cm. A segment of equal length
taken from the internal popliteal of the right
sciatic of dog No. 27, cut June 6, 27 days previous and used as a
transplant. One central and distal waxed fine silk
thread suture placed; good alignment attained, but distal end of
transplant rotated; good approximation of nerve
ends. Wound closed. August 9, killed. Dog emaciated; small neurotrophic
ulcer right hind foot. Wound well healed.
On exposing the right sciatic, it is found that the external popliteal
is closely adherent to the operated internal
popliteal; was not dissected free. Distinct increase of connective
tissue in the region of operation, about the sciatic.
The transplant found well ii place; demarked by its light yellow color.
No distinct central bulb noted. External and
operated internal popliteal bundle removed together and fixed in
ammoniated alcohol for pyridine-silver staining.
Good differential neuraxis staining attained.
Microscopic
findings.- In longitudinal sections of the central wound region
neuraxes from the central stump
in large numbers can be traced into the central end of the transplant.
In cross sections of the transplant, 1 cm. distal
to the central wound, numerous neuraxes are found within the
transplant, in the form of small bundles, separated by
strands of fibrous tissue. In longitudinal sections of the transplant,
it may be observed, that while these small bundles
have in the main a longitudinal direction, contiguous bundles
frequently are found anastomosing. Only a small
number of old myelin remnants are found in the transplant. A few of the
down-growing neuraxes have reached the
distal wound and can be traced for a short distance into the central
end of the distal popliteal; by far the greater
portion of the distal popliteal showing only degenerated nerve fibers.
EXPERIMENT
No. 132.- Dog No. 37; medium size; full grown; 146 days. June 18. 1918,
left sciatic
exposed; internal popliteal freed, resected 2.7 cm. A segment of equal
length, taken from the internal popliteal
bundle of the left sciatic of dog No. 23, cut May 31, 18 days previous,
used as transplant. One central and distal
waxed fine silk thread suture placed; good approximation. Wound closed.
November 11, killed. On this day
participated in fight with another dog and nearly killed; was still
breathing when found. Dog in good condition. No neurotrophic changes left
hind foot
noted. On exposing the left sciatic, external popliteal found free; no
distinct bulb
on central internal popliteal. Transplant found well in place, has the
appearance of normal nerve, except that a light
pink color is evident. Distal nerve has the appearance of normal nerve.
Calf and the plantar muscles exposed and
external popliteal resected and removed. After freeing the internal
popliteal and
1187
transplant from the bed, on slowly
cutting
the nerve central to transplant, good contraction of calf and
interossei
muscles observed. On cutting posterior tibial at heel, interossei
muscles seen to contract. Internal popliteal and the
transplant, posterior tibial, internal plantar and portions of several
interossei muscles removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
neuraxis staining attained.
Microscopic
findings.- In longitudinal sections of the central wound region, a
long spindle-shaped bulb
evidenced structurally from the distal end of which numerous
down-growing neuraxes can be traced to the central
end of the transplant. In cross sections of the transplant 1 cm.
distal to the central wound, the perineural sheaths of
the transplant found thickened. Within
these sheaths are found, within the funiculi, numerous small bundles of
neuraxes, certain of which are myelinated, separated by strands of
fibrous tissue. Large numbers of the neuraxes in
these small bundles may be traced to and through the distal wound into
the distal internal popliteal, in which new
neuraxes are found in all of the funiculi. New neuraxes can he traced
to the interfascicular nerve branches in the
interossei muscles; a few motor ending observed. Good regeneration of
the distal popliteal attained.
EXPERIMENT
No. 133.-Dog No. 8a; large dog; full grown; 316 days. July 9, 1918.left
sciatic exposed;
internal popliteal freed; resected 3.8 cm. A segment of equal length,
taken from the internal popliteal of the sciatic of
dog No. 26, cut June 7, 32 days previous, used as transplant. One
central and distal waxed fine silk thread suture
placed. Good distal approximation; central good alignment, but after
tying distal suture, central suture gave way
slightly, so that nerve ends were nearly 2 mm. apart. Wound closed. May
21,1919, killed. Dog in very good
condition; uses left hind foot well; no neurotrophic changes. On
exposing the left sciatic, the external popliteal is
found free. No distinct enlargement on central internal popliteal
noted. The transplant found well in place and
presents the appearance of a normal nerve, though somewhat spread out
and of flattened form. Distal popliteal has
the appearance of a normal nerve. Calf and plantar muscles exposed;
external popliteal resected and removed. After
separating nerve and transplant from bed, on slowly cutting nerve with
scissors central to the transplant,
distinct and
vigorous contraction of calf and foot muscles noted. Internal popliteal
and transplant, posterior tibial, portions of calf
and foot muscles removed and fixed in ammoniated alcohol for
pyridine-silver staining. Good differential neuraxis
staining attained.
Microscopic
findings.-In longitudinal sections of the central wound region,
quite distinct spindle-shaped
bulb evidenced structurally, from the distal end of which numerous
neuraxes enter the transplant. In cross sections of
the transplant, taken at levels near the central and distal wounds, the
transplanted nerve segment found to be well
outlined with thickened fibrous sheaths. Within the transplant are
found numerous small bundles of neuraxes
separated by strands of fibrous tissue. Numerous small bundles of
neuraxes also found in the connective tissue
surrounding the nerve transplant. Many of the neuraxes within and
without the transplant are found to be myelinated.
New neuraxes call, in sections made at successive levels, be traced
through the transplant into and through the distal
would into the distal popliteal, in which they are followed to the
interossei muscles. In sections of portions of the
interossei muscles, new nerve fibers may be observed in
inter-fascicular nerve branches and as single nerve fibers,
on and between muscle fibers. Motor endings found not well
differentiated. Nearly complete regeneration of the
distal popliteal observed.
EXPERIMENT No. 134.-Rabbit No. 78; large;
full grown; 7 days. June 3, 191, left sciatic exposed and
resected 2.5 cm. A segment of equal length, taken from the external
popliteal of dog No. 21, the left sciatic of which
was cut 16 days previous, used as transplant. One central and distal
waxed fine silk thread suture placed; good
approximation. Wound closed. June 10, rabbit found dead in the morning.
Wound well healed. On exposing the
sciatic, tissues about the nerve found congested. Transplant found well
in place, though distal suture had drawn out a
little. Transplant united to resected nerve ends; good color. Sciatic
and the transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining. Fairly good silver
differentiation of neuraxes attained.
Microscopic
findings.-In longitudinal sections of the central wound region the
very early stages of a
bulbous end on central sciatic stump noted. Certain of the larger
neuraxes
1188
of the central stump present large,
bulbous
ends; growing end-discs noted just central to central wound. Central
wound consists of loose fibrocellular tissue, coagulum, and tissue
detritus. In longitudinal sections of the transplant,
remnants of old neuraxes, in the formof short segments, twisted,
coiled, or bent, are to be observed. Faintly stained
nuclei are found within the old neurolemma sheaths. In the distal
sciatic beginning of nerve degeneration observed.
EXPERIMENT
No. 135.- Rabbit No. 75; full grown; emaciated; 13 days. May 10, 1918,
left sciatic exposed
and resected 2.5 cm. A segment of equal length, taken from the internal
popliteal bundle of the left sciatic of dog No.
2, cut April 23, 17 days previous, used as transplant. One central and
distal waxed, fine silk thread suture passed;
good approximation. Wound closed. May 23, rabbit found dead in the
morning; snuffles; wound well healed. On
exposing the left sciatic, transplant found well in place; demarked by
sutures. Transplant seems of slightly larger
diameter than when used, and found surrounded by newly formed
connective tissue. Beginning of bulbous
enlargement on the distal end of the central stump. Sciatic and the
transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. Very good differential staining,
especially central stump, attained.
Microscopic findings.-In a series of longitudinal sections
of the
central wound region, distinct bulbous end
of central stump evidenced structurally, at the distal end of which is
found the wound line, consisting of fibrocellular
tissue; suture found in sections. Many down-growing neuraxes of the
central stump have reached the wound line.
Many of these show bulbous end-discs; certain of them are directed
centralward, others toward the periphery. In
longitudinal sections of the transplant, the fibrous tissue sheaths are
found very materially thickened by means of
newly formed connective tissue containing many leucocytes. The
neurolemma sheaths very materially thickened.
These in longitudinal sections present a wavy zigzag course. Globules
of myelin and remnants of neuraxes observed.
Many wandering leucocytes are found between the old nerve fibers. The
distal sciatic presents early stages of
degeneration.
EXPERIMENT No. 136.- Rabbit No. 85; nearly
full grown; Belgian hare; 42 days. July 9, 1918, left sciatic
exposed and resected 2.2 cm. A segment of equal length, taken from the
right median of dog No. 26, cut June 7, 32
days pervious, used as transplant. One central and distal suture of
waxed, fine silk thread placed; approximation
good, though the transplant has slightly greater diameter than the
sciatic resected. Wound closed. August 20, rabbit
found dead in the morning; very much emaciated; large neurotrophic
ulcer on left heel. On exposing the left sciatic,
the transplant is found well in place; of larger diameter than the
resected nerve and of yellow-white color. No
distinct central bulb noted. Transplant and suture lines surrounded by
relatively dense fibrous tissue and adherent to
underlying muscle. Sciatic and the transplant removed and fixed in
neutral formalin. Sections stained in iron-hematoxylin and
picro-fuchsin; safranine and licht-grün.
Microscopic
findings.- In longitudinal sections of the wound regions, the
resected nerve ends and ends of
transplant found firmly united. There is noted a marked increase of
fibrous tissue about the transplant. In
longitudinal sections of the transplant, the neurolemma sheaths of the
transplanted nerve fibers appear thickened and
as if consisting of a delicate fibrillar structure. Near the central
and distal wound leucocytes found within the
neurolemma sheaths and here and there are found to contain globules. In
cross sections of the transplant, about 1 cm.
distal to the central wound, numerous small funiculi consisting of
nonmyelinated fibers found in the connective
tissue surrounding the transplant, outside of its perineural sheaths.
Distal popliteal found in advance stages of nerve
degeneration. Near the distal wound leucocytes found within the
neurolemma sheaths of the distal popliteal.
EXPERIMENT No. 137.- Rabbit
No. 77; full
grown; 48 days. May 20, 1918, left sciatic exposed and
resected 2.2 cm. A segment of equal length taken from the right ulnar
of dog No. 22, cut April 29, 21 days previous,
used as transplant. One central and distal fine Chinese silk thread
suture placed; good approximation. Wound closed.
July 7, rabbit found dead in the morning; neurotrophic changes left
heel. On exposing the left sciatic, transplant is
found well in place, of light yellow color, of slightly smaller
diameter distally and surrounded
1189
by a relatively firm layer of fibrous
tissue.
Only slight evidence of bulbous enlargement of central sciatic noted.
Distal sciatic presents the appearance of a normal nerve. Sciatic and
transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining.
Microscopic
findings.-In series of longitudinal and cross sections taken at
successive levels, nearly the
entire nerve transplant is very clearly demarked by reason of a
peculiar silver reaction. Exclusive of the perineural
sheaths, and the nerve fibers immediately adjacent, the entire
transplant is stained a jet-black, making it
nontransparent even in sections of 5 microns thickness, so that no
structure can be made out in the parts thus stained.
In longitudinal sections of the central wound region, numerous neuraxes
growing from the central nerve can be
traced through the wound tissue to the beginning of the transplant, but
appear to pass no distance into the transplant.
Certain of these neuraxes deviated to one side and may be traced for a
distance of several millimeters in the
connective tissue sheath surrounding the transplant. Distal sciatic
degenerated.
EXPERIMENT
No. 138.- Rabbit No. 77a; full grown; 48 days. May 20, 1918, right
sciatic exposed and
resected 2.2 cm. A segment of equal length, taken from the right median
of dog No. 22, cut April 29, 21 days
previous, used as transplant. One central and distal fine Chinese silk
thread suture placed; good approximation
central; distal "fair." Wound closed. July 7, rabbit found dead in the
morning; neurotrophic changes right heel. On
exposing the right sciatic, transplant is found well in place, of light
yellow color, of firm consistency; united to the
resected nerve ends. No material increase of connective tissue found
surrounding the transplant. Distinct central bulb
noted. Distal sciatic presents the appearance of a degenerated nerve.
Sciatic and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining.
Microscopic
findings.- In longitudinal and cross sections taken at successive
levels, trans-plant clearly
demarked by reason of its jet-black color after silver staining.
Neuraxes from the central sciatic may be observed to
grow toward the central end of the transplant, but not to penetrate it.
Certain of these neuraxes deviate to one side
and can be traced distal ward into the connective tissue sheath of the
transplant. These relatively few neuraxes can be
traced in the connective tissue sheath, in cross and longitudinal
sections of the transplant tonear the distal wound,
where they escape the plane of section. Relatively few neulraxes are
again recognized in the distal wound and for a
distance of about 2 mm. in the central end of the distal sciatic stump,
in longitudinal sections of which only ten to
fifteen neuraxes are recognized in one section, all other nerve fibers
included in the section degenerated.
EXPERIMENT
No. 139.- Rabbit No. 76; large; full grown; 52 days. May 17, 1918,
right
sciatic exposed
and resected 2 cm. A segment of equal length taken from the right ulnar
of dog No. 21, cut April 29, 18 days
previous, used as transplant. One central and distal fine Chinese silk
thread suture placed; good approximation.
Wound closed. July 8, rabbit found dead in the morning; severe
neurotrophic changes right heel. On exposing the
right sciatic an encapsuled abscess in the region of the transplant
found. The transplant appears to have pulled free
from distal stump and has almost completely disappeared; only a short
segment, of light yellow color, adhering to
central sciatic stump. Large bulbous end found on the distal end of
central sciatic. Central sciatic and bulbous end
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Very good silver differentiation attained.
Microscopic
findings.-In two series of sections, the segment of the transplant
remaining, clearly demarked
by reason of its jet-black color. In longitudinal sections through the
central bulb and contiguous central end of
transplant, it is evident that there was not obtained as end-to-end
suture of resected nerve end and transplant, the
central end of the transplant having slipped to one side, so that the
distal end of the central sciatic stump rests against
the perineural sheath of the transplant. A well-developed central bulb
is evidenced structurally from the end of which
numerous neuraxes grow distalward; meeting the perineural sheath of the
transplant, they are diverted from their
course and form small convoluted bundles of nerve found in the
surrounding connective tissue. Many of the central
neuraxes end dis-tally in large end-discs. In the bulb itself, just
central to the wound region, numerous spirals
composed of neuraxes may be observed. Central neuraxes can be traced
distally for only a short distance. In cross
sections of the transplant, I cm. distal to the central wound, no
neuraxes are found in the connective tissue
surrounding the transplant. The distal sciatic was found completely
degenerated.
1190
EXPERIMENT No. 140- Rabbit No. X2; full
grown;
62 days, July 8, 1918, right sciatic exposed anil
resected 2.6 cm. A segment of equal length taken from the external
popliteal bundle of the left sciatic of dog No. 25,
cut June 7, 31 days previous, used as a transplant. One central and
distal waxed, fine silk thread suture placed; good
approximation. Wound closed. September 8, rabbit found dead in the
morning; very severe neurotrophic changes
right hind foot; foot in part missing; “fungus'' cars. On exposing the
right sciatic, transplant is found well in place, of
distinct yellow color, thus clearly demarked from resected sciatic
ends. Transplant found of larger diameter than the
sciatic. Well-developed central sciatic bulb noted. Sciatic and nerve
transplant removed and fixed in neutral
formalin. Sections stained in iron-hemmatoxylin and picro-fuchsin;
safranine and licht grün.
Microscopic
findings.-In a series of longitudinal sections through the distal
end of the central stump and the
central end of the transplant, it may be observed that nucleated
syncytial strands of protoplasm extend for a short
distance into the central end of the transplant; beyond this region the
thickened neurolemma sheaths of the
transplanted nerve fibers are found and seem to contain granular and
globular detritus, and inwandered cells. There
is observed a distinct small cell infiltration in this region. In the
connective tissue to one side of the transplant,
protoplasmic syncytial strands, grouped in small bundles, are observed
in cross sections. These can not be definitely
traced to the distal wound. The distal sciatic found completely
degenerated.
EXPERIMENT No. 141.- Rabbit No. 86; only about
one-half grown; 65 days. July 9, 1918, left sciatic
exposed and resected 2.5 cm. A segment of equal length taken from the
external popliteal bundle of the left sciatic of
dog No. 26, cut June 7, 32 days previous, used as transplant. One
central and distal waxed, fine silk thread suture
placed; distal approximation good; central, good alignment but nerve
ends about 2 mm. apart. Wound closed.
September 12, found dead in the morning; much emaciated; slight
neurotrophic changes left heel; posterior half of
body paralyzed for past few days. On exposing the left sciatic, the
transplant is found well in place; clearly
demarked by its light yellow color; of good size and consistence and
adherent to the underlying muscle. Quite
distinct central sciatic bulb noted. Sciatic and the transplant removed
and fixed in ammoniated alcohol for pyridine-silver staining. Not
satisfactory silver differentiation attained.
Microscopic
findings.- In sections, transplant clearly demarked by reason of
its
jet-black coloring. Neuraxes
from the central nerve are seen to approach the central end of the
transplant but do not penetrate it. Certain few
neuraxes pass into the connective tissue to one side of the transplant, passing distally
in the
connective tissue. No
new neuraxes are observed as having reached the distal wound. Distal
sciatic degenerated.
EXPERIMENT
No. 142.- Rabbit No. 80; full grown; 61 days. July 5, 1918, left
sciatic
exposed and resected
3 cm. A segment of equal length, taken from the right median of dog No.
26, cut June 7, 27 days previous, used as a
transplant. One central and distal waxed, fine silk thread suture
placed; good approximation. Adrenal in used to
control oozing. Wound closed. September 4, found dead in the morning;
seemed in good Condition; slight
neurotrophic ulcer left heel. On exposing the left sciatic, transplant
is found well in place, of small diameter and of
light yellow color; adherent to the underlying muscle. Distinct bulbous
enlargement of the distal end of the central
stump noted. The sciatic and transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. Fair
silver differentiation attained.
Microscopic
findings.-In longitudinal sections of the central wound. region,
down-growing neuraxes from
the central stump in small number are seen to pass distally to one side
of the transplant and enter the connective
tissue in which they may be traced not quite to the distal wound
region. The region of the transplanted nerve fibers
stained jet black; no structural details can be ascertained.
EXPERIMENT
No. 143.- Rabbit No. 80a; full grown; 63 days. July 3, 1918, the right
sciatic exposed and
repete 1 3 cm. A segment of the right ulnar of dog No. 26, cut June
6,27 days previous, used as transplant. One
central and distal waxed, fine silk thread suture placed; good
approximation. Adrenalin used to stop oozing; wound
closed. September 4, rabbit found dead in the morning; seemed in good
condition; neurotrophic ulcer right heel. On
exposing the right sciatic, transplant is found well in place; clearly
demarked
1191
by its light yellow color; is of good
size
and consistency and is found adherent to the underlying muscle.
Distinct
central bulb noted. Sciatic and transplant removed and fixed in neutral
formalin. Sections stained in iron-hematoxylin and picro-fuchsin;
safranine and licht grün.
Microscopic
findings.-In longitudinal sections through the central wound
region, distinct central bulb
evidenced structurally, from the distal end of which nucleated,
syncytial, protoplasmic strands can be traced to the
connective tissue found to one side of the transplant. In longitudinal
sections of the transplant, the of neurolemma
sheaths of certain of the transplanted nerve fibers seen, these appear
thickened and present a wavy or zigzag course,
containing a granular and globular detritus. Here and there inwandered
leucoctes may be observed. The perineural
sheaths present small cell infiltration. The distal nerve completely
degenerated. No new nerve fibers found in the
connective tissue surrounding the greater length of the transplant.
EXPERIMENT
No. 144.-Rabbit No. 79; full
grown; 84 days. June 19, 1918, the left sciatic exposed; internal
popliteal freed and resected 3.1 cm. .A segment of
equal length, taken from the distal ulnar of dog No. 23, cut May 31, 19
days previous, used as transplant. One
central and distal waxed, fine silk thread suture placed. Good
approximation of nerve ends attained centrally; distally
"fair.” Wound closed. September 11, rabbit found dead in the morning;
scarcely any neurotrophic changes in left
hind foot. On exposing the left sciatic, external popliteal found free.
The operated internal popliteal presents large
central bulb. The transplant found well in place; is of light yellow
color, of small diameter, especially in its middle
portion; and found adherent to underlying muscle. The nerve and
transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. The tissues removed in this
experiment were lost in process of fixing and
staining; no sections made.
EXPERIMENT
No. 145.-Rabbit No. 79a; full grown; 84 lays. June 19, 1918, right
sciatic exposed; internal
popliteal freed and resected 3 cm. A segment of equal length taken from
the right median of dog No. 23, cut May 31,
19 days previous, used as transplant. One central and distal waxed,
fine silk thread suture placed; good
approximation. Wound closed. September 11. Rabbit found dead in the
morning; very slight neurotrophic changes
right hind foot. On exposing the right sciatic, operated internal
popliteal is found to present large bulb along side of
which external popliteal is found closely adherent. Transplant found
well in place; clearly demarked by reason of
light yellow color, and is adherent to underlying muscle. Nerve and
transplant removed and fixed in neutral
formalin. Sections stained in iron-hematoxylin and picro-fuchsin;
safranine and light grün.
Microscopic
findings.- In longitudinal sections of the central wound region, a
large, distinct bulb is
evidenced structurally, from the distal end of which nerve fibers, in
part myelinated, pass to the connective tissue to
one side of the transplant. In cross sections of the middle transplant
region, the perineural sheaths found distinctly
thickened and penetrated by inwandered cells. Within this sheath
necrotic remains of the transplanted nerve fibers
are found. To one side of the transplant, and outside of the perineural
sheath, numerous small funiculi of nerves with
certain fibers myelinated are to be observed. In cross and longitudinal
sections taken at successive levels, these small
bundles of nerves may be traced to the distal wound region, coursing in
the connective tissue outside of the
transplant; certain few are found to have reached the central end of
the distal popliteal, here clearly recognized as
small myelinated fibers.
EXPERIMENT
No. 146.- Rabbit No. 81; full grown; 93 days. July 5, 1918, left
sciatic
exposed and resected
2.4 cm. A segment of equal length taken from the right median of dog
No. 28, cut June 7, 28 days previous, used as
a transplant. One central and distal waxed, fine silk thread suture
placed. Good central approximation attained; distal
suture does not include the external popliteal branch. Wound closed.
October 6, killed. Rabbit found dying; much
emaciated; severe neurotrophic ulcer left heel. On exposing, the left
sciatic, transplant is found well in place; is of
good size and light yellow color, and only moderately adherent to
underlying muscle. Only slight spindle-shaped
enlargement on central sciatic noted. Sciatic and transplant removed
and fixed in ammoniated alcohol for pyridine-silver staining. Good
silver differentiation attained.
1192
Microscopic findings.-In series of longitudinal and cross
sections taken at successive levels, the
transplanted nerve segment is clearly demarked by reason of the
jet-black color assumed in the silver stain. For a
distance of approximately 2 mm., at the central and distal end of the
transplant and in the peripheral part, adjacent to
the perineural sheath the substance responsible for the peculiar
jet-black silver reaction noted, has apparently
disappeared, in that in these regions the transplant is colored a
yellow brown. In longitudinal sections of the central
wound region, certain neuraxes may be traced into central end of the
transplant, to the region of the jet-black
coloring; here they can no longer be differentiated. Other neuraxes
pass to one side of the transplant, to the
connective tissue. In cross sections of the transplant, mainly to one
side, numerous small bundles of neuraxes are
found in the connective tissue sheath. New neuraxes are observed in
longitudinal sections of the distal wound region;
certain of these appear to enter the distal wound through the
transplant, others from the surrounding connective
tissue. New neuraxes are found in good number in all of the funiculi of
the distal popliteal in the region of the distal
wound.
EXPERIMENT
No. 147.-Rabbit No. 81a; full grown; 93 days. July 5, 1918, right
sciatic exposed and
resected 2.2 cm. A segment of equal length taken from the right ulnar
of dog No. 28, cut June 7, 28 days previous,
used as a transplant. One central and distal waxed, fine silk thread
suture placed; good central and distal
approximation. Wound closed. October 6, killed. Rabbit found dying;
much emaciated; severe neurotrophic ulcer
right heel. On exposing the right sciatic, transplant is found well in
place; demarked by its light yellow color. At
distal suture transplant appears to have pulled away slightly from
distal sciatic stump. Transplant found only
moderately adherent to underlying muscle. Quite distinct central bulb
noted. Sciatic and the transplant removed and
fixed in ammoniated alcohol for pyridine-silver staining. Fairly good
silver differentiation attained.
Microscopic
findings.-In series of cross and longitudinal sections, taken at
successive levels, it may be
observed that certain neuraxes coming from the central sciatic stump,
enter the central end of the transplant and may
be traced in it for a short distance. However, the majority of the
central neuraxes are found to pass into the
connective tissue to one side of the transplant and in cross sections
of the transplant these are found in the form of
small nerve funiculi outside of the perineural sheaths. Neuraxes can be
traced through the distal wound into the
distal popliteal stump. Certain of these appear to take exit from the
distal end of the transplant; these can not be
identified more centrally by reason of the jet-black coloring of the
greater part of the transplant. The neuraxes found
in the distal popliteal appear to be about equally distributed through
the several fuiniculi and can be traced distally to
the end of the series of sections approximately 3 em. beyond the distal
wound.
EXPERIMENT
No. 148.-Rabbit No. 83; not quite full grown; 217 days. July 8,
1918,left sciatic exposed
and resected 2.0 cm. A segment of equal length taken from the external
popliteal of dog No. 25, the sciatic of which
was cut June 7, 31 days previous, was used as a transplant. Dog No. 25
stopped breathing while under ether
anesthesia, 45 minutes before the nerve was removed. One central and
distal waxed, fine silk thread suture passed. Central suture not good;
removed and another made; slight trauma of nerve ends; finally central
and distal
approximation good. Wound closed. February 10, 1919, killed. Rabbit in
good condition; part of left hind foot
missing; practically healed over; scarcely any evidence of
long-standing neurotrophic ulcer left heel. On exposing
the left sciatic, a large central bulb is found. The nerve in region of
transplant adherent to underlying muscle. The
distal sciatic presents the appearance of a normal nerve. After
exposing the calf muscles and the leg flexors, and
freeing nerve and transplant from the bed, on slowly cutting the
sciatic with scissors, central to the transplant, good
contraction of the calf and leg flexor muscles noted; the same on
cutting nerve distal to the transplant. The calf
muscles have nearly recovered size, but are of a pale red color. The
sciatic and the transplant and portions of the calf
muscles removed and fixed in ammoniated alcohol for pyridine-silver
staining. Very good silver differentiation
attained.
Microscopic
findings.-In series of longitudinal and cross sections, taken at
successive levels, it is observed
that except for two small regions, of about 1.5 mm. in length, near the
distal and central ends of the transplant, which
are colored jet-black, the remainder ofthe nerve transplant is colored
a light yellow-brown, as is the remainder of the
nerve. In longitudinal sections of the central wound region numerous
new neuraxes can be traced from
1193
the distal end of the large central bulb
into
the transplant as well as into the connective tissue surrounding the
transplant. In cross sections of the transplant in its middle region
many small nerve funiculi, separated by endoneural
fibrous tissue, are seen with the perineural sheath of the transplant. There are also found many
small
nerve bundles
in the connective tissue outside of the perineural sheaths of the
transplant. New neuraxes can be traced to and
through the distal wound into the distal sciatic. In cross sections of
the internal popliteal, taken at the lower level of
the popliteal space, new neuraxes in large numbers are found in all of
its several funiculi. In sections of the calf
muscles new neuraxes in good relative numbers are found in the
interfascicular muscle nerves and as single fibers on
and between muscle fibers; motor endings and nerve endings in
neuromuscular spindles are observed.
EXPERIMENT
No. 149.-Rabbit No. 84; Belgian hare; not quite full grown; 240 days.
July 9, 1918, right
sciatic exposed and resected 2.2 cm. A segment of equal length, taken
from the right ulnar of dog No. 26, cut June 7,
32 days previous, used as a transplant. One central and distal waxed,
fine silk thread suture passed; good
approximation. Diameter of the degenerated ulnar segment slightly
greater than that of the resected sciatic.
Adrenalin used to obtain dry field; wound closed. March 6, 1919,
killed. Rabbit in good condition. No neurotrophic
ulcer on right heel. On exposing the right sciatic a large central bulb
is found on the central sciatic. Transplant is
found of light yellow color, of good size and adherent to underlying
muscles. The distal sciatic presents the
appearance of a normal nerve. After exposing the calf muscles and
freeing the sciatic from bed, on slowly cutting
with scissors, sciatic central to the transplant, good contraction of
calf muscles observed. Calf muscles are found to
have nearly recovered size but are of pale red color. Sciatic and the
transplant and portions of the calf muscles
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Very good differential silver staining attained.
Microscopic findings.-In
series of longitudinal and cross
sections taken at successive levels the transplanted
nerve segment is clearly demarked by reason of the jet-black coloring
assumed by the transplanted nerve tissue. In
longitudinal sections of the central wound region numerous central
neuraxes can be traced to the periphery, mainly
in the connective tissue outside of the transplant, as clearly seen in
cross sections, taken about midway between
central and distal wounds, in which two areas, situated at opposing
sides of the transplant, there are found in the
connective tissue numerous small bundles of nerve fibers situated
outside of the perineural sheaths. Whether any
neuraxes pass through the transplant cannot be determined by reason of
the jet-black coloring of the nerve bundle
remains of the transplant. New neuraxes are observed in the distal
wound and in the central end of the distal sciatic,
in which they are found evenly distributed through the several
fulliculi. In sections of the calf muscle new neuraxes
are found in the interfascicular nerve bundles, and here and there as
single nerve fibers on and between muscle
fibers.
As
concerns degenerated auto-nerve transplant, Experiments No. 126 to No.
128, while
only three in number, they may serve to show that a degenerated nerve
can serve the purpose of
an auto-nerve transplant though there is no indication that
regeneration from the central stump
through such a transplant takes place more readily than when an
undegenerated auto-nerve
transplant is used. Indeed the results attained are, on the whole, less
satisfactory, if one may
judge from the relatively few experiments. There are relatively more
extrafunicular nerve fibers
in the experiments in which a degenerated auto-nerve transplant was
used than in the
experiments in which cable-auto-nerve transplants were made.
In
the series of five experiments (No. 129 to No. 133) in which
degenerated homo-nerve
transplants were used, the end results were on the whole very
satisfactory and may compare very
favorably with the end results in experiments in which a homogenous
transplant was made, using
a fresh nerve. Attention is especially called to Experiment No. 131,
terminated 37 days after the
operation. A nerve segment 3.4 cm. in length. taken from the distal
portion of
1194
a nerve cut 27 days
previously, was used as a nerve bridge. In this experiment, numerous
down-growing neuraxes are readily determined within the funiculi of the
transplant; relatively few new
nerve fibers are extra-funicular. In Experiment No. 132, a little over
four months' duration, it was
possible to trace new-neuraxes to the foot interossei muscles, with
good return of function. It is
notlikely that a degenerated nerve would be available for an
auto-nerve transplant, in human
surgery. It is quite within the bounds of possibility that a
degenerated nerve from another
individual, one to several months after injury, may be available for
bridging a nerve defect, in
which event it may be stated that experimental evidence warrants the
use of a degenerated homo-nerve transplant. In nerve defect bridged by
degenerated auto- and homo- nerve transplants, the
down-growing central neuraxes make use of the patent or semipatent
neurolemma sheath of the
transplanted nerve fibers. There is no evidence that the transplanted
syncytial nucleated strands
stand in any definite relation to tie down-growing neuraxes, since
these strands undergo change,
degenerate, after transplantation.
The
experiments on degenerated hetero-nerve transplants (No. 134 to No.149)
did not
substantiate the conjecture that the less specifically differentiated
protoplasm of the "bandfasern ", which may
be regarded as in a measure representing a reversion to embryonic
structure, offered a better avenue for the down growth of central
neuraxes than would an
undegenerated nerve trans-plant of the heterogenous origin. It may be
noted that in the majority
of the experiment protocols the notation is made that the transplant
presents a light yellow color
when the nerve is exposed some time after the operation. This enables
ready demarkation of the
transplant and is indicative of a necrobiotic change, involving not
only the transplanted nerve
fibers but the fibrous tissue sheaths of the nerve funiculi. The
products of this necrobiotic change
show a peculiar reaction to the pyridine-silver stain in that they
assume a jet-black color, in
which no tissue elements can be made out, and would mask any neuraxes
in case they were
present. This series of sixteen experiments need not be discussed
seriatim; they range in time
after operation from 7 days to 244 days. The results may be summarized
by stating that a
degenerated hetero-nerve transplant was found less serviceable than a
nondegenerated nerve
transplantof heterogenous origin owing to the fact that a degenerated
hetero-transplant undergoes
further change of necrobiotic nature, resulting in the formation of
tissue detritus which appears
to offer an effective block to the down-growing neuraxes. Whether this
block is largely of a
mechanical or to a large part of a chemical nature has not been
determined. In all of the
experiments under observation after the initial operation for more than
45 days, down-growing
neuraxes could be traced into the central wound, but no distance into
the transplant. Numerous
neuraxes could be traced into the connective tissue surrounding the
transplant, thus having extra
funicular position. Only in a few experiments were nerve-fibers in
number found within the
nerve funiculi of the transplant. Cross sections of the transplant
region with good differential
neuraxis staining are necessary to determine the relative position of
the neuraxes, whether
extrafunicular or intrafunicular, the latter indicating the efficacy of
the trans-plant.
1195
STORED HOMO-NERVE
TRANSPLANTS
SERIES NO. 11
HOMO-NERVE TRANSPLANTS,
STORED IN STERILE VASELINE SERIES NO. 12
HOMO-NERVE
TRANSPLANTS,
STORED IN LIQUID PETROLATUM SERIES NO. 13
HOMO-NERVE
TRANSPLANTS,
STORED IN 50 PERCENT ALCOHOL
In
these series of stored homogenous transplants, totaling 67 experiments,
we present a
body of experimental observations, which we regard as of crucial
importance in determining the
true function of a nerve transplant. In none of these experiments can
the transplant he regarded
as being in the state of a living tissue.
The
experiments under Series No. 11 were suggested to us through the
publication of
Dujarier and Francois,76 who reported briefly a series of 20
cases in which homogenous nerve
transplants. stored in vaseline, were used to bridge nerve defects.
Dujarier and Francois
recommended that nerves removed from amputated limbs under aseptic
precautions be placed in
sterile vaseline and kept at nearly 00 temperature. In their
work as reported, nerves were kept in
this way for 41 davs. Before use the vaseline was warmed to melting,
the nerve segment
removed and rinsed in warmed serum, then sutured between the severed
nerve ends. In the cases
reported, healing took place by primary intention. Not enough time had
elapsed from the time of
operation to the time of the publication to make a report on the
ultimate results. At the time our
observations were undertaken we were not aware of any experimental
observations in which
stored nerve transplants had been used. We followed as closely as
possible the method as briefly
outlined by Dujarier and Francois. The sciatics of large and full grown
rabbits were removed
under aseptic precautions, placed in large tube vials containing
sterile melted vaseline, after
which the tube vials were plugged with sterile cotton plugs. The tube
vials were then placed in a
small ice chest regulated to 30 C.. in which they remained
for periods varying in the several
experiments from 9 days to13 days. The nerves thus stored were used to
bridge defects in the
sciatics of rabbits caused by resection. Just before use the vial
containing the nerve to be selected
for the experiment was carefully warmed to an extent sufficient to melt
the vaseline. The
contained nerve segment was then removed and rinsed in warmed sterile
serum, and a segment
of proper length cut and sutured to the resected stumps of a rabbit's
sciatic nerve. One fine,
waxed silk suture was placed centrally and distally. The experimental
operations are relatively
simple. A nerve segment stored in vaseline is readily manipulated: the
small amount of vaseline
clinging to the nerve was disregarded at the operation, since it seemed
to play no special part in
the healing of the wound. The necessary warming of the vaseline, so
that the nerve segment may
be readily removed, with possibility of overheating the nerve segment,
more particularly the
washing of the nerve segment in serum, seemed to he objections to the
1196
method as suggested by
the French observers. It occurred to us that the same ends might be
attained by using liquid petrolatum as a medium for storing nerve
segments. This method of
procedure was tested in Series No. 12,40 experiments, in which
homogenous nerve transplants
stored in liquid petrolatum were used. In our experiments we used
Squibb's liquid petrolatum,
which is a clear, bland fluid. The required quantity was placed in
large tube vials, corked with
cotton plugs anti autoclaved on successive days. After cooling to room
temperature the tube vials
were placed in a small ice chest regulated to 3VC. The sciatics of
rabbits were removed under
asepsis, placed in sterile cooled liquid petrolatum and stored in the
ice chest until required for
operation, for periods varying from 7 days to 39 days in the several
experiments. Before an
experiment the tube vial containing the nerve selected was taken from
the ice chest and placed in
the operating room, and when required the nerve segment was taken from
the tube vial by means
of forceps and, grasping the nerve segment at one end, was allowed to
drain for a few minutes. The sutures were then placed at requisite
distance and the nerve cut about 2 mm.distal to the
suture and the nerve transplant sutured proximally and distally to the
resected nerve ends. Nerve
segments stored in liquid petrolatum have good consistency four to five
weeks after removal
from the animal and have nearly the same appearance as a normal nerve.
The excess of liquid
petrolatum drains off very readily; the thin coating clinging to the
nerve transplant plays no part
in the healing of the wound, so far as can be determined. It was our
experience that storing of
nerves in liquid petrolatum, as used by us, was much to be preferred to
storing in vaseline as
suggested by Dujarier and Francois.
Homogenous
nerves transplants stored in 50 percent alcohol were used in a further
series
of experiments (Series No. 13). The suggestion for this series of
experiments came quite
indirectly from observations published by Nageotte. 77 Nageotte had
determined as a result of
bilateral experimental operations on the sciatics of six dogs, in which
on one side direct suture of
the severed sciatic was made, while on the other side a 5 mm. long
hetero-nerve transplant which
had been stored in 50 percent alcohol for some time was interposed
between the severed ends of
the cut sciatics and sutured in place, that better results could be
reported in certain experiments
for the side in which the short heterogenous nerve segment stored in
alcohol was used. In
Nageotte's experiments the heterogenous nerve was obtained from the
slaughter house, placed in
50 percent alcohol in sealed tubes, some of which were kept as long as
15 months. In our
experiments the sciatics of full grown rabbits were removed under
aseptic precautions and
placed at once in 50 percent alcohol, in sterile, wide-mouthed
glass-stopped bottles, in which
they were kept for periods varying from 7 days to 29 days. In the 50
percent alcohol the nerve
trunk becomes hardened, though not brittle, and of course can not be
regarded as tissue retaining
latent viability. Just before use as nerve transplants the nerve
segments were taken from the
alcohol and placed for 10 to 20 minutes in warmed, sterile, normal salt
solution, in which, after a
short stay, the nerve again becomes quite pliable. The nerve segments
were taken from the
normal salt solution; the sutures placed at requisite distance, the
ends freshened by cutting with
sharp scissors about 2 mm. beyond the suture lines, and
1197
the operation completed
by placing the alcoholized transplant between the resected sciatic
stumps and sutured in place by making one central anal one distal
suture with fine silk thread
waxed with sterile wax. The nerve segments stored in alcohol, after a
short stay in the saline
solution, are of good consistency and lend themselves readily to
operative technique; sutures
pass easily; end-to-end approximation is easily made. In our
experimental work, nerve segments
were stored in 50 percent alcohol for about four weeks and at room
temperature; they were kept
in a dark cabinet. We have no observations indicating that nerve
segments might not be stored in
50 per cent alcohol for a period of four months or more and then used
as nerve transplants. This
method of storing nerve transplants is so simple, the necessary
precautions so easily met, that
this method should commend itself as at least worthy of further
experimental test.
Protocols
of experiments under Series No. 11, No. 12, and No. 13, homo-nerve
transplants stored in vaseline, liquid petrolatum, and 50 percent
alcohol follow:
PROTOCOLS
EXPERIMENT
No. 150.- Rabbit No. 97; large; full grown; 66 days. October 4,
1918,left sciatic exposed,
internal popliteal bundle freed and resected 3 cm. For nerve transplant
there was used the internal popliteal bundle of
another rabbit, removed nine days previous and stored in sterile
vaseline at a temperature of 30 C. Just before use as
transplant, the nerve segment washed for some minutes in sterile
rabbit's serum. One central and one distal waxed
fine silk suture placed. Good central and distal approximation of nerve
end attained. Dry field. Wound closed.
December 8, rabbit found dead in the morning. Wound well healed. On
exposing left sciatic no material increase of
connective tissue about nerve and transplant noted. Transplant found
well in place. Indistinct central bulbous
enlargement; no material enlargement of central end of distal internal
popliteal stump. Nerve and transplant not
adherent to muscle bed. Central and distal popliteal and trans-plant
removed and fixed in ammoniated alcohol for
pyridine-silver staining.
Microscopic
findings.-Numerous down-growing neuraxes can be traced from the
distal end of the central
stump, through central wound to proximal end of transplant. Through
this neuraxes can be traced in good number to
and through distal wound to proximal end of the distal internal
popliteal. In cross sections of the transplant neuraxes
are found in small groups, separated by small areas containing
vesicular cells and tissue detritus.
EXPERIMENT
No. 151.- Rabbit No. 97a; large; full grown; 66 days. October 4,
1918,right sciatic exposed,
internal popliteal bundle freed and resected 3 cm. A nerve segment of
equal length,-taken from the sciatic of another
rabbit, stored in sterile vaseline nine days at 30° C. temperature,
washed in sterile rabbit's serum several minutes, used
as transplant. One central and one distal waxed, fine silk suture
placed; good nerve-end approximation attained Dry field. Wound closed.
December 8, rabbit found dead in the morning. Wound well healed. Small
neurotrophic
ulcer right heel. Right sciatic exposed. Transplant found well in
place. Only indistinct central bulbous enlargement.
No material increase of connective tissue about nerve and transplant.
Nerve and transplant removed and fixed in 5
percent neutral formalin. Sections stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
Microscopic
findings.- Structurally considered, quite well defined central
bulbous
enlargement from the distal end of
which many small nerve fibers nucleated, syncytial strands of
protoplasm can be traced into the proximal end of the
transplant and through this to the distal wound. Certain of the nerve
fibers within the nerve transplants present thin
myelin sheaths. The great majority of the new nerve fibers found within
the transplant are arranged in the form of
small bundles of narrow bands, here and there anastomosing, and
separated by small areas or columns of vesicular
cells and tissue detritus. The endoneural and perineural connective
tissue not materially increased.
1198
EXPERIMENT No. 152.- Rabbit No. 99;
medium
size; full grown; 89 days. October 7,1918, left sciatic
exposed, internal popliteal bundle freed and resected 3.0 cm. A nerve
segment of equal length taken from the sciatic
of another rabbit, stored 13 days in sterile vaseline, temperature 30
C., used as transplant. One central and one distal
suture of waxed, fine silk thread placed. Good central and distal
nerve-end approximation attained. Dry field. Wound
closed. January 4, 1919, rabbit found dead 1 p. m.; living in the
morning. Moderate emaciation; neurotrophic ulcer
left heel. Wound well healed. Left sciatic exposed full length.
External popliteal bundle found adherent along
central wound. Transplant found well in place; small spindle-shaped
central bulbous enlargement. Transplant found
slightly adherent to underlying muscle; of light gray color and not
quite as glistening as normal nerve. Distal wound
not distinctly made out. Central and distal sciatic and transplant
removed and fixed in ammoniated alcohol for
pyridine-silver staining.
Microscopic
findings.-Good differential neuraxis staining attained. From the
distal end of central bulbous
enlargement which embraces central end of the transplant, numerous
necuraxes are traced through the transplant, to
and through the distal wound and into the proximal end of the distal
popliteal stump in which for several centimeters
well differentiate neuraxes are found in large numbers. In cross
sections of the transplant, the new neuraxes present
are found in the form of small funiculi separated by strands of
endoneural connective tissue. Here and there small
groups of vesicular cells, inclosing what appear to be lipoid globules,
are noted. Distal internal popliteal well
regenerated.
EXPERIMENT No. 153.- Rabbit No. 99a; medium
size; full grown; 89 days. October7, 1918, right sciatic
exposed, internal popliteal bundle freed; resected 3.2 cm. A segment of
equal length taken from the sciatic of
another rabbit, stored in sterile vaseline, at a temperature of 30° C.
for 13 days, used as transplant. One central and
one distal waxed, fine silk thread suture placed. Good central and
distal approximation attained. Dry field; wound
closed. January 4, 1919, rabbit found dead 1 p. m.; nerve removed at
once. Moderately emaciated; slight
neurotrophic ulcer right heel. Wound well healed. Right sciatic exposed
full length. Transplant found well in place;
clearly demarked by presence of central and distal suture. Small
spindle-shaped, central, bulbous enlargement.
External popliteal bundle not adherent to underlying muscle. No
appreciable distal enlargement. Central and distal
sciatic and transplant removed and
fixed in 5 percent neutral formalin. Sections stained in
iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
Microscopic
findings.-Quite distinct central bulbous enlargement evidenced
structurally, from the distal end
of which many fine, myelinated nerve fibers and nucleated,
proto-plasimic, syncytial strands pass through the
transplant to the distal wound. In cross sections of the transplant
about 1 cm. distal to central wound, one large
funiculus and two small funiculi of the transplant almost completely
filled with new nerve fibers with only here and
there small areas of tissue detritus and vesicular cells evident. The
perineural sheaths of the transplanted nerve
funniculi well maintained and only slightly thickened. Apparent
regeneration through transplant; used histologic
methods do not enable full determination of distal growth of new
neuraxes.
EXPERIMENT
No. 154.-Rabbit No. 98; large; full grown; Belgian hare; 96 days.
October 5, 1918, left
sciatic exposed, internal popliteal freed; resected 2.5 cm. A segment
of equal length,
taken from the
sciatic of
another rabbit, stored in sterile vaseline, temperature 3?C.,
11 days, used as nerve transplant. One central and one
distal suture of waxed, fine silk thread placed. Only fair central and
distal nerve-end approximation attained. Dry
field; wound closed. January 9, 1919, killed. Rabbit much
emaciated;"fungus" ears; severe neurotrophic ulcer left
heel; on the whole quite active. Wound well healed. Left sciatic
exposed full length. External popliteal bundle found
quite free. Large spindle-shaped central bulbous enlargement noted on
central internal popliteal stump; slight
enlargement of the central end of distal stump. Transplant well in
place; light gray color, not adherent to underlying
muscle. Unoperated external popliteal bundle resected and removed. Calf
muscles fully exposed; operated internal
popliteal and transplant completely freed from bed. On slowly cutting
with scissors sciatic central to transplant
doubtful, feeble contractions of calf muscles. On cutting internal
popliteal lower level of popliteal space, feeble
contraction of calf muscles; uncertain. Central and distal sciatic and
transplant
1199
and pieces of calf muscles removed and
fixed in ammoniated alcohol for pyridine-silver staining.
Microscopic
findings.- Oily fair silver differentiation attained; calf muscles
silver staining good. Distinct
central bulbous enlargement evidenced structurally from the distal end
of which numerous new neuraxes pass
through the transplant to the distal popliteal nerve. In sections of
the calf muscles, numerous new neuraxes found in
the larger muscular branches, relatively fewer in the smaller
interfasicular branches and here and there single nerve
fibers seem to pass to muscle fibers. Muscle fibers of small diameter,
but show distinct cross striations. Muscle
capillaries very numerous and very tortuous. Regeneration of distal
popliteal to muscular branches of the calf
muscle, beginning recovery of in motor function of these muscles.
EXPERIMENT
No. 155-Rabbit No. 98a; large; full grown; Belgian hare; 96 days.
October 5, 1918, right
sciatic exposed; internal popliteal bundle freed; resection 2.5 cm. A
segment of equal length taken from the sciatic
of another rabbit, stored 11 days in sterile vaseline at 3? C., used as transplant. One central and one distal waxed, fine
silk thread suture placed; quite good approximation of nerve ends
attained. Dry field; wound closed. January 9,
1919, killed. Rabbit much emaciated; 'fungus' ears; severe neurotrophic
ulcer right heel. Wound well healed. Right
sciatic exposed full length. External polpliteal bundle quite free;
resected and removed. Operated internal popliteal
bundle shows the transplant well in place, of good size and light gray
color. Large, spindle-shaped central bulbous
enlargement noted . After fully exposing the calf muscles and freeing the internal
popliteal
bundle from bed, on
slowly cutting with scissors, the nerve central to transplant, no
distinct twitching of calf muscles; the same on cutting
distal to transplant. Operated nerve with transplant and portions of
calf muscles removed and fixed in ammoniated
alcohol for pyridine-silver staining. Silver differentiation fair; calf
muscles good.
Microscopic
findings.- Large central bulb evidenced structurally, from the
distal end of which numerous
new neuraxes may be traced through the transplant to the distal
segment. In sections of calf muscles, numerous new
neuraxes noted in the muscular nerves; a few of these may be traced
between muscle fibers. Distal regeneration to
and into the calf muscles.
EXPERIMENT
No. 156- Rabbit No. 100; large; full grown; 155 days. October 8, 1918,
left sciatic exposed;
internal popliteal bundle freed and resected 3.0 cm. A segment of equal
length taken from the sciatic of. another
rabbit, stored 12 days in sterile vaseline temperature 3?C.,
used as transplant. One central and one distal -waxed,
fine silk thread suture placed. Good central and distal nerve-end
approximation attained. Dry field; wound closed. March 12, 1919,
killed. Rabbit in very good condition; neurotrophic ulcer healed; left
foot appears normal; walks
well, except now and then toe-drop; spreads toes of left foot on
holding up by ears. Left sciatic exposed the whole
length; external popliteal bundle free; resected and removed. Internal popliteal in operated region has
the
appearance
of a normal nerve; scarcely any evidence of central bulb; no
enlargement at the distal wound. Transplant not
adherent; no material increase of connective tissue surrounding
operated nerve. After exposing the calf muscles and
removing skin to heel and completely freeing the operated nerve, on
slowly cutting the nerve central to the
transplant, vigorous and contraction of calf muscles and apparently
foot muscles; the same on cutting nerve distal to
transplant. Operated nerve removed and fixed in ammoniated
alcohol for
pyridine-silver staining; portions of calf
muscles removed for gold chloride method of staining nerve
terminations. Differential silver staining only of a
portion of the nerve good
Microscopic
findings.-Transplant well united to resected nerve ends; scarcely
any evi-dence of central and
distal wounds; these demarked by retained silk sutures. New neuraxes in
great numbers pass through transplant to
the distal nerve. For the transplanted nerve segment, the perineural
sheaths of the funiculi well maintained. Within
the funiculi the new neuraxes arranged in small groups, separated by
endoneural connective tissue, much more
extensive than in normal nerve. An attempt was made to endeavor to
stain the motor nerve ending in gold chloride.
This attempt not successful. In certain of the large muscular nerve
bundles the neuraxes beautifully differentiated
even into the smaller branches, but motor ending not differentiated. It
seems clear that this is due to faults in the
method,
1200
perhaps impurity of chemical used. Very
complete regeneration of distal nerve through the transplanted nerve
segment.
EXPERIMENT
No. 157.-Rabbit No. 10a; full grown; 155 days. October 8, 1918,right
sciatic exposed;
internal popliteal bundle freed and resected 3.0 cm. A segment of equal
length taken from the sciatic of another
rabbit, stored 12 days in sterile vaseline at3° C. used as
transplant. One central and distal suture of waxed, fine silk
thread placed. Central suture nerve-end approximation good; distal not
good. Slight manipulation caused this distal
suture to give way. Another suture placed; slight traumatism of nerve
end, otherwise approximation good. Fairly dry
field; wound closed. March 12, 1919, killed. Rabbit very good
condition; small neurotrophic ulcer right heel. Right
foot otherwise normal; spreads toes on holding up by ears. Left sciatic
exposed the full length. External popliteal
free full length; resected; removed. Operated internal popliteal
presents scarcely any evidence of central bulb;
transplant well in place; good color; good size. After exposing fully
the calf muscles and freeing internal popliteal,
on slowly cutting nerve central to transplant, good contraction of calf
muscles. Operated nerve and transplant
removed and fixed in ammoniated alcohol for pyridine-silver staining;
calf muscles removed for gold chloride
staining. Silver differentiation of neuraxes fairly good.
Microscopic findings.-Transplant well united to resected
nerve
ends; only slight struc-tural evidence of
central bulbous enlargement. New neuraxes in large numbers traced
through transplant to distal nerve. In the
transplant these new neuraxes arranged in the form of small bundles
separated by endoneural connective tissue. An
attempt made to stain the motor endings in gold chloride not
successful. Numerous neuraxes found in the larger and
smaller nerve branches clearly differentiated, but not motor endings.
The muscle fibers present the size and structure
of normal muscle fibers. Very good regeneration of distal nerve through
the transplant.
EXPERIMENT No.
158.-Rabbit No. 108; large; full grown; 1 hour. December 17, 1918, left
sciatic exposed; internal popliteal bundle freed;
resected 3.0 cm. A segment of equal length taken from the sciatic of
another rabbit, stored seven days in sterile
liquid petrolatum at 3? C., used as transplant. One central
and one distal waxed fine silk thread suture placed; good
approximation attained. Wound closed. As soon as wound was closed
rabbit stopped breathing and could not be
revived. Wound was reopened and the sciatic and transplant removed,
about one hour after the operation was
completed, and fixed in ammoniated alcohol for pyridine-silver
staining. Experiment is recorded, since it enabled
examining histologically a nerve stored in liquid petrolatum
immediately after it had been placed in the wound.
Good differential silver staining.
Microscopic findings.-The appearance presented in cross and
longitudinal sections of the transplant,
embedded in living tissue only about one hour, may be regarded as
essentially the same as that of a nerve stored in
liquid petrolatum for a period and examined before transplantation. The
sections obtained present in essentials the
appearance presented by a fresh nerve fixed and stained after the
pyridine-silver method. Especially is this true of
cross sections. In longitudinal sections the neuraxes are seen as
unsegmented strands of regular contour. The "Golgi-funnels" of the
myelin, are distinctly evident though not quite so regular as in a
fresh, normal nerve. The sheath cells
were not differentiated.
EXPERIMENT
No. 159.-Rabbit No. 108a; large; full grown; 1 hour. December 17, 1918,
right sciatic
exposed; internal popliteal freed; resected 3.0 cm. A segment of equal
length removed
from the sciatic
of another
rabbit, stored seven days in sterile liquid petrolatum at 30° C., used
as transplant. One central and one distal waxed,
fine silk thread suture placed. Good approximation attained. Wound
closed. Rabbit stopped breathing while this
operation was being completed and could not be revived. About one hour
after the operation was begun, sciatic and
the transplant removed and fixed in neutral formalin. Stained in
iron-hematoxylin and picro-fuchsin and in safranine
and licht grün.
Microscopic
findings.-Cross and longitudinal sections of the transplant present
appear-ances which
resemble very closely that of a normal nerve fixed and stained as above
indicated In cross sections of the nerve
transplant, the nerve fibers have not so compact an arrangement as in a
normal nerve, though the fibers themselves
have the appearance of normal nerve fibers. In longitudinal sections,
the fibers present a regular contour, the
neuraxes even
1201
borders and are not shrunken; the
neurokeratin net of the myelin, very regular and distinct. The sheath
nuclei present
normal form and size and reaction to stains.
EXPERIMENT
No. 160.-Rabbit No. 105; full grown; Belgian hare; 2 days. November
S.1918, left sciatic
exposed; internal popliteal freed; resected 3.0 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored 38 days in liquid petrolatum at 3? C.,used
as
transplant. One central and one distal waxed, fine silk thread
suture placed; good approximation attained. Wound closed. November 10,
rabbit found dead in the morning. Wound clean; healing. Left sciatic
exposed. Quite a large blood clot over nerve region of central wound. Nerve
sutures in place. Ends of transplant and resected nerve ends not as yet
united. Sciatic and transplant removed and
fixed in neutral formalin. Stained iniron-hematoxylin, picro-fuchsin
and safranine and licht grün.
Microscopic
findings.-In both cross and longitudinal sections of the
transplant, it may be observed that the
transplanted nerve fibers retain their form and structure very well.
The neuraxes are not segmented, the myeline
sheaths show clearly a neurokeratin net, the sheath nuclei distinctly
evident and stain readily, though of more
uniform color than normal nuclei.
EXPERIMENT
No. 161.-Rabbit No. 105a; full grown; Belgian hare; 2 days. November 8,
1918, right
sciatic exposed; internal popliteal freed; resected 2.8 cm. A segment
of equal length taken from the sciatic of another
rabbit, stored in liquid petrolatum 38 days at 30 C., used as
transplant. One central and one distal waxed, fine silk
thread suture placed; good approximation. Wound closed. November 10,
rabbit found dead in the morning. Wound
clean; healing. Right sciatic exposed. Nerve transplant found well in
place, not adherent to resected nerve ends and
surrounding tissues. Sciatic and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining.
Microscopic
findings.-Silver staining not successful; no differentiation of
neuraxes in normal central stump.
In the transplanted nerve the neurolemma sheaths differentiated. These
appear slightly thickened; other structures
not clearly differentiated.
EXPERIMENT
No. 162.-Rabbit No. 106; full grown; 2 days. November 8, 1918, left
sciatic exposed;
internal popliteal freed; resected 2.5 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
38 days in liquid petrolatum at 30 C., used as transplant.
Central and distal waxed, fine silk suture placed; good
approximation. Wound closed. November 10, rabbit found dead in the
morning. Sciatic and transplant removed and
fixed in neutral formalin. Stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
Microscopic
findings.-Nerve fibers of the transplant very well preserved. No
segmentation of the neuraxes
of nerve fibers of the transplant noted. In many of the nerve fibers
neurokeratin net of the myelin well stained, in
others no longer evident. Sheath nuclei evident and well stained.
Transplant loosely adherent to resected nerve ends.
Centrally very little inwandering of leucocytes into the nerve
transplant. Centrally and distally, hemorrhage into
resected nerve ends. As yet no evidence of degeneration of the nerve
fibers of the distal nerves.
EXPERIMENT
No. 163.-Rabbit No. 106a; full
grown; 2 days. November 8, 1918, right sciatic exposed;
internal popliteal bundle freed; resected 2.5 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored in liquid petrolatum 38 days at 3? C., used as
transplant. One central and one distal waxed, fine silk thread
suture placed; approximation good. Wound closed. November 10, rabbit
found dead in the morning. Sciatic and
transplant removed and fixed in ammoniated alcohol for pyridine-silver
staining.
Microscopic
findings.-In cross sections of the nerve transplant, neuraxes
differentially stained, though of
paler color than in normal nerve; neurolemma sheaths stand out clearly
and appear as if slightly thickened.
EXPERIMENT
No. 164.-Rabbit No. 102; full grown; 4 days. November 4, 1918, left
sciatic exposed;
internal popliteal freed; resected 2.8 cm. A segment of equal length
taken from the
sciatic of
another rabbit, stored in
sterile petrolatum 35 days at 3VC., used as transplant. One central and
one distal waxed, fine silk thread suture
placed; good approximation. Wound closed. November 8, rabbit found dead
in the morning. Superficial wound clean and dry; nearly healed. Left sciatic exposed. Transplant found
well in
place; sutures show
1202
clearly. Transplant presents a light
yellow-white color; not adherent to underlying muscle; loosely united
to the
resected nerve ends. Resected nerve ends appear congested. Sciatic and
the transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining. Fair differential
silver staining attained.
Microscopic
findings.-In the transplanted nerve segment , both in cross and
longitudinal sections, the
neuraxes still evident, though staining very lightly, In the majority
not as vet frag- mented; certain ones showing a
granular change. Neurolemma sheaths well maintained, and appear
slightly thickened. Neurokeratin net and Golgi
funnels not clearly seen. In the central end of the transplant are seen
a number of distended capillaries, grown into
the transplant from the central nerve stump. These capillaries have
only endothelial walls and are distended with
blood cells and have grown toward the periphery between the nerve
fibers of the transplant. The distal segment
presents evidence of early stages of nerve degeneration.
EXPERIMENT
No. 165.-Rabbit No. 102a; full grown; 4 days. November 4, 1918, right
sciatic exposed;
internal popliteal freed; resected 2.8 cm. A segment of equal length
taken from the sciatic of another rabbit and
stored in sterile liquid petrolatum 35 days at 30 C., used as
transplant. One central and one distal waxed, fine silk
thread suture placed; good approxi- mation. Wound closed. November 8,
rabbit found dead in the morning.
Superficial wound found clean and dry and nearly healed. Right sciatic
exposed. Transplant found well in place, of
yellow-white color, nonadherent and loosely united to the resected
nerve ends. Sciatic and transplant removed and
fixed in neutral formalin. Stained in iron-hematoxylin and picro-fuchsin; safranine and licht grün.
Microscopic
findings.-In cross and longitudinal sections of the nerve
transplant, the nerve fibers found to be
very well maintained; neuraxes present and not fragmented. The
neurokeratin net of myelin only here and there
clearly brought out. The neurolemma sheaths not collapsed, and of
regular contour. Neuraxes of the transplant seen
best preserved in the immediate vicinity of the central and distal
wounds; in these regions stain much more clearly
than in the body of the transplant. Nerves of the distal segment show
beginning stages of degeneration evidenced in
fragmentation of the myelin.
EXPERIMENT
No. 166.- Rabbit No. 117; full grown; 4 days. December 27, 1918, left
sciatic exposed;
internal popliteal freed; resected 3.1 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
13 days in sterile liquid petrolatum at 3° C., used as
transplant. One central and one distal waxed, fine silk thread
suture placed; good approximation. Wound closed. December 31, rabbit
found dead in the morning. Superficial
wound healed. On removing skin over operated field, bloody exudate in
subcutaneous tissue about wound and in
deeper wound about transplant noted. Transplant found well in place;
not adherent to surrounding tissue, loosely
united to resected nerve ends. Sciatic and transplant removed and fixed
in ammoniated alcohol for pyridine-silver
staining. In part very good silver differentiation attained.
Microscopic findings.-In longitudinal sections of the
transplanted nerve segment, it may be observed that the neuraxes are
undergoing changes; many appear fragmented
into longer or shorter segments, of distinctly granular structure. The
neurolemma sheaths well maintained, though in
many fibers showing alternate slight distensions or constriction
Capillaries coming from the central nerve stump
extend nearly the whole length of the nerve transplant. Distal nerve
shows early stages of degeneration.
EXPERIMENT
No. 167.- Rabbit No. 117a; full grown; 4 days. December 27, 1918, right
sciatic exposed;
internal popliteal freed; resected 3.2 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
13 days in sterile liquid petrolatum at 3? C., used as
transplant. One central and one distal waxed, fine silk suture
placed; good approximation. Diameter of transplant smaller than that of
the resected nerve. Wound closed. December 31, rabbit found dead in the
morning. Superficial wound found healed. Right sciatic exposed.
Transplant
found well in place; but surrounded by a blood clot. Sciatic and
transplant removed and fixed in neutral formalin.
Stained in iron-hematoxylin and picro-fuchsin; safranine and licht
grün.
Microscopic
findings.- In cross and longitudinal sections of the
transplanted nerve
segment, it is observed
that the neuraxes are beginning to show a fragmentation. These
fragments of neuraxes are found inclosed in nmyelin
segments in which the neurokeratin net ;
1203
is still evident, and are found within
neurolemma sheaths. No evidence of proliferation of the sheath cells of
the
transplanted nerves ascertained. Capillaries containing blood cells,
and extravasated blood cells found between the
nerve fibers of the transplant. In the distal segment, beginning
fragmentation of neuraxes and myelin; hypertrophy of
the sheath cells noted; here and there these fill the neurolemma
sheaths; as yet no distinct proliferation of the sheath
cells observed.
EXPERIMENT
No. 168.-Rabbit No. 127; full grown; 5 days. March 4, 1919, left
sciatic exposed; internal
popliteal freed; resected 3.1 cm. A segment of equal length taken from
the sciatic of another rabbit, stored twenty-one days in liquid
petrolatum at 3° C., used as transplant. One central and one
distal waxed, fine silk thread suture
placed. Good central approximation attained; distal only fair. Wound
closed. March 9, rabbit found dead in the
morning. Transplant found well in place, easily demarked by sutures;
united to resected nerve ends; not adherent to
surrounding tissue. Sciatic and transplant removed and fixed in neutral
formalin. Stained in safranine and licht grün.
Microscopic
findings.-In longitudinal sections of the transplanted nerve
segments
fragmentation of
neuraxes noted; these fragments have a granular structure. The
neurolemma sheaths well maintained but of irregular
contour. Long, rod-shaped nuclei are found in relation with the nerve
fibers. It is difficult to determine whether these
nuclei are within it he neurolemma sheaths or situated on their outer
surface. The appearances presented in cross
sections of the transplant enable the determination that the majority
of these nuclei are situated between the nerve
fibers, thus outside of the neurolemma sheaths and of connective tissue
derivation. Numerous wandering leucocytes
found between the nerve fibers of transplant in the immediate vicinity
of both the central and distal wounds.
EXPERIMENT
No. 169.-Rabbit No. 112; full grown; 6 days. December 21, 1918, left
sciatic exposed;
internal popliteal freed; resected 2.3 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
nine days in sterile liquid petrolatum at 3° C.,used as
transplant. One central and one distal waxed, fine silk thread
suture placed. Central suture not good; removed and resutured;
approximation fair; distal good. Wound closed. December 27, rabbit
found dead in the morning. Superficial wound healed; deep wound, blood
clot about transplant.
Central suture not good. Sciatic and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining.
It part good silver differentiation attained.
Microscopic
findings.-New neuraxes budding from central stump; neuraxes can be
traced into the central
wound; these not as yet numerous. In the transplant, the neuraxes of
the transplanted nerves found for the greater
part in the form of short segments having wavy or spiral course.
Neurolemma sheaths well maintained and of regular
contour. Beginning stages of nerve degeneration noted in the distal
segment.
EXPERIMENT
No. 170.-Rabbit No. 112a; full grown; 6 days. December 21. 1918, right
sciatic exposed;
internal popliteal freed; resected 2.6 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
nine days in sterile liquid petrolatum at 3? C., used
as
transplant. One central and one distal waxed, fine silk suture
placed; good approximation; small hematoma under fascial tissue in
popliteal space. Wound closed. December 27,
rabbit found dead in the morning. Wound well healed. On exposing
sciatic, transplant found well in place and united
to the resected nerve ends. Sciatic and transplant removed and fixed in
neutral formalin. Stained in iron-hematoxylin
and picro-fuchin, safranine and licht grün.
Microscopic
findings.-In longitudinal sections of the transplanted nerve
segment, the neuraxes of the
transplanted nerves appear fragmented in short segments. These segments
are here and there swollen and globular
and for the most part inclosed in myelin in which a neurokeratin net is
still evident. The neurolemma sheaths are
well maintained. Within these sheaths are found the myelin segments and
neuraxes segments shrunken in
longitudinal direction, leaving spaces in which a granular precipitate
is seen. Sheath cells not evident. Capillaries
course between the nerve fibers of the transplant. Distal segment found
degenerating.
EXPERIMENT
No. 171.-Rabbit No. 109; full grown; Belgian hare; 12 days. December18,
1918, left sciatic
exposed and internal popliteal bundle freed; resected 2.4 cm. A segment
1204
of equal length taken from the sciatic
of
another rabbit, stored eight days in liquid petrolatum at 3? C., used as
transplant. One central and one distal suture placed; approximation,
both central and distal, only fair. Wound closed. December 30, rabbit
found dead in the morning. Wound well healed. Left sciatic exposed.
Transplant found well in
place and adherent to surrounding tissue which is discolored; bloody
exudate. Sciatic and transplant removed and
fixed in ammoniated alcohol for pyridine-silver staining. Silver
differentiation good; nuclei in part stained.
Microscopic
findings.-Early stages of central bulbous enlargement evidenced
struc-turally. Central end of
transplant well united to central stump; fibrous and cellular tissue
constitutes central wound. Down-growing
neuraxes from the central stump noted in passage through central wound. Certain of these
have
reached the central
end of the transplant in which they have passed distally to the extent
of approximately 2 mm. In the greater part of
the nerve transplant no new neuraxes seen. Many remnants of old
neuraxes evident,
FIG. 228- Cross section of
homo-nerve
transplant, stored in liquid petrolatum, at 3°C., 8 days
before use as
transplant, Experiment No. 171, 12 days after operation;
pyridine-silver prepara- tion. Note the distinct funicular
structure of the nerve transplanted and the want of fibro blastic
differentiation about the nerve transplant as a
whole either deeply stained fragments or of lighter color and granular
structure. Sheath cells here and there evident.
Myelin not clearly differentiated. In the distal nerve segment, nerve
fibers in degeneration, sheath cells proliferated;
many nucleated, syncytial protoplasmic bands; myelin ovoids and
fragments of old neuraxes present.
EXPERIMENT
No. 172.-Rabbit No. 109a; full grown; Belgian hare; 12 days. December
18, 1918, right
sciatic exposed; internal popliteal bundle freed; resected 2.5 cm. A
segment of equal length taken from the sciatic of
another rabbit, stored eight days in sterile liquid petrolatum at 3°
C., used as transplant. One central and one distal
waxed, fine silk-thread suture placed; good approximation attained. Dry
wound; wound closed. December 30, rabbit
found dead in the morning. Superficial wound well healed. Oil removing
skin over operated area, small area of focal
infection noted; deep wound healed, no evidence of infection.
Transplant found well in place; only moderately
adherent to surrounding tissue. The sciatic and transplant removed and
fixed in neutral formalin. Stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
1205
Microscopic
findings.-Transplant firmly united to central and distal ends of
resectednerve by means of
cellular fibrous tissue layer. Distinct central bulbous enlargement and
slight distal enlargement. In longitudinal
sections of the transplant, taken from its middle third, neurolemma
sheaths of the transplanted nerve fibers well
maintained and appear as slightly thickened. Myelin observed in the
form of smaller and larger globules or
segments, the larger of which inclose fragments of old neuraxes.
Fibrous sheaths of the transplant invaded by
wandering cells. Within the transplant many long nuclei with rounded
ends. The majority of these appear to be
situated between the nerve fibers; others appear to be within the
neurolemma sheaths; their histogenesis uncertain.
Distal segment of nerve found in degeneration.
EXPERIMENT
No. 173.-Rabbit No. 107; large; full grown; Belgian hare; 23 days.
November 10, 1918, left
sciatic exposed; internal popliteal bundle freed; resected 3.2 cm. A
segment of equal length taken from the sciatic of
another rabbit, stored thirty-nine days in sterile liquid petrolatum at
3º C., used as transplant. One central and one
distal waxed, fine silk-thread suture placed; very good approximation
attained. Dry field; wound closed. December
2, rabbit found dead in the morning. Wound well healed. Left sciatic
exposed full length. External popliteal free and
runs normal course. The nerve transplant found well in place. Material
increase of connective tissue about the central
and distal wounds. Transplant of yellow-white color and appears as if
slightly congested. Transplant firmly united to
resected nerve ends. Sciatic and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining.
Silver differentiation centrally very good, distally not uniform.
Microscopic
findings.-A distinct central bulb evidenced structurally. From the
distal end of this bulb
numerous neuraxes pass to and through the central wound into central
end of transplant, in which they may be traced
to the neighborhood of the distal wound. The distal wound appears not
to have been penetrated by down-growing
neuraxes nor area any new neuraxes to be found in the central end of
the distal nerve. In cross sections of the nerve transplant, about 1 cm.
distal to the
central wound, new neuraxes found in all parts of the transplanted
nerve. In
many regions small groups of new neuraxes appear to pass distally
within one old neurolomma sheath; certain
neuraxes observed between or out-side of neurolemma sheaths. Perineural
sheaths of the transplanted nerve funiculi
not materially thickened.
EXPERIMENT
No. 174.-Rabbit No. 107a; large, full grown; Belgian hare; 23 days.
November 9, 1918,
right sciatic exposed; internal popliteal freed; resected 3.2 cm. A
segment of equal length taken from the sciatic of
another rabbit, stored 39 days in sterile liquid petrolatum at 30 C.,
used as transplant. One central and one distal
waxed, fine silk-thread suture placed; good approximation; dry field;
wound closed. December 2, rabbit found dead
in the morning. Wound healed. Cold abscess over right gluteal region;
not related to wound. The right sciatic
exposed full length. Transplant found well in place and firmly united
to the resected nerve ends; quite adherent to
surrounding tissue; of yellow-white color. Quite well developed central
bulbous enlargement. Sciatic and transplant
removed and fixed in neutral formalin. Stained in iron-hematoxvlin and
picro-fuchsin; safranine and licht grün.
Microscopic
findings.-Fibrocellular central wound into which extend nucleated
prot plasmic bands. In
longitudinal sections of the transplant, from about its middle third,
myelin of the transplanted nerve segments
in the form of larger and smaller globules, certain of which are found
to contain fragments of the
old neuraxes. Numerous, relatively large round or oval nuclei found
within the old neurolemma
sheaths. Histogenesis of these is uncertain. The neurolemma sheaths
well maintained and appear
slightly thickened. Distal nerve not sectioned.
EXPERIMENT No. 175.-Rabbit No. 133; large;
old; Belgain hare; 82 days. March 15,1919, left sciatic
exposed; internal popliteal freed; resected 3 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored seven days in sterile liquid petrolatum at 3ºC.,
used as transplant. One central and one distal waxed, fine silk-thread
suture placed; good approximation attained. Wound not quite dry; wound
closed. June 5, killed. For several
days had not eaten well; much emaciated; moribund when killed. Severe
neurotrophic
1206
ulcer left heel. Wound well healed.
Left, sciatic exposed full length. External popliteal found free from
operated internal popliteal. The transplant found well in place; no
material increase of connective tissue about
transplant. Large, spindle-shaped central bulbous enlargement. Distal
suture clearly seen. Calf muscles exposed;
these are atrophic and of pale-red color; appearance of degenerated
muscles. Sciatic and transplant removed and
fixed in ammoniated alcohol for pyridine-silver staining. Silver
differentiation not uniform throughout.
FIG. 229.- Cross section of homo-nerve
transplant, stored in liquid petrolatum at 30 C. for 39 days before
use,
Experiment No. 174, removed 23 days after operation; pyridine-silver
preparation. Attention is called to the distinct
funicular structure presented by this nerve and the small amount of
fibrous tissue development surrounding the nerve
Microscopic
findings:-New down-growing neuraxes can he traced from distal end
of central bulbous
enlargement to and into transplant and in this to and through the
distal wound into the central end of the distal nerve
segment. Within the transplant these new neuraxes have a very regular,
longitudinal course and appear to pass
distally within and outside of old neurolemma sheaths. Areas of
degenerated or fragmented myelin of the
transplanted nerves observed, between which and around which the
down-growing neuraxes pass.
EXPERIMENT
No. 176.-Rabbit No. 131; large; full grown; 82 days. March 12,
1919.left sciatic exposed;
internal popliteal bundle freed; resected 2.9 cm. A segment of equal
1207
length taken from the sciatic of another
rabbit, stored in sterile liquid petrolatum 23 days at 3ºC., used as
transplant. One central and one distal suture of waxed,
fine silk thread placed. Central suture pulled out; resutured, a little
traumatism to central resected stump resulted; central approximation
only fair; distal good. Wound closed. June 2,
rabbit found dead in the morning. Slightly emaciated; neurotrophic
ulcer left heel. Wound well healed. Left
sciatic exposed full length. No material increase of connective tissue
about nerve. External adherent to side of
operated internal popliteal. Transplant well in place; of light
reddish-brown color; not adherent to surrounding
tissue. Sciatic and transplant
FIG. 230.- Cross section of
homo-nerve
transplant stored in liquid petrolatum 39 days at 3º C.
before use; Experiment No. 174. Experiment terminated 23 days after
operation. Higher magnification of portion of the larger funiculus
shown in Figure 229. Note the new neuraxes seen in cross section as
fine black dots, many of which are found
within neurolemma sheaths of the transplanted nerve fibers
removed and fixed in ammoniated alcohol
for
pyridine-silver staining. Silver differentiation only partially
successful; tissue not well embedded and difficult to cut; sections
torn.
Microscopic
findings.-Numerous new neuraxes can be traced from the central
stump and through the distal
wound. The differential staining of the distal nerve not successful,
thus can not clearly determine whether new
neuraxes have reached the distal popliteal.
EXPERIMENT
No. 177.-Rabbit No. 129; full grown; 112 days. March 7, 1919, left
sciatic exposed;
internal popliteal freed; resected 2.9 cm. A segment of
equal length
taken from the sciatic of another rabbit, stored in
sterile liquid petrolatum 17 days at 3° C., used as
1208
transplant. One central and one distal
waxed,
fine silk thread suture placed; good approximation. Wound closed.
June 27, killed. Rabbit much emaciated; not well; severe neurotrophic
ulcer left heel. Wound well healed. Left
sciatic exposed full length. External popliteal adherent to operated
internal popliteal; both bundles surrounded by a
dense fibrous tissue sheath and adherent to underlying muscle.
Transplant found well in place and of good size. Calf
muscles fully exposed; are atrophic and of pale red color. Sciatic
completely freed from bed. On slowly cutting with
scissors, sciatic central to transplant, vigorous contraction of the
foot flexors supplied by the external popliteal,
unoperated, but only very feeble and doubtful twitching of calf muscles
supplied by operated internal popliteal. Sciatic and transplant removed
and fixed in ammoniated alcohol for pyridine-silver staining. Fair
differential silver
staining throughout the series of sections attained.
Microscopic
findings.-Large, spindle-shaped central bulbous enlargement
evidenced structurally, from the
distal end of which new, down-growing neuraxes may be traced through
the transplant, to and through the distal
wound and in good numbers into the central end of the distal popliteal,
in which they may be traced to the lower
level of the popliteal space. Unfortunately the calf muscles were not
removed for microscopic examination; it is thus
not possible to report on the presence or absence of new neuraxes in
the calf muscles. Microscopic findings indicate
partial regeneration of the distal nerve segment through the nerve
transplant.
EXPERIMENT
No. 178.-Rabbit No. 104; full grown; 117 days. November 7, 1918, left
sciatic exposed;
internal popliteal freed; resected 3 cm. A segment of equal length
taken from the sciatic of another rabbit, stored 38
days in sterile liquid petrolatum at 3º C., used as
transplant. One central and one distal waxed, fine silk thread suture
placed; good central approximation, distal fair. Wound closed. March 4,
1919, killed. Rabbit found nearly moribund;
"fungus" ears; eyes infected; much emaciated; wound well healed;
neurotrophic ulcer left heel. On exposing the left
sciatic, transplant found well in place, of small diameter, adherent to
underlying muscle. Large, spindle-shaped
central bulb. Calf muscles fully exposed; these appear atrophic and of
pale red color and do not respond distinctly on
cutting the sciatic central to the transplant. Sciatic and transplant
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Not complete and uniform silver
differentiation.
Microscopic
findings.-Sections show sufficient silver differentiation of
neuraxes to determine the
observation that neuraxes growing from the central bulb enter the
transplant and pass through this to and through
distal wound into the central end of distal popliteal, in which region
the staining is better; here numerous new
neuraxes are differentiated. Regeneration through transplant of central
end of distal popliteal.
EXPERIMENT
No. 179.-Rabbit No. 104a; full grown; 117 days. November 7, 1918,right
sciatic exposed;
internal popliteal freed; resected 2.5 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
38 days in sterile liquid petrolatum at 3º C.,used as
transplant. One central and distal waxed, fine silk thread suture
placed; good approximation. Wound closed. March 4, 1919, killed. Rabbit
found nearly moribund; only slight
neurotrophic ulcer right heel. On exposing right sciatic, transplant is
found well in place, of good size and only
slightly adherent to the underlying muscle. Large central bulb. No
record of test of muscles. Sciatic and the
transplant removed and fixed in ammoniated alcohol for pyridine-silver
staining. Silver differentiation very
unsatisfactory and imperfect.
Microscopic
findings.-Transplant well united to resected nerve end. New
neuraxes appear to be present in
the transplant; this can not be determined definitely since silver
differential staining is unsuccessful. Experiment not
conclusive.
EXPERIMENT
No. 180.-Rabbit No. 130; full grown; 120 days. March 10, 1919, left
sciatic exposed;
internal popliteal bundle freed; resected 3.4 cm. A segment of equal
length taken from another rabbit, stored 20 days
in sterile liquid petrolatum at 3º C., used as transplant. One central and one distal waxed, fine
silk thread suture
placed; centrally, good approximation; distally only fair. Wound
closed. July 8, rabbit found dead in the morning;
examined soon after death. Neurotrophic ulcer left heel noted. On
exposing left sciatic, the nerve transplant found
well in place, of good size and dull-white color and only moderately
adherent to underlying muscle. Small, spindle-shaped central bulb, and
slight enlargement
1209
of central end of distal stump noted.
Calf
muscles fully exposed; these appear as if partly recovered; good color
though not full size. Muscles could not be tested as regards functional
return, because animal had been dead some
time before it was examined. Sciatic and transplant removed and fixed
in ammoniated alcohol for pyridine-silver
staining. Fairly good silver differentiation attained.
Microscopic
findings.-In alternate cross and longitudinal sections of the
operated nerve, numerous new
neuraxes coming from the central stump may be traced through the
trans-plant to the distal popliteal. In cross
sections of the transplant near the central and distal wounds, there
may be observed an increase of the endoneural
connective tissue but no material thickening of the perineural sheaths
of the funiculi. The new neuraxes are found in
small groups, separated by endoneural connective tissue and are equally
distributed through all parts of the
transplant.
EXPERIMENT
No. 181.-Rabbit No. 114; full grown; 145 days. December 24, 1918,left
sciatic exposed;
internal popliteal freed; resected 2.1 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
11 days in sterile liquid petrolatum at 3 º C.,used as
transplant. Only fair central and distal approximation attained.
Wound closed. May 18, 1919, rabbit found dead in the morning.
Emaciated; "fungus" ears, neurotrophic ulcer left
heel, which seemed to be healing; wound well healed. On exposing left
sciatic, transplant found well in place, no
material increase of connective tissue about operated nerve not
adherent to underlying muscle. Quite distinct central
bulb noted. Distal nerve presents the appearance of a normal nerve.
Calf muscles fully exposed, have the appearance
of regenerating muscle, though not fully recovered. Could not be tested
as to functional return-animal dead. Sciatic
and transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining; silver staining faint but
differential.
Microscopic
findings.-Neuraxes in very good numbers pass from the distal end of
the central stump,
through the transplant to the distal nerve, in which they are
distributed in good numbers in all of the funiculi. In cross
sections of the transplant, the new neuraxes found mostly in small
groups, separated by strands of endoneural tissue;
quite evenly distributed over the entire transplant. Here and there
small areas or columns of m yeling lobules
and detritus, derived from the myelin sheaths of the transplanted nerve
fibers, are to be found. Such areas not
generally traversed by neuraxes. Very complete regeneration of the
distal nerve, through the transplant, evidenced
structurally.
EXPERIMENT
No. 182.-Rabbit No. 114a; full grown; 145 days. December 24, 1918,
right sciatic exposed;
internal popliteal bundle freed; resected 2.9 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored 11 days in sterile liquid petrolatum at 3 º C., used
as transplant. One central and one distal waxed, silk thread
suture placed. Good central, only fair distal approximation attained.
Wound closed. May 18, 1919,rabbit found dead
in the morning. Large neurotrophic ulcer right heel; apparently
healing. On exposing right sciatic, transplant found
well in place; external popliteal looped over it, though not adherent;
no material increase of connective tissue about
nerves. Distinct spindle-shaped central bulb, only indistinct
enlargement of central end of distal stump. Distal nerve
has the appearance of normal nerve. Calf muscles exposed; not fully
recovered, though present the appearance of
regenerating muscle. Could not be tested as to functional return.
Sciatic and transplant removed and fixed in neutral
formalin. While tissues were being prepared for embedding and serial
section, preparatory to staining iniron-hematoxylin and picro-fuchsin,
it was accidentally thrown out, thus not available for report as to
microscopic
findings.
EXPERIMENT
No. 183.-Rabbit No. 128; full grown; Belgian hare; 138 days. March 5,
1919, left sciatic
exposed; internal popliteal freed; resected 3 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored 22 days in sterile liquid petrolatum at 3 º C., used
as transplant. One central and distal waxed, fine silk-thread
suture placed. Good approximation attained. Wound closed. July 21,
rabbit found dead in the morning; much
emaciated. Severe neurotrophic ulcer left heel. On exposing the left
sciatic, transplant found well in place, of good
size and of an appearance similar to resected nerve. Moderately large
central bulb noted. Calf muscles still appear
somewhat atrophic and of pale red color. Nerve and transplant removed
and fixed in ammoniated alcohol for
pyridine-silver staining. Good differential silver staining attained.
1210
Microscopic
findings.-Large numbers of
neluraxes pass from distal end of central stump, through central
wound and transplant, through distal wound into distal popliteal.
Certain of the neuraxes passing through the
transplant have acquired a myelin sheath. Spindle-shaped areas of
myelin globules and granular detritus noted ill
longitudinal sections of the transplant. These lie between bundles of
descending neuraxes. Endoneural connective
tissue not materially increased; while the perineural sheaths are
materially thick Numerous new neuraxes in the
distal popliteal in all of the funniculi. Regeneration of the distal
nerve evidenced structurally.
EXPERIMENT
No. 184.-Rabbit No. 101; full grown; 155 days. October 8, 1918, left
sciatic exposed; the
internal popliteal freed; resected 3.5 cm. External popliteal bundle
accidently cut while separating it from the
internal popliteal; disregarded .A segment of equal length taken from
the sciatic of another rabbit, stored nine days in
sterile liquid petrolatum at 3 º C., used as transplant.
One central and one distal waxed, silk thread suture placed.
Approximation of central ends fair; distally good direction, but suture
not well placed, not good approximation
attained. Muscle torn in exposing nerve; oozing, not fully controlled.
Wound closed. March 12, 1919, killed. Rabbit
in very good condition. One toe left foot missing; neurotrophic ulcer
of left heel practically healed; does not spread
toes of left foot on lifting up rabbit by ears. On exposing the left
sciatic, transplant found well in place, of good size;
quite material increase of connective tissue about operated nerve. Only
indistinct central bulb. External popliteal
accidently cut and not sutured, found united, slight bulbous
enlargement at the place of cutting. Calf muscles and
other leg muscles fully exposed, and internal popliteal and transplant
completely freed from bed. On slowly cutting
internal popliteal bundle central to transplant, vigorous contraction
of calf muscles; same on cutting distal to
transplant; no distinct response from plantar foot muscles. Plantar
foot muscles have nearly recovered normal size
and are of pale red color. Sciatic and transplant removed and fixed in
ammoniated alcohol for pyridine-silver
staining; portions of calf muscles removed for gold chloride staining.
Good differential silver staining attained.
Microscopic
findings.-Numerous new fibers, both myolinated and nonmyelinated,
pass through transplant
to the distal stump. Scarcely any myelin globules, remains of myelin of
transplanted nerve, to be found in the
transplant. In cross sections of the transplant near both central and
distal wounds, numerous neuraxes, evenly
distributed over transplant, to be seen. Very little increase of
endoneural connective tissue to be noted; perineural
tissue not materially increased. Numerous new neuraxes in distal
popliteal in all of the funiculi. In the calf muscles
stained after the gold chloride method, the neuraxes of the nerve
fibers of the larger muscular bundles well stained,
as also in certain smaller muscular branches. Motor endings nowhere
stained. This is regarded as inconclusive, and
appears to be due to imperfect differentiation, since the teased muscle
fibers appear to present normal structure.
Regeneration and return of motor function in calf muscle, though this
latter is not fully checked by histologic
findings.
EXPERIMENT
No. 185.-Rabbit No. 101a; full grown; 154 days. October 9, 1918, right
sciatic exposed;
internal popliteal freed; resected 3 cm. A segment of equal length
taken from the sciatic of another rabbit, stored nine
days in sterile liquid petrolatum, at 3° C..used as
transplant. One central and one distal waxed, fine silk thread suture
placed; good approximation attained. Wound closed. March 12, 1919,
killed. Rabbit in very good condition, healed
neurotrophic ulcer right heel; spread toes of right foot on elevating
rabbit by ears. On fully exposing right sciatic and
calf muscles, transplant found well in place with only slight increase
of connective tissue about operated nerve.
Transplant of good size and good color. Only slight bulbous enlargement
of central stump noted. After completely
freeing the operated internal popliteal and transplant, cutting the
same central to the transplant, good contraction of
calf muscles, contraction of foot muscles somewhat uncertain. Operated
nerve and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining; portions of calf
muscles for gold chloride staining. Good silver
differentiation attained.
Microscopic
findings.-Numerous, both myelinated and nonmyelinated neuraxes to
be traced from the distal
end of the central stump to and through transplant, to distal
popliteal.
1211
In cross sections of the transplant,
neuraxes
seem to be evenly distributed over transplant. Narrow streaks of myelin
remains, with these certain large vesicular cells, found between
bundles of new neuraxes; these remains not
numerous. Endoneural connective tissue not materially increased. In the
gold chloride stained pieces of muscle,
neuraxes well stained in the larger and smaller muscular nerves. The
motor endings not differentiated; apparently
due to faulty differential staining; muscle fibers present a normal
structure. Regeneration of distal popliteal through
transplant.
EXPERIMENT
No. 186.-Rabbit No. 111; full grown; 196 days. December 20, 1918, left
sciatic exposed;
internal popliteal bundle freed; resected 3.0 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored 10 days in sterile liquid petrolatum at 3º C., used
as transplant. One central and one distal suture placed,
waxed, fine silk thread used. Good approximation attained. Dry field;
wound closed. July 4, 1919, rabbit found dead
in the morning; seemed in fairly good condition the day before; severe
neurotrophic ulcer left heel; healing. On
exposing the left sciatic, transplant found well in place and presents
the appearance of a normal nerve; no material
increase of connective tissue about it. Large oval-shaped central bulb;
central end of distal stump not materially
increased. Distal nerve presents the appearance of a normal nerve
trunk. The calf muscles exposed; they present a
pale red color and are still slightly atrophic. Could not be tested as
to functional return. Sciatic and the transplant
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Silver differentiation not wholly satisfactory.
Microscopic
findings.-In cross and longitudinal sections, sufficient
differential silver staining of neuraxes
found to determine the fact that numerous, both myelinated and
non-myelinated neuraxes, extend through the
transplant from the central to the distal stump. Columns and
spindle-shaped areas of myelin globules and detritus,
are here and there noted in the longitudinal sections of the
transplant; these show as round or oval areas in cross
sections of the transplant. Apparent regeneration of the distal nerve
through the transplant.
EXPERIMENT
No. 187.-Rabbit No. 111a; full grown; 196 days. December 20, 1918,
right sciatic exposed;
internal popliteal freed; resected 2.6 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
10 days in sterile liquid petrolatum at 3º C used as
transplant. One central and one distal waxed, fine silk thread
suture placed; good approximation attained. Dry field; wound closed.
July 4, 1919, rabbit found dead in the morning.
Seemed in fairly good condition the day before; healing neurotrophic
ulcer right heel. On exposing the right sciatic,
it is found that the transplant is well in place of good size and color
and not adherent to underlying muscle. Small,
oval-shaped central bulb noted. Distal nerve presents the appearance of
normal nerve trunk. Notes do not record the
appearance and condition of the calf muscles. Sciatic and transplant
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Silver differentiation not wholly
satisfactory.
Microscopic
findings.-In cross and longitudinal sections, sufficient
differentiation of neuraxes to enable
determining the fact that numerous neuraxes, both myelinated and
non-myelinated, pass from the central stump
through the transplant to the distal internal popliteal. Scarcely any
remains of the myelin of the transplanted nerve
noted. Apparent regeneration of the distal popliteal through the
transplant.
EXPERIMENT
No. 188.-Rabbit No. 116; full grown; 223 days. December 27, 1918, left
sciatic exposed;
internal popliteal freed; resected 3.1 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
13 days in sterile liquid petrolatum at 3º C.,used as
transplant. One central and distal suture placed; good
approximation attained. Slight oozing of blood from distal stump into
distal wound; not fully controlled. Wound
closed. August 7, 1919, rabbit found dead in the morning; seemed in
good condition, "fungus" ears; neurotrophic
ulcer left heel, seems to be healing. On exposing the left sciatic,
transplant found well in place; of good size and
color; presents the appearance of normal nerve; not materially adherent
to underlying muscle. Calf muscle exposed,
of nearly normal size, of yellow-red color, streaked with narrow yellow
stripes. Sciatic and portions of calf muscles
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Fairly good silver differentiation attained
throughout whole length of nerve.
Microscopic
findings.-Well-developed central bulbous enlargement evidenced
structur-ally, from the distal
end of which numerous myelinated and nonmyelinated neuraxes can be
1212
traced through the transplant to the
distal
popliteal. Scarcely any neuraxes in the connective tissue, surrounding
the
transplant, found. In cross sections of the transplant, it may be
observed that the down-growing neuraxes pass
through and between the old neurolemma sheaths. Endoneural and
perineural connective tissue not found materially
increased. Numerous new neuraxes found in all the funiculi of the
distal pop)liteal cut at the lower level of the
popliteal space. In longitudinal and cross sections of pieces of calf
muscle, silver stained, new neuraxes observed in
the larger muscular nerve branches, in the smaller inter-fascicular
nerve branches and as single fibers between the
muscle fibers; here and there evidence of motor nerve-endings noted.
Regeneration of distal popliteal through the
transplant, recovery of motor function in calf muscles, as evidenced
structurally, obtained.
EXPERIMENT
No. 189.-Rabbit No. 116a; full grown; 223 days. December 27, 1918,
right sciatic exposed;
internal popliteal freed; resected 3 cm. A segment taken from the
sciatic of another rabbit, stored 13 days in sterile
liquid petrolatum at 3º C., used as transplant. One
central and distal waxed, fine silk thread suture placed; good
approximation. Oozing in deep popliteal space, not fully controlled.
Wound closed. August 7, 1919, rabbit found
dead in the morning; seemed in good condition, "fungus" ears; severe
neuro-trophic ulcer right heel; apparently
healing. On exposing right sciatic, transplant found well in place; of
good size and color; surrounded by relatively
dense connective tissue, adherent to underlying muscle. Calf muscles
fully exposed; are of good size, yellow-red
color, with narrow yellow streaks evident. Sciatic and transplant, with
portions of calf muscles removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
silver staining throughout.
Microscopic
findings.-Distinct, large spindle-shaped central bulb, from the
distal end of which numerous
new neuraxes pass through the transplant to the distal popliteal.
Scarcely any neuraxes course in the connective
tissue outside of the perineural sheaths of the transplanted nerve. In
cross sections of the transplanted nerve it may be
observed that new neuraxes are distributed quite evenly over the entire
transplant. In the distal popliteal lower level
of the popliteal space, numerous neuraxes, both myelinated and
nonmyelinated, found in all of the funiculi. In
sections of the calf muscles, both in cross and longitudinal sections,
new down-growing neuraxes found in the larger
and smaller muscular branches and as single terminal nerve fibers on
and between the muscle fibers. Regeneration of
the distal popliteal through transplant and recovery of the motor
fibers in the calf muscle.
EXPERIMENT
No. 190.-Rabbit No. 115; full grown; 235 days. December 26, 1918,left
sciatic exposed;
internal popliteal freed; resected 2.9 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
13 days in sterile liquid petrolatum at 3º C.,used as
transplant. One central and one distal suture placed, waxed, fine
silk thread suture; approximation good. Dry field; wound healed. August
18, 1919, killed. Rabbit in good condition;
holds head to left side; when attempting to walk forward rolls over;
some semi-circular canal condition not pertinent
to experiment. On exposing the left sciatic, transplant found well in
place; presents appearance of normal nerve,
though not as distinctly bounded; only moderate increase of connective
tissue about transplant. Distinct central bulb;
only slight enlargement of central end of distal stump. External
popliteal adherent to operated internal popliteal; cut
and in part resected. Calf muscles fully exposed; these present nearly
normal size and color. After completely
freeing operated internal popliteal and transplant from bed and slowly
cutting with scissors internal popliteal central
to the transplant, vigorous contraction of the muscles and movement of
toes; the same on cutting distal to the
transplant. Sciatic nerve and transplant and portions of calf muscles
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Only in part good silver differentiation
attained.
Microscopic
findings.-Large spindle-shaped bulb, to which is adherent the
external popliteal. From the
distal end of the central bulbous enlargement on the internal
popliteal, numerous myelinated and nonmyelinated
neuraxes can be traced through the transplant to the distal popliteal.
A few small funiculi of nerve fibers found in the
connective tissue outside of the perineural sheaths of the transplanted
nerves, on the side toward the adherent
external popliteal. In the distal popliteal, new neuraxes in large
numbers in all of the funiculi. In sections of the calf
muscles, neuraxes noted in the larger and smaller intramuscular
branches -
1213
Regeneration of the distal popliteal
through
the transplant with regeneration of motor nerves to the calf
muscles. Interossei not removed and studied.
EXPERIMENT
No. 1919.-Rabbit No. 115a; full grown; 235 days. December 26,
1918, right sciatic
exposed; internal popliteal freed; resected 3 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored 13 days in sterile liquid petrolatum at 3º C.,used
as transplant. One central and distal waxed, fine silk thread
suture placed; good approximation. Dry field; wound closed. August 18,
1919, killed. Good general condition; holds
head to left side; when attempting to walk, falls to side. On exposing
the right sciatic, transplant found well in place;
presents the appearance of a normal nerve; external popliteal adherent.
Large central bulb; central end of distal
segment distinctly enlarged. On exposing calf muscles, which are nearly
of normal size and color, and completely
freeing the internal popliteal and transplant from its bed, slowly
cutting with scissors the internal popliteal central to
the transplant, causes feeble contraction of calf muscles; more
vigorous contraction on cutting distal to the
transplant; contraction and movement of toes doubtful. Sciatic and
transplant and portions of calf muscles removed
and fixed in ammoniated alcohol for pyridine-silver staining. Only in
part good differential silver staining attained.
Microscopic
findings.-Large central bulb, which tapers into
transplant. From
the distal end of bulb,
numerous myelinated and nonmyelinated neuraxes traced through the
transplant to the distal popliteal. Scarcely any
neuraxes found in the connective tissue outside of the perineural
sheaths of the transplanted nerve. These perineural
sheaths found quite distinctly thickened. All of the funiculi of the
distal popliteal nerve possess numerous new
neuraxes, many of which are myelinated. In sections of the calf
muscles, new neuraxes found in the intramuscular
branches and as single terminal branches on the muscular fibers.
Regeneration of distal popliteal through the
transplant, also motor nerves in the calf muscles.
EXPERIMENT
No. 192.-Rabbit No. 113; full grown; 238 days. December 23, 1918,left
sciatic exposed;
internal popliteal freed; resected 2.5 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
11 days in sterile liquid petrolatum at 3º C., used as
transplant. One central and distal waxed, silk thread suture
placed; approximation central good; distal good direction,, but
transplant twisted one-half spiral. Field not quite dry;
wound closed. August 18, 1918, killed. Rabbit not in good
condition;"fungus" ears; emaciated; neurotrophic ulcer
left heel, not completely healed. On exposing left sciatic, it is
noted that muscles of thigh look pale and flabby.
Transplant found well in place; good size and color; no material
increase of connective tissue about it; well-developed central bulb;
quite distinct enlargement of central end of distal stump. Calf muscles
fully exposed; these
are small and of pale color. After freeing nerve and transplant from
bed and on cutting slowly with scissors nerve
central to transplant, feeble but distinct contraction of calf muscles
and movement of toes noted; also on cutting
distal to transplant. Sciatic and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining. Differential silver
staining very good in part; granular deposit obscures in part.
Microscopic
findings.-Large central bulb from the distal end of which numerous
new neuraxes can be
traced to distal popliteal, in which to the level of entrance of
branches into the calf muscles new neuraxes are found
in large numbers in all of the funiculi. Scarcely any neuraxes found in
the connective tissue outside of the perineural
sheaths of the transplanted nerves. Portions of calf muscle, in this
experiment, were accidently lost. Regellera-tion of
distal popliteal to level of calf muscles through the transplant.
EXPERIMENT
No. 193.-Rabbit No. 113a; full grown; 238 days. December 23, 1918,
right sciatic exposed;
internal popliteal bundle freed; resected 2.4 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored 11 days in sterile liquid petrolatum at 3º C.,used as
transplant. One central and one distal suture of waxed,
fine silk thread placed; good approximation. Dry field; wound closed.
August 18, 1919, killed. Rabbit not in good
condition; much emaciated; neurotrophic ulcer right heel; not
completely healed. On exposing the right sciatic,
external popliteal found free; transplant well in place; good size and
color; connective tissue not materially increased
about it. Calf muscles fully exposed; these appear small and of pale
red color. After freeing nerve and transplant
completely, on slowly cutting nerve with scissors central to the
transplant, good contraction of the calf
1214
muscles and distinct movement of the
toes
noted, the same on cutting distal to the transplant. Sciatic and
transplant
and portions of calf muscles removed and fixed in ammoniated alcohol
for pyridine-silver staining. Silver
differentiation only in part successful.
Microscopic
findings.-From the distal end of a long, spindle-shaped central
enlargement embracing the
central wound, numerous myelinated and nonmyelinated neuraxes traced
through the transplant to the distal
popliteal, in which new neuraxes are found in large numbers in all of
the funiculi. Scarcely any neuraxes found in
the connective tissue surrounding the transplant. Pieces of calf muscle
accidently lost. Regeneration of distal
popliteal through transplant.
EXPERIMENT
NO. 194.-Rabbit No. 110; full grown; 242 days. December 19, 1918, left
sciatic exposed;
internal popliteal freed; resected 2.5 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
eight days in sterile liquid petrolatum at 3º C..used as
transplant. One central and one distal suture of waxed, fine
silk thread used; good approximation; dry field; wound closed. August
18, 1919, killed. Rabbit in good condition;
walks well; neurotrophic ulcer left heel very nearly healed. On
exposing the left sciatic, the external popliteal found
in very close approximation to operated internal popliteal. The
transplant found well in place; good size and color,
no material increase of connective tissue about the operated nerve.
Distinct central bulb and distinct enlargement of
central end of distal popliteal. Calf muscles and plantar foot muscles
fully exposed; these of normal size and color.
After completely freeing the operated nerve from bed, slowly cutting
the nerve central to transplant, continued and
vigorous contraction of calf and plantar foot muscles; the
latter
exposed so that contraction was directly observed.
Sciatic and transplant and portions of calf muscles removed and fixed
in ammoniated alcohol for pyridine-silver
staining. Fair silver differentiation attained.
Microscopic
findings.-From distinct bulbous enlargement of the central stump,
numerous myelinated and
nonmyelinated neuraxes traced through the transplant to the distal
popliteal, through which they are traced to the
level of entrance to calf muscles. Scarcely any neuraxes in the
connective tissue surrounding the transplanted nerve
segments. Numerous neuraxes noted in the intramuscular branches in the
sections of the calf muscles. Regeneration
of distal popliteal through the transplant, recovery of calf muscles.
EXPERIMENT
NO. 195.-Rabbit No. 110a; full grown; 242 days. December 19, 1918, right sciatic exposed; internal
popliteal
freed; resected 3 cm. A segment of equal length taken from the sciatic
of
another rabbit, stored in liquid petrolatum in eight days at 3º
C., used as transplant. One central and distal suture of
waxed, fine silk thread used; good approximation; field not quite dry;
wound closed. August 18, 1919, killed. Rabbit
in very good condition; uses right hind foot well; neurotrophic ulcer
on right heel very nearly healed. On exposing
right sciatic, external popliteal quite free, resected. The transplant
found well in place; good size and color, no
material increase of connective tissue about it. Distinct central bulb
and quite distinct enlargement of central end of
distal popliteal. Calf muscles and plantar foot muscles fully exposed;
these of normal size and color. After freeing
transplant and nerve from bed, on slowly cutting with scissors central
to the transplant, good contraction of foot and
calf muscles noted. Sciatic and transplant and portions of calf muscles
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Only partially successful silver
differentiation attained. This owing to fact that while this
and several other series were being embedded in paraffin, steam escaped
into chamber containing paraffin dishes
with tissues. Sufficient silver differentiation obtained to enable
determination of the neuraxes, though these are not
distinctly stained.
Microscopic
findings.-Large spindle-shaped central bulb, from the distal end of
which numerous neuraxes,
myelinated and nonmyelinated, can be traced through the transplant to
the distal popliteal, in which neuraxes in large
numbers are found in all of the funiculi. In sections of the calf
muscles, neuraxes noted in the larger and smaller calf
muscles and as single terminal nerve branches between and on the muscle
fibers. Regeneration of distal popliteal
through the transplant, and recovery of motor nerves in calf muscles.
EXPERIMENT
No. 196.-Rabbit No. 103; large; full grown; Belgian hare; 286 days.
November 5, 1918,
left sciatic exposed; internal popliteal freed; resected 3 cm. A
segment of equal length taken from the sciatic of
another rabbit, stored 36 days in sterile liquid petrolatum
1215
at 3 ? C., used as
transplant. One central and one distal waxed, fine silk-thread suture
placed. Centrally one
funiculus of central stump not in good approximation; distally good
approximation attained. Dry field; wound
closed. August 18, 1919, killed. Rabbit in good condition; walks well;
neurotrophic ulcer left heel very nearly
healed. On exposing left sciatic, external
popliteal found in close apposition to operated internal popliteal.
Transplant found well in place; good size and color, very little
connective tissue increase about it. Only small,
indistinct central bulbous enlargement noted, distally scarcely any
enlargement. Calf muscles fully exposed; these
have the appearance of normal muscle. After completely freeing
transplant and nerve, on slowly cutting nerve with
scissors central to transplant, vigorous contraction of calf muscles
and movement of toes noted. Sciatic and
transplant and portions of calf muscles removed and fixed in ammoniated
alcohol for pyridine-silver staining. Only
partially successful silver differentiation attained.
Microscopic
findings.-Not well marked central bulbous enlargement noted, in the
center of which an
accumulation of small cells, not clearly defined in silver stain, but
presenting the appearance of a small localized pus
pocket, is noted. From the distal end of this bulbous enlargement,
numerous neuraxes, both myelinated and
nonmyelinated, can be traced through the transplant to the distal
popliteal. In cross sections of the transplant,
approximately 1 cm. from the central wound, an accumulation of small
cells under the perineural sheath is noted;
possibly a small focus of pus cells. Perineural and endoneural
connective tissue of the transplant found materially
increased. Numerous small nerve bundles in the connective tissue
outside of perineural sheaths observed. Muscle
pieces came in contact with water while in paraffin; silver
differentiation unsuccessful. Regeneration through
transplant, although this gives evidence of having been slightly
infected, of the distal popliteal to the level of
muscular branches to calf muscles, more distally not controlled
histologically.
EXPERIMENT No. 197.-Rabbit No. 103a; large;
full grown; 286 days. November 5, 1918, right sciatic
exposed; internal popliteal freed; resected 2.5 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored 36 days in liquid petrolatum at 3º C., used as
transplant. One central and distal waxed, fine silk-thread suture
placed; good approximation; dry field; wound closed. August 18, 1919,
killed. Rabbit in very good condition; small
healing neurotrophic ulcer left heel. On exposing the right sciatic,
external popliteal found in close apposition to
operated internal popliteal. Transplant found well in place, good size
and color; very little increase of connective
tissue about it. Only small central bulbous enlargement noted.
Observations necessarily and unavoidably interrupted
at this point; before they could be resumed sufficient time had elapsed
to make it impossible to obtain contraction of
muscles supplied by unoperated external popliteal. Calf muscles
presented the appearance of normal muscles, both
as to size and color; return of function could not be tested. Sciatic
and portions of calf muscles removed, fixed in
ammoniated alcohol for pyridine-silver staining. Only partial silver
differentiation attained.
Microscopic
.findings.-Silver differentiation sufficient to determine the fact
that neuraxes, both myelinated
and nonmyelinated, pass through the transplant to the distal popliteal,
where they were traced to and into the
muscular branches of the calf muscles. In cross sections of the
transplant it is observed that very few neuraxes pass
distally in the connective tissue surrounding
the transplanted nerve segment. In cross sections of the distal
popliteal,
numerous neuraxes to be observed in all of its funiculi. Regeneration
of distal popliteal through the transplant to the
calf muscles.
EXPERIMENT
NO. 198.-Rabbit No. 120; full grown; 2 days. January 10, 1919, left
sciatic exposed;
internal popliteal freed; resected 2.5 cm. A segment of equal length
taken from the sciatic of another rabbit, and
stored 11 days at room temperature in sterile 50 percent alcohol, used
as transplant. Before use, nerve was taken
from alcohol and placed for15 minutes in warm, sterile saline solution.
One central and distal waxed fine silk thread
suture placed; good approximation; slight oozing from central stump,
not fully controlled; wound closed. January 12,
rabbit found dead in the morning. On exposing sciatic, dry field noted.
Transplant found well in place, of dull gray-green color; sutures in
place. Ends of resected nerve found congested. Sciatic with transplant
removed and fixed in
ammoniated alcohol for pyridine-silver staining. Silver staining very
pale.
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Microscopic findings.-In longitudinal sections of the
transplanted nerve segment the neurolemma sheaths of
the nerve fibers distinctly made out; in in myelin in many places
traces of Golgi funnels; neuraxes not found
segmented but staining very lightly, having even borders and of approximately normal
size. In cross
sections outline
of nerve fibers well maintained, distinctly bounded by neurolemma
sheaths; myelin scarcely stained; neuraxes
centrally placed in fibers and staining very lightly.
EXPERIMENT
No. 199.-Rabbit No. 120a; full grown; 2 days. January 10, 1919, right
sciatic exposed;
internal popliteal freed; resected 3.3 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
11 days at room temperature in sterile 50 percent alcohol, used as
transplant. Before use, placed in warm, sterile
saline solution for one hour. One central and distal waxed fine silk
thread suture placed; good approximation.
Wound closed. January 12, rabbit found dead in the morning. On exposing
right sciatic, transplant found well in
place, sutures evident. Transplant of dull gray-green color, and found
not adherent to surrounding tissues. Nerve and
transplant removed and fixed in neutral formalin. Sections stained in
iron-hematoxylin and picro-fuchsin; safranine
and licht grün.
Microscopic
findings.-In longitudinal sections of the transplant, the
neurolemma sheaths of the nerve fibers
found well maintained; neurokeratin net of myelin only faintly stained.
Neuraxes found not segmented. In
longitudinal sections embracing the central and distal wounds,
respectively, inwandered leucocytes in ends of the
transplant distinctly observed. These inwandered cells extend for a
distance of about 2 mm., both at the central and
distal ends of the transplant, mainly between the nerve fibers, certain
few within the neurolemma sheaths of the
transplanted nerve fibers. No neurolemma sheath cells of transplanted
nerves clearly made out.
EXPERIMENT
No. 200.-Rabbit No. 123; full grown; 23 days. January 18, 1919,left
sciatic exposed; internal popliteal freed;
resected 2.8 cm. A segment of equal length taken from the sciatic of another rabbit, stored 17
days
at room
temperature in sterile 50 per cent alcohol, used as transplant. Before
use, placed in sterile, warm saline solution 10
minutes. One central and distal waxed, fine silk thread suture placed;
good approximation. Wound closed. February
10. Died, nerve taken out just after death of rabbit; still warm;
beginning neurotrophic ulcer left heel. Wound well
healed. On exposing the left sciatic, transplant found well in place,
united to resected nerve ends; of slightly smaller
diameter in middle portion than at ends; no material increase of
connective tissue about transplant. Distinct, central
bulbous enlargement noted. The nerve and transplant removed and fixed
in ammoniated alcohol for pyridine-silver
staining. Silver staining differential but faint.
Microscopic findings.-Numerous neuraxes extend from distal
end of
the central stump, through central
wound into the central end of the nerve transplant, in which they may
be traced distally for a distance of
approximately 2 cm. In cross sections of the middle of the transplant
small groups of neuraxes found within as well
as outside of the neurolemma sheaths are to be observed. Neurolemma
sheaths in certain regions widely distended or
broken down. In such regions myelin globules, granular detritus, and
large vesicular cells enclosing what appears to
be lipoid globules encountered. Perineural sheaths of transplant well
maintained, not materially thickened. No
neuraxes found in the connective tissue out-side of this sheath. New
neuraxes have not reached the distal stump; this
shows nerve fibers in process of degeneration.
EXPERIMENT
No. 201.-Rabbit No. 123a; full grown; 23 days. January 18, 1919,right
sciatic exposed;
internal popliteal freed; resected approximately 3 cm. A segment of
equal length taken from the sciatic of another
rabbit, stored 17 days in 50 percent alcohol at room temperature, used
as transplant. One central and one distal
suture placed. While manipulating transplant, central suture pulled
out; transplant resected and resutured, final
length approximately 2 cm.; good approximation. Wound closed. February
10, died. Nerve taken out just after death;
still warm. Wound well healed. On exposing the right sciatic,
transplant found well in place; united to resected nerve
ends, of good size and dull gray-green color. Distinct central bulbous
enlargement noted. Nerve and transplant
removed and fixed in neutral formalin. Sections stained in safranine
and licht grün.
1217
Microscopic findings.-Transplant found well united to
central and
distal resected ends of internal popliteal;
only narrow connective tissue wounds evident. In longitudinal
sectionsof the transplanted nerve segment, strands of
syncytial nucleated protoplasmic bands, apparently extending from the
distal end of the central stump into the
transplant, are found separated by narrow areas or columns of myelin
globules, granular detritus, and vesicular cells
with lipoid globules, the remains of the myelin of the transplanted
nerve fibers. This structure extends to the distal
end of the transplant, where, near the distal wound, the protoplasmic
bands are more widely separated and less
numerous, the intervening spaces wider. The central end of the distal
stump presents the appearance of a nerve in
degeneration.
EXPERIMENT
No. 202.-Rabbit No. 118; full grown; 42 days. December 28, 1918,left
sciatic exposed; the
internal popliteal bundle freed; resected 2.4 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored seven days at room temperature in sterile 50 percent alcohol,
used as transplant. Before use, nerve placed in
sterile, warmed saline solution ten minutes. One central and one distal
waxed, fine silk thread suture placed. Good
approximation attained, though the transplanted nerve segment is of
distinctly smaller diameter than the resected
nerve. Wound closed. February 8, 1919, killed. Rabbit not in good
condition; "fungus" ears; emaciated; neurotrophic
ulcer left heel. Wound well healed. On exposing the left sciatic, the
external popliteal found adherent to operated
internal popliteal. Transplant found well in place; of yellow-white
color; adherent to underlying muscle. Large
central bulbous enlargement. Distal
nerve presents the appearance of a degenerated nerve. Nerve and
transplant
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Good differential silver staining throughout.
Microscopic
findings.-In longitudinal sections of central and distal wounds,
the transplant well united to
resected nerve ends, little connective tissue intervening. From the
distal end of the central bulb, numerous neuraxes
may be traced into the central end of the transplant, in which they end
distally, grouped mainly to one side in the
transplant, along the inner surface of its perineural sheath; only a
few scattered bundles of neuraxes in the substance
of the transplant. In the transplant areas and columns of myelin
globules, granular detritus and masses of large
vesicular cells, with lipoid globules. The downgrowing neuraxes traced
to and through the distal wound, only a few
having reached the central end of the distal popliteal, in which they
may be traced distally for a distance of about 1
cm.
EXPERIMENT
No. 203.-Rabbit No. 118a; full grown; 42 days. December 28, 1918, right
sciatic exposed;
the internal popliteal freed; resected 2.5 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored seven days in sterile 50 per cent alcohol at room temperature,
used as transplant. One central and distal
waxed, fine silk thread suture placed. Good central approximation
attained, distal good direction, end of transplant
twisted one half turn. Wound closed. February 8, 1919, killed. Rabbit
not in good condition; "fungus" ears;
emaciated; neurotrophic ulcer right heel. Wound well healed. Right
sciatic exposed. External popliteal found
adherent. Transplant found well in place; of yellow-white color,
clearly demarked; adherent to underlying muscle.
Large central bulb. Nerve and transplant removed and fixed in neutral formalin. Sections
stained
in safranine and
licht grün.
Microscopic
findings.-In longitudinal sections of central and distal wounds,
the transplant found well
united to resected nerve ends. New nerve fibers and nucleated,
syncytial protoplasmic bands extend from distal
end of the central stump into the transplant. In longitudinal sections
of the transplant, larger and smaller bundles of
syncytial protoplasmic bands, having in the main a longitudinal
direction, but here and there anastomosing, and
separated by areas and columns of large vesicular cells, are to be
observed. In cross sections of the transplant about 1
cm. distal to central wound, one relatively large bundle of syncytial
protoplasmic bands, placed largely to one side,
but extending into the middle of the transplant, is recognized. Fewer
of these nucleated protoplasmic bands seen in
the distal part of the transplant, but may be traced to and into the
distal wound. The distal nerve presents the
appearance of a degenerated nerve.
EXPERIMENT
No. 204.-Rabbit No. 121; full grown; 70 days. January 14, 1919, left
sciatic exposed;
internal popliteal freed; resected 3.2 cm. A segment of equal length
taken
1218
from the sciatic of another rabbit,
stored 14
clays in sterile 50 per cent alcohol at room tempera-ture, used as
transplant. Before use, the nerve placed for eight minutes in sterile,
warmed saline solution. One central and distal
waxed, fine silk thread suture placed. Central approximation
recorded
as good, distal "fair." Wound closed. March
25, rabbit found dead in the morning. Had had convulsions previous day; much
emaciated;
severe neurotrophic ulcer
left heel. Wound well healed. On exposing the left sciatic, transplant
found well in place, of light yellow-white color,
of smaller size than when used; no material increase of connective
tissue about it. Relatively large central bulb
noted. The nerve and the transplant removed and fixed in neutral
formalin. Sections stained in safranine and licht grün.
Microscopic
findings.-No distinct central bulb evidenced structurally. New
nerve fibers and syncytial
protoplasmic strands extend from the distal end of the central stump
into the nerve transplant, in the proximal half of
which these are arranged in small bundles, within the perineural
sheaths of the nerve transplant, with relatively few
myelin globules and vesicular cells separating such bundles. In the distal
half
of the transplant these small bundles of
nucleated protoplasmic bands are separated by larger and smaller areas
or columns of vesicular cells and myelin
globules. Many of the nucleated protoplasmic bands reach and penetrate
the distal wound. The distal popliteal found
degenerated; numerous nucleated, syncytial protoplasmic strands noted;
relatively few myelin globules are evident.
EXPERIMENT
No. 205.-Rabbit No. 121a; full grown; 70 days. January 14, 1919, right
sciatic exposed;
internal popliteal freed; resected 3.3 cm. A segment of equal length
taken from the sciatic of another rabbit, stored
14 days in sterile 50 per cent alcohol at room temperature, used as
transplant. Nerve placed in sterile, warmed saline
solution forty-five minutes before use. One central and distal waxed,
fine silk thread suture placed; good
approximation. Wound closed. March 25, rabbit found dead in the
morning; much emaciated; severe neurotrophic
ulcer right heel. Wound well healed. On exposing the right sciatic,
transplant found well in place, of light yellow-white color, much
smaller diameter than when use; not adherent. Large central bulb. Nerve
and transplant removed
and fixed in neutral formalin. Sections stained in safranine and licht
grün.
Microscopic
findings.-Transplant well united to resected nerve ends. Distinct
central bulb evidenced
structurally, from the distal end of which numerous new nerve fibers
and nucleated, syncytial strands extend into the
transplant, extending to and into the distal wound. In the distal end
of the transplant, areas and columns of large
vesicular cells found between protoplasmic strands. The distal nerve
presents the appearance of a degenerated nerve.
EXPERIMENT
No. 206.-Rabbit No. 119; full grown; 62 days. January 9, 1919, left sciatic exposed;
internal popliteal freed; resected 3 cm. A segment of equal length
taken from the sciatic of another rabbit, stored 10
days at room temperature in sterile 50 percent alcohol, used as
transplant. Nerve, before use, placed fifteen minutes
in sterile, warmed saline solution. One central and distal suture of
waxed, fine silk thread placed; good
approximation. Field not quite dry; wound closed. March 12, rabbit
found dead in the morning. Not much
emaciated; severe neurotrophic ulcer left heel. Wound well healed. On
exposing the left sciatic, external popliteal
found closely adherent to operated internal popliteal. Transplant found
well in place, in part of light pink color in
part dull white color; no material increase in connective tissue
surrounding operated nerve. Large central bulbous
enlargement, adherent to underlying muscle. Nerve and transplant
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Throughout, good differential neuraxis
staining attained.
Microscopic
findings.-The transplant found well united to resected nerve ends.
From the distal end of the
central bulb, numerous down-growing neuraxes found growing distally
through central wound to central end of
transplant. In cross sections of the transplant about1 cm. distal to
central wound, numerous small bundles of
neuraxes, separated by endoneural connective tissue are to be found. In
cross sections taken near the distal wound,
essentially the same structural appearance observed for the greater
part of the transplant; to one side, within
perineural sheath, a relatively large area, containing large vesicular
cells and granular detritus noted. In this field no
neuraxes observed. New neuraxes traced through the distal wound into
the distal nerve segment, in which they may
be traced in good numbers for a
1219
distance of about 2 cm. Regeneration of
proximal end of distal nerve through the nerve transplant.
EXPERIMENT
No. 207.-Rabbit No. 119a; full grown; 62 days. January 9, 1919, right
sciatic exposed;
internal popliteal bundle freed; resected 2.2 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored at room temperature in sterile 50 percent
FIG. 231.- From a
longitudinal section of
homo-nerve transplant, stored in 50 per cent alcohol for 10 days
before use as transplant; Experiment No. 200. Nerve removed 62 days
after operation. Note the regular
course of the new neuraxes, evident as black lines, as they pass
distally within the neurolemma sheaths of
the transplanted nerve fibers
alcohol for a period of 10 days, used as
transplant. Nerve placed in sterile, warmed saline solution one hour
and ten
minutes before use. One central and distal waxed, fine silk thread
suture placed. Central suture torn out; resected and
resutured; approximation good. Field not quite dry; wound
closed. March
12, rabbit found dead in the morning; not
much emaciated; severe neurotrophic ulcer right heel. Wound well
healed. On exposing the right
1220
sciatic, external popliteal found
closely
adherent to operated internal popliteal. The transplant found well in
place;
relatively small diameter; not adherent to underlying muscle. Central
end of transplant of dull white color; distal of
light pink color. Large, oval-shaped central bulb. Nerve and transplant
removed and fixed in neutral formalin.
Sections stained in safranine and licht grün.
Microscopic
findings.-Transplant found well united to the resected
nerve ends; narrow connective tissue wounds. From the distinct central
bulb, new small nerve fibers and
FIG. 232.-From a cross
section of homo-nerve
transplant, stored in 50 percent alcohol for 10 days before use as
transplant; Experiment No. 206. Nerve removed 62 days after operation.
Section made approximately 15 mm. distal
to the central wound. Note the numerous central neuraxes seen in cross
section, showing as fine darkly stained
points, very evenly distributed through the field. There is here
evident excellent neurotization of the transplanted
nerve segment
nucleated, protoplasmic bands extend
into the
transplant in which they may be traced to and through the distal
wound. Especially in the longitudinal sections taken from the distal
half of the transplant, irregular columns and
areas of large vesicular cells and cell detritus, separating bundles of
new nerve fibers, are to be noted.
EXPERIMENT
No. 208.-Rabbit No. 135; large; old; Belgian hare; 67 days. March18,
1919, left sciatic
exposed; internal popliteal freed; resected 3.5 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored at room temperature for 28 days in sterile 50 percent alcohol,
used as transplant. Nerve placed in sterile saline
solution 15
1221
minutes before use. One central and
distal
waxed, fine silk thread suture placed; good approximation. Dry field;
wound closed. May 24, rabbit found dead in the morning; not much
emaciated; severe neurotrophic ulcer left heel.
Wound well healed. On exposing the left sciatic, external popliteal
found free. Transplant well in place, found only
moderately adherent to underlying
muscle; of yellow-white color, tinged here and there a brown color.
Distinct
central bulb; central end of distal nerve enlarged. Nerve and
transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining. Silver differentiation not successful
throughout.
Microscopic
findings.- Transplant
well united to resected nerve ends. The silver differ-entiation of
sufficient clearness to determine the fact that many
new neuraxes coining from The distal end of the central bulb pass to
and through the transplant. These are seen to
descend mainly along the inner surface of the perineural sheath and
peripheral part of the main funiculus, the core of
which is occupied by a relatively large area containing large vesicular
cells and granular detritus. Few, if any, of the
down-growing neuraxes appear to have reached the distal segment of the
resected nerve, which presents the
appearance of a degenerated nerve.
EXPERIMENT
No. 209.- Rabbit No. 122; full grown; 144 days. January 16, 1919, left
sciatic exposed;
internal popliteal bundle freed; resected 3.0 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored at room temperature for a period of 15 daysin sterile 50 percent
alcohol, used as transplant. Before use placed
in warmed, sterile saline solution 15 minutes. One central and distal
waxed, fine silk thread suture placed; good
approximation attained. Wound closed. June 9, rabbit found dead in the
morning; not much emaciated; small
neurotrophic ulcer left heel. Nerve and transplant removed, fixed in
ammoniated alcohol for pyridine-silver staining.
Fair silver differentiation attained; not well embedded, sections torn.
Microscopic
findings.- Transplant found well united to the resected nerve ends.
From the distal end of the
central bulb, numerous neuraxes are found to pass to the transplant in
which they are
arranged in small
bundles
separated by endoneural connective tissue, presenting much greater
amount than in a normal nerve trunk. To one
side of transplant, remains of the transplanted nerve fibers noted
particularly in cross sections. Neuraxes of the
transplant pass to and through the distal wound and are found in good
numbers in the distal nerve. Regeneration of
the central end of the distal segment through the transplant.
EXPERIMENT
No. 210.- Rabbit No. 122a; full grown; 144 days. January 16, 1919,
right
sciatic exposed;
internal popliteal freed; resected 2.5 cm. A segment of equal length
taken from the sciatic of another rabbit, stored at
room temperature for 15 days in sterile 50 per cent alcohol, used as
transplant. Before use, nerve placed for one hour
in warmed, sterile saline solution. One central and distal waxed, fine
silk thread suture placed; distal resutured, first
very unsatisfactory; good approximation attained. Small blood clot in
the connective tissue near distal wound.
Wound closed. June 9, rabbit found dead in the morning; not much
emaciated; moderately large neurotrophic ulcer
right heel. On exposing the right sciatic, external popliteal found
free. Transplant found well in place; of good size;
only moderately adherent to underlying muscle. Large central bulb. The
nerve and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining. Fair silver
differentiation attained; tissue not well embedded,
sections torn.
Microscopic
findings.-Neuraxes coming from the distal end of the central
bulbous enlargement can be
traced through the transplant into the distal segment of the resected
nerve in which they are present in large numbers.
Within the transplant, these down-growing neuraxes are arranged in small bundles, separated by
endoneural
connective tissue, present in larger amount than in a normal nerve
trunk. Regeneration of the distal nerve segment
through the nerve transplant attained.
EXPERIMENT
No. 211.- Rabbit No. 137; small rabbit; seemed full grown; 152 days.
March 19, 1919, left
sciatic exposed; internal popliteal freed; resected 2.5 cm. A segment
of equal length taken from the sciatic of another
rabbit, stored for a period of 29 days at room temperature in sterile
50 percent alcohol, used as transplant. Before
use, nerve placed for 10 minutes in warmed, sterile saline solution.
One central and distal waxed, fine silk thread
suture placed. Good central approximation attained; a small amount of
1222
clotted blood in central wound;
distally,
good direction, but distal end of transplant twisted one half turn.
Wound
closed. August 18, killed. Rabbit in good condition; not large, but
appears well fed; neurotrophic ulcer left heel,
which appears to be healing. On exposing the left sciatic, external
popliteal found in close approximation to the
operated internal popliteal. Transplant found well in place, of good
size; has the appearance of a normal nerve, though of slightly brown
color. No distinct central bulbous enlargement noted. Calf muscles
fully exposed, these
present a pale red color but have not fully recovered their normal
size. The external popliteal cut central and distal to
the region of the transplant and the internal popliteal and transplant
completely freed from bed. On slowly cutting
the sciatic central to the transplant good contraction of the calf
muscles and slight movement of the toes noted; the
same cutting distal to the transplant. The nerve and the transplant and
portions of the calf muscles removed and
fixed in ammoniated alcohol for pyridine-silver staining. Silver
differentiation not good for distal portion of nerve.
Microscopic
findings.- Numerous new neuraxes traced through the transplant into
the distal portion of
resected nerve to level of calf muscles. In the transplant these
neuraxes in the form of small bundles separated by
endoneural connective tissue. Very little detritus derived from the
transplanted nerves noted. In sections of the calf
muscles, numerous neuraxes observed in the intrafascicular nerve
bundles and as single nerve fibers, between and on
muscle fibers; a few motor nerve endings noted. In sections of the
posterior tibial nerve, not successful silver
differentiation. Regeneration of distal popliteal including motor
branches and endings in the calf muscles attained.
EXPERIMENT No. 212.- Rabbit
No. 134; full
grown; not large; 154 days. March 17, 1919, left sciatic
exposed; internal popliteal freed; resected 3 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored at room temperature in sterile 50 per cent alcohol for a period
of 27 days, used as transplant. Before use, nerve
placed for 15 minutes in warmed, sterile saline solution. One central
and distal nerve suture placed; good
approximation. Wound closed. August 18; killed. Rabbit in good
condition; neurotrophic ulcer left heel nearly
healed. On exposing the left sciatic, the external popliteal found in
close apposition to the operated internal popliteal.
Transplant found well in place; of small diameter; but presents the
appearance of a normal nerve; only moderately
adherent to the underlying muscle. Distinct central bulb noted. Distal
nerve presents the appearance of a normal
nerve. Calf muscles fully exposed; these still somewhat atrophic and of
pale-red color. Nerve and transplant
completely freed from the bed. On cutting slowly with scissors central
to the transplant, indistinct contractions-"feeble contractions"-of
calf muscles noted. Nerve and transplant and portions of the calf
muscles removed and fixed
in ammoniated alcohol for pyridine-silver staining. Good differential
silver staining for central part of nerve, but not
for distal part, attained.
Microscopic findings.- Numerous neuraxes can be traced from
the
distal end of the central stump through
the transplant to the distal nerve. Silver staining of pieces of calf
muscles not satisfactory-no neuraxes stained.
Regeneration of distal nerve through transplant, recovery of calf
muscles not confirmed by microscopic findings.
EXPERIMENT
No. 213.- Rabbit No. 125; full grown; 208 days. January 22, 1919,left
sciatic exposed;
internal popliteal freed; resected 2.9 cm. A segment of equal length
taken from the sciatic of another rabbit, stored at
room temperature for 21 days in sterile 50 percent alcohol, used as
transplant. Nerve placed in sterile saline solution
for 15 minutes before use. One central and distal waxed, fine silk
thread suture placed; good approximation. Wound
closed. August 18, killed. Rabbit in fairly good condition; healing
neurotrophic ulcer left heel; walks on heel and
does not bring foot down to floor. On exposing left sciatic external
popliteal found free; transplant well in place; of
small diameter; only slightly adherent to underlying muscle. Large and
distinct central bulb noted; evident
enlargement of the central end of distal nerve. Calf muscles fully
exposed; these still slightly atrophic, of pale red
color, streaked with light yellow bands. External popliteal resected,
operated internal popliteal and transplant
completely freed from bed. On slowly cutting nerve with scissors
central to the transplant, feeble but distinct
contraction of calf muscles noted; the same on cutting distal to
transplant. No distinct movement of the toes
observed. Nerve and transplant and portions of calf muscles removed and
fixed in ammoniated alcohol for pyridine-silver staining. Fairly good
differential silver staining attained.
1223
Microscopic findings.-The distinct central bulb evidenced
structurally, from the distal end of which
numerous new neuraxes can be traced through the transplant to the
distal nerve. Within the transplant the neuraxes
arranged in the form of small funiculi separated by endoneural
connective tissue. New neuraxes traced into the calf
muscles in which they are found in the intrafascicular nerves and as
separate nerve fibers between and on the muscle
fibers. Regeneration of distal nerve through transplant, partial return
of motor function in calf muscles.
EXPERIMENT No. 214.-Rabbit No. 125a; full
grown; 203 days. January 27, 1919, right sciatic exposed; the
internal popliteal bundle freed; resected 2.9 cm. A segment of equal
length taken from the sciatic of another rabbit,
stored at room temperature in sterile 50 percent alcohol for 21 days,
used as transplant. Before use, nerve kept in
sterile saline solution for 50 minutes. One central and distal waxed,
fine silk suture placed; good approximation.
Wound closed. August 18, killed. Rabbit in fairly good condition;
healing neuro-trophic ulcer right heel. On
exposing the right sciatic, it is found that the external popliteal is
closely adherent to operated internal popliteal. The
transplant found well in place and about one-half the diameter as when
used; only moderately adherent to underlying
muscle. Relatively large central bulb; central end of distal nerve
found only slightly enlarged. Calf muscles fully
exposed; these have not fully recovered size; pale red color. The nerve
and the transplant completely freed and
external popliteal cut in popliteal space; on slowly cutting with
scissors, the nerve central to the transplant, distinct
but feeble contractions of the calf muscles noted; the same on cutting
distal to the transplant; no toe movement
noted. Nerve and transplant and portions of calf muscles removed and
fixed in ammoniated alcohol for pyridine-silver staining. Good
differential silver staining attained.
Microscopic
findings.-From the large central bulb, numerous new neuraxes can be
traced through
the
transplant to the distal nerve and through the muscular branches to the
calf muscles. Very good regeneration of
motor fibers in calf muscles noted. Regeneration of distal nerve
through the transplant including muscular branches
to calf muscles.
EXPERIMENT
No. 215.-Rabbit No. 126; full grown; 208 days. January 22, 1919, left
sciatic exposed;
internal popliteal freed; resected 2.6 cm. A segment of equal length
taken from the sciatic of another rabbit, stored at
room temperature in sterile 50 percent alcohol for 22 days, used as
transplant. Before use, nerve placed in warmed,
sterile saline solution for 15 minutes. One central and distal waxed,
fine silk-thread suture placed; central
approximation not quite end to end, distal good. Wound closed. August
18, killed. Rabbit in good condition; small
healing neurotrophic ulcer left heel; not full use of foot. On exposing
the left sciatic, it is found that external
popliteal is in close approximation to operated internal popliteal.
Transplant found well in place; nearly of same size
as when used. Distinct central bulb noted; moderate enlargement of
central end of distal nerve. Calf muscles fully
exposed; these have not fully recovered size. Nerve and the transplant
completely freed from bed. On slowly cutting
nerve central to transplant, contraction of the calf muscles noted, as
also slight movement of the toes; same on
cutting distal to the transplant. Nerve and transplant and portions of
calf muscles removed and fixed in ammoniated
alcohol for pyridine-silver staining. Fairly good differential silver
staining attained; pale.
Microscopic
findings.- Transplant firmly united to resected nerve ends.
Well-developed central bulb
evidenced structurally, from the distal end of which numerous
myelinated nerve fibers can be traced through the
transplant to the distal nerve. In cross sections of the transplant
made about 1.5 cm. distal to the central wound, it
may be observed that the perineural sheaths of the transplanted nerve
segment are intact and only moderately
thickened, while the endoneural tissue is distinctly increased in
amount. The neuraxes are found in small groups
separated by endoneural tissue. In sections of the calf muscles new
neuraxes are found in the interfascicular nerve
bundles, and here and there as single fibers passing to the muscle
fibers. Good regeneration of distal internal
popliteal through the nerve trans-plant attained.
EXPERIMENT
No. 216.-Rabbit No. 126a; full grown; 208 days. January 22, 1919, right
sciatic exposed;
internal popliteal freed; resected 2.9 cm. A segment of equal length
taken from the sciatic of another rabbit, stored at
room temperature in sterile 50 percent cent alcohol for 22 days, used
as a transplant. Before use, nerve placed in
warmed, sterile
1224
saline solution for one hour. One
central and
distal waxed, fine silk-thread suture placed; good approximation.
Wound closed. August 18, killed. Rabbit in good condition; healing
neurotrophic ulcer right heel. On exposing the
right sciatic, external popliteal found closely adherent to operated
internal popliteal. Transplant found well in place;
of good size; of dull white color and only moderately adherent to
underlying muscle. Large central bulb noted;
central end of distal nerve only slightly enlarged. Calf muscles fully
exposed; these appear to have nearly recovered
size and color. The nerve and the transplant completely freed from bed
and external popliteal cut in popliteal space.
On slowly cutting with scissors the nerve central to the transplant,
good contraction of the calf muscles observed.
Nerve and transplant and portions of the calf muscles removed for
pyridine-silver staining. Pale, but fairly good
differential silver staining attained.
Microscopic
findings.-Transplant found well in place and firmly united to the
resected nerve ends; line of
suture hardly evident. From the central bulb numerous neuraxes traced
into proximal end of
the
transplant, relatively
few traced into the connective tissue surrounding the transplant. In
cross sections of the transplant taken about 1.5
cm. distal to the central wound, the epineural sheaths found materially
thickened and there is noted a marked
increase of the endoneural connective tissue. Within the transplant,
nerve fibers, both myelinated and
nonmyelinated, observed in small bundles, separated by varying amounts
of endoneural connective tissue. These
neuraxes can be traced through the transplant to the distal nerve
within which they are present in large numbers, both
myelinated and nonmyelinated fibers, and are found quite evenly
distributed in the several funiculi. In sections of the
calf muscles, neuraxes observed in the interfascicular nerve branches
and as single nerve fibers on and between
muscle fibers. Structurally considered, the muscles appear as
regenerated. Fairly complete regeneration of the distal
nerve through the transplant, including nerves to calf muscles,
attained.
The
end results of the experimental observations on stored, homo-nerve
transplants are
on the whole very satisfactory. Functional return is recorded for all
of the experiments of longer
duration. Stored homo-nerve transplants seem to serve the purpose of
nerve bridge quite as well
as fresh homo-nerve transplants, thus obviating in a large measure
certain difficulties connected
with the use of homo-nerve transplants in human surgery. If nerves
obtained at amputations can
be stored for weeks, to be at hand when required, with promise of
favorable results on use, stored
homo-nerve transplant deserves consideration in human surgery. It is
our belief that smaller
nerve bundles, used if necessary as cable or multiple nerve
transplants, should give promise of
more favorable end results than the use of one large nerve, such as the
sciatic or its main
branches used as a nerve bridge.
In
all of the experiments (No. 150 to No. 157) in which a homogenous nerve
bridge of
nerve stored in vaseline was made there was noted relatively little
increase in the connective
tissue surrounding the nerve transplant at the time when the nerve was
exposed for study of
functional return. The transplant presented the appearance of a normal
nerve. In all of these
experiments down-growing neuraxes derived from the central stump
neuraxes were traced
through the central wound into the transplant, and through the
transplant to and through the
distal wound into the distal stump. In the cross sections of the
transplants the down-growing
neuraxes encountered are manv of them found within what appear to be
neurolemma sheaths
remains of transplanted nerve fibers. Tissue detritus and large
vesicular phagocytic cells, unlike
the end results of Wallerian degeneration, are met with within the
nerve funiculi. In the
experiments of about two months' duration (No. 154and No. 155) feeble
muscle contraction was
noted and interfascicular, muscular
1225
nerve bundles with new
neuraxes were noted in the sections of the calf muscles; and in
experiments of nearly five months' duration (No. 156 and No. 157)
regeneration of the distal
segment of the nerve with down-growing neuraxes was quite complete. On
the whole, very
satisfactory neurotization of the degenerated distal segment was
obtained in experiments dealing
with homo-nerve transplants, stored in vaseline, following in the main
the method of procedure
suggested by Dujarier and Francois. 76 The much larger
series of homogenous-nerve transplants
stored in liquid petrolatum (No. 158 to No.197) included 14 experiments
of relatively short
duration (1 hour to 12 days) in which the behavior of the transplant
soon after it was placed as a
nerve bridge could be studied. A nerve stored in liquid petrolatum at
3º C. retains its
microscopic structure quite completely and will stain differentially by
the pyridine-silver
method. Two days and even four days after such a transplant is placed
the neuraxes of the nerve
fibers as seen in the pyridine-silver preparations are not fragmented.
From 6 days to 12 days
after transplantation the neuraxes are found segmented and show a
granular change. The myelin
shows fragmentation, but there is no evidence of proliferation of
sheath cells. At the end of 12
days there are still found fragments of old neuraxes in the
transplanted nerve segment. In the
central wound region down-growing central neuraxes have penetrated the
wound region and
certain ones have extended into the transplant for a distance of about
2 mm. Experiments Nos.
173 and 174 deserve special consideration. A homogenous-nerve
transplant stored 39 days in
liquid petrolatum was used to bridge a nerve defect. The animal died 23
days after the operation
but was used for histologic study. In cross sections of the
transplants, made about 1 cm. distal to
the central wound, new neuraxes were found in all parts of the
transplant. In many parts of the
field more than one neuraxis was found in one neurolemma sheath, while
other neuraxes are
found outside of the neurolemma sheaths. Extensive neurotization of the
transplant had taken
place, by downward growth of central neuraxes, at the end of 23 days
after the operation. Of the
experiments of this series 20 were carried on for a period of 3 months
or longer; the longest for a
period of nearly 7 months. In all of these experiments, where
functional tests could be made,
return of functions in the calf muscles is recorded, and incertain of
the longer time experiments
return of function in the foot interossei was observed. All of the
experiments were controlled by
histologic study of practically the whole sciatic nerve, and in all of
the experiments could central
neuraxes be traced through the transplant into the distal popliteal
nerve and thence into the calf
muscles. In cross sections of the transplanted nerves in the respective
experiments, stained by the
pyridine-silver method, it could be determined in nearly every
experiment that the down-growing central neuraxes made use of the
neurolemma sheaths of the transplanted nerve fibers in
their course through the transplant. In all of these experiments
relatively few nerve fibers are
found in the connective tissue surrounding the perineural sheaths of
the funiculi of the nerve
transplant, interpreted as meaning that in this series the nerve
transplant is the main avenue along
which the down-growing neuraxes reach the distal stump. The
experimental observations dealing
with homogenous-nerve transplants stored in liquid petrolatum seem
1226
to us to warrant the
deduction that human nerves obtained from amputated members and stored
in liquid petrolatum as here directed and, on need, used for bridging
nerve defects, deserve
serious consideration as a surgical procedure. We were agreeably
surprised at the favorable
results attained on use of homogenous-nerve transplants stored in 50
percent alcohol for purpose
of nerve bridge. In this series of 18 experiments (No. 198 to No. 216)
relatively few were of
short duration. In Experiments No. 198 and No. 199 the rabbit was found
dead 2 days after
operation. In sections of the transplant stained by the pyridine-silver
method the neuraxes were
found to stain very lightly, but were found unsegmented. Inwandered
leucocytes were found in
theends ot the transplant at the central and distal wounds, both within
the neurolemma sheaths
and between the nerve fibers. In Experiments No. 200 and No. 201
(compare Experiments No.
173 and No. 174) the rabbit had died 23 days after the operation but
the tissue was used for
histologic study. In preparations stained after the pyridine-silver
method down-growing central
neuraxes can be traced through the central wound and for a distance of
about 2 cm. into the
transplant. In cross sections of the transplant the down-growing
neuraxes are found within as
well as without the neurolemma sheaths, but practically no nerve fibers
are found in the
connective tissue surrounding the transplant, outside of the perineural
sheaths. By the end of 42
days, more clearly 2 months after the operation, down-growing neuraxes
were traced through the
transplant to the distal wound and through this into the central end of
the distal popliteal, the
down-growing neuraxes decreasing in number the farther distal the
observation is made. In the
experiments of longer duration, 8 in number, in which the observations
were carried on to from 4
months to nearly 6 months after the operation, functional return was
noted in the experiments in
which this could be tested and histologically new neuraxes were found
in the distal nerve,
conveyed there through the transplant. In several experiments new
neuraxes were found in the
interfascicular and intrafascicular nerve bundles of the calf muscles.
By
way of summary it may here be added that very good neurotization was
attained
through homogenous nerve bridges which had been stored in 50 percent
alcohol. The supposition
is permissible that in nerves stored in sterile vaseline and liquid
petrolatum at a temperature of 3º C. there maybe some degree of
viability of certain tissue
elements-sheath cells or
connective
tissue cells-even though there is no satisfactory evidence of the
proliferation of the sheath cells
of transplanted nerve fibers, nor of the participation of the sheath
cells of the nerve transplant,
direct or indirect, in the down growth of the central neuraxes. In case
of nerves stored in alcohol,
it can not be supposed that any viability is retained by the tissue
elements or cells of the nerves
transplanted. There is no evidence of sheath cell participation and no
evidence that they
proliferate. The fragmentation of the myelin and neuraxes of the
transplanted nerves after
storage in vaseline, liquid petrolatum, and alcohol is a necrobiotic
change and not a secondary
degeneration-Wallerian degeneration---as observed in the distal
segment.
1227
STORED HETERO-NERVE TRANSPLANTS
SERIES NO. 14
HETERO-NERVE TRANSPLANTS STORED IN
LIQUID
PETROLATUM
SERIES NO. 15
HETERO-NERVE TRANSPLANTS STORED IN 50
PERCENT ALCOHOL
In
the discussion of Series No. 11, No. 12 and No. 13, stored homogenous
transplants,
consideration was given to the fact that little if any viability is
retained by any of the tissue
elements of nerves stored for stated periods before use as a
transplant, especially so when stored
in 50 percent alcohol. Therefore, it was thought that the sheath cells
of the stored, transplanted
nerves take no active part in the fragmentation of the neuraxes and
myelin sheaths of the
transplanted nerves and, so far as can be determined, are not causally
related to the downgrowth
of the central neuraxes, in their passage through the transplant to
reach the distal segment of the
resected nerve. The conviction seems warranted that the neurolemma
sheaths of the stored,
transplanted nerve fibers, which do not fragment with the neuraxes and
myelin sheaths, act in a
purely mechanical way in serving as conduits through which the
down-growing neuraxes are
conveyed through the transplant to the distal nerve segment. Therefore,
the supposition seemed
justified that a hetero-nerve transplant, stored in liquid petrolatum
and especially in alcohol,
would prove more satisfactory as a nerve- bridge than a fresh
heterogenous nerve transplant.
Series No. 14 and No. 15 were undertaken to test this hypothesis. In
Series No. 14, the internal
popliteal or ulnar nerve of dogs was removed under aseptic precautions
and stored in liquid
petrolatum, as described under Series No. 12, for periods varying for
from 12 days to 25 days
and were then used to bridge nerve defects caused by resecting the
sciatic nerve of rabbits. One
central and one distal fine waxed silk suture was placed to fix the
transplant to the resected nerve
ends. In Series No. 15, segments, taken from the internal popliteal and
ulnar nerves of dogs and
stored for periods varying from 5 days to 7 days in 50 per cent
alcohol, were used to bridge
nerve defects in the sciatic of rabbits caused by resection and sutured
in place by fine waxed silk
sutures.
The
protocols of the experiments of Series No. 14 and No. 15, stored
heterogenous
nerve-transplants, are as follows:
PROTOCOLS
EXPERIMENT
No. 217.- Rabbit No. 127a; full grown; 5 days. March 4, 1919, the right
sciatic exposed;
internal popliteal freed; resected 3.1 cm. A segment of equal length
taken from the internal popliteal of a dog, stored
for 10 days in sterile liquid petrolatum at 3º C, used as
transplant. The transplant of dull white color and of larger
diameter than the resected nerve. One central and distal suture of
waxed, fine silk thread placed; good
approximation. Dry field; wound closed. March 9, rabbit found dead in
the morning. Superficial wound healed. On
exposing the right sciatic, transplant is found well in place; loosely
united to resected nerve ends; not adherent to
surrounding muscle. Nerve and transplant removed and fixed in neutral
formalin. Sections stained in safranine and
licht grün.
Microscopic
findings.-Longitudinal sections, embracing central and distal
wounds, show very good
approximation; a few extravasated blood cells found in the intervening
connective
1228
tissue. Leucocytes noted in the central
and
distal ends of the transplant for a distance of about 8 mm. The great
majority of these found between the nerve fibers. Leucocytes have
wandered in less number and for a shorter
distance into the resected nerve ends. In cross and longitudinal
sections of the transplant taken from its middle third,
the contained nerve fibers appear as very well preserved; the neuraxes
staining pale, though readily made out, and
not fragmented; the myelin sheaths not fragmented; the neurolemma
sheaths clearly seen. The few sheath cell nuclei
here and there seen, appear in form and staining reaction much as do
similar nuclei in normal nerves. The perineural
sheaths present the characteristic appearance of this structure.
EXPERIMENT
No. 218.- Rabbit No. 133a; large; old; Belgian hare; 82 days. March15,
1919, right sciatic
exposed; internal popliteal freed; resected 3 cm. A segment of equal
length taken from the left ulnar of a dog, stored
25 days in sterile liquid petrolatum at 3º C.,used as
transplant. One central and distal waxed, fine silk thread suture
placed; good approximation. Wound closed. June 5, killed. For several
days rabbit had not been well; emaciated;
nearly moribund, when killed; right heel swollen and red, no ulcer. On
exposing the right sciatic, external
popliteal
found free. Transplant found well in place and firmly united to
resected nerve ends; seemed of smaller diameter than
when used; of distinct light yellow color; only moderately adherent to
the underlying muscle. Large central bulb,
which tapers toward the transplant; slight enlargement of central end
of distal nerve noted. Calf muscles very
atrophic; no response on cutting
nerves. Nerve and the transplant removed and fixed in ammoniated
alcohol for
pyridine-silver staining. Good silver differentiation attained.
Microscopic
findings.- In longitudinal sections, the large central bulb clearly
demarked from the transplant.
In the portion of the bulb developed from the distal end of the central
stump the light yellow coloring, differential
staining of neuraxes characteristic for pyridine silver methods, is to
be observed. The sections of the transplant
throughout, present a jet-black, nontransparent coloration, by reason
of which structural differentiation can not be
made out. By reason of this silver reaction, it is not possible to
determine whether neuraxes coming from the central
stump penetrate the transplant. In cross sections of the transplant,
its connective tissue sheaths present a brown-yellow color. In close
relation with this sheath new neuraxes are observed. Within the
sheaths, the portions
containing the nerve fibers of the funiculi colored jet-black. The
distal internal popliteal stump completely
degenerated.
EXPERIMENT
No. 219.-Rabbit No. 131a; large; full grown; 82 days. March 12, 1919,
right sciatic exposed; internal popliteal
freed; resected 2.8 cm. A segment of equal length taken from the right
ulnar
of a dog, stored in sterile liquid petrolatum at 3º C. for
a period of 20 days, used
as
transplant. One central and distal
waxed, fine silk thread suture placed. Good central approximation
attained; at the distal wound, thread through
transplant very nearly cut through. Wound closed. June 2, rabbit found
dead in the morning; moderate emaciation;
severe neurotrophic ulcer right heel. On exposing the right sciatic, it
is noted that the transplant is united to central
end of resected nerve, but pulled free from the distal segment, the
transplant ending free 1.5 cm. distal to central
wound; remaining transplant segment yellow-white color; large central
bulb. The central and distal segments of the
resected nerve and remains of transplant removed and placed in
ammoniated alcohol for pyridine-silver staining.
Microscopic
findings.-Numerous neuraxes can be traced from the distal end of
the central bulb along the
side of the transplanted nerve segment, but do not appear to have
penetrated the same. Transplanted nerve segment
clearly demarked by reason of its jet-black coloration. Distal nerve
completely degenerated.
EXPERIMENT
No. 220.-Rabbit No. 129a; full grown; 112 days. March 7, 1919, right
sciatic exposed;
internal popliteal freed; resected 2.8 cm. A segment of equal length
taken from the left internal popliteal bundle of a
dog, stored 14 days in sterile liquid petrolatum at 3º C.,
used as transplant. One central and distal waxed, fine silk
thread suture placed; good approximation. The diameter of the
transplant somewhat greater than that of the resected
nerve. Dry field; wound closed. June 27, killed. Rabbit not well for
several days; neurotrophic ulcer right heel. On
exposing right sciatic. external popliteal found free
1229
Transplant found well in place and
firmly
united to resected nerve ends; seems of slightly larger diameter than
when
used; distinct yellow-white color, which enables demarking it clearly.
Moderately large central bulb. Calf muscles
atrophic. No response on cutting nerve central and distal to the
transplant. Nerve and transplant removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
silver staining attained.
Microscopic
findings.-Distinct central bulb evidenced structurally, from the
distal endof which new
neuraxes pass to the side of the transplant. The transplant itself is
stained a deep black color, admitting no
determination of structural details. In cross and longitudinal sections
of the transplant, it is not possible to
differentiate any neuraxes within he perineural sheaths of the
transplant; this by reason of the dark silver reaction. In
cross nd longitudinal sections of the internal popliteal distal to the
transplant a goodly number of new neuraxes are to
be observed. In a series of longitudinal sections embracing the distal
wound and adjacent nerve ends, neuraxes are to
be observed entering the field of the distal ound to one side of the
distal end of the transplant. It would appear,
though by reason f the peculiar staining of the transplant this can not
be determined conclusively, regeneration in the
distal stump is attained through neuraxes that pass distally outside of
the transplant.
EXPERIMENT
No. 221.- Rabbit No. 130a; full grown; 121 days. March 10, 1919,right
sciatic exposed;
internal popliteal freed; resected 3.2 cm. A segment of equal length
taken from the right ulnar of a dog, stored in
sterile liquid petrolatum 17 days at 3º C., used as
transplant. One
central and distal suture waxed, fine silk thread
placed; good approximation. The diameter of the transplant greater than
that of the resected nerve. Wound closed.
July 8, rabbit found dead in
the
morning; moderately emaciated; severe neuro-trophic ulcer right heel.
On exposing
the right sciatic, external popliteal found free; trans-plant well in
place; clearly demarked by reason of its light
yellow color; no material increase of connective tissue about it. Large
central bulb, adherent to underlying muscle,
noted. Calf muscles still atrophic, present the appearance of
degenerated muscle. Nerve and transplant removed and
fixed in ammoniated alcohol for pyridine-silver staining. Good silver
differentiation attained.
Microscopic
findings.- From the distal end of the central bulb new neuraxes
call
be traced mainly to one side
of the transplant; some few appear to enter the transplant, but by
reason of the dark, nontransparent coloration they
can not be traced any distance in the transplant. No neuraxes appear to
have reached the distal internal popliteal,
which structurally considered has the appearance of a completely
degenerated nerve.
EXPERIMENT
No. 222.- Rabbit No. 129a; full grown; Belgian hare; 138 days. March5,
1919, right sciatic
exposed; internal popliteal freed; resected 3.2 cm. A segment of equal
length taken from the
internal
popliteal of the
right sciatic of a dog, stored in sterile liquid petrolatum for 11 days
at 3º C., used as transplant. One central and distal
waxed, fine silk thread suture placed; good approximation. Wound
closed. July 21, rabbit found dead in the morning;
much emaciated; severe neurotrophic ulcer right heel. On exposing the
right sciatic, external popliteal found closely
adherent to operated internal popliteal. Transplant found well in
place; of distinct yellow-white color, thus clearly
demarked. Large spindle-shaped central bulb. Calf muscles atrophic;
present the appearance of degenerated muscle.
Nerve and transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining. Silver differentiation not
good in all parts of the series.
Microscopic
findings.- From the distal end of the very well developed central
bulb, numerous neuraxes
passing mainly to one side of the transplanted nerve segment noted. In
cross and longitudinal sections of the nerve
transplant, the appearance presented in sections warrants conjecture
that the chemical state of the transplanted nerve
segment, which may be correlated with the peculiar jet-black coloration
noted on staining with the pyridine-silver
method, is undergoing a change in that the outer portion of the
transplant no longer presents this peculiar coloration,
only the core or central portion being thus colored. No neuraxes are to
be observed within the transplant nor in the
distal stump, which presents the appearance of a completely degenerated
nerve.
EXPERIMENT
No. 223.-Rabbit No. 135a; old; Belgian hare; 67 days. March 18,1919,
right sciatic
exposed; the internal popliteal freed; resected 3.3 cm. A segment of
equal
1230
length taken from the right ulnar of a
dog,
stored at room temperature in sterile 50 per cent alcohol for 6 days,
used
as transplant. Before use, the nerve was placed in warm,
sterile saline
solution for 15 minutes. One central and distal
waxed, fine silk thread suture placed. Wound closed. May 24, rabbit found dead in the
morning; moderate
emaciation; severe neurotrophic ulcer right heel. On exposing the right
sciatic, the external popliteal found free.
Transplant found well in place, united to resected nerve ends; clearly
demarked by its yellow color; no material
increase of connective tissue about it. Large spindle-shaped bulb
noted. Calf muscles atrophic and flabby. Nerve
transplant and nerve removed and fixed in ammoniated alcohol for
pyridine-silver staining. Good neuraxes
differentiation attained; tissue blocks not well embedded, sections in
part torn.
Microscopic
findings.-In longitudinal sections embracing the central wound,
scattered neuraxes traced from
the central nerve stump into central end of the transplant. In cross
sections of the transplant, approximately 1.5 cm.
distal to the central wound, the perineural sheath of the transplanted
nerve segment is found very materially
thickened; within this there is found a detritus, the remains of the
transplanted nerves. In it no definite tissue can be
recognized; even the neurolemma sheaths of the transplanted nerves have
disappeared. No new neuraxes are to be
recognized. In longitudinal sections of the transplant the same general
appearances are presented, except that here
and there short fragments of old neuraxes, having no definite
arrangement, are found scattered through the detritus.
Distal nerve completely degenerated.
EXPERIMENT
No. 224.- Rabbit No. 137a; small; full grown; 152 days. March 19,1919,
right sciatic
exposed; internal popliteal freed; resected 3 cm. A segment of equal
length taken from the left ulnar of a dog, stored
at room temperature in sterile 50 percent alcohol for 7 days, used
as a transplant. Before use, the nerve was
placed for 15 minutes in a sterile saline solution. One central and distal waxed, fine silk
thread suture
placed; very good approximation of nerve ends. Wound closed. August 18,
killed. Rabbit in good condition; small
neurotrophic ulcer of the left heel. On exposing the right sciatic,
external popliteal found free. Transplant found well
in place; clearly demarked by its yellow-white color; good size and
firmly united to resected nerve ends. Calf
muscles ex-posed; atrophic and of a pale yellow-red color. Nerve and
transplant freed from bed, on slowly cutting
the nerve central to the transplant, no response of calf muscles noted;
no evidence of contraction. Nerve and
transplant removed and fixed in ammoniated alcohol for pyridine-silver
staining. Silver differentiation only in part
successful. Resulting sections somewhat torn.
Microscopic
findings.-In longitudinal sections of the central wound region, it
is to be observed
that
neuraxes passing from the distal end of the central bulb, pass to the
region of the central wound, which they do not
penetrate for any distance; certain of them turning centralward. In the
central end of the transplant, near the central
wound and for several millimeters distal, quite long fragments of the
old neuraxes of the transplanted nerves,
differentially stained in silver, may be observed; distal to this
region, such neuraxes remains no longer observed. In
cross and longitudinal section of the transplant 1.5 cm. to 2 cm. and 3
cm. distal to the central wound, no new
neuraxes observed within the transplanted nerve segment. The nerve
fibers of the transplant in part completely
broken down, in part the old neurolemma sheaths found persisting,
filled with detritus and leucocytes filled with
lipoid globules. Just central to the distal wound, new neuraxes
recognized in the transplant, passing through the
distal wound into the distal popliteal in which they maybe traced to
the level of the calf muscles. Apparent
regeneration of the distal nerve, down-growing neuraxes appearing to
pass distally mainly outside of the transplant is
concluded.
EXPERIMENT
No. 225.-Rabbit No. 134a; full grown; 154 days. March 17, 1919, right
sciatic exposed;
internal popliteal freed; resected 3.0 cm. A segment of equal length
taken from the external popliteal bundle of the
left sciatic of a dog, stored in sterile 50 percent alcohol at room
temperature for 5 days, used as a transplant. Before
use, nerve placed15 minutes in warmed, sterile saline solution. One
central and distal waxed, fine silk thread suture
placed; good approximation. Clean, dry field; wound closed. August 18,
killed. Rabbit in good condition;
neurotrophic ulcer on right heel nearly healed; does not use right hind
leg and foot normally. On exposing the right
sciatic, the external popliteal found
1231
quite free. Transplant found well in
place;
demarked by light yellow color; united to resected nerve ends.
Spindle-shaped central bulb noted. Calf muscles atrophic and of pale
red color. Section of nerve causes no contraction of the
calf muscles. Nerve and transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. Very good
silver differentiation attained.
Microscopic
findings.- In longitudinal sections embracing the central wound,
new
neuraxes can be traced
from the distal end of the central stump into the central end of the
transplant, either as single neuraxes or as small
groups of such, which course distally in collapsed neurolemma sheaths.
In cross sections of the transplant
approximately 1.5 cm. distal to the central wound, it may be observed
that mainly to one side many new neuraxes
are found within the perineural sheath of the transplant, in part
within this sheath, as also in the detritus, derived
from the transplanted nerve fibers. Within and between the persisting
neurolemma sheaths, numerous leucocytes
greatly distended with lipoid globules are to be observed. Certain of
the neuraxes which are found in the transplant
and its sheath are to be traced to and through the distal wound into
the distal popliteal through the transplant
attained.
The
end results of the experiments on stored hetero-nerve transplants are,
on the whole,
unsatisfactory. As concerns Series No. 14, heterogenous nerve
transplants stored in liquid
petrolatum, in none of the experiments of longer duration was
regeneration of the distal segment
of the resected and bridged nerve attained through the heterogenous
transplant. The nerve
segment was found firmly united to the central and distal nerve stump.
On staining after the
pyridine-silver method, the stored, heterogenous nerve transplant
presented a peculiar reaction
toward the silver nitrate in that the silver appeared to be reduced en
masse, so that no
differentiation of elements was possible within the perineural sheath
of the funiculi transplanted.
This made a close histologic study of the behavior of the transplanted
nerve segments in these
experiments difficult and in the main unsatisfactory, in that it could
not be determined with
certainty whether down-growing neuraxes of central origin passed
through the transplant to
reach the distal segment of the nerve. Down-growing neuraxes were found
in the central nerve
bulb and from this could be traced in the general direction of the
central end of the nerve
transplant, but also into the connective tissue surrounding the
transplant and in this connective
tissue to the level of the distal wound. In none of the experiments was
neurotization of the distal
segment attained. In the experiments of Series No. 15, in which
heterogenous nerve transplants
stored in 50 percent alcohol were used, the end results attained are
much less satisfactory than in
the series in which homogenous nerve transplants were used (Series No.
13). The several
animals were under observation for from 64 days to 154 days, thus for a
time of sufficient length
to admit of regeneration through the transplant, under favorable
conditions. It may be noted on
study of the protocols that to a limited extent downgrowth of central
neuraxes through the
transplants was observed; our results thus con- firming Nageotte.77 The long persistence of
fragments of the neuraxes of the transplanted nerves is to be noted,
especially in Experiment No.
224, terminated 152 days after the operation. In the central portion of
the transplant near the
central wound and for several millimeters distal, quite long fragments
of old neuraxes stained
differentially by the pyridine-silver method are to be found. Distal to
this region they have
disappeared from the remains of the transplanted
1232
nerve fibers. Judging
from the limited number of experiments here presented (3), testing the
value
of heterogenous nerve transplants stored in 50 per cent alcohol, it
seems clear that this form of
nerve bridge is not to be advocated as worthy of consideration in human
surgery. The
experiments of this series in so far as they can be compared with the
series in which homogenous
nerve transplants stored in 50 per cent alcohol (Series No. 13) were
tested, indicate that there is
distinct difference as regards serviceability between homogenous and
heterogenous nerve
transplants stored in 50 per cent alcohol and in favor of the
alcoholized homogenous nerve
transplants.
AUTO-NERVE
TRANSPLANTS WRAPPED IN PROTECTIVE MATERIAL
SERIES NO. 16
AUTO-NERVE TRANSPLANTS WRAPPED IN CARGILE MEMBRANE
In
this and the following several series (Series No. 16, No. 17, No. 18,
and No. 19) we
have attempted to test the merits of certain membranous structures
which had been
recommended for use in surgical practice, as a covering for suture
lines in operations of nerve
suture or as a wrapping about a nerve transplant and the suture lines
or in other operative
procedures in peripheral nerve repair. Incidental references are found
in surgical literature to a
number of membranous structures used for wrapping nerves or tendons
after operative
procedure. Our list of experiments might have been extended had
cognizance been given to all of
the materials used for this purpose. References to the use of Cargile
membrane are not
infrequent. It seemed to be used sufficiently frequently to warrant
renewed experimental inquiry.
Morris 78 states that he had received from Dr. Charles H.
Cargile, of Arkansas,"sterilized animal
membrane" (dried and sterilized peritoneum of the ox) with the request
that he test its use and
value in surgical practice, especially as a means of preventing
adhesions in certain cases of
abdominal surgery. Twelve experiments on rabbits were made. Morris
found that the membrane
resisted absorption for more than 10 days but less than 30 days when
placed in the peritoneal
space. Craig and Ellis 79 undertook a series of
experiments on dogs using both chromatized and
unchromatized Cargile membrane to wrap tendons and also nerves. They
reached the conclusion
that both the chromatized and the unchromatized membrane are of value
in preventing adhesions
of wounded nerves and tendons when such structures lie in tissue
subjected to trauma. It was
their observation that especially unchromatized Cargile membrane is
absorbed relatively quickly
in the tissues; macroscopically within 5days, microscopically within 14
days. The membrane
appears to be destroyed by a lytic substance contained in the body
fluids, phagocytes being
regarded as of less importance in this process of disintegration and
absorption. Sherren, 80 in
several places, refers to the use of Cargile membrane or foil in
connection with nerve suture and
nerve transplantation. Other writers refer to the use of other animal
membranes such as hernial
sac, peritoneum, omentum, etc., used as fresh or as dried sterilized
membranes. Meuriot and
Platon 81 used strips some 20 cm. long and 5 cm. wide, cut
from rubber gloves and wrapped
spirally
1233
about the nerve, at the
seat of injury. This technique was used in 100 cases and in 9:3 without
unfavorable reaction.
In
experiments of Series No. 16, the sciatic nerve of a dog was resected
to the extent of
approximately 4 cm. and the defect bridged by a segment of necessary
length removed from the
ulnar of the opposite side of the same dog. After the nerve transplant
had been completed with
the necessary sutures placed, one or several layers of Cargile membrane
of sufficient length to
extend about 1 cm. beyond the central and distal suture lines were
wrapped about the nerve
transplant and the ends of the central and distal stumps as closely and
as evenly as could be. The
Cargile membrane used was that made by Johnston and Johnston and was
designated as
"medium hard chromic." Pieces of requisite size, either of one laver or
of several layers, were
cut from pieces found within the several envelopes, as found in the
market, and used at once as
wrapping for the operated nerve, after which the wound was closed. An
attempt was made to
sterilize the portion of the Cargile membrane not used at any one
operation, until it occurred to
us to place the unused portion of any membrane in 70 per cent or 95 per
cent alcohol, in which
the membrane fragments were kept until further used. Before actual use,
the membrane piece to
be used was placed in absolute alcohol for several hours or perhaps a
day. From the absolute
alcohol the membrane was placed, just before use, on a dry, sterile
towel so as to enable the
absolute alcohol to evaporate. In this dry state, after the evaporation
of the alcohol, the
membrane was used as a wrapping for an operated nerve. As will be noted
on reading the
protocols, Cargile membrane thus stored in absolute alcohol reacts very
differently toward
tissues than Cargile membrane not stored in alcohol. In our discussion
we shall use the term
"alcoholized Cargile membrane" meaning thereby Cargile membrane, either
chromatized or
unchromatized, which had for a time been kept in alcohol. The
characteristics of an alcoholized
Cargile membrane were discovered quite by accident. Our own
observations pertain to the use of
such a membrane as a wrapping for an operated nerve; its wider
application in surgery has not
been considered.
The
protocols of experiments under Series No. 16, auto-nerve transplants
with a
wrapping of " Cargile membrane " and " alcoholized Cargile
membrane,"are as follows:
PROTOCOLS
EXPERIMENT
No. 226.-Dog No. 34; medium size; full grown; 20 hours. May 28,1918,
left sciatic
exposed and internal popliteal freed. Right ulnar exposed. A segment
4.6 cm. length of right ulnar transplanted to the
resected internal popliteal; one central and distal fine silk thread
suture used; distally a second epineural suture
placed. Good approximation attained. A single layer of Cargile
membrane, cut long enough to overlap suture lines 5
mm., wrapped about nerve; well applied, forms close-fitting tube. Both
wounds closed. May 29, dog found dead
next morning; distemper. Wound reopened, and sciatic exposed. Resected
nerve ends appear slightly congested.
Transplant and Cargile membrane found well in place; a small amount of
fluid noted within membrane; membrane
loosely adherent to surrounding tissues; adhesions easily broken down. Nerve and transplant surrounded by
Cargile
membrane removed and fixed in neutral formalin. Sections stained in
iron-hematoxylin and picro-fuchsin.
Microscopic findings.-In cross and longitudinal sections,
Cargile membrane
presents the appearance of a
thin layer of dense collagenous connective tissue. Numerous leucocytes
1234
between membrane and epineural sheath of
the
transplant. Coagulum and numerous leucocytes on outer surface of
membrane. At the central wound, beginning degeneration of distal end of
central nerve fibers noted; leucocytes and
extravasated red blood cells between these fibers. In central end of
transplant, for a distance of about 1 mm., myelin
degeneration noted; here leucocytes in and between neurolemma sheaths
of fibers. More distal in the transplant, few
leucocytes observed.
EXPERIMENT
No. 227.- Dog No. 33; half grown; medium size; 3 days. May 27, 1918,
left sciatic exposed
and the internal popliteal freed. Right ulnar exposed and freed. A
segment of 5 cm. length of right ulnar transplanted
to left internal popliteal. One central and distal silk suture placed.
Distal suture gave way; in resuturing this central
suture gave way; central resutured. Fair approximation attained. A
single layer of Cargile membrane wrapped about
transplant and suture lines; well applied. Wounds closed. May 30, dog
found dead in the morning; distemper.
Superficial wounds healed. On exposing sciatic, slight infection of
deep wound noted. The Cargile membrane
evident; small amount of exudate within the membrane. Resected nerve
and transplant with Cargile membrane
removed and fixed in neutral formalin. Sections stained in
iron-hematoxylin and picro-fuchsin.
Microscopic findings.-In sections, Cargile membrane is found
well
in place. Coagulum leucocytes,
extravasated blood observed within membrane and about its outer
surface. Beginning degeneration of distal end of
central stump and central end of the transplant to be observed. Central
end of transplant and distal end of central
stump united; fibrin, coagulum, leucocytes, extravasated red blood
cells intervening. Leucocytes observed in and
between neurolemma sheaths of the transplanted nerves.
EXPERIMENT
No. 228.- Dog No. 3; medium size; full grown; 56 days. June 11, 1918,
right sciatic
exposed and the internal popliteal freed. The left ulnar exposed. A
segment 2 cm. length of left ulnar transplanted to
the right internal popliteal. One central and distal fine silk thread
suture placed; good approximation. Two layers of
Cargile membrane wrapped about transplant and the resected nerve ends;
well applied, forming close-fitting tube.
Slight oozing from resected nerve ends, not controlled. Both wounds
closed. August 6, killed. Dog in good
condition; active; no neurotrophic ulcer right foot. Wound well healed.
On exposing the right sciatic, transplant is
found well in place; no trace of Cargile membranes evident. Quite a
little increase of connective tissue about the
transplant and suture lines noted; adherent to underlying muscles. No
distinct central bulb noted. No contraction of
the calf muscles on cutting the nerve. Resected nerve and transplant
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Differential neuraxis silver staining not
entirely satisfactory.
Microscopic findings.-In both cross and longitudinal
sections of
the region of the transplanted nerve
segment no trace of the Cargile membranes observed. Distinct thickening
of the epineural sheath of the transplant
observed. New neuraxes can be traced from the distal end of the central
stump, through the central wound into the
transplant, and through the transplant into the central end of the
distal popliteal; relatively few neuraxes have passed
the distal wound. Remains of degenerated myelin observed in the
transplant. Many small myelin ovoids seen in the
distal popliteal, as also numerous nucleated syncytial bands in which
no neuraxes are differentiated observed.
EXPERIMENT
No. 229.- Dog No. 30; large; full grown; 129 days. May 22, 1918, two
segments of the right
ulnar of 2.3 cm. length transplanted to the resected left sciatic. Each
segment sutured separately, centrally, and
distally, using fine Chinese silk sutures. Fair approximation attained.
The transplants and the resected nerve ends, for
a distance of 8 mm., wrapped in a single layer of Cargile membrane well
applied. Both wounds closed. September
28, dog found dead in the morning. Seemed fairly well day previous;
moderate emaciation; skin disease; no
neurotrophic changes left foot. On removing skin over operated nerve a
small encapsuled stitch abscess noted; does
not extend to deeper tissues. On exposing the left sciatic, no material
increase of connective tissue noted. Transplants
found well in place, demarked by presence of sutures. Transplant
presents the appearance of a normal nerve. No
trace of Cargile membrane observed. No distinct central bulb noted.
Calf muscles of good size and color. Left
sciatic and transplant, posterior tibial and external popliteal removed
and fixed in ammoniated alcohol for pyridine-silver staining.
1235
Microscopic findings.-No trace of Cargile membrane observed
in
sections. In cross sections of the
transplant about 1 cm. distal to the central wound, the funicular
structure of both of the transplanted ulnar segments
preserved, and are surrounded by common fibrous tissue sheath. All of
the funiculi on the transplanted ulnar
segments contain new neuraxes, certain of these are myelinated, the
majority not. Numerous small bundles of nerves
observed in the connective tissue intervening between the two nerve
segments transplanted. Numerous neuraxes can
be traced from the transplants through the distal wound into the distal
sciatic segment, all of the funiculi containing
them. New neuraxes in good number observed in the posterior tibial and
the external popliteal.
EXPERIMENT No. 230.- Dog No. 2; medium size;
full grown; 342 days. June 12, 1918, right sciatic
exposed and the internal popliteal bundle freed. The left ulnar exposed
and freed. A segment of 2 cm. length of the
left ulnar transplanted to the right internal popliteal. One central
and one distal fine silk thread suture placed; good
approximation. A double layer of Cargile membrane wrapped about
transplant and resected nerve ends; well applied.
Both wounds closed. May 20, 1919, killed. Dog in very good condition;
uses right foot well as normal dog. On
exposing the right sciatic, external popliteal bundle found free.
Distinct central bulb, which tapers toward the
transplant, noted. Transplant has the appearance of normal nerve,
though surrounded by quite dense connective
tissue and adherent to underlying muscle. No trace of Cargile membrane.
Calf muscles exposed; these have the
appearance of normal muscle. Nerve and transplant completely freed. On
slowly cutting nerve with scissors central
to the transplant, vigorous contraction of calf and plantar foot
muscles. Nerve and the transplant removed and fixed
in ammoniated alcohol for pyridine- silver staining. Neuraxes only very
lightly stained.
Microscopic
findings.- Numerous myelinated and nonmyelinated nerves traced from
central bulbous
enlargement to the distal popliteal. In cross sections of the
transplant funiculi are found to be well maintained, with
only moderate increase of connective tissue about the transplant. Calf
and plantar muscle not studied in this
experiment.
EXPERIMENT No. 231.- Dog No. 35; small dog;
full grown; 350 days. June 1, 1918, left sciatic exposed;
internal popliteal bundle freed. Right ulnar exposed. A segment. 3.4
cm. length taken from the right ulnar and
transplanted to the resected left internal popliteal. One central
suture of vessel silk; vessel silk suture attempted for
distal suture, broken twice; finally Chinese silk suture used. Good
central approximation attained, distal “fair.” Double layer of Cargile
membrane wrapped about transplant and the resected nerve ends; well
applied; formed close
fitting tube. Both wounds closed. May 16, 1919, killed. Dog in very
good condition; active; no neurotrophic changes
on left hind foot. On exposing the left sciatic, external popliteal
bundle found free. Operated internal popliteal
presents appearance of a normal nerve, except that region of the
transplanted nerve appears slightly smaller than
resected nerve. No trace of Cargile membrane, only very moderate
increase of connective tissue about the transplant.
Small spindle-shaped central bulb noted. Calf muscles exposed; these
have the appearance of normal muscle.
External popliteal resected and internal popliteal freed from bed. On
cutting nerve slowly with scissors central to the
transplant, vigorous contraction of calf and plantar muscles observed.
Resected nerve and transplant removed and
fixed in ammoniated alcohol for pyridine-silver staining. Silver
differentiation faint.
Microscopic findings.- In longitudinal sections embracing
central
wound, line of central wound is indistinct.
Numerous myelinated and nonmyelinated nerve fibers can be traced from
central stump through the transplant to the
distal nerve. In cross sections made about middle of the transplant,
many myelinated and nonmyelinated fibers
observed within the transplant, the funiculi of which are well
maintained. Outside of perineural sheath, but within
the denser connective tissue surrounding the transplant, many small
funiculi of nerve fibers observed. Many new
nerve fibers, both myelinated and nonmyelinated, noted in the distal
popliteal. No trace of Cargile membrane
observed in any of the sections.
EXPERIMENT
No. 232.- Dog No. 32; medium size dog; full grown; 358 days. May 24,
1918, left sciatic
exposed; internal popliteal freed. Right ulnar exposed and freed. A
segment of 3 cm. length taken from the right
ulnar transplanted to the left internal popliteal. Three epineural
sutures placed distally; good approximation. A single
layer of Cargile
1236
membrane wrapped about transplant and
resected nerve ends; well applied. Both wounds closed. May 19, 1919,
killed. Dog in very good condition; walks well. No neurotrophic changes
left hind foot. On exposing the left sciatic
external popliteal found free. Operated internal popliteal presents a
small spindle-shaped central bulb; otherwise the
appearance of a normal nerve. No trace of Cargile membrane. No material
increase of connective tissue about the
transplant noted. Calf muscles exposed; these of normal size and
appearance. The internal popliteal and transplant
freed from the bed. On slowly cutting the nerve with scissors central
to the transplant, good contraction of the calf
and plantar muscles observed. Nerve and transplant removed and fixed in
ammoniated alcohol for pyridine-silver
staining. Fairly good differential silver staining attained.
Microscopic
findings.- In longitudinal sections of the central wound region,
the
central wound not easily
located. Numerous myelinated and nonmyelinated nerves pass from distal
end of the central bulb to and through the
transplant to the distal nerve. In cross sections of the transplant
taken near the central wound, many new nerve fibers
found within the transplant. Funiculi and perineural sheaths
maintained. Many small nerve funiculi in the connective
tissue surrounding the transplant. In cross sections through the distal
part of the transplant, perineural sheaths of
transplant not so distinct. Numerous smaller and larger funiculi in the
connective tissue outside of the transplant, in
distribution more or less clearly bounded by an outer fairly dense
connective tissue sheath, probably connective
tissue replacing the Cargile membrane. Many new nerve fibers, nearly as
many as seen in a normal nerve, traced
through the distal wound into the distal popliteal. Very complete
regeneration through the transplanted nerve
segment.
EXPERIMENT
No. 233.- Dog No. 31; large; full grown; 359 days. May 23, 1918, left
sciatic exposed and
freed. Right ulnar exposed and freed. A segment of 2.9 cm. length taken
from the right ulnar transplanted to the left
sciatic. One central and distal fine silk thread suture placed; fairly
good approximation attained. One layer of Cargile
membrane wrapped about the transplant and resected nerve ends; well
applied, forming closely fitting tube. Both
wounds closed. May 19, 1919, killed. Dog very good condition; uses left
hind leg well; no neurotrophic changes left
hind foot. On exposing the left sciatic, the region of the nerve
transplant is located by reason of the distinct central
bulbous enlargement. Transplant has the appearance of a normal nerve;
no material increase of connective tissue
about it. No trace of Cargile membrane. Calf muscles exposed; these
have the appearance of normal muscle. After
freeing nerve and transplant from the bed, on slowly cutting nerve
central to transplant, vigorous contraction of calf
and the plantar foot muscle noted. Sciatic and the transplant removed
and fixed in ammoniated alcohol for pyridine-silver staining. Good
differential silver staining attained.
Microscopic
findings.-In longitudinal sections through the central wound,
central bulb distinctly evidenced
by crisscrossing and tangling of the neuraxes of this region; line of
central wound not clearly demarked. Numerous
neuraxes pass from central bulb to and through the transplant. In cross
sections of the transplanted nerve funicular
structure and sheaths clearly are maintained. Numerous new nerve fibers
observed with the transplant. Nearly all of
the neuraxes observed in cross sections of the transplant found within
its sheaths; only a few small scattered nerve
funiculi found in the connective tissue surrounding the transplant.
Numerous nerve fibers, myelinated and
nonmyelinated, can be traced to the distal sciatic in which they are
found in all of its several funiculi about equally
distributed.
EXPERIMENT
No. 234.- Dog No. 30; large; full grown; 44 days. August 15, 1918,
right
sciatic exposed
and internal popliteal bundle freed. Left ulnar exposed and freed. A
segment 2.1 cm. length taken from the left ulnar
transplanted to the right internal popliteal. One central and one
distal waxed, fine silk thread suture placed; good
approximation. Two layers of Cargile membrane which had been stored
several days in 70 per cent alcohol, then for
24 hours in absolute alcohol and before use spread on a dry, sterile
towel until dry, wrapped about the nerve and the
resected nerve ends. (Cargile membrane thus treated is in subsequent
experiments referred to as alcoholized Cargile
membrane.) Cargile membrane well applied; close-fitting tube formed.
Both wounds closed. September 28, dog
found dead in the morning; seemed fairly well the day before; skin
disease; moderate emaciation. Wound well
healed. On exposing the right sciatic, external popliteal found free.
Region of the
1237
transplant in the internal popliteal
easily
located by reason of the presence of the Cargile membrane, which
appeared
wrapped about the nerve, forming a closely fitting sheath which was
only slightly adherent to the surrounding
connective tissue. It seemed evident that there had taken place no
absorption of the alcoholized Cargile membrane.
Nerve and the transplant with the Cargile membrane removed and fixed in
neutral formalin. Sections stained in iron-hematoxylin and
picro-fuchsin; hematoxylin and eosin; safranine and licht grün.
Microscopic
findings.- Alcoholized Cargile membrane evident in all of the
sections,
cross and longitudinal,
taken at different levels in the transplant and through central and
distal wounds. In cross sections of the transplant,
the two layers of the membrane appear as undulating membranes of
fibrous tissue, which show no evidence of
undergoing absorption. On both faces of the membranes newly formed,
vascularized connective tissue observed. Cargile membranes found to
overlap central and distal wounds for a distance of 6 mm. to 8 mm. The
transplanted
nerve segment found well united to resected nerve ends. In cross
sections of the transplant, it may be observed that
the funicular arrangement is well maintained, as also the perineural
sheath of the funiculi. Between these perineural
sheaths
FIG.
233.- Cross section of
auto-nerve
transplant, wrapped with two layers of alcoholized Cargile membrane,
Experiment No. 234, 44 days after operation. Tissue fixed in formalin
and stained in iron-hematoxylin. The deeply
stained and folded lines in the figure represent sections of the
Cargile membrane. Note the absence of marked
connective tissue proliferation and the Cargile membrane newly formed
connective tissue is found. In this
connective tissue numerous small nerve funiculi observed; these are
limited in distribution peripherally by the
Cargile membrane.
EXPERIMENT
No. 235.- Dog No. 56; large; full grown; 172 days. July 24, 1918, left
sciatic exposed;
internal popliteal bundle freed. The right ulnar exposed and freed. A
segment of 4 cm. length taken from the right
ulnar transplanted to the left internal popliteal. One central and
distal waxed, fine silk thread suture placed. Central
approximation good; distal fair, improved by epineural suture.
Transplant and the resected nerve ends wrapped in
two layers of alcoholized Cargile membrane; well applied, forming
closely fitting tube. Adrenalin used to control
oozing; dry, clean field. Both wounds closed. January 11, 1919,dog had
been very active. Found dead in the
morning, having hung himself on a tie rope. No neurotrophic changes
left hind foot. On exposing the left sciatic
external popliteal found free; only very loosely adherent to operated
internal popliteal. Operated internal popliteal
appears of relatively large size. Closer inspection reveals that the
alcoholized Cargile membrane had not been
absorbed, and is surrounded by a thin layer of connective tissue only
loosely adherent to the surrounding tissue. No
distinct central bulb evident,
1238
Cargile membrane extending over central
suture. Calf muscles exposed; these present the appearance of normal
muscles. The whole of the sciatic nerve, with transplant and the
Cargile membrane sheath removed in one piece and
fixed in ammoniated alcohol for pyridine-silver staining. Good
differential silver staining, though pale, attained.
Microscopic
findings.- In all of the several series of sections, though
especially in cross sections of the
transplant, the two layers of the Cargile membrane distinctly observed, surrounded by a thin layer of
fairly
dense
connective tissue. The membranes have the structural appearance of
closely felted fibrous tissue, though silver stain
used does not differentiate this tissue clearly. The funiculi of the
transplanted nerve segment evident. Numerous
myelinated and nonmyelinated nerve fibers observed within the
transplant. Between the denser connective tissue
enveloping the Cargile membrane and the perineural sheaths, a looser
connective tissue observed; in this, here and
there, groups of fat cells seen. In this looser connective tissue,
smaller and larger nerve funiculi seen. Regenerating
nerve fibers traced through the distal wound into the distal popliteal
nerve, in which there may be ob- served, in all
of the funiculi, numerous myelinated and nonmyelinated nerve fibers.
FIG.
234.- Cross section of
auto-nerve
transplant, wrapped in alcoholized Cargile membrane, Experiment No.
236, terminated 272 days after the operation; pyridine-silver
preparation. The Cargile membrane as a wavy, undulating
layer embedded in the fibrous tissue surrounding the nerve trunk. Note
the neurotization of the transplanted nerve
segment as seen in the figure
EXPERIMENT
No. 236.- Dog No. 35; small dog; full grown; 272 days. August 20,
1918,right sciatic
exposed and the internal popliteal bundle freed. Left ulnar exposed and
freed. A segment of 3 cm. length taken from
the left ulnar transplanted to the right internal popliteal. One
central and distal waxed, fine silk thread suture placed.
Only fair central and distal approximation attained. One layer of
alcoholized Cargile membrane wrapped about
trans-plant and the resected nerve ends; fairly smooth tube formed.
Both wounds closed. May19, 1919, killed. Dog
in very good condition. No neurotrophic changes right hind foot. On
exposing the right sciatic, external popliteal
found free. Quite distinct central bulb on internal popliteal noted.
Macroscopically, no trace of Cargile membrane.
Moderate increase of connective tissue about operated internal
popliteal in region of the transplant recorded. Calf
muscles exposed; these have the appearance and size of normal muscles.
After freeing operated internal popliteal
and transplant and cutting the external popliteal
1239
near head of fibula, on slowly cutting
with
scissors the nerve central to the transplant, good contraction of calf
and
foot muscles observed. Sciatic and the transplant removed and fixed in
ammoniated alcohol for pyridine-silver
staining. Fairly good differential silver staining attained.
Microscopic
findings.-In longitudinal sections of the central wound,
distinct
central bulb, evidenced by
twisting and intercrossing of neuraxes, noted. Numerous myelinated and
nonmyelinated nerve fibers enter the
transplant. In cross sections of the transplant 1 cm.distal to the
central wound, evidence of the Cargile membrane
made out in the form of a wavy, undulating membrane of fibrous tissue
enveloped in a fairly dense layer of fibrous
tissue. This not so clearly observed in longitudinal sections of the
transplant. The funiculi of the transplanted nerve
segment clearly demarked; many new nerve fibers observed within these
funiculi; both myelinated and
nonmyelinated. A looser connective tissue intervenes between the
perineural sheaths and the peripheral denser layer
of the fibrous tissue enveloping the Cargile membrane. In this a few
small nerve funiculi observed. Numerous
myelinated and nonmyelinated nerve fibers observed in the distal
popliteal in all of its nerve funiculi.
EXPERIMENT
No. 237.-Dog No. 32; medium size; full grown; 274 days. August 17,1918,
right sciatic
exposed and the internal popliteal bundle freed. The left ulnar exposed
and freed. A segment of 2.1 cm. length taken
from the left ulnar transplanted to the resected right internal
popliteal. One central and distal waxed, fine silk thread
suture placed. "Fair"'central and distal approximation attained. Two
layers of alcoholized Cargile membrane
wrapped about the transplant and resected nerve ends; good tube formed
distally, not so good centrally. Both
wounds closed. May 19, 1919, killed. Dog in very good condition; uses
right hind foot well; no neurotrophic
changes right hind foot. On exposing the right sciatic, external
popliteal bundle found free. Moderate increase of
connective tissue about operated internal popliteal in region of the
transplant. No macroscopic evidence of Cargile
membrane. Calf muscles exposed; these have the size and appearance of
normal muscles. After cutting the external
popliteal near head of fibula and completely freeing the sciatic and
the transplant from the bed, on slowly cutting
with scissors the nerve central to the transplant, good contraction of
calf and foot muscles observed. Sciatic and the
transplant removed and fixed in ammoniated alcohol for pyridine-silver
staining. Good differential silver staining in
only part of the series; the remainder pale.
Microscopic
findings.-In cross sections of the transplanted nerve segment made
about1 cm. distal to the
central wound, there is observed a dense fibrous tissue layer separated
from the epineural and perineural sheaths of
the transplant by looser connective tissue. This outer, denser layer of
connective tissue may contain remnants of the
Cargile membrane; if so, these are not clearly differentiated in the
silver stain. Numerous myelinated and non-myelinated nerve fibers
within the funiculi of the transplanted nerve segment observed; as also
in the connective
tissue surrounding the transplant. Numerous myelinated and
non-myelinated nerve fibers can be traced through the
transplant and distal wound to the distal popliteal.
EXPERIMENT
No. 238.-Dog No. 31; large; full grown; 275 days. August 16, 1918,
right sciatic exposed;
internal popliteal bundle freed. The left ulnar exposed and freed. A
segment of 3.6 cm. length taken from the left
ulnar transplanted to the resected right internal popliteal. Quite a
little bleeding; controlled. One central and distal
waxed, fine silk thread suture placed; good approximation. Two layers
of alcoholized Cargile membrane wrapped
about the transplant and resected nerve ends; well applied, forming
close-fitting tubular sheath. Both wounds closed.
May 19, 1919, killed. Dog in very good condition; used right hind foot
well; no neurotrophic changes right foot. On
exposing the right sciatic, external popliteal found free. Only
moderate increase of connective tissue about operated
internal popliteal, especially transplant region, observed; here somewhat adherent to
underlying muscle.
No
macroscopic evidence of Cargile membrane noted. Small spindle-shaped
central bulb found. Calf muscles exposed;
these have the appearance and size of normal muscles. Nerve and
transplant freed from bed. On slowly cutting with
scissors nerve central to the transplant, contraction of calf muscles
and movement of toes observed. The nerve and
the transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining. Fair differential silver staining
attained.
1240
Microscopic findings.- In longitudinal sect ions of the
central
wound area, central bulb is evidenced
structurally by twisting and crisscrossing of neuraxes. In cross
sections of the transplant, it is observed that the
funicular structure of the nerve is well maintained; each funiculus
with its perineural sheath. Numerous myelinated
and nonmyelinated nerve fibers observed within these sheaths. A
relatively dense layer of fibrous tissue surrounds
the transplant; in this layer no distinct evidence of the Cargile
membrane noted, except near distal wound; here, in a
series of longitudinal sections, remnants of Cargile membrane seen. A
layer of looser connective tissue intervenes
between the perineural sheaths and the peripheral layer of denser
fibrous tissue; in this looser fibrous layer many
small funiculi of nerve fibers observed. Numerous myelinated and
nonmyelinated nerve fibers can be traced through
the distal wound into the distal popliteal nerve.
EXPERIMENT No. 239.- Dog No. 52; medium size;
full grown; 300 days. July 19, 1918, left sciatic
exposed; internal popliteal freed. Right ulnar exposed and freed. A
segment of the right ulnar of 3.8 cm. length
transplanted to the resected left internal popliteal. One central and
distal waxed, fine silk thread suture placed; very
good central and distal approximation. Four layers of alcoholized
Cargile membrane wrapped about the transplant
and the resected nerve ends. Wound not quite dry; a small amount of
blood with Cargile membrane sheath,
especially near distal suture. Both wounds closed. May 15, 1919,
killed. Dog in very good condition; uses left hind
foot well; no neurotrophic changes. On exposing the left sciatic, it is
observed that the external popliteal is
moderately adherent to the operated internal popliteal, especially near
distal wound. Moderate increase of connective
tissue about the transplant. Transplant appears relatively thick in its
middle third; it could not be determined on gross
inspection whether a portion of the Cargile membrane sheath had not
been absorbed. Calf muscles exposed; these have appearance and
size of
normal muscles. Nerve and transplant completely freed from bed.
Observer was
unavoidably interrupted and could not test the functional return of
muscles until about one-half hour after dog was
killed. Cutting the nerve central to transplant causes only very feeble
contraction of the calf muscles; no toe
movement noted. Nerve and transplant removed and fixed in ammoniated
alcohol for pyridine-silver staining. Good
differential silver staining central portions, distal only fair.
Microscopic
findings.- In longitudinal sections of the central wound area,
evidence of central bulb observed,
this evidenced by the twisting and crisscrossing of neuraxes in region
of central wound and central stump proximal
thereto. Many nerve fibers traced to the central end of the transplant.
In cross sections of the transplant taken about 1
cm. distal to the central wound, the appearance presented suggests the
possibility that two nerve segments were
transplanted ulnar and median or ulnar and musculocutaneous in that two
relatively large nerves, distinctly separated
and surrounded by a relatively dense layer of connective tissue, are
observed. No distinct evidence of the Cargile
membrane sheath noted in this denser fibrous layer. Between the
perineural sheaths of the nerve transplant and the
peripheral denser fibrous sheath a looser connective tissue intervenes;
in this are found numerous small nerve
funiculi. Numerous myelinated and nonmyelinated nerve fibers can be
traced through the transplant and distal
wound into the distal popliteal, in which they are found in large
numbers.
Our
experimental observations relating to the use of Cargile membranes as a
wrapping
for operated or liberated peripheral nerves confirms the observations
of Craig and Ellis79 in so far
as concerns the early absorption of both the unchromatized and the
chromatized Cargile
membrane such as is furnished commercially for use in surgical
practice. A number of our
experiments are not here listed owing to the death of animals from
intercurrent infectious
disease. A number were of relatively short duration and permitted
observation as to the early
disappearance of the Cargile membrane, when placed in tissue. In a
number of discarded
experiments there was wound infection. Taking into consideration these
experiments not listed
it is our observation that Cargile membrane when wrapped about a
peripheral nerve and inclosed
1241
within an aseptic wound
disintegrates and is absorbed within 10 davs to 15 days. Experiments
No. 226 and No. 227 may serve to show that a Cargile membrane when
wrapped about a nerve
incites relatively little connective-tissue proliferation. Leucocytes
are evident in the tissue fluids
within and outside of the membrane. By the middle of the second month
after the operation
(Experiment No. 228) there could be found no trace of the two layers of
the Cargile membrane
used in this transplant. It is especially during the first two months
after the operation of
peripheral nerve suture or of nerve transplantation that a membranous
structure wrapped about a
nerve would be most effective in preventing ingrowth of connective
tissue and prevent the
spread of down-growing neuraxes. Downgrowth of central neuraxes is not
pronounced until
toward the end of the second week, although evident prior to this time.
Cargile membrane as
found in trade, therefore, can not exert much influence one way or the
other when used as a
wrapping about an operated peripheral nerve. Four of the experiments
(No. 230 to No. 233) were
carried on respectively for nearly a year. In these experiments there
was found quite complete
repair of the peripheral nerve through the transplant, and, as the
records show, not very much
increase of connective tissue in the region of the transplant. The
increase in the connective tissue
noted is evident in an increase in the density of the epineural sheath
as also in the formation of a
layer of fibrous tissue which appears to have replaced the Cargile
membrane.
The
results attained in the experiments in which "alcoholized
Cargile membrane" was
used were wholly unexpected. The method of storing unusedportions of
Cargile membrane in
alcohol was resorted to as a ready means for keeping sterile portions
of the membrane not used
at any one experiment. Much surprise was experienced on exposing the
operated nerve in
Experiment No.234, 44 days after the operation, to find the region of
the operation completely
surrounded by a layer of Cargile membrane, which, like the nerve
itself, above and below the
seat of the operation was only very loosely attached to the surrounding
tissue. It had been
anticipated in this experiment that no trace of the Cargile membrane
would be found. On
consulting the records it was found that the Cargile membrane used in
this case had been stored
in alcohol prior to use in the operation. In Experiment No. 234, which
terminated approximately
one and one-half months after operation, the two layers of Cargile
membrane wrapped about the
nerve at the time of operation appear not to have been affected by the
tissue fluids nor by
phagocytic action. The two layers of Cargile membrane and the nerve
funiculi of the
transplanted nerve segment are occupied by cellular, loose connective
tissue. In the connective
tissue are found small bundles of neuraxes, confined within the Cargile
membrane. To what
extent the presence of the alcoholized Cargile membrane would operate
to prevent the ingrowth
of connective tissue can only be conjectured. It should be borne in
mind that the connective
tissue found in the regions of the central and distal wounds in the
early stages of nerve repair
after resection and bridging by a nerve transplant, or in the one wound
after simple suture, is
histogenetically to a large extent derived from the connective tissue
of the severed nerve trunk,
its endo-, peri-, and epineurium. Even after the most favorable primary
nerve suture, in aseptic
tissue, with desired
1242
approximation of severed
nerve ends, embryonic connective tissue which progresses toward the
stage of connective tissue fibril formation is formed between the
severed nerve ends. Slight
hemorrhage with formation of blood clot increases the connective tissue
formation in proportion
to clot formation. Wrapping with Cargile or other membranous structures
does not prevent this. The connective tissue found between the central
stump of a resected nerve and the central end of
a nerve transplant, at the time when the central neuraxes begin to grow
toward the periphery
during the first 10 days to 14 days after the operation, is not
materially influenced by the
presence or absence of an alcoholized Cargile membrane. In an operation
for nerve
transplantation in which a nerve segment of perhaps 6 cm. to 8 cm. in
length is used as a nerve bridge the central neuraxes would not reach
the region of the distal wound until after the
expiration of from 8 weeks to 12 weeks after the operation, at which
time the connective tissue
at the distal wound would be quite fully organized. There seems warrant
for the statement that in
the distal wound region the presence of the alcoholized Cargile
membrane would influence the ingrowth and differentiation of the
connective tissue. In Experiment No. 235, terminated
somewhat over five months after the operation, the two layers of
alcoholized Cargile membrane
used at the operation were still evident macroscopically at the time
the nerve was exposed and
removed for study. The Cargile membrane was found surrounded by a thin
layer of connective
tissue only loosely adherent to the surrounding tissue. Between the
Cargile membrane and the
perineural sheaths of the funiculi of the nerve transplant, there is
found a loose areolar tissue
containing here and there fat cells arranged in small groups or singly.
Denser areolar connective
tissue surrounds the external surface of the Cargile membrane. In this
experiment the small
bundles of neuraxes found outside of the perineural sheaths of the
nerve transplant are noted in
the loose areolar tissue observed within the Cargile membrane. In
experiments terminated
approximately nine months after the operation (Experiments No. 236 to
No. 239) in which
alcoholized Cargile membrane was used to wrap the nerve in the field of
operation, either as
single layer or as several layers, the Cargile membrane was not
recognized macroscopically at
the time the nerves were removed for study nor with any degree of
certainty microscopically in
sections. A layer of relatively dense fibrous tissue, in the form of
wavy, undulating, fibrous
bands, more readily recognized in cross sections of the transplant
region, appear to have replaced
the Cargile membrane. Within this layer there is an area of looser
areolar tissue with groups of
fat cells, separating the denser layer from the transplanted nerve
trunk. In each of the four
experiments of relatively long duration it is worthy of note that the
funicular structure of the
transplanted nerve segments was well maintained; neurotization of the
distal segment of the
operated nerve had been obtained through down growth of central
neuraxes, which pass in the
main through the funiculi of the transplanted nerve segments.
The
experiments in which alcoholized Cargile membrane was used as a sheath
for the
operated nerve in the field of nerve repair seem to us to warrant the
deduction that Cargile
membrane stored in alcohol after the manner here
1243
detailed remains
unabsorbed when inclosed in aseptic wounds for a period extending at
least
four months. Alcoholized Cargile membrane was not found to incite
unduly connective tissue
proliferation; it remains closely adherent to the nerve transplant and
the resected nerve ends and
does retain within the limits of the membrane the down-growing
neuraxes. The presence of the
alcoholized Cargile membrane does not appear to influence the
down-growth of the central
neuraxes through the funiculi of the nerve transplant. Our experiments
seem to us to warrant the
conclusion that the use of alcoholized Cargile membrane, prepared as
above stated, and used in
double or triple layers as a sheath for wrapping nerve trunks at the
suture line after the nerve
suture or as a wrapping for a nerve transplant when such sheathing is
deemed necessary,
deserves consideration in operations for peripheral nerve repair.
SERIES NO. 17
AUTO-NERVE TRANSPLANTS, WRAPPED IN
AUTO-FASCIAL SHEATHS OF FASCIA LATA
In
a series of auto-nerve transplants, the transplant and the central and
distal wound
regions were insheathed with a layer of fascia lata, taken at the time
of operation from the same
animal. In these experimental operations the sciatic nerve of a dog was
resected and bridged by a
nerve transplant taken from the ulnar of the opposite side of the same
dog. After thus bridging a
nerve defect, the fascia lata on the side on which the sciatic nerve
was operated upon was
exposed through a long incision, denuded of its subcutaneous covering
and a piece 5 cm. to 6
cm. long and 2 cm. wide excised, rinsed in warm sterile salt solution
and applied as a sheath
inclosing the nerve transplant and the central and distal wounds. A
close-fitting tube was formed
by placing central and distal stay sutures and intervening half
mattress sutures. The inner surface
of the fascia lata was placed adjacent the nerve. The operation was
somewhat tedious and
necessitated the making of three rather extensive surface wounds. The
three wounds were closed
and, in the majority of the experiments, healed by primary union.
Auto-fascial sheaths have been
quite extensively used in surgery otherwise than in connection with
peripheral nerve repair.
Denk 82 used fascia lata tubulization in connection with
cases of neurolysis in the Balkan Wars.
The cases are not discussed and the value of the fascial sheaths is not
clearly brought out. Döpfner 83 and Hirschel 84 advocate the use of fascial sheaths in
nerve repair. Kredel 83 had
opportunity to reoperate a case 24 days after a fascial sheath was
placed about the tibialis which
bad been liberated and longitudinally incised. It was found that the
fascial sheath which had been
loosely applied had contracted so as to fit the nerve closely. He
expresses the fear that a fascial
sheath may contract so as to strangulate the nerve. Kirk and Lewis 88 present a series of
experimental observations in which fascial sheaths were used to form a
tubular suture. It was
found that neuraxes of central origin would pass through the lumen of
the fascial tube to reach
the distal segment. Their experiments conceived for a different purpose
are comparable in so far
as concerns the behavior of a fascial sheath in relation with a wounded
peripheral nerve.
1244
The
protocols of experiments on auto-fascial sheaths for auto-nerve
transplants are as
follows:
PROTOCOLS
EXPERIMENT No. 240.- Dog No. 18; large;
full
grown; 14 days. May 15, 1918, left sciatic exposed and freed.
Right ulnar exposed and freed. Two segments of the right ulnar, each
having 3 cm. length, transplanted to the
resected left sciatic. For each segment, one central and distal suture
of fine Chinese silk placed; good central, "fair"
distal approximation-
FIG. 235.- Cross section of
an auto-nerve
transplant, wrapped in an auto-fascial sheath, Experiment No. 240,
terminated 14 days after operation; formalin fixation iron-hematoxylin
staining. Note the funicular structure of the
two ulnar nerves used as transplants. The tube of fascia is clearly
evident in the figure. Epineural fibrous tissue is materially increased
tion attained. The fascia lata of the
left
leg exposed and a piece 4.5 cm. long and 2 cni.wide exsected and
wrapped
about the nerve transplants and resected. nerve ends, with theinner
surface of the fascia lata adjacent to the nerve.
Central and distal. stay sutures of Chinese silk and two intervening
half mattress sutures placed, forming a fascial
tube. The three wounds closed. May 29, dog found dead in the morning.
The fascial and ulnar wounds open. Sciatic
wound, deep wound healed, superficial wound several stitches have given
away. On exposing the left sciatic, fascial
sheath found well in place; surrounded by newly
1245
formed connective tissue; adherent to
the
surrounding tissue and the underlying muscle. Fascial sheath presents a
glistening white appearance. Deep wound not congested; no distinct
evidence of infection noted. Sciatic and
transplant and fascial sheath removed and fixed in neutral formalin.
Serial sections stained in iron-hematoxylin and
picro-fuchsin.
Microscopic findings.-In longitudinal sections of the central
and distal wound
areas, it is noted that the
distal end of the central stump and the central end of the distal stump
present early degenerative changes of the nerve
fibers. In cross sections of the transplant and the fascial sheath, the
outer surface of the fascial sheath is seen to be
covered with coagulum, extravasated red blood cells, numerous
leucocytes and newly formed connective tissue. The
cross cut transplanted nerves are clearly demarked; their perineural
sheaths appear as thickened. Between the inner
surface of the fascial sheath and the nerve transplants, newly formed connective tissue,
containing
many leucocytes
and phagocytic cells,
FIG.
236.- Cross section of
auto-nerve
transplant wrapped in auto-fascial sheath, Experiment No. 241,
terminated 15
days after operation; formalin fixation, iron-hematoxylin staining. The
very complete auto-fascial tube formed is
evident in the section. Connective tissue proliferation is clearly
recognized but is not excessive observed. The nerve
fibers of the nerve transplant do not present the same type of
degeneration as do the nerve fibers of the distal sciatic;
fragmentation of the myelin not so far advanced.
EXPERIMENT
No. 241.-Dog No. 17; medium size; full grown; 15 days. August 13.1918,
right sciatic
exposed and freed. Left ulnar exposed and freed. A segment of 3.6 cm.
length taken from the left ulnar transplanted
to the resected sciatic. One central and distal waxed, fine silk thread
suture placed; good approximation. A portion of
the fascia lata taken from the right leg of the same dog wrapped about
the transplant and resected nerve ends. Three
half mattress sutures placed. Good fascial tube formed. The three
wounds closed. August 28, killed. Dog not well
since operation. All three wounds in part open; superficial skin
wounds, deep wounds healed. On exposing the right
sciatic, deep wound found healed; appears not to be infected. Fascial
sheath and transplant found well in place.
Fascial sheath surrounded by newly formed connective tissue; adherent
to surrounding tissue; evidence of
sanguineous fluid within the fascial sheath. Sciatic and transplant
1246
plant and fascial sheath removed and
fixed in
neutral formalin. Sections stained in iron-hematoxylin and
picro-fuchin; safranine and licht grün.
Microscopic
findings.-In cross sections of the transplant and the fascial
sheath,
trans- planted nerve found
clearly demarked, its perineural sheaths appear thickened. On both
surfaces of the fascial sheath newly formed
connective tissue, containing leucocytes, extravasated red blood cells,
and coagulum. The tendon cells of the
transplanted fascial sheath present normal shape and staining reaction.
EXPERIMENT No. 242.- Dog No. 40; medium size;
not quite full grown; 22 days. August 19, 1918, right
sciatic exposed and internal popliteal freed. Left ulnar exposed and
freed. A segment of 3 cm. length taken from the
left ulnar transplanted to the right internal popliteal. One central
and distal waxed, fine silk thread suture placed;
approximation not good. Central and distal epineural suture improves
approximation. An auto-fascial sheath taken
from the right fascia lata of the same dog, wrapped about the
transplant and resected nerve ends. One central and
distal stay sutures and three intervening half mattress silk sutures
placed. Good fascial tube formed. The three
wounds closed. September 10, killed. Much emaciated; severe skin
disease; trophic ulcer over right hip. Sciatic
wound not completely healed, several stitches had given away; deep
wound seemed healed. On exposing the right
sciatic, slight evidence of infection of deep wound noted; parts
congested. Transplant and fascial sheath found well
in place, surrounded by connective tissue and adherent to underlying
muscle. External popliteal found adherent to
side of fascial sheath. Sciatic, transplant, and fascial sheath removed
and fixed in neutral formalin. Sections stained
in iron-hematoxylin and picro-fuchsin; safranine and licht grün.
Microscopic findings.-In cross sections of the transplant
and
fascial sheath, fascial sheath found surrounded
by newly formed connective tissues containing numerous leucocytes.
Between transplanted nerve and fascial sheath
newly formed connective tissue, numerous leucocytes, and extravasated
blood cells observed. In longitudinal
sections of the central and distal wound areas, leucocytes and
phagocytic cells especially numerous in the region of
central and distal wounds. Distal nerve in process of degeneration.
Fragmentation of myelin and breaking down of
the nerve fibers of the transplanted nerves not of the same nature as
in distal popliteal; proliferation of sheath cells
not noted.
EXPERIMENT
No. 243.- Dog No. 57; small dog; full grown; 46 days. July 25, 1918,
left sciatic exposed;
internal popliteal freed. Right ulnar exposed and freed. A segment 3.2
cm. length taken from the right ulnar
transplanted to the resected left internal popliteal. Centrally one
through-and-through suture and one epineural
suture, distally one suture of waxed, fine silk thread placed;
approximation good. Adrenalin used; dry field. Fascial
sheath taken from the fascia
lata of the left leg of the same dog wrapped about transplant and
resected nerve ends.
Central and distal stay sutures and three intervening half mattress
sutures placed. Good, even fascial tube formed.
The three wounds closed. Toward the end of July developed skin disease;
had not been well some weeks. September
9, the dog found dead in the morning. On exposing the left sciatic,
external popliteal found free. Moderate increase
of connective tissue about sheath. Distinct central bulb showing
through central end of the fascial tube. Sciatic,
transplant, and fascial sheath removed and fixed in neutral formalin.
Sections stained in iron-hematoxylin and picro-fuchsin; safranine and
licht grün.
Microscopic
findings.- In cross sections through the transplant and the fascial
sheath there is noted a fairly
dense layer of fibrous tissue surrounding the fascial sheath. Sheath in
close relation to perineural sheath of
transplanted nerve segment, very little connective tissue intervening.
Neurolemma sheaths of transplanted nerve
segment evident; appear thickened. Certain ones contain ovoids of
myelin and phagocytes filled with lipoid
granules; others contain syncytial protoplasmic bands; these also
observed outside of neurolemma sheaths. Distinct
central bulb evidenced structurally. Fascial sheath extends over the
central bulb.
EXPERIMENT
No. 244.-Dog No. 55; large, full grown; 47 days. July 22, 1918, left
sciatic exposed and the
internal popliteal freed. The right ulnar exposed and freed. A segment
of 3 cm. length taken from the right ulnar
transplanted to the left internal popliteal. One central and distal
waxed, fine silk thread suture placed; fairly good
approximation
1247
attained. A fascial sheath taken from
the
facsia lata of the left leg of the same dog wrapped about the
transplant and
resected nerve ends. One central and distal stay sutures and two
intervening half mattress sutures placed. Good tube
formed. Dry field. The three wounds closed. September 8, dog found dead
in the morning; much emaciated; skin
disease. On exposing the left sciatic external popliteal found
moderately adherent to the operated internal popliteal;
easily dissected. Fascial sheath found well in place, distinct increase
of connective tissue about it; adherent to
underlying muscle. Distal internal popliteal present a distinct,
light-yellow color. Nerve and transplant and the facial
sheath removed and fixed in neutral formalin. Sections stained in
iron-hematoxylin and picro-fuchsin ; safranine and
licht grün.
Microscopic
findings.- In cross sections of transplanted nerve and sheath, it
is
observed that a relatively
thick laver of fibrous tissue surrounds fascial sheath. Between the
fascial sheath and the transplanted nerve, and
blending with the perineural sheath of the same, distinct layer of
fairly dense fibrous tissue. In longitudinal sections
embracing central and distal wounds, numerous leucocytes observed
within the fascial sheath. In cross sections of
the nerve transplant, increase in the amount of endoneural connective
tissue noted. Within the old neurolemma
sheaths, in many instances, one, two, three, or four small medullated
fibers observed; other neurolemma sheaths
distended with detritus derived from breaking down nerve fibers.
Numerous nucleated, syncytial protoplasmic
strands noted within the transplant in longitudinal sections of the
same.
EXPERIMENT
No. 245.- Dog No. 38; medium size; full grown; 61 days. June 21, 1918, left sciatic
exposed; internal popliteal freed. The right ulnar exposed and freed. A
segment of 2.5 cm. length taken from the
right ulnar transplanted to the left internal popliteal. One central
and distal waxed, fine silk thread suture placed;
good approximation. Fascial sheath taken from the fascia lata of the
left leg of the same dog wrapped about the
transplant and resected nerve ends. One central and distal stay suture
and one half mattress suture placed. Adrenalin
used to control oozing. The three wounds closed. August 22, dog used in
the morning for another operation; found
dead 1.30 p. in.; did not recover from second operation. Dog in good
condition; slight toe-drop left hind foot;
neurotrophic ulcer dorsum of left foot. Sciatic and other wounds well
healed. On exposing the left sciatic, the
external popliteal found firmly adherent to the fascial sheath about
operated internal popliteal. Fascial sheath clearly
demarked; marked increase of connective tissue about it. Distinct
central bulb evident through proximal end of the
fascial sheath. Calf muscles found very atrophic. Nerve and the fascial
sheath removed and fixed in ammoniated
alcohol for piridine-silver staining. Quite good differential silver
staining attained.
Microscopic
findings.-In cross sections of the transplant and the fascial
sheath, sheath found in close
relation to the transplanted nerve segment; a thin layer of fibrous
tissue surrounds the sheath. Endoneural connective
tissue of the transplant distinctly increased. New neuraxes, which in
longitudinal sections of the central wound can
be traced from the distal end of the bulbous enlargment into the
transplant, in cross sections are found arranged in
the form of numerous very small nerve funiculi, often containing only a
few nerve fibers, and without special
fibrous
sheath, but separated by endoneural connective tissue. New neuraxes
traced through the transplant and through distal
wound into the distal stump. In cross sections of the distal popliteal,
scattered neuraxes found in all of its funiculi, in
many instances more than one in old neurolemma sheath. Beginning
regeneration of distal popliteal through
transplant attained.
EXPERIMENT
No. 246.-Dog No. 41; small dog; full grown; 31 days. July 28, 1919,
left sciatic exposed;
internal popliteal freed. Right ulnar exposed and freed. A segment of
the right ulnar of 3.5 cm. length transplanted to
the resected left internal popliteal. One central and distal waxed,
fine silk thread suture placed. Good central
approximation; distal partly pulled out as the sheath was being
applied, a fascial sheath taken from the left fascia lata
of the same dog wrapped about the transplant and resected nerve ends.
One central and distal stay suture and one
half mattress suture applied. Good fascial tube formed. Wounds clean
and dry. All three wounds closed. August 28,
dog found dead in the morning; had not been well for some time; much
emaciated; small neutrophic
1248
ulcer on dorsum of left foot. On
exposing the
left sciatic, external potpliteal found quite adherent to fascial
sheath.
Fascial sheath well in place;- moderate increase of connective tissue
about it noted. Found loosely adherent to
underlying muscle. Sciatic and transplant with fascial sheath removed
and fixed in ammoniated alcohol for pyridine-silver staining. Only fair
differential neuraxis staining attained. Tissues not well embedded;
sections much torn.
Microscopic
findings.-In cross sections of the transplant and the fascial
sheath, it is found that
the
sheath is
surrounded by dense layers of fibrous tissue. Sheath in close relation
to nerve transplant, very little connective tissue
intervening. The transplanted nerve presents areas in which the old
neurolemma sheaths are either broken down or
distended with detritus and phagocytic cells with lipoid globules. Only
a few neuraxes can be traced from the distal
end of the central stump, through the transplant, to the distal
popliteal. This is no doubt in part accounted for by the
imperfect differentiation of neuraxes attained in the pyridine-silver
staining.
EXPERIMENT
No. 247.- Dog No. 4; medium size; full grown; 66 days. June 13, 1918,
right sciatic
exposed; internal popliteal freed. Left ulnar exposed and freed. A
segment of2.5 cm. length taken from the left ulnar
transplanted to the resected right internal popliteal. One central and
distal waxed, fine silk thread suture placed;
good approximation. A fascial sheath taken from the right fascia lata
of the same dog wrapped about the transplant
and the resected nerve ends. One central and distal stay suture and
three intervening sutures placed. Wound not quite
dry, slight oozing, which was not fully controlled. The three wounds
closed. August 18, killed. Much emaciated; had
not been active for several days; no neurotrophic changes right hind
foot. On exposing the right sciatic, the external
popliteal is found adherent to the fascial sheath. Fascial sheath found
well in place; forms closely fitting tube,
surrounded by fibrous tissue; only moderately adherent to underlying
muscle. Quite distinct central bulb, evident
through the transplant. Sciatic and transplant with fascial sheath
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Distal posterior tibial fixed in neutral
formalin. Good differential neuraxis staining attained.
Tissues not well embedded; sections torn.
Microscopic findings.-In cross sections of the nerve
transplant
and the fascial sheath, it may be observed
that the sheath is surrounded by a relatively thick layer of fairly
dense fibrous tissue. In alternate cross and
longitudinal sections of operated nerve, it may be seen that neuraxes
pass from the distal end of the central bulb,
through the transplant into the distal popliteal.
EXPERIMENT No. 248.- Dog No. 40; medium size;
dog not quite full grown; 65 days. July 7, 1918, ]eft
sciatic exposed; internal popliteal freed. Right ulnar exposed and
freed. A segment of 3.0 cm. length taken from the
right ulnar transplanted to the resected left internal popliteal. One
central and distal suture of No. 00 catgut placed.
Approximation not satisfactory; not as good as when waxed, fine silk
thread is used for suture. A fascial sheath
taken from the left fascia lata of the same dog wrapped about the
transplant and resected nerve ends. Central and
distal stay sutures and one intervening suture all Of fine silk thread
placed. Good fascial tube formed. Dry wound.
The three wounds closed. September 10, killed. Dog much emaciated,
severe skin disease. On exposing the left
sciatic, external popliteal found adherent along side of the fascial
sheath. Fascial sheath found well in place; its
proximal and distal ends not clearly demarked; moderate increase of
connective tissue about it; adherent to
underlying muscle. No distinct central bulb made out. Calf muscles
exposed; atrophic; do not respond when nerve is
cut. Sciatic and the transplant. with the fascial sheath removed and
fixed in ammoniated alcohol for pyridine-silver
staining. Very good differential neuraxes staining attained.
Microscopic
findings.- Only indistinct central bulb evidenced structurally. In
cross sections of the transplant
and sheath, sheath is found surrounded by a relatively loose layer of
fibrous tissue. The transplanted nerve clearly
demarked, its perineural sheath not materiallv thickened, between these
perineural sheaths and the inner surface of
the fascial sheath a layer of loose fibrous tissue. In the transplanted
nerve many new neuraxes, singly or in small
bundles, observed; endoneural connective tissue only moderately
increased. These
1249
new neuraxes can be traced through the
transplant and distal wound into the distal popliteal to the level of
the calf
muscles. Partial regeneration of the distal popliteal attained.
EXPERIMENT No. 249.-Dog No. 17; medium size,
full grown; 106 days. May 14, 1918, left sciatic
exposed. Right ulnar exposed. Two segments, each measuring 1.6 cm.
taken from the right ulnar transplanted to the
resected right sciatic. One central and distal suture of fine Chinese
silk for each segment placed; only fair
approximation attained. A fascial sheath taken from the fascia lata of
the left side of the same dog wrapped about the
transplants and the resected nerve ends. One central and distal stay
suture and continuous over and over suture
between, placed. The three wounds closed. All wounds healed well.
August 28, killed. Dog had not been well for
some time; nearly moribund when killed. On exposing the left sciatic,
moderate increase of connective tissue about
tile transplant is found; adherent to underlying muscle. Fascial sheath
distinctly evident; its central and distal limits
not distinctly made out. Nerve distal to transplant presents the
appearance of normal nerve. On exposure, the calf
muscles seem still somewhat atrophic and are of pale red color. On
slowly cutting the sciatic central to sheath and
transplant, no contraction of calf muscles; this may in part be
accounted for by condition of dog when killed. Sciatic
with the transplant and sheath removed and fixed in ammoniated alcohol
for pyridine-silver staining. Good
differential neuraxis staining attained.
Microscopic
findings.-Distinct central bulb evidenced structurally. In cross
sections of the transplants and
sheath, the fascial sheath appears not to have been reduced in
thickness and is found surrounded by a layer of
relatively dense fibrous tissue. The two transplanted ulnar segments
clearly demarked within the fascial tube. Their
perineural sheath relatively thick, but the funicular structure is not lost.
Very
little connective tissue found between
the perineural sheaths and the fascial sheath. Each of the transplant
nerve segments, as seen in cross sections,
contains numerous new neuraxes; in about equal number in two nerve
segments. These neuraxes can, in sections, be
traced through the distal wound to the distal sciatic, found
approximately equally distributed through its several
funiculi. Regeneration of the central end of distal sciatic attained.
EXPERIMENT
No. 250.- Dog No. 42; large dog; full grown; 268 days. August 21, 1918,
right sciatic
exposed; internal popliteal freed. Left ulnar exposed and freed. A
segment of3 cm. length taken from the left ulnar
transplanted to the right internal popliteal. One central and distal
waxed, fine silk thread suture placed. Centrally
good approximation; distally a second, an epineural, suture placed;
approximation fair. Fascial sheath taken from the
fascia lata of the right side of the same dog, wrapped about transplant
and the resected nerve ends. Central and distal stay sutures and five
intervening
half mattress sutures placed. Good tube formed. The three wounds
closed. May 16,
1919, killed. Dog in good condition; walks well, but does not climb
stairs as easily as normal dog; no neurotrophic
changes right hind foot. On exposing the right sciatic external
popliteal bundle found free. Quite marked increase of
connective tissue about the transplant noted, so that fascial sheath is
not clearly made out. Calf muscles exposed;
these have the appearance and size and color of normal muscle. Cutting
of nerve central to transplant causes good
contraction of calf muscles; movement of toes feeble and indistinct.
Nerve and transplant with sheath fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
silver staining attained.
Microscopic
findings.- In cross sections of the transplant and sheath, fascial
sheath is clearly demarked; does
not appear to have been reduced in thickness by absorption; surrounded
by a relatively dense layer of fibrous tissue,
containing here and there small lobules of adipose tissue. The
transplanted ulnar segment presents a funicular
structure with perineural sheaths thickened, and endoneural connective
tissue materially increased. A loose
connective tissue intervenes between perineural sheaths and fascial
sheath; in this there may be observed numerous
small funiculi of nerve fibers delimited peripherally by the fascial
sheath. The funiculi of the transplanted nerve
contain numerous new neuraxes scattered or in small bundles. In series
of alternate cross and longitudinal sections,
new neuraxes can be traced to the distal popliteal in which, in each of
the several funiculi, there may be observed
numerous both myelinated and nonmyelinated nerve fibers. Very complete
regeneration of the distal popliteal
through the transplant attained.
1250
EXPERIMENT No. 251.-Dog No. .39; medium
size;
full grown; 276 lays. August 14, 1918, right sciatic
exposed; internal popliteal freed. Left ulnar exposed and freed. A
segment of 3.5 cml. length taken from the left
ulnar transplanted to the resected right internal popliteal. One
central and distal waxed, fine silk thread suture placed;
good approximation, Fascial sheath taken from the right fascia lata of
the same dog wrapped about the transplant
and the resected nerve ends. The piece of fascia cut a little too
narrow at one end so that complete fascial tube could
not be made. Central and distal stay sutures and two intervening half
mattress sutures placed. Three wounds closed. May 16, 1919, killed. Dog
in very good condition; used right hind leg and foot well; no
neurotrophic changes. On
exposing the right sciatic, the external popliteal found free. Operated
internal popliteal in
FIG.
237.-Cross section of
auto-nerve
transplant, wrapped in auto-fascial sheath, Experiment No. 2,50,
terminated
268 days after the operation. Nerve funiculi of transplant are
maintained and fully neurotized. Auto-fascial sheath
still distinctly evident somewhat over six months after operation
the region of the transplant and sheath
surrounded by quite dense connective tissue and adherent to the
underlying
muscle. Fascial sheath not clearly made out. Calf muscles exposed;
these have appearance, both as to size and
color, of normal muscle. Sciatic freed from bed and external popliteal
resected. On slowly cutting with scissors
nerve central to the transplant, good contraction of calf and foot
muscles noted. Sciatic, transplant and sheath
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Good differential neuraxis staining attained.
Microscopic
findings.-In cross sections of the transplant and
sheath, the
fascial sheath is found well in
place; appears not to have been reduced in thickness by absorption;
presents essentially the same structure as in
short-time experiments of this series; surrounded by a
1251
distinct layer of fibrous tissue in
which
many fat cells are seen. The transplanted nerve segment is clearly
demarked,
having retained its funicular structure. The perineural sheaths of
transplant found thickened and for nearly the whole
circumference in relation with inner surface of the fascial sheath;
very little connective tissue intervening. New
neuraxes traced from central stump through the transplant into distal
popliteal in which are found numerous
myelinated and nonmyelinated nerve fibers arranged singly or in small
bundles and separated by endoneural
connective tissue which is distinctly increased in amount. Almost
complete regeneration of the distal popliteal
through the transplant attained.
EXPERIMENT
No. 252.-Dog No. 42; large dog; full grown; 318 days. July 2, 1918,
left sciatic exposed;
internal popliteal freed. Right ulnar exposed and freed. A segment of
3.6 cm. length of right ulnar transplanted to the
resected left internal popliteal. One central and distal waxed, fine
silk thread suture placed; good approximation.
Fascial sheath taken from the left fascia lata of the same dog wrapped
about transplant and the resected nerve ends.
One central and distal stay suture, no intervening sutures placed. Good
tube formed. Field not quite dry; oozing
controlled by use of adrenalin. The three wounds closed. May16, 1919,
killed. Dog in very good condition, walks
well but does not climb stairs as easily as normal dog; no neurotrophic
changes left hind foot. Left sciatic exposed;
skill adherent along wound line. External popliteal found free.
Operated internal popliteal, transplant and sheath
surrounded by quite dense layer of connective tissue and adherent to
underlying muscle. Fascial sheath not clearly
made out. Calf muscles exposed; these have the appearance and size of
normal muscle. Cutting of sciatic, after
removing external popliteal and removing nerve from bed, central to the
transplant, calls forth good contraction of
calf and foot muscles. Sciatic, transplant and sheath removed and fixed
in ammoniated alcohol for pyridine-silver
staining. Good differential neuraxis staining attained.
Microscopic
findings.-Structural evidence of well-developed central bulb.
Down-growing central neuraxes
cross and recross distal part of the bulbous enlargement; evidence of
resistance spiral noted. Many neuraxes
observed as passing to central end of transplant. In cross sections of
the transplant and sheath, fascial sheath is
clearly made out for the greater part of the circumference, to one
side, it would appear that the lip of the fascial
sheath separated, admitting an ingrowth of connective tissue. The
transplanted nerve segment clearly demarked, with
funicular structure retained. Fairly dense connective tissue intervenes
between the several funiculi and the inner
surface of the fascial sheath. Numerous myelinated and nonmyelinated
neuraxes are transmitted by the transplant to
the distal popliteal, cross and longitudinal sections of which present
an appearance which resembles that of a nearly
completely regenerated nerve.
EXPERIMENT
No. 253.-Dog. No. 39; medium size; full grown; 326 days. June
24,1918, left sciatic exposed; internal popliteal freed. Right ulnar
exposed and freed. A segment of 3.2 cm. length of
the right ulnar transplanted to the left internal popliteal. On central
and distal waxed, fine silk thread suture placed;
good approximation. Fascial sheath taken from the left fascia lata of
the same dog wrapped about transplant and the
resected nerve ends. One central and distal and two intervening half
mattress sutures placed. Good tube formed.
Wound not quite dry; oozing controlled by use of adrenalin. The three
wounds closed. May 16, 1919, killed. Dog in
very good condition; rises left leg well; no neurotrophic changes. On
exposing left sciatic, external popliteal found
free. Operated internal popliteal surrounded by relatively dense layer
of fibrous tissue, adherent to underlying
muscle. Distal nerve has the appearance of normal nerve. Calf muscles
exposed; these have the appearance of
normal muscle. After freeing sciatic from bed and cutting the external
popliteal, slowly cutting with scissors the
sciatic central to trans-plant, calls forth good contraction of calf
and foot muscles. Nerve, transplant and sheath removed and fixed in
ammoniated alcohol for pyridine-silver staining. Good differential
neuraxes staining attained.
Microscopic findings.-Central neuraxes pass without special
line
of demarcation to trans-plant. In cross
sections of transplant and sheath, fascial sheath found well in place
and not materially reduced in thickness through
absorption; covered on its outer surface by distinct layer of fibrous
tissue. The transplanted nerve segment clearly
demarked; perineural sheath thickened, these in close relation to inner
surface of the fascial sheath. Numerous small
1252
funiculi of nerve fibers in the
connective
tissue within the fascial sheath, but outside of perineural sheath,
observed;
especially to one side. Numerous neuraxes, both myelinated and
nonmyelinated, transmitted by the transplant to the
distal popliteal, which in cross and longitudinal sections presents the
appearance of a nearly completely regenerated
nerve.
The
experiments of Series No. 17, 14 in number, are sufficiently varied as
to time under
observation and sufficiently numerous to admit of formulating certain
general deductions
relative to auto-fascial sheaths. Experiments No. 250 to No. 253 were
under observation for
periods varying, respectively, from somewhat over 8 months to nearly 11
months, and in each of
these experi-ments it is noted that the fascial sheath could be clearly
made out in microscopic
sections of the transplant region. These four experiments were studied
chiefly with reference to
the behavior of the down-growing neuraxes, which were thus fixed for
pyridine-silver staining.
In preparations stained after this method the fascicular structure of
the transplanted fascial
sheaths could be clearly made out, the cellular elements were not
clearly differentiated.
Therefore it can not be stated whether the fixed connective tissue
cells-tendon cells-of the fascial
sheaths were maintained after transplantation. Lewis and Davis 87 have shown that a fascial tube
remains patent for an extended period. In a case in which a fascial
tube was used in tendon
repair, the sheath was evident 255 days after the operation. In these
experiments of long duration
there is no distinct evidence of a secondary contraction of the fascial
tube. There is found a layer
of areolar tissue between the inner surface of the fascial sheath and
the perineural sheaths of the
funiculi of the transplanted nerve segments. This varies in thickness
in the several experiments
and also indifferent regions of the same experiment. The newly formed
nerve fibers found within
the funiculi of the nerve transplant are of normal appearance and were
especially numerous in
Experiment No. 253, terminated 326 days after the operation at which
the fascial sheath was
placed. In this experiment the fascial sheath was well maintained and
there was found relatively
little loose areolar tissue within the fascial sheath. The contraction
noted by Kredel 85 in the case
of neurolysis of the tibialis in which the fascial sheath was found
contracted 24 days later is not
conclusive. It may be asked whether the correct operative procedure was
undertaken in the first
place. It may be repeated that these experiments seem to indicate that
there is relatively little
secondary contraction of a fascial sheath. From the experiments here
reported it is evident that
an auto-fascial sheath of fascia lata does incite connective tissue
proliferation even in an aseptic
wound in healthy tissue, a wound passing in the main through
intermuscular planes. It seems
quite impossible to remove a piece of fascia lata without having
extravasated blood cells and
tissue fragments adhere especially to its outer surface, the more so if
a layer of subcutaneous fat
is removed with the fascia, as has been recommended. The inner surface
is quite smooth if the
portion removed is correctly oriented. In all of our experiments a
distinct development of fibrous
tissue is noted surrounding the fascial sheath. This layer is quite
cellular in the experiments of
short duration and in it there are found many leucocytes and
extravasated red blood cells.
Incertain of the experiments the fascial sheath was found adherent to
the muscle bed, to the
extent necessitating dissection; this shows connective tissue
proliferation.
1253
This newly
formed connective tissue surrounding the fascial sheaths, even in
aseptic
wounds in healthy tissue, on subsequent contraction and cicatrization
may be regarded as having
deleterious effect on the structural and functional regeneration of an
injured nerve, sheathed by
fascial sheath, rather than the secondary contraction of the fascial
sheath itself. While thus
inciting connective tissue growth, the fascial sheath does appear to
retard the growth of
connective tissue into the central and distal wound and the immediate
environs of a nerve
transplant. Experiment No. 252 bears on this indirectly. In this
experiment, studied 318 days
after the primary operation, the fascial tube appears to have opened
along the side. There was an
ingrowth of connective tissue through this cleft, to the extent that a
fairly dense layer of con-nective tissue intervenes between the nerve
funiculi and the inner surface of the fascial sheath,
much more so than when the fascial sheath remained closed in tube form
as in the majority of
the experiments. However, even in this experiment there was found good
neurotization of the
distal segment through the nerve transplant.
The
general conclusion seems warranted that an auto-fascial sheath is very
slowly
absorbed, evidence of its persistence having been noted nearly a year
after it was placed at
operation in the wound in healthy tissue. However, even in aseptic
wounds in healthy tissue
there is noted a distinct proliferation of the surrounding connective
tissue, which would
prejudice against the use of fascial sheaths in connection with
operations of nerve repair,
especially where such operations pass through cicatricial tissue. It
would appear that auto-fascial
sheaths incite more connective tissue proliferation than does
alcoholized Cargile membrane, the
application of which is technically much simpler and serves every
purpose that could be gained
on use of a fascial sheath.
SERIES NO. 18
AUTO-NERVE TRANSPLANTS WRAPPED IN
FORMALIZED
ARTERIAL SHEATHS
This
short series of experiments was suggested through records of clinical
and
experimental observations in which arteries or veins, used either fresh
or after fixation and taken
as auto-, homo-, or heterogenous vessels were placed asa wrapping or as
a tube to ensheath the
suture lines in operations for repair of peripheral nerves. To review
in extenso the literature
involved is not here justifiable. The brief experimental observations
of Foramitti, 88 have
influenced later operators and experimenters and may thus be given
brief consideration here, the
more so since we have followed his method of preparing arterial tubes.
though Büngner 27 some years earlier had used a segment of a sterilized human brachial
artery to bridge a nerve
section. We shall consider "tubular sutures"under Series No. 20, in
connection with which series
the bridging of nerve defects by means of tubular structures will be
considered. Ensheathing a
nerve suture after severance, or a nerve transplant with a tubular
structure is not a " tubular suture" in the
correct use of this term. Three animals were operated by Foramitti.
Both
fresh and hardened arteries were used, either applied to a liberated
nerve, by cutting the vessel
wall longitudinally and slipping the vessel wall over one end of a
resected nerve, making a
central nerve flap and moving the arterial
1254
segment so as to cover
the field of operation: Or. as a tubular suture. The longest
observation,
that of tubular suture, extended only six weeks. Foramitti found that
on use of both fresh an(l
hardened arteries, the inclosed peripheral nerve tissues was only
lightly adherent to the wall of
the artery. The experiments of Foramitti are not conclusive and leave
further doubt when he
states "die physiologische Function des Nerven war hergestellt," in
speaking of a section and
sutured sciatic of the dog studied three weeks after operation. We have
used in this series only
prepared arterial walls, taken from the carotid of large dogs, and used
for the purpose of making
a tubular sheath after nerve transplantation. The arteries used were
prepared as follows: The
carotids of large dogs were stretched over glass tubes of suitable
size, were then fixed in 5 per
cent to 10 per cent formalin solution for 48 hours, washed in water
for 24 hours, boiled in
distilled water for 20 minutes, and then stored in 70 percent to 95
percent alcohol. They were
stored on glass rods in the alcohol in wide mouthed, glass-stoppered
bottles, for several days to
several weeks depending on the time when they were used at operation.
Before use at operation
an arterial segment of required length was slipped from the glass rod,
cut longitudinally along a
line and placed in sterile salt solution for about 30 minutes. The
arterial sheath thus prepared
was then wrapped about the nerve transplant, sutured in place and
allowed to extend 5 mm. to 8
mm. over the central and divided suture lines, and was fixed in place
by central and distal stay
sutures and intervening half mattress sutures, using for suture fine,
waxed silk thread. Experiments with fresh arteries or veins used as
sheaths were not made: neither have we tested
autogenous nor heterogenous vessels. Foramitti recommended the use of
formalized arteries of
the calf. With the treatment given the tissue, namely, formalin
fixation, boiling for 20 minutes
and storage in 95 percent alcohol, it is to be questioned whether
homogenous vessels obtained
from amputations or even at autopsy (in selected cases) could not be
used for ensheathing
operated nerves in human surgery. The experiments of Eden 89 of
inserting the central and distal
ends of the resected anterior crural through fine slits into the
femoral artery or vein, with the
circulation maintained, did not seem to us worthy of repetition.
The
protocols of experiments on the use of formalized arterial walls for
the purpose of
ensheathing nerve transplants are as follows:
PROTOCOLS
EXPERIMENT
No. 254.- Dog No. 50; large dog; full grown; 6 days. July 17, 1918,
left
sciatic exposed;
internal popliteal freed. Right ulnar exposed and freed. A segment of 3
cm. length transplanted to the resected left
internal popliteal. One central and distal waxed, fine silk thread
suture placed; centrally fair, distally good
approximation attained. A segment of formalized artery of a dog, split
longitudinally along one side, placed so as to
surround the transplant and the resected nerve ends. A central and
distal stay suture and three intervening half
mattress sutures placed. Adrenalin used to obtain dry field. Wounds
closed. July 23, dog found dead in the morning.
The superficial wound seemed healed. On reopening wound, evidence of
infection noted in deep wound; parts
congested. Transplant and tube surrounded by sanguineous exudate.
Arterial sheath found well in place. The nerve
transplant and the arterial sheath removed and fixed in neutral
formalin. Sections stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
1255
Microscopic findings.- As seen in cross sections of the
transplant
and sheath, arterial sheath forms a well-closed tube with edges
overlapping. About the sheath blood coagulum, tissue detritus, numerous
wandering
leucocytes and phagocytes. Within the sheath relatively few leucocytes.
In longitudinal sections of the region of the
central and distal wounds leucocvtes have penetrated for a distance
into the central and distal stump, and central and
distal ends of the transplant, where they are found between the nerve
fibers as also within the neurolemma sheaths.
The nerve fibers of the transplanted nerve segment present little
evidence of beginning degeneration. Their myelin
sheaths stain pale, but as yet no distinct evidence of myelin
fragmentation. Proliferation of sheath cell nuclei not
observed.
EXPERIMENT No. 255.-Dog No. 48; medium size;
full grown; 57 days. July 15, 1918, left sciatic
exposed; internal popliteal freed. Right ulnar exposed and freed. A
segment of 2.5 cm. length of right ulnar
transplanted to the resected left internal popliteal. One central and
distal waxed, fine silk thread suture placed; good
approximation. An arterial sheath, formed by cutting longitudinally a
segment of formalized carotid artery of a dog
and wrapped about transplant and resected nerve ends placed. One
central and distal stay suture and two intervening
half mattress sutures used. Good tube formed. Dry field after using
adrenalin. Wounds closed. September 10, dog
found dead in the morning; much emaciated. On exposing the left
sciatic, arterial sheath is found well in place.
Proximal and distal ends of sheath covered with connective tissue and
adherent to epineural sheath of the resected
nerve. No material increase of connective tissue about sheath. Nerve,
transplant and sheath fixed in neutral formalin.
Sections stained in iron-hematoxylin and picro-fuchsin; safranine and
licht grün.
Microscopic
findings.-In cross sections of sheath and transplant, arterial
sheath clearly recognized in
sections; centrally the lips of the arterial sheath have rolled in so
that to one side of the transplanted nerve a segment
is exposed; distally arterial sheath forms a tube completely inclosing transplant. In
section it may be
observed that
the elastic tissue of the intima and media, and the fibrous tissue of
the adventitia are best preserved; the in- voluntary
muscle of the media still recognizable, though many muscle cells appear
fragmented. Only a thin layer of fibrous
tissue surrounds the arterial sheath. The transplanted nerve segment
has retained its funicular structure, with
perineural sheaths materially thickened. Dense fibrous tissue
intervenes between nerve and arterial sheath, especially
centrally, where sheath is incomplete. Many small medullated fibers
found within the transplant.
EXPERIMENT No. 256.-Dog No. 45; small dog;
full grown; 63 days. July 12, 1918, left sciatic exposed;
internal popliteal freed. Right ulnar exposed and freed. A segment of
the right ulnar of 3 cm. length transplanted to
the resected left internal popliteal. One central and distal waxed,
fine silk thread suture placed. Centrally fair, distally
good approximation attained. An arterial tubular sheath formed by
splitting longitudinally a segment of formalized
carotid artery of a dog, and wrapping the same about the transplant and
the resected nerve ends. Stay sutures and two
intervening half mattress sutures placed. Good tube formed. Wounds
closed. September 13, dog nearly moribund;
killed. Much emaciated; severe skin disease. On exposing left sciatic,
arterial sheath is found well in place. The two
half mattress sutures appear to have given away, since a slit can be
recognized along one side of "tube," for nearly its
whole length. No material increase of connective tissue about the
sheath. Nerve, transplant, and arterial sheath
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Only faint silver staining attained; especially
in the region of the transplant.
Microscopic
findings.-In cross sections, it may be observed that the arterial
sheath forms a closely fitting
tube surrounding the transplant. A very thin fibrous tissue sheath
surrounds the arterial sheath. Arterial wall not so
clearly defined in silver-stained preparations as when other fixatives
and certain other staining methods are used.
However, in the silver preparation it is possible to differentiate the
arterial wall and especially its elastic tissue. The
perineural sheath of the transplanted nerve segment in close relation
to the inner surface of the arterial sheath, very
little connective tissue intervening. In series of longitudinal and
cross sections, it is possible to trace numerous
neuraxes from the central
1256
stump through the transplant and distal
wound
to the distal popliteal in which a few scattered neuraxes can be
traced distally for a distance of about 2 cm.
EXPERIMENT
No. 257.- Dog No. 49; medium size; full grown; 117 days. July 16, 1918,
left sciatic
exposed; internal popliteal freed. Right ulnar exposed and freed. A
segment of the right ulnar of 3.5 cm. length
transplanted to the resected left internal popliteal. One central and
distal waxed, fine silk thread suture placed; good
approximation. An arterial sheath made by cutting longitudinally along
one side, a segment of a formalized carotid
artery of a clog and wrapping same about transplant and resected nerve
ends. Stay sutures and three half mattress
sutures placed. Good tube formed. Dry field obtained after using
adrenalin. Wounds closed. November 10, dog
found dead in the morning, much emaciated; severe skin disease. Oni
exposing the left sciatic, arterial sheath found
well in place; no material increase of connective tissue about sheath.
No distinct central bulb noted. Condition of calf
muscles not recorded. Nerve, transplant, and sheath removed and fixed
in ammoniated alcohol for pyridine-silver staining. Faint but fairly good differential neuraxis staining
attained.
Microscopic findings.-In cross sections of the transplant
and
sheath, it is observed that arterial sheath forms
complete tube about transplanted nerve segment and is surrounded by
only a thin layer of fibrous tissue. Sheath in
close relation with the perineural sheaths of the transplanted nerve
segment, the funicular structure of which is
retained; the endoneural connective tissue of the funiculi materially
increased. In alternate cross and longitudinal
sections, numerous new nueraxes may be traced from the central stump
through the transplant to the distal popliteal.
EXPERIMENT
No. 258.- Dog No. 43; small dog; full grown; 130 days. July 11, 1918,
left sciatic freed.
Right ulnar freed. A segment of the right ulnar of approximately 3 cm.
length transplanted to the resected left sciatic.
One central and distal waxed, fine silk thread suture placed.
Approximation fair; a small amount of blood exudate in
central nerve wound. An arterial sheath made by splitting
longitudinally a segment of a formalize carotid artery of a
dog and wrapping same about the transplant and the resected nerve ends.
Stay sutures and several mattress sutures
placed. Good tube formed. Wounds closed. November 18, dog seemed fairly
well in the morning; found dead 4 p.
m.; seemed in good condition; well nourished; no neurotrophic changes
on left foot. On exposing the left sciatic,
arterial sheath found well in place, moderate increase of connective
tissue about it. No distinct central bulb, only
slight enlargement noted. Calf muscles exposed; these slightly
atrophic, but of good color. Nerve, transplant, and
sheath removed and fixed in ammoniated alcohol for pyridine-silver
staining. Good differential silver staining
attained.
Microscopic findings.- In cross sections of the transplant
and
sheath, arterial sheath is found to have been
well maintained; forming closely fitting tube about the transplant;
with scarcely any connective tissue between
transplanted nerve segment and inner surface of sheath and only a thin
layer of fibrous tissue surrounding it. In cross
and longitudinal sections, it is to be observed that new neuraxes in
large numbers may be traced from the central
stump through the transplant to the distal popliteal in which numerous
neuraxes are found in its peripheral
distribution, namely, to the posterior tibial several centimeters above
the heel and into the small interfascicular nerve
branches in the calf muscles. Regeneration of distal popliteal through
the transplant attained.
EXPERIMENT
No. 259.- Dog No. 44; small dog; full grown; 243 days. July 12,
1918, left sciatic exposed;
internal popliteal freed. Right ulnar exposed and freed. A segment of
the right ulnar of 3 cm. length transplanted to
the resected left internal popliteal. One central and distal waxed,
fine silk thread suture placed. Central suture gave
way; resutured, one through-and-through suture and one epineural
suture; central approximation fair, distal good. An
arterial sheath made by splitting longitudinally a segment of the
formalized carotid artery of a dog and wrapping the
same about the transplant and the resected nerve ends. Two stay sutures
and three half mattress sutures placed. Good
tube formed. Dry field after use of adrenalin. Wounds closed. March 12,
1919, killed. Dog in good condition; no
neurotrophic changes left foot; uses left hind foot and leg well. On
exposing the left sciatic no macroscopic evidence
of arterial sheath found. No material increase of connective tissue
about operated internal popliteal; nerve only
moderately adherent to underlying
1257
muscle. Only small central bulb noted.
Calf muscles exposed; these present the appearance of normal muscle.
After freeing the operated nerve from bed and slowly cutting with
scissors central
to the
transplant good contraction
of calf muscles observed, but only feeble and indistinct movement of
the toes noted. Nerve and transplant removed
and fixed in ammoniated alcohol for pyridine-silver staining. Good
differential neuraxis staining attained.
Microscopic
findings.-Scarcely any structural evidence of a central bulb noted.
In longitudinal sections of
the central and distal wound region and in cross and longitudinal
sections of the transplant no distinct structural
evidence of the arterial sheath noted. In the silver stained
preparations the presence or absence of the sheath is not
readily determined. The transplant and regions of the nerve wounds
surrounded by a relatively thin layer of fibrous
tissue in which no clear determination of the elastic tissue of the
arterial sheath could be gained. In cross sections of
the transplant it is to be observed that the endoneural connective
tissue is very materially increased. The numerous
neuraxes, which can be traced from the central stump through the
transplant, within the transplant are found arranged
in small funiculi, separated by endoneural connective tissue. These
neuraxes can be traced to the distal popliteal, in
which they are found in large numbers. Very complete regeneration of
the distal popliteal through the transplant
attained.
This
series of experiments is unsatisfactory to the extent that such a large
per cent of the
experimental animals died from intercurrent disease not related to the
experiments, that a
function test could not be made in certain of the experiments in which
such test would have been
desirable. The whole series could be and was used to determine
morphology. It was found, confirming Foramitti, that a formalized
arterial tube incites relatively little connective tissue
proliferation when placed in normal tissue in aseptic wounds. In the
experiments of long
standing, the arterial tube was found surrounded by only a relatively
thin layer of fibrous tissue
which was only loosely adherent to adjacent connective tissue. Between
the perineural sheath of
the funiculi of the transplanted nerve segment and the inner surface of
the arterial sheath there
was found only a relatively small amount of areolar tissue. The
arterial sheath was clearly made
out macroscopically in Experiment No. 258 somewhat over four months
after it was placed
about the operated nerve. It is more particularly the elastic tissue of
the vessel wall that resists
absorption, forming a compact tubular structure easily recognized in
cross sections of the
transplant. There is no evidence of a secondary contraction of the
vessel wall after it is placed in
the tissue. It is recognized, of course, that a tubular structure which
persists for a period of
approximately 4 months has fulfilled any useful purpose which may be
hypothecated to it, when
considered in connection with the wound region in a peripheral nerve.
In Experiment No. 259, of
nearly 8 months' duration, the arterial sheath used at the operation
could not be made out
macroscopically nor was it recognized in sections, stained after the
pyridine-silver method. The
neurotization of the distal segment was very satisfactory in all of the
experiments in which an
auto-nerve transplant was ensheathed in a formalized arterial tube,
especially so in experiments
observed for a time sufficient to admit of downgrowth of central
neuraxes. Attention is particularly called to the protocols of
Experiments Nos. 258 and 259 in this regard. Since formalized
arterial sheaths are so easily prepared and may be kept on hand in 70
percent to 95 percent
alcohol, ready for use on need, the method deserves consideration in
surgical practice when
sheathing of the suture line in nerve suture or of a nerve transplant
after bridging a nerve defect
is deemed
1258
necessary. However, this
type of sheathing presents no advantage over a sheath or tube formed
with a double or triple layer of an alcoholized Cargile membrane, which
is more easily prepared
and applield. A formalized arterial wall used as sheath or tube appears
to incite less connective
tissue proliferation than does an auto-fascial sheath or tube as judged
by the experimental
evidence presented.
SERIES NO. 19
AUTO-NERVE
TRANSPLANTS
WRAPPED IN AUTOGENOUS-FAT FLAP
Relatively
frequent reference is made in literature to the use of pedicled or
nonpedicled
fat sheaths or flaps in connection with operation for the repair of
peripheral nerves or of
neurolysis. This method of sheathing an operated nerve was for a time
especially recommended
in case the nerve repair or liberation was undertaken in the presence
of scar tissue. The behavior
of a fat flap or sheath, either pedicled or nonpedicled, has not been
considered experimentally so
far as we are able to ascertain. It has been the intention to extend
this series of experiments but
for various reasons further experiments were not undertaken. In one of
the two experiments, the
fat membrane was taken in the region of fascia lata through a skin
wound made for this purpose;
in the other the fat membrane was taken through the wound exposing the
sciatic. The fat
membrane was thus taken from subcutaneous tissue. There is of necessity
free oozing of blood
on liberating a fat layer, with consequent adherence of blood coagulum
to the tissue removed.
The fat membrane, which had an average thickness of 5 mm., was rinsed
in sterile salt solution
before it was wrapped about the nerve transplant. It was held in place
by several stay sutures
made with fine, waxed silk thread. The fat sheath thus made was without
pedicle and was
autogenous tissue, slightly cooled during manipulation and rinsing in
the saline solution. The
protocols of the two experiments under this series are as follows:
PROTOCOLS
EXPERIMENT
No. 260.-Dog No. 54; large dog; not full grown; 4 days. July 22, 1918,
left sciatic exposed
and the internal popliteal freed. The right ulnar exposed and freed. A
segment of the right ulnar of 3.8 cm. length
transplanted to the resected left internal popliteal. One central and
distal waxed, fine silk thread suture placed; good
approximation. A layer of subcutaneous fat removed from the region of
the fascia lata of the left leg of the same
dog, trimmed to proper size and rinsed in warm, sterile saline solution
to remove the adherent blood, was placed
under the transplant and the resected nerve ends and folded over so as
to form a fat sheath. Two proximal and two
distal stay sutures and three intervening sutures placed; fairly even
fat sheath formed. Wounds closed. July 26, dog
found dead in the morning. Sciatic wound found open in part; field
congested: a small amount of pus noted. Fat
sheath of yellow-brown color; soft and pliable. Nerve transplant and
fat sheath removed and fixed in neutral
formalin. Sections stained in iron-hematoxylin and picro-fuchsin;
safranine and licht grün.
Microscopic
findings.-In cross sections of the transplant and fat sheath, it
may be observed that the nerve
transplant is necrotic and as seen in longitudinal sections of the
central wound, had torn free from the central stump.
The fat sheath is found to have been penetrated from all sides and
through its entire thickness by numerous
leucocytes and phagocytes. Many of the fat cells appear collapsed and
empty of fat globule; others partially so. The
interlobular connective tissue of the fat sheath presents evidence of
beginning
1259
necrosis, evidenced by fragmentation and
curling of fiber bundles, especially of elastic tissue.
EXPERIMENT
No. 261.- Dog No. 47; medium size; full grown; 240 days. July 15, 1918,
left sciatic
exposed; internal popliteal freed. Right ulnar exposed and freed. A
segment 2.5 cm. length from the right ulnar
transplanted to the resected left internal popliteal. One central and
distal suture of waxed, fine silk thread placed;
good approximation. A layer of subcutaneous fat removed from the region
of the wound, trimmed and washed in
warmed, sterile saline solution, placed under nerve and transplant and
folded over to form a tube; central and distal
stay sutures and
several
intervening sutures placed. Wounds closed. Sciatic wound healed slowly;
stitches did not
give away, but small droplets of liquid fat appeared to escape from
wound; no infection. March 12, 1919, killed. Dog
in good condition; no neulotrophic changes left hind foot. On exposing
left sciatic dense, fibrous tissue was found in
the line of the wound, and dense fibrous tissue surrounded the operated
nternal popliteal. No evidence of fat
sheath noted; this replaced by dense fibrous tissue. Large central bulb
observed. Nerve in region of transplant of
smaller diameter than resected nerve; distal popliteal has the
appearance of a normal nerve. Calf muscles exposed;
these have nearly recovered full size, are of pale yellow color
streaked with light yellow lines. On cutting nerve
central to the transplant, distinct though not vigorous contraction of
calf muscles observed; feeble toe movements
noted. Nerve and transplant removed and fixed in ammoniated alcohol for
pyridine-silver staining. Very good silver
differentiation attained.
Microscopic
findings.- Neither in cross nor longitudinal sections is there
observed any evidence of the fat
sheath. In the region of central and distal wounds and the intervening
transplant, distinct increase of dense fibrous
tissue about the nerve. In cross sections of the nerve transplant,
distinct increase of the endoneural connective tissue
observed. New neuraxes traced from the central stump through the
transplant are within the transplant found
arranged in small bundles, spaced by intervening connective tissue. New
neuraxes found in abundance in the distal
internal popliteal in all of its funiculi, traced in peripheral
distribution in alternate cross and longitudinal sections.
Regeneration of distal popliteal through the transplant with great
increase of connective tissue in the field of
operation attained.
Experiment
No. 260 loses in value by reason of the slight infection of the wound
region
and the early termination of the experiment by reason of the death of
the animal. Attention is
called to the relatively early disappearance of the fat from certain of
the transplanted fat cells, so
that many of these cells appear collapsed, shriveled, and shrunken.
There was noted marked
leucocyte invasion into the fat flap, perhaps in part to be ascribed to
the infection present. It
was noted in this experiment and in Experiment No. 261 for a few days
after the operation that
there was taking place a slight oozing of a lipoid fluid from the
wound. It was observed in
connection with Experiment No. 261 that the wound healed relatively
slowly, though infection
was not evident. In this experiment the dog was in good condition
throughout the time he was
under observation, was active, and was kept nearly eight months after
the operation. On
exposing the sciatic nerve at the termination of the experiment there
was found very marked
increase of fibrous tissue in the region of the wound and operated
sciatic. This fibrous mass was
more dense and more extensive than found after any of the other
operations in which the nerve
transplant was sheathed. The nerve and the nerve transplant, through
which neurotization of the
distal segment had taken place, were found embedded in the deeper
portion of this fibrous tissue,
which was adherent superficially to the skin.
1260
A general
deduction seems hardly justifiable on the basis of a single
experiment.
However, the results here presented argue against the use of a
completely detached, autogenous-fat sheath or flap, in connection with
operated or liberated peripheral nerves, since the fat
membrane appears to be replaced by dense fibrous tissue, persisting
only a relatively short time
as a fat layer. It is to be questioned whether a pedicled fat layer
used as a sheath for wrapping an
operated nerve would be maintained for a longer time as a fat layer and
thus serve the purpose
hypothecated to it.
NERVE SUTURE
SERIES NO. 20
TUBULAR SUTURE WITH USE OF FORMALIZED ARTERY
Tubular
suture in the repair of peripheral nerves with loss of substance has
been given
extensive consideration and came into use relatively early in the
development of operative
technique as regards peripheral nerve repair. The term " tubular
suture" as here employed
recognizes the union of severed nerve ends by means of a tubular
structure, which may be empty
or filled at the time of use by inserting and maintaining in place the
central and distal stumps of
the severed nerve within the lumen of the tubular structure, centrally
and distally. As previously
stated, wrapping a nerve after neurolysis or after suture, or after
nerve transplantation with a
membranous structure is, correctly speaking, not a tubular suture but
should be regarded as a
procedure for ensheathing an operated nerve. Tubular structures were
suggested as a means of
union of severed nerves and are today used, with a view of maintaining
a channel along which
central neuraxes (monogenetic view) or central and distal neuraxes
(polygenetic view) may be
enabled to grow, on the theory that such tubular structures along a
certain direct path would
prevent connective tissue proliferation and organization between the
severed and resected nerve
ends and at the same time prevent dispersion of the newly formed
neuraxes.
Among
the various methods tried by Glick 90 for the purpose of
bridging nerve defects
was that of tubular suture, made by inserting the severed nerve ends
into a " Neuber's bone drain. " In no instance
did regeneration of the distal stump take place. Vanlair 26 instituted a
series of experiments on tubular nerve suture also using "bone drains."
In a young dog with the
sciatic resected 3 cm. and the ends united by means of a bone drain
tubular suture, four months
after the operation the tissue intervening between the nerve ends was
found to contain many
nerve fibers. Nerve fibers were also found in the distal stump. Büngner 27 united the resected
and separated nerve ends by means of tubular sutures made from
sterilized human brachial
artery. At the end of about a month and a half nerve fibers were found
in the space between the
nerve ends. Huber 30 reported eight experiments in which
decalcified bone tubes made from the
ulna of chicken were used for purpose of tubular suture of the resected
ulnar nerves of dogs.
Three of these experiments were observed for a period varying,
respectively, from about four
months to about five months, and in these the neuraxes regarded as of
central origin were found
in the central
1261
end of the distal stump.
A relatively early absorption of the bone tube was noted in the
experiments of shorter duration. The tubes were found replaced by a
relatively loose connective
tissue, thus leaving a path of less densely organized connective tissue
between the severed nerve
ends. These several lines of investigation give experimental foundation
for two types of tubular
structure perhaps more frequently used in practical surgery than
others, namely, bone tubes and
arterial tubes. Numerous other tubular structures have been used for
this purpose. More than
mention of the majority of these is not justified here; nearly all have
been or should be discarded,
since their use is not. justified experimentally. Mention is here made
of tubes formed of
iodoform gauze, W olfer; 91 of magnesium tubes, Payr; 92 hardened gelatin tubes, Lotheisen; 93 galalith tubes (case in treated with formalin), Auerbach; 94 rubber tubes and rubber tubes filled
with serum, Steinthal; 95 rubber bandages, Meuriot and
Platon. 81 These and other tubular
structures of like nature are more of academic than practical interest
and their consideration need
not occupy space here. Brief recognition should be given, if only to
condemn it, to the method of
tubular suture suggested by Edinger,96 who, largely on
theoretic grounds and without sufficient
experimental warrant, recommended the use of arteries filled with agar,
for the purpose of
bridging nerve defects. Edinger appears to have reasoned that if
neuraxes would grow into agar
or blood serum in tissue culture, a tubular suture filled with agar
should prove more serviceable
than an empty tube. These "Edinger tubes" were prepared commercially
and for a period were
used extensively in the German service, even in cases in which a direct
suture could have been
made. A series of contributions appeared so soon as the observations on
the results obtained on
the use of the Edinger tube could be ascertained; Stracker 97 and
a number appearing in 1917 may
be listed here, Hohmann and Spielmeyer, 98 Enderlen and
Lobenhoffer, 99 Spitzy, 100 Wollenberg, 101, Blenke, 102 and Eden 103 all of
whom discredited use of the Edinger tube even in case the
prepared artery was filled with autoserum as was later suggested. This
method was not tested
experimentally in our laboratory but was condemned on a priori
considerations. The
experimental work reported on briefly by Hohmann and Spielmeyer, 98 in which arterial tubes
filled with agar were tested, led to the conclusion that agar in the
arterial tubes appeared to
block the downgrowth of neuraxes rather than facilitate their growth.
The use of fascial tubes in
the repair of peripheral nerves with loss of substance was tested
experimentally by Kirk and
Lewis. 86 They conclude that a defect in a nerve may be
successfully bridged by means of a
fascial tube, regeneration taking place entirely through nerve fibers
growing from the central
stump. They give directions and precautions for use of a fascial tube
in the repair of peripheral
nerves. Their experiments were controlled by study of histologic
sections stained after
differential neuraxes staining methods and had been completed so
recently that they could be
considered a part of these experimental observations.
Tubular
nerve suture with the use of vessels is mentioned so frequently in
literature on
the repair of peripheral nerves and to our knowledge had not been given
more than passing
consideration experimentally since the few experiments made by
Foramitti 88 were recorded, that
it seemed to us desirable to make
1262
use for this purpose of
certain of the ulnar nerves resected to obtain auto-nerve transplants
for
Series No. 16, No. 17 and No. IS as previously reported. In all 13
experiments of tubular suture
were made. The arteries used were the carotids of dogs. The arteries
were obtained from large
dogs after bleeding while uniler anesthesia, were slipped over glass
rods of suitable size and
fixed in 5 per cent to 10 per cent solution of formalin, for 48 hours:
were then washed in water
for 24 hours; boiled in distilled water for 20 minutes and placed in70
per cent to 95 per cent
alcohol until needed. Before use, pieces of desired length of the
artery selected, were slipped
from the glass rod and placed in sterile saline solution for about 30
minutes. On applying the
formalized arterial tube for purpose of tubular suture the following
procedure became routine: A
fine, waxed silk suture armed with a fine needle at each end was passed
through the central and
distal stumps of the resected ulnar from 2 mm. to 3 mm. from the cut
ends. The needles of each
suture were then passed through the opposing sides of the formalized
arterial tube from 7 mm. to
8 mm. from the respective ends of the tube and the ends of the resected
nerve, central and distal,
drawn into the lumen of the arterial tube and held in place by knotting
the silk sutures over one
side of the arterial tube. The wound was then closed by using the
necessary fascial and skin
sutures. In this series of experiments no nerve trans-plant was
inserted between the resected
nerve ends: the ends of the resected ulnar, from 3 cm. to nearly 5 cm.
apart in the several
experiments, were merely inserted into the ends of the arterial tubes
and kept in place by means
of stay sutures.
The
protocols for the experiments under Series No. 20, tubular sutures with
formalized
arterial tubes, are as follows:
PROTOCOLS
EXPERIMENT
No. 262.- Dog No. 50; large; full grown; 6 days. July 17, 1918, right
ulnar exposed;
resected 3.5 cm. The resected ends of the ulnar inserted into the ends
of a segment of a formalized carotid artery of a
dog, 4.5 cm. length, and held in place by central and distal stay
sutures. Dry field obtained after use of adrenalin;
fascia stitched over nerve and arterial tube; wound closed. July 23,
dog found dead in the morning. Ulnar wound
wide open; arterial tube exposed. Distal end of ulnar pulled out from
arterial tube. Ulnar and arterial tube removed
and fixed in neutral formalin. Sections stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
Microscopic
findings.- Distal end of central ulnar stump found within the lumen
of the arterial tube. In
longitudinal sections of this region, the usual degeneration of central
stump in region of wound observed. Arterial
tube found collapsed to flat ribbonlike structure. Within its lumen, as
seen in cross section, is found a small amount
of stainable granular precipitate and fine shreds of fibrin; scarcely
any cellular elements. Walls of arterial tube well
preserved. The looser, outer connective tissue coat of arterial tube
invaded by wandering leucocytes, extravasated
red blood cells and phagocytes present in large numbers in the tissue
surrounding the arterial tube.
EXPERIMENT
No. 263.- Dog No. 46; small dog; full grown; 17 days. July 13, 1918,
right ulnar exposed
and resected 3.5 cm. The resected ends of the ulnar inserted into the
ends of a segment of formalized carotid artery
of a dog, 4.5 cm. length, and held in place by central and distal stay
sutures. Adrenalin used to obtain drv field.
Fascia stitched over arterial tube; wound closed. July 31, dog found
dead in the morning. Superficial wound healed;
a dead place found under skill in operative field; fascia healed over
arterial tube. Arterial tube found well in place;
distinct bulbous enlargement on central ulnar stump. Arterial tube
collapsed; appears as flat band. Arterial tube with
ulnar nerve removed
1263
moved and fixed in neutral formalin.
Sections
stained in iron-henatoxylin and picro-fuchsin; safranine and licht
grün.
Microscopic
findings.-In longitudinal sections, including the distal end of the
central stump and the central
end of the arterial tube, bulbous end of the central stump found well
within arterial tube. Bulbous end of central
stump presents early stages of regeneration down-growing neuraxes and
rich capillary net. Beyond the end of the
nerve, within the arterial tube, felt-work of newly formed fibrous
tissue, syncytial protoplasmic bands and
capillaries. In cross sections of the arterial tube, about its middle,
vessel wall clearly made out; media and greater
part of the adventitia intact. Within the lumen of the collapsed tube,
newly formed fibrous tissue fibroblasts and here
and there capillary sprouts notes; relatively few leucocytes and a
stained granular precipitate. Only a thin layer of
loose connective tissue surrounds the tube. Distal nerve is found in
process of degeneration.
EXPERIMENT
No. 264.- Dog No. 51; medium size; full grown; 18 days. July 18, 1918;
right ulnar
exposed; resected 4 cm. Resected ends of ulnar inserted into the ends
of a segment of formalized carotid artery of
dog, of 4 cm. length. One central and distal stay suture placed. The
diameter of the lumen of the tube greater than
that of the nerve. Each end of tube split longitudinally for a distance
of 0.5 cm., edges overlapped and held in place
by half mattress sutures; ends of tube made to fit nerve closely.
Wounds closed. August 5, killed. Dog not in good
condition. Ulnar wound well healed. On exposing right ulnar, arterial
tube is found well in place, united to the
resected nerve ends. Arterial tube surrounded by newly formed
connective tissue; tube collapsed. Light pressure on
it causes a small amount of sanguineous fluid to escape at the distal
end. Ulnar and arterial tube removed and fixed
in ammoniated alcohol for pyridine-silver staining. Fairly good
differential neuraxis staining attained. Only central
bulb and central end of arterial tube cut; tissue did not embed well,
sections torn.
Microscopic
findings.-In longitudinal sections of the central bulb and the central
end of the arterial tube, the
normal ulnar can be traced into the bulbous end, clearly evidenced
structurally, this bulbous end surrounded by the
arterial tube, which is well preserved. Beyond the distal end of this
central bulbous enlargement, small bundles of
neuraxes can be traced into newly formed connective tissue continuous
with the same, this mainly along the inner
wall of the arterial tube, for a distance of about 1 cm.
EXPERIMENT
No. 265.- Dog No. 53; small dog; full grown; 41 days. July 20, 1918,
light ulnar exposed
and resected 4 cm. As tubular suture, used a segment of a formalized
carotid artery of a dog, 4 cm. long. One central
and distal stay suture placed. Distally a second suture used to narrow
the lumen of the tube. Dry field obtained by
use of adrenalin. Wound closed. Five to eight days after operation,
slight evidence of infection; stitch abscess.
Wound treated with tincture of iodine; apparent infection stopped.
August 30,dog found dead in the morning; some
emaciation; wound well heated. On exposing the right ulnar, arterial
tube found well in place: united to resectedc
nerve ends. Distinct central bulb seen through tube wall. A small
amount of sanguineous fluid noted within the tube. Tube surrounded by
newly formed connective tissue; adherent to surrounding tissue. Ulnar
and arterial tube removed
and fixed in neutral formalin. Sections stained in iron-hema-toxylin
and picro-fuchsin; safranine and licht grün.
. Microscopic
findings.- In longitudinal sections of area of junction of the
central and distal resected nerve
ends and arterial tube, it is to be observed that the arterial wall is
united to the resected nerve ends by fibrous tissue.
The structure of the arterial wall well preserved a concerns elastic
and fibrous tissue, with a layer of fairly dense
fibrous tissue on its outer surface. In longitudinal sections of the
central end of arterial tube, distinct central bulb is
evidenced structurally, beyond which very few structures are traced
distally within the lumen of the tube. Cross
sections of the arterial tube approximately 1.5 cm. from its central
bed, shows the tube collapsed and practically
empty; scarcely any cellular elements found within the lumen of the
tube in this region and distal thereto.
EXPERIMENT
No. 266.-Dog No. 57; small dog; full grown; 46 days. July 25, 1918,
right ulnar exposed;
resected 3.6 cm. A tubular suture made with a 4 cm. long segment of a
formalized carotid artery of a dog, held in
place by means of one central and distal stay suture. Dry field
obtained after use of adrenalin. Wound closed. About
10 days after the operation
1264
after the wound had healed, the skin of
this dog became infected; log not in good condi-tion. September 8, dog
found dead in the in morning; emaciated. No neurotropic changes right
fore foot. Superficial wound well healed. On
exposing nerve, a small pus pocket found over arterial tube; this found
to contain a short segment of thread. Arterial
tube collapsed; centrally attached to nerve; distally nerve seems to
have pulled out of tube. Ulnar and arterial tube
removed and fixed in neutral formalin. Sections stained in
iron-hematoxylin picro-fuchsin;
safranine and licht grün.
Microscopic
findings.-In longitudinal sections of central and distal ends of
the arterial tube and resected
nerve ends, ends of nerve are found to be within the lumen of the
arterial tube and united thereto by means of fibrous
tissue. Large central bulb evidenced structurally; this ends free
within the lumen of the tube. Surrounding end of
bulb, numerous leucocytes and phagocytes; very little structural
evidence of organized tissue. In cross sections of the
arterial tube, approximately its middle wall, of artery presents
evidence of disintegration; elastic layers of media
present very wavy course and are widely spaced. Within the lumen of the
tube, numerous leucocytes and
phagocytes; no organized tissue. It is concluded that there was present
slight infection in this experiment.
EXPERIMENT
No. 267.- Dog No. 55; large; full grown; 47 days. July 22, 1918, right
ulnar exposed;
resected 3.5 cm. A tubular suture made, using a segment of 4 cm. length
of a formalized carotid artery of a dog. One
central and distal stay suture placed. Arterial tube cut a little too
short so that resected ulnar, after suture, was
slightly under tension. Dry field obtained after use of adrenalin.
Wound closed. September 8, dog found dead in the
morning; much emaciated; severe skin disease. Ulnar wound well healed.
On exposing the ulnar, a small dead space
is found over the arterial tube with a small amount of sanguineous pus.
Arterial tube well in place, united to resected
nerve ends. Nerve and arterial tube removed and fixed in neutral
formalin. Sections stained in iron-hematoxylin and
picro-fuchsin; safranine and licht grün.
Microscopic
findings.- In longitudinal sections of the central and distal ends
of arterial tube and the
resected nerve ends, the arterial tube is found to be well in place
united to resected nerve ends by fibrous tissue.
Tube wall very well preserved and found of compact structure. Distinct
central bulb evidenced structurally, from the
distal end of which there is found to extend into the lumen of the tube
a newly formed connective tissue consisting
of fine interlacing fibers and fibroblasts practically filling the
collapsed lumen of the tube and extending within the
lumen to the distal nerve segment; arterioles, venules, and capillaries
found in this tissue. Within this tissue, traced in
successive series from the central bulb, are also found small funiculi
of nerve bundles, especially along the inner
surface of the arterial tube. These nerve bundles do not extend to the
distal nerve, which is degenerated. Sections
present no evidence of infection within the lumen of the arterial tube.
EXPERIMENT
No. 268.- Dog No. 48; medium size; full grown; 57 days. July 15, 1918,
right ulnar exposed
and resected approximately 3 cm. A tubular suture made by using a 4 cm.
segment of the formalized carotid artery of
a dog. One central and distal stay suture placed. Wound closed.
September 10, dog found dead in the morning; much
emaciated, ulnar wound well healed. On exposing the right ulnar,
increase of connective tissue in region of wound
noted; possible evidence of deep wound infection not recognized.
Arterial tube found well in place, ends adherent to
resected nerve ends. Large central bulb within the arterial tube noted.
Tube collapsed; surrounded by connective
tissue, adherent to surrounding tissues. Ulnar nerve and arterial tube
removed and fixed in neutral formalin. Sections
stained in iron-hematoxylin and picro-fuchsin; safranine and licht
grün.
Microscopic
findings.- In central and distal longitudinal sections, arterial
tube is found firmly united to
resected nerve ends. The large central bulb is found to be partly
within and partly without the lumen of the arterial
tube; from the distal end of the bulb there extends into the lumen of
the tube a vascularized fine fibrillar connective
tissue which extends to the distal ulnar. In this tissue small funiculi
of nerve fibers may be observed in cross sections
of the tube about its middle region. The distal ulnar stump completely
degenerated.
EXPERIMENT
No. 269.- Dog No. 45; medium size; full grown; 63 days. July 12, 1918,
right ulnar
exposed; resected 3.5 cm. A tubular suture made by using a segment of
4.5 cm. length of a formalized carotid artery
of a dog. One central and distal stay suture placed.
1265
Arterial tube was cut a little too long;
when
sutured in place was found bent a little in its middle portion. Wound
closed. September 13, killed. Dog in poor condition; emaciated; skin
disease. Superficial wound well healed. On
exposing nerve, slight evidence of deep wound infection noted. Arterial
tube found pulled free from central ulnar
stump; distally united to distal ulnar segment. The central stump found
to end in large central bulb, from the free end
of which no nerve fibers can be traced distalward. Only central bulb
removed and fixed in ammoniated alcohol for
pyridine-silver staining. Pale but differential silver staining
attained.
Microscopic
findings.-In longitudinal sections of the central bulb, distinct
structural evidence of the central
end of the arterial tube found in the peripheral connective tissue
sheath of the bulb; arterial tube appears to have been
torn rather than to have pulled free from the central stump. A few
neuraxes can be traced beyond the distal end of the
bulb extending for a short distance into the surrounding connective
tissue.
EXPERIMENT
No. 270.- Dog No. 49; small dog; full grown; 117 days. July 16, 1918,
right ulnar exposed;
resected 4 cm. A tubular suture made by using a segment of 4.5 cm.
length of formalized carotid artery of a dog; one
central and distal stay suture. Quite a little venous bleeding finally
controlled by use of adrenalin; dry field; wound
closed. November 10, dog found dead in the morning; emaciated; no
neurotrophic changes right fore foot. On
exposing the right ulnar, arterial tube is found well in place, firmly
united to resected nerve ends. Only moderate
amount of connective tissue surrounds nerve ends and arterial tube;
only loosely adherent to the surrounding tissue;
tube collapsed. Distinct bulbous enlargement of the distal end of the
central ulnar stump. A segment of the central
ulnar. arterial tube and 10 cm. of distal ulnar removed, fixed in
ammoniated alcohol for pyridine- silver staining.
Good differential silver staining attained; tissue not well embedded;
difficult to cut after silver impregnation.
Microscopic
findings.- In a series of longitudinal sections including the
central bulb and central end of the
arterial tube, distinct central bulb evidenced structurally, from the
distal end of which many neuraxes, grouped in
small funiculi, separated by connective tissue pass distally in the
lumen of the arterial tube. As seen in cross
sections at successive levels, neuraxes more abundant in the central
than in the distal part of the arterial tube, though
numerous neuraxes reach the distal end of the arterial tube and pass
into the central end of the distal ulnar, in which
they may be traced at least 5 cm. distal. In the distal ulnar the
neuraxes are fairly evenly distributed through the
several funiculi. Partial regeneration of the distal ulnar through
arterial tubular suture.
EXPERIMENT
No. 271.- Dog No. 43; small dog; full grown; 130 days. July 11, 1918,
right ulnar exposed
and resected 3 cm. A tubular suture made by using a segment of 4 cm.
length of the formalized carotid artery of a
dog; one central and distal stay suture placed; distally an additional
half mattress suture used, to narrow the lumen of
the tube. Dry field obtained by using adrenalin. Wound closed. November
18, dog seemed fairly well in the
morning; found dead in the afternoon. Seemed in good condition; no
neurotrophic changes right fore foot. On
exposing the right ulnar, arterial tube is found well in place; it
seems of smaller diameter than when used; firmly
united to resected nerve ends; only partly collapsed. Only moderate
amount of connective tissue found about the
tube; loosely adherent. Large central bulb noted; central end of distal
ulnar only slightly enlarged. Distal ulnar of
small diameter, but has not the appearance of a degenerated nerve. Fore
leg muscles supplied by ulnar exposed; they
are found only slightly atrophic and of pale red color. Ulnar nerve and
arterial tube removed and fixed in
ammoniated alcohol for pyridine-silver staining. Fairly good silver
differentiation attained.
Microscopic
findings.-In series of cross and longitudinal sections, the wall of
the arterial tube found well
preserved. Wall of tube found contracted and presenting a number of
folds. In cross section it is observed that the
lumen of the tube contains fairly dense fibrous tissue which in the
sections is retracted slightly from the inner wall of
the tube. Within this connective tissue core, and occupying the central
field proximally, more to one side distally, are
found numerous small funiculi of nerve fibers. These may be traced,
becoming less numerous distally, to and into
the distal ulnar in which a relatively small number of neuraxes, about
equally distributed through the several
funiculi, may be traced distally for several
1266
centimeters; to the limit of the
sections.
Partial regeneration of distal ulnar through arterial tube attained.
EXPERIMENT
No. 272.- Dog No. 47; medium size; full grown; 240 days. July 15, 1918,
right ulnar
exposed; resected a little over 3 cm. A tubular suture made by using a
segment of about 4 cm. length of a formalized
carotid artery of a dog; one central and distal stay suture placed. Dry
field. Wound closed. March 12, 1919, killed.
Dog in good condition; no neurotrophic changes. Ulnar nerve exposed,
first as it passes over elbow. Pressing and
touching nerve in this region with forceps, calls forth good
contraction of forearm muscles supplied by ulnar. After
exposing forearm muscles, cutting the nerve below the elbow causes good
contraction; individual muscles seen to
contract. The ulnar was then exposed centralward. Arterial tube found
well in place and firmly united to resected
ends of ulnar. Quite large central bulb encased in central end of
arterial tube; central end of distal ulnar not
materially enlarged. Ulnar with arterial tube removed and fixed in
ammoniated alcohol for pyridine-silver staining.
Good differential silver staining attained.
Microscopic
findings.- In cross sections of the arterial tube, this is found
collapsed to nearly form of ribbon;
vessel wall found well preserved; not materially reduced in size by
absorption. In a series of longitudinal sections
including the central bulb and central end of the arterial tube, it may
be observed that from the distal end of the bulb
there extend downward numerous small, intercrossing funiculi of nerve
fibers, certain of which are myelinated.
Within the lumen of the tube, best seen in cross sections, only small
amount of fibrous tissue separated these larger
and smaller nerve funiculi, which can be traced in decreasing number to
the distal ulnar in which they extend
distalward in relatively large number. Fairly complete regeneration of
distal ulnar, through formalized arterial tube
attained.
EXPERIMENT
No. 273.- Dog No. 44; small dog; full grown; 243 days. July 12, 1918,
right ulnar exposed;
resected 3.5 cm. A tubular suture made by using a segment of 4 cm.
length of a formalized carotid artery of a dog;
one central and distal stay suture placed. Dry field after use of
adrenalin. Wound closed. March 12, 1919, killed.
Dog in very good condition. No neurotrophic changes. Right ulnar first
exposed near elbow, after freeing from
connective tissue and then slowly cutting with scissors, feeble
contraction of forearm muscles observed. On
exposing the ulnar centralward, it was observed that the arterial tube
was attached to the central ulnar stump. The
arterial tube could be easily traced for distance of a little more than
2 cm., but appeared to have pulled free from the
distal ulnar stump. Several fine nerve bundles could be traced in the
connective tissue beyond the distal end of the
arterial tube, but could not be followed to the distal stump; some
intervening connective tissue having unfortunately
been removed before the condition was recognized. It would seem that
even though the distal tubular suture had
given way, certain of the down-growing neuraxes led to the neighborhood
of the distal ulnar stump, had reached and
penetrated it, with a result of partial regeneration of the nerve. As
the experiment, beyond the function test, owing to
accident, was incomplete, tissue was not removed for microscopic study.
EXPERIMENT
No. 274.- Dog No. 52; medium size; full grown; 300 days. July 19,1918,
right ulnar
exposed and resected 4 cm. A tubular suture made, using a segment of
4.5 cm. length of a formalized carotid artery
of a dog; one central and distal stay suture placed. Dry field; wound
closed. May 15, 1919, killed. Dog in good
condition. No neurotrophic changes; appears to use right fore leg as
well as left. On exposing the ulnar, it is found
that the arterial tube remained connected with the distal ulnar stump,
was much collapsed and folded to one side, the
central end of the arterial tube having pulled free from the central
ulnar stump; presumably soon after the operation.
Large bulbous enlargment on the distal end of the central ulnar,
surrounded by quite dense fibrous tissue. No nerve
bundles could be traced beyond the bulb. The distal ulnar segment
completely degenerated, and gives no response on
cutting or crushing at the level of the elbow. Central ulnar bulb
removed for study of neuroma. Experiment not
successful as far as showing tubular suture is concerned. The fact that
a formalized artery may remain embedded in
normal tissuefor more than seven months, is of interest.
1267
In
this series, in which the use of formalized, arterial, tubular nerve
sutures is considered,
it is observed that the formalized arteries placed in aseptic wounds in
normal tissue at the time of
operation remain unabsorbed for a relatively long time, for a period of
approximately 8 months,
thus fulfilling very well certain of the requirements of a tubular
nerve suture, namely, that of
remaining unabsorbed until the time when central neuraxes may have
opportunity to reach the
distal stump. Experiment No. 272 is the most satisfactory of those of
this series observed for a
long time after operation, in this case 240 days. A distance of 3 cm.
was successfully bridged by
means of tubular suture as attested by function tests and by histologic
examination. The arterial
tube was found well in place, though much collapsed, with lumen nearly
obliterated. Within the
lumen there was found a small amount of connective tissue and in this
numerous small funiculi
of nerve fibers, which in the main present a longitudinal course. In
Experiments No. 270 and No.
271,of approximately 4 months' duration, neuraxes of central origin can
be traced through the
lumen of the arterial tube to the distal segment in which they may be
followed for a short
distance. In a number of the experiments of shorter duration, the
observations were terminated
by death of the animals from disease not related to the experiment.
These observations are listed
serially as to time, and the tissues obtained were studied so far as
circumstances permitted. It
will be noted that distinct neuromata found on the distal end of the
central stump and within the
lumen of the arterial tubes are described for nearly all of the
experiments. There is found within
the lumen of the tubes a scanty development of connective tissues which
appears to have arisen
from fibroblasts derived from the central and distal nerve stumps,
rather than from the tissue
surrounding the arterial tubes. Whether sheath cells participate in the
formation of the syncytial
net found within the tube in early stages has not been determined. This
fibrous tissue forms a
scaffolding on which the neuraxes proceed distalward. It is of special
interest to note, and it
confirms in a very satisfactory manner the monophyletic view of the
regeneration of the distal
stump, that the neuraxes within the lumen of the vessel appear first
near the central bulb, later
progressively more distant the longer the time intervening between the
operation and the time of
observation. The distal segment remains degenerated until the central
neuraxes have reached in
their downgrowth the distal portion of the arterial tube and thus the
central end of the distal
stump.
These
experiments may serve to show that tubular suture may,
under favorable
conditions, serve to convey neuraxes from the central to the distal
stump of a severed and
resected nerve. This has been shown for tubular suture made with
decalcified bone tubes, Huber, 30 for fascial tubes by Kirk and Lewis, 86 and
for formalized arterial tubes in the experiments here
recorded. However, the method of tubular suture can not be recommended
for adoption in
surgical practice since other methods for bridging nerve defects offer
greater assurance for
success. " Tubulization offers a single large path for the down-growth
of neuraxes and, for this
reason, is mechanically inferior to nerve trans-plantation for nerve
regeneration, since the latter
method offers numerous small paths which serve as individual conducting
tubules for the
neuraxes"(Stookey) ."
1268
SERIES NO. 21
TENSION SUTURES; RESECTED NERVES SUTURED
UNDER EXTREME TENSION, WITH OR
WITHOUT SECONDARY WRAPPING IN ALCOHOLIZED CARGILE MEMBRANE OR
FORMALIZED
ARTERIAL SHEATHS
In
this series of 13 experiments the ulnar nerve of dogs, which had been
resected for the
purpose of obtaining auto-nerve transplants to be used in Series No.
16, No. 17, and No. 18, was
used for the purpose of testing nerve suture under tension, the ends of
the resected nerve being
brought together as closely as possible by direct suture. It is clearly
recognized in surgical
practice that a distance of separation of severed and resected nerve
ends to the extent of 2 cm.
to3 or 4 cm. of one of the major extremity nerves can be overcome, as a
rule, by liberation of the
nerve and the application of traction, so that a suture may be placed.
The extent of
approximation which can be attained in this way varies with the nerve
and, to some extent, with
the location of the injury. We have reached the conclusion, based on
experimental observations,
that nerves can be freely mobilized without material injury or causing
degeneration. In many of
our experiments on the sciatic of dogs, after exposing the nerve for
its entire length from the
sciatic notch to the popliteal space, and then liberating the nerve
from its bed and separating the
two popliteal branches for their entire length, the internal popliteal
branch alone was operated
upon, resected, and other-wise treated while the other branch remained
intact. In such procedure,
the external popliteal branch, though freely manipulated and perhaps
under tension, showed no
sign of degeneration and functioned without interruption. We feel
warranted in saying that quite
extensive liberation of a human nerve is permissible if necessity
demands and that this is without
material injury to the nerve nor does it lessen the progress of
regeneration. In every nerve injury
with severance of continuity and loss of nerve substance an attempt
should be made to
approximate the severed nerve ends and perform a simple suture. The
extent of tension permitted
in connection with a nerve suture is a question of judgment, and
experience will enable decision
for each case; no general rule can be given not applicable to general
surgical procedure. Owing
to the unsatisfactory reports found in the literature relative to
various methods of procedure for
bridging nerve defects surgeons have shown a timidity and hesitancy
with regard to adopting
methods of nerve transplantation and have attempted by direct suture to
maintain in apposition
nerve ends after loss of substance when, to accomplish such, the united
nerve ends and sutures
were under tension to a degree not justified. Such a condition we have
endeavored to simulate in
this series of experiments. A resection in the ulnar of a dog above the
elbow to the extent of from
2.5 cm. to nearly 5 cm. is a relatively much greater loss of nerve
substance than a segment of
equal length removed from the human ulnar. In our experiments, after
the resection of the ulnar
nerve for purpose of obtaining an auto-nerve transplant which was used
to bridge a defect in the
sciatic of the same dog, followed by wrapping the region of the
transplant after one of the
methods described under Series No. 16, No.17, and No. 18, the operation
on the sciatic nerve
was completed to closure of the skin wound; in the meantime protection
was given to the ulnar
wound.
1269
The details of the
operation on ulnar nerve varied somewhat in the several experiments in
this
series. In the majority of the operations a silk suture was passed
through the central and distal
stumps of the resected nerve and then, after liberating the nerve
centrally and distally, however,
without freeing the distal ulnar from its fibrous bed at the elbow,
tension was applied mainly by
means of the suture and the nerve ends approximated as nearly as could
be without breaking the
suture or tearing it our. In some of the experiments it was possible to
bring the nerve ends in
relatively close approximation, in others a distance of 1 cm. Or even
more intervened between
the nerve ends. In many of the experiments the field of suture was
wrapped with several layers
of alcoholized Cargile membrane with about 1 cm. Of the adjacent nerve
ends included. This
was to closely wrapped about the nerve to form a close-fitting tube. In
carotid artery of a dog,
was slipped over the central nerve stump prior to suture of the nerve
ends, and after the suture
was completed was placed over the region of the tension suture and the
adjacent nerve ends. In other experiments no
protection was given to the suture region. Purposely no attempt was
made to immobilize the operated foreleg in these experiments. The
tension used in bringing
together the resected nerve ends in these experiments. it is thought,
was no greater than that used
by certain operators in the repairof injured nerves with loss of
substance in humans; and in this
respect our experiments are comparable to their operations.
PROTOCOLS
EXPERIMENT
No. 275.- Dog No. 40; medium size; not full grown; 22 days. August19,
1918, left ulnar
exposed; resected nearly 4 cm.; resected ends retracted so that they
were 4.6 cm. apart. One waxed, silk thread
suture was passed through each end of the resected ulnar and then
brought together as closely as possible; the sutures
tied. The suture line was wrapped with two layers of alcoholized
Cargile membrane, forming a tube about 2 cm.
long. Fascia stitched over nerve; wound closed. The left forearm was
not immobilized. September 10, dog killed;
much emaciated. Ulnar wound healed. On removing skin and fascia over
the ulnar field, it was found that the tension
suture had given way; the resected nerve ends were found to be about 3
cm. apart. The central stump terminated in a
well-developed bulbous enlargement. The alcoholized Cargile membrane
was found partly spread out, embedded in
connective tissue. The central bulbous end removed and fixed in
ammoniated alcohol for pyridine-silver staining.
Microscopic findings.-Longitudinal sections show typical
structure of amputation neuroma.
EXPERIMENT
No. 276.- Dog No. 30; large; full grown; 44 days. August 15, 1918, left
ulnar exposed;
resected 3 cm. One through-and-through silk suture passed and resected
nerve ends brought together and suture tied.
As knot was being tied, nerve ends slipped apart to the extent of 5 mm.
The suture line wrapped with double layer of
alcoholized Cargile membrane. Fascia stitched over nerve; wound closed.
September 28, dog found dead in the
morning. Ulnar wound well healed. After removing skin and fascia over
ulnar field, it was observed that the suture
had given way; resected ulnar ends nearly 3 cm. a part. Large bulbous
enlargement found on central ulnar stump.
Cargile membrane found adherent to distal stump; folded over and embedded in fibrous tissue.
Portions of
central
and distal ulnar stump removed and fixed in neutral formalin.
Microscopic
findings.- Well stained neuroma showing typical neuroma
structure;
small funiculi of nerve
fibers found in connective tissue distal to neuroma.
1270
EXPERIMENT No. 277.- Dog No. 3; medium
size;
full grown; 56 days. June 11, 1918, left ulnar exposed
and resected approximately- 2.5 cm. One through-and-through silk suture
passed and resected nerve ends brought
together and tied; resected nerve ends 2 minn. apart Two layers of
Cargile membrane wrapped about suture line and
about 1 cm. of resected nerve ends. Fascia stitched over nerve and
wound closed. Left foreleg not immobilized. August 6, killed. Dog in
good condition. On exposing the ulnar, it is found that the resected
nerve ends are still in
close approximation; about as at the close of operation. No trace of
Cargile membrane found. Firm connective tissue
surrounds and unites the resected nerve ends. Distinct large central
bulb noted. Large segments of central and distal
nerve ends with intervening connective tissue removed and fixed in
ammoniated alcohol for pyridine-silver staining.
Unsuccessful differentiation attained; tissues not well embedded;
sections torn.
Microscopic
findings.- No trace of Cargile membrane in sections. In
longitudinal
sec-tions through the
wound region, a few new neuraxes distinguished in the central end of
the distal ulnar stump. In cross sections of
distal ulnar 2 cm. distal to wound, nerve presents the appearance of a
degenerated nerve.
EXPERIMENT No. 278.- Dog. No. 41; small dog;
full grown; 61 days. June 28, 1918, right ulnar resected 4
cm. One through-and-through waxed, silk suture passed, and under
tension resected nerve ends brought together and
suture tied. After suture was tied the resected nerve ends were found
to be 1 cm. apart. Fascia stitched over the nerve
and wound closed. August 28, dog found dead in the morning. Wound well
healed. On exposing the right ulnar, it
was observed that the suture had given way; the resected nerve ends
were found to be about 3 cm. apart. Large
bulbous end on central ulnar stump observed; no nerve bundles can be
traced beyond it distally. The central ulnar
bulb was removed and fixed in ammoniated alcohol for pyridine-silver
staining.
Microscopic
findings.- Typical neuroma evidenced structurally.
EXPERIMENT
No. 279.- Dog No. 38; medium size; full grown; 61 days. June 21, 1918,
right ulnar
exposed; resected approximately 3 cm. One through and through silk
thread suture passed and resected nerve ends
brought together under tension. After tying knot, approximation of
nerve ends good. Fascia stitched over nerve and
wound closed. Foreleg not immobilized. August 22, dog reoperated in the
morning; found dead early afternoon;
seemed in very good condition. On exposing the right ulnar, it is
evident the suture had given away; resected nerve
ends found nearly 3 cm. apart. Very large bulbous enlargement noted on
end of central ulnar stump. No nerve fibers
can be traced from the distal end of this bulb. Central ulnar and bulb
removed and fixed in ammoniated alcohol for
pyridine-silver staining.
Microscopic findings.- Very large neuroma, with typical
neuroma
structure evidenced structurally.
EXPERIMENT
No. 280.- Dog No. 40; medium sized dog; full grown; 47 days. July
25,1918, right ulnar
exposed and resected 4 cm. One through-and-through suture of No. 00
cat-gut passed and tension made; catgut
suture broke. A double silk thread suture passed and under tension the
resected nerve ends brought together; suture
tied. Fascia stitched over the nerve; wound closed. Right foreleg not
immobilized. September 10, killed. Dog much
emaciated; skin disease. On exposing the right ulnar, it is evident
that the suture had given away; resected nerve ends
about 3 cm. apart. Large central ulnar bulb; within it, suture is
recognized. Central ulnar and central end of distal
ulnar stump removed and fixed in ammoniated alcohol for pyridine-silver
staining.
Microscopic
findings.- Large central neuroma evidenced structurally; suture
included in the sections. Distal
ulnar degenerated.
EXPERIMENT
No. 281.-Dog No. 56; large dog; full grown; 172 days. July 24, 1918,
right ulnar exposed
and resected 4 cm. A segment of a formalized carotid artery of a dog
slipped over the central ulnar stump, which was
freed from bed for sufficient length to admit of this. One
through-and-through waxed, silk thread suture passed, and
under tension resected nerve ends brought together and suture tied.
After tying knot, resected nerve ends found to be
1.5 cm. apart. The formalized arterial tube was then slipped down over
the suture and the resected nerve ends; fascia
stitched and the wound closed. January 11, 1919, during
1271
the night, dog hung himself on tic rope;
was in good condition. On exposing the right ulnar, arterial tube is
found to be well in place; with central and distal ulnar stumps firmly
fixed within the arterial tube. Black, tension
suture clearly seen through wall of arterial tube. No
material increase
of connective tissue about arterial tube and
nerve observed. Large central ulnar bulb noted; distal ulnar has the
appearance of a normal nerve. Fore-leg muscles
supplied by ulnar not atrophic
and good color. Dog had been dead some hours so could not test muscles
as to
functional return. Central and distal ulnar and arterial tube removed
and fixed in ammoniated alcohol for pyridine-silver staining. Good
differential silver staining attained.
Microscopic
findings.-In longitudinal sections of the central ulnar stump and
the arterial tube, vessel wall
was found to be well preserved and firmly united to the central ulnar
stump. Neuraxes can be traced from the distal
end of the ulnar bulb through the arterial tube to the distal ulnar
stump. In cross sections of the arterial tube in the
interval between the two ulnar stumps, the suture can be clearly made
out, as also numerous small nerve bundles
separated by connective tissue; much as in a tubular suture without
tension suture. In the distal ulnar, numerous new
neuraxes are observed in all of the funiculi.
EXPERIMENT
No. 282.- Dog No. 35; medium size; full grown; 269 days. August 20,
1918, left ulnar
exposed; resected 4 cm. One through-and-through waxed, silk thread
suture passed, and under tension resected nerve
ends brought together to within 8 mm. Suture line wrapped with two
layers of alcoholized Cargile membrane. Fascia
stitched over the nerve; wound closed. Right foreleg not immobilized.
May 16, 1919, killed. Dog in very good
condition. On exposing the left ulnar, it is evident that the suture
gave way; perhaps soon after the operation;
resected nerve ends separated. Central ulnar stump found to end in
large bulb, from which some fine nerve bundles
could be traced through the connective tissue to the distal ulnar
stump; which shows slight bulbous enlargement. No
trace of the suture or Cargile membrane could be detected. Foreleg
muscles supplied by the ulnar present normal
color, though are slightly atrophic. A segment of the central and
distal ulnar with intervening connective tissue and
fine nerve bundles removed and fixed in ammoniated alcohol for
pyridine-silver staining. Differential though faint
silver staining attained.
Microscopic
findings.- In longitudinal sections of the distal end of the
central
stump and the fibrous tissue 1
cm. distal thereto, it is observed that the alcoholized Cargile
membrane wrapped about the suture line at the time of
operation, came to lie one side of the distal end of the central stump
when the suture gave way, where it is found
embedded in fibrous tissue. In cross sections of the connective tissue
field, found between the resected nerve ends,
about 1.5 cm. distal to the central stump, the Cargile membrane is
again observed, embedded in dense fibrous tissue
and to one side there may be seen numerous small intercrossing bundles
of nerve fibers which may be traced to the
central end of the distal ulnar stump, in which scattered neuraxes are
to be found.
EXPERIMENT
No. 283.- Dog No. 39; medium size; full grown; 275 days. August 14,
1918, left ulnar
exposed; resected 4 cm. One through-and-through waxed, silk thread
suture passed, and under tension nerve ends
approached to within about 1 cm.; suture tied. The suture line wrapped
with double layer of alcoholized Cargile
membrane. Fascia stitched over nerve; wound closed. Left foreleg not
immobilized. May 16, 1919, killed. Dog in
good condition. On exposing the left ulnar, it is evident that the
suture had given way. The central ulnar stump is
found to end in large bulb, from the distal end of which a few small
nerve bundles can be traced into the connective
tissue for a short distance beyond the bulb, but can not be traced to
the distal ulnar stump. No trace of suture or
Cargile membrane seen. Distal ulnar presents the appearance of a
degenerated nerve. The central bulb and the
central end of the distal ulnar stump removed and fixed in ammoniated
alcohol for pyridine-silver staining. Fairly
good silver differentiation attained.
Microscopic
findings.- In longitudinal sections of the central ulnar bulb and
the con- nective tissue distal
thereto, it is to be observed that numerous small nerve funiculi,
having very tortuous course, may be observed in the
connective tissue and the surrounding adipose tissue. In cross and
longitudinal sections of the distal ulnar stump, a
few scattered new neuraxes are observed,
not evenly distributed through the several funiculi. These become less
numerous distalward.
1272
EXPERIMENT No. 284.- Dog No. 31; medium
size;
full grown; 276 days. August 16, 1918, right ulnar
exposed and resected 4.7 cm. One through-and-through waxed, silk
thread suture passed, and under tension resected
nerve ends brought together to within a little less than 2 cm. The
resected nerve ends and the suture region wrapped
in three layers of alcoholized Cargile membrane. Fascia stitched over
nerve; wound closed. Right foreleg not
immobilized. May 19, 1919, killed. Dog in very good condition. On
exposing the right ulnar, it is evident that the
suture had given way. Central ulnar is found to end in a large bulb,
from the distal end of which several fine nerve
bundles pass distalward in the connective tissue, spreading out
fan-shaped over the adjacent muscle. None of these
nerve bundles could be traced to the distal ulnar stump, which
appears
to end free and is only very slightly enlarged.
The distal ulnar presents the appearance
of a degenerated nerve. Central ulnar bulb and the central end of the
distal
ulnar stump removed and fixed in ammoniated alcohol for pyridine-silver
staining. Differential, but faint silver
staining attained.
Microscopic
findings.- From the distal end of a large central ulnar bulb,
evidenced structurally, numerous
small nerve funiculi can be traced into the connective tissue; these
having a very tortuous course. Remnants of the
alcoholized Cargile membrane, embedded in fibrous tissue, noted. In the
distal ulnar stump only a few scattered
neuraxes, found mainly in one large funiculus, noted; very few in the
several other funiculi observed.
EXPERIMENT
No. 285.- Dog No. 32; medium size; full grown; 273 days. August 16,
1918, left ulnar
exposed; resected 3.4 cm. One through-and-through waxed, silk thread
suture passed, and under tension nerve ends
approached until they nearly touched; suture tied. Suture line wrapped
with two layers of alcoholized Cargile
membrane. Oozing in field not fully controlled. Fascia stitched over
nerve; wound closed. Foreleg not immobilized.
May 16,1919, killed. Dog in very good condition. On exposing the left
ulnar, it is found that the central ulnar stump
ends in a long spindle-shaped bulb which leads directly to the distal
ulnar stump. It is evident that the suture
maintained. Traces of the Cargile membrane made out, though not
clearly, since area is surrounded by connective
tissue. Distal ulnar presents the appearance of a normal nerve. Foreleg
muscles supplied by ulnar present the
appearance of normal muscle. Central and distal ulnar segment removed
and fixed in ammoniated alcohol for
pyridine-silver staining. Good silver differentiation attained.
Microscopic
findings.- In longitudinal sections, including the central ulnar
bulb, suture line and central end
of distal ulnar stump, it can be clearly seen that in this case the
tension suture did not give way, since in the sections
the sections of the suture thread can clearly be made out and are found
in proper position. Distinct evidence is had of
the Cargile membrane, wrapped about the suture line at the time of
operation. This is found embedded in fibrous
issue. Neuraxes coming from the central ulnar stump can be traced
directly into the distal ulnar stump, in which they
may be traced to the region of muscle innervation. In cross sections of
the distal ulnar at the level of the elbow,
numerous neuraxes distributed evenly through all of the funiculi, are
to be observed. Very complete regeneration of
the distal ulnar obtained.
EXPERIMENT
No. 286.- Dog No. 39; medium size; full grown; 326 days. June 24, 1918,
right ulnar
exposed; resected 3.2 cm. One through-and-through silk thread suture
passed. Under tension the resected nerve ends
brought together to within 1 cm.; suture tied. The suture lines wrapped
with two layers of Cargile membrane. Fascia
stitched over nerve; wound closed. Foreleg not immobilized. May 16,
1919, killed. Dog in very good condition. On
exposing the ulnar nerve, it is evident suture had given way; ends of
resected ulna; separated. Central ulnar stump
found to end in large bulb, from the distal end of which fine nerve
bundles may be traced about 2 cm. distal over the
adjacent muscle, but do not appear to reach the distal ulnar stump.
Distal ulnar presents the appearance of a
degenerated nerve. Central ulnar bulb and distal ulnar stump fixed in
ammoniated alcohol for pyridine-silver
staining. Fairly good silver differentiation attained.
Microscopic
findings.- From the distal end of the large central ulnar bulb,
numerous
small nerve funiculi can
be traced distalward in the connective tissue, having very tortuous
course. In cross and longitudinal sections of the
distal ulnar stump, at successive levels to the elbow, only scattered
neuraxes
are found and these are not found evenly distributed through the
several funiculi. Partial but very incomplete
regeneration of the distal ulnar attained.
1273
EXPERIMENT
No. 287.- Dog No. 2; medium size; full grown; 342 days. June 12, 1918,
left ulnar exposed;
resected 2.5 cm. One through-and-through silk thread suture passed.
Under tension the resected nerve ends brought
together until they meet; suture tied. Suture line wrapped with two
layers of Cargile membrane. Fascia stitched over
the nerve; wound closed. May 20, 1919, killed. Dog in very good
condition. On exposing the left ulnar, evident
suture had given way; resected ulnar ends found separated. Central
ulnar ends in large bulb, from the distal end of
which there can be traced several fine nerve bundles which are found to
spread out fan-shaped over the adjacent
muscle. These fine nerve bundles could not with certainty be traced to
the distal ulnar. The distal ulnar presents the
appearance of a partially regenerated nerve. On slowly cutting the
distal ulnar at the level of the elbow, after
exposing the forearm muscles supplied by ulnar, feeble contraction of
these muscles is noted. Certain of the central
fibers appear to have reached the distal ulnar segment. Central and
distal ulnar and intervening connective tissue
removed and fixed in ammoniated alcohol for pyridine-silver staining.
Fairly good silver differentiation attained.
Microscopic
findings.- Very large central ulnar bulb evidenced structurally,
from the distal end of which
numerous small nerve funiculi, having very tortuous course, can be
traced into the connective tissue. No trace of
Cargile membrane observed. In cross and longitudinal sections of the
distal ulnar there are observed a good number
of new neuraxes, fairly evenly distributed through the several
funiculi; these are clearly made out in cross sections of
the distal ulnar at the level of the elbow. Fairly complete
regeneration of the distal ulnar attained.
In
10 of the 13 experiments of tension sutures, it is quite evident that
the tension sutures
gave way, permitting the nerve ends to separate and to withdraw
centrally or distally or both
from the tubular sheath applied. This separation of nerve ends
apparently occurred within a few
days after the operation. The pressure of the suture on the epineural
and perineural con- nective
tissue in the line of tension can not help but weaken these fibrous
tissue layers and cause them to
give way in the direction of the suture pull. Immobilization of the
part may lessen the tendency
of the tension suture to tear and obviate certain gross strains but can
not prevent the direct action
of the suture on the fibrous sheaths of the nerve. In the experiments
in which the tension suture
gave way, the approximation of the nerve ends, made for the purpose of
facilitating the down-growing central neuraxes to reach the distal
stump was probably lost before the regenerative
process was well under way. Of interest are the records of the
experiments in which it seemed
apparent that the tension sutures had given way, which had been kept
for periods varying in the
several experiments (No. 282, No. 283, No. 286 and No. 287) from about
9 months to nearly 11
months. In all of these experiments the nerve ends were found separated
to nearly the distance
recorded at the time the tension suture was applied. In each case there
was found a large central
bulb and from this there could be traced a variable number of larger
and smaller nerve bundles,
spread out fan-shaped on the muscle bed or winding their way in
tortuous course through the
connective tissue. It was not possible to trace these small nerve
funiculi to the distal stump, but
in sections of the central end of the distal stump neuraxes were found
scattered through the
funiculi, clearly differentiated in pyridine-silver preparations. These
observations show the
extent to which down-growing neuraxes will grow in connective tissue.
The manner of the
downgrowth of these neuraxes confirms the view that the tension sutures
gave way within a few
days after operation. The downgrowth of neuraxes in connective beds, in
intermuscular septa, in
the connective tissue between muscle fasciculi and over fascial layers,
centimeters
1274
distal to the central
nerve bulb, in several of these experiments reaching the distal stump,
explains the manner of spontaneous regeneration after nerve severance,
a phenomena of not
unusual occurrence. The downgrowth of central neuraxes in the manner
above indicated needs to
be considered in judging by the mere "return of function" in
experimental and in clinical work
the worth of operative procedures used for bridging nerve defects; the
down-growing neuraxes in
the experiment or in the clinical case in question may have reached the
distal stump in spite of
the operative procedure. A careful control, based on a study of serial
sections stained by methods
giving differential neuraxis staining is necessary before the results
of a particular method of
peripheral nerve repair can be evaluated.
In
three of the experiments the tension sutures maintained. In Experiment
No. 277, the
left ulnar nerve was resected only 2.5 cm. With a single suture the
nerve ends were brought
together to within 2 mm. On exposing the ulnar 54 days after the
operation the nerve ends were
found in approximately the same relative position. A relatively small
number of new neuraxes
were found in the central end of the distal stump having passed the
connective tissue layer
intervening between the nerve ends. In Experiment No. 281, examined
somewhat over five
months after the operation, the right ulnar had been resected 4 cm. By
tension suture the ends
were brought together, but on tying had again separated to the extent
of 15 mm. In this case a
formalized arterial tube had been slipped over the suture region, the
experiment was thus to
some extent a tubular suture. At the time the ulnar was exposed the
suture in place could be seen
through the wall of the tubular sutures also found well in place. This
dog had accidentally hung
himself on the tie rope; the nerve could thus not be tested
functionally. In pyridine-silver
preparation numerous new neuraxes were found in the distal ulnar which
could be traced to the
central nerve bulb, through the arterial tube. It is clear that in this
experiment the tension suture
maintained and that the tubular suture prevented dispersion of the
down-growing neuraxes. The
neurotization of the distal ulnar was quite complete. In Experiment No.
285, examined
approximately nine months after the operation, the left ulnar was
resected to the extent of 3.4
cm. and under tension suture the nerve ends were approached until they
nearly touched; two
layers of alcoholized Cargile membrane were wrapped about the suture
line. On exposing the
ulnar a long spindle-shaped central nerve-bulb was found to lead
directly to the distal ulnar
segment. In sections, the suture was found in place. Numerous neuraxes
derived from the central
stump and found distributed quite evenly through the several funiculi
of the distal ulnar segment
could be traced to the level of the elbow. These three experiments
indicate that should a tension
suture maintain, regeneration from the central stump is in no way
inhibited by the tension to
which the nerve ends are subjected. It is evident from the study of
microscopic sections that the
tubular sheaths employed facilitate materially the down growth of the
central neuraxes. Tension sutures, wrapped with alcoholized Cargile
membrane or formalized arterial tube, while
in a measure successful in a limited number of experiments of this
series, are not to be
recommended in preference to other methods of bridging nerve defects,
notably nerve
transplantation, which offers greater assurance of success.
1275
GENERAL CONCLUSIONS
1.
The experimental observations here presented, controlled for the great
majority of the
experiments through microscopic study of either the entire operated
nerve or so much thereof as
was deemed advantageous, treated en bloc by the pyridine-silver method,
cut and mounted
serially and stained with special reference to neuraxis
differentiation, when considered
collectively, present convincing evidence in support of the monogenetic
view of the regener-ation of peripheral nerves degenerated as a
consequence of mechanical or chemical injury.
According to this view, regeneration of the distal, degenerated segment
of a peripheral nerve is
through downgrowth of neuraxes sprouts or buds derived from the
undegenerated neuraxes of
the central stump. The series of experiments on nerve transplantation,
and more particularly such
in which homogenous nerve segments were used to bridge nerve defects,
appear to us to warrant
the deduction that the sine qua non of peripheral nerve regeneration is
the downgrowth of central
neuraxes, since the sheath cells of the transplanted nerve fibers
presented no evidence of latent
vitality as manifested by proliferation and appeared to be without
biological significance so far
as growth of neuraxes through the transplanted nerve fiber is
concerned. That down-growing
neuraxes may grow relatively long distances in the absence of sheath
cells derived from either
the central or distal stump of a divided nerve seems to be established
by these experimental
observations, the experiments confirming deductions drawn from
observations on tissue culture
and experimental embryological studies (Harrison) to the effect that
sheath cells are not essential
to the growth of the neuraxes. The ultimate relation of sheath cells to
the budding and growing
neuraxes and the ultimate relation of the down-growing neuraxes to the
syncytial protoplasmic
bands (Büngner's " bandfasern "), the end product of Wallerian
degeneration of peripheral
nerve fibers, has not been conclusively determined. The pyridine-silver
methods in common
with other silver precipitation methods of neuraxis staining, while
permitting excellent neuraxis
differentiation, are not methods which would be selected for the study
of finer cytologic details.
Other methods of histologic study were not given consideration. The
reason for this series of
experimental studies on peripheral nerve repair did not warrant
extended duplication of
experiments and of necessity influenced the special fields of inquiry.
Our observations answer
only in a very general way and not decisively the question of the
intraprotoplasmic or the
extraprotoplasmic position of the new neuraxes. The end-discs found in
our preparations, so far
as can be determined, present the same form and structure as those
found on the end of nerve
fibers growing in tissue culture (Harrison) and are of a diameter which
is several times greater
than the diameter of the protoplasmic syncytial bands. A decisive
answer to the question of the
relation of the down-growing neuraxes and the syncytial protoplasmic
bands of degenerated
peripheral nerves is perhaps not to be
1276
found as a result of
study of sections, but rather to be sought in experimental observations
on the
regeneration of nerve fibers devoid of sheath cells.
2.
These experimental observations warrant the conclusion that bridging a
nerve defect
by means of a nerve transplant is at legitimate operation and that on
the whole the most
satisfactory results are to be obtained by use of auto-genous-nerve
transplants. For purpose of
clinical surgery a multiple or cable auto-nerve transplant is
recommended using several
segments of one or of more than one cutaneous nerve, which may be
sacrificed without material
loss of function. The question of the particular cutaneous sensory
nerve to be selected for
purpose of nerve bridge is not material and depends largely on the
convenience of the operators;
the question of the funicular arrangement of the nerve selected is of
quite secondary importance;
whether the central or distal end of the nerve segment to be
transplanted is placed centralward it
is not necessary to consider. The sum total of the nerve segments
transplanted should
approximate in cross diameter that of the nerve bridged; experimental
evidences at hand showing
clearly the value of accurate end-to-end approximation of the cut
surfaces in placing a nerve
bridge. The suture material found experimentally to be the most
serviceable is a fine, waxed silk
thread, threaded on fine round and half-curved needles, which are
passed through the nerve and
transplant and adjusted so as to obtain accurate apposition of the cut
surfaces of the nerve ends.
In many of the experiments in which sutures were placed, the suture
line and the adjacent nerve
segments were cut longitudinally into serial sections. It is surprising
to note the slight evidence
of connective tissue reaction, even in experiments examined a long time
after the operation. The
down-growing neuraxes derived from the central stump, penetrate the
transplant through the
central wound and course distally within the funiculi of the
transplanted nerve segments and to a
large extent within the neurolemma sheaths of the transplanted nerve
fibers. Such down-growing
neuraxes as reach the distal wound pass through this and penetrate the
distal segment of the
nerve. A histologic study of material obtained from numerous
experiments on bridging nerve
defects with nerve transplants, even when made from autogenous tissue,
convinces that the
function of the nerve transplant is to large extent merely mechanical,
in that it offers numerous
microscopic tubular structures, which maintain for a relatively long
period and serve for the
down-growth of central neuraxes. Even in autogenous peripheral nerve
tissue when used as a
nerve bridge the sheath cells of the transplanted nerve fibers are
with-out biological significance.
The value of a nerve transplant is proportionate to the extent in which
the neurolemma sheaths
are patent relatively early after transplantation, and it is a question
whether the superiority of
autogenous and homogenous transplants as against heterogenous-nerve
transplants is not to be
ascribed to the relative potency of the neurolemma sheaths relatively
early after transplantation
rather than to other ascribed causes. The funicular pattern of the
central segment of a bridged
nerve is to a large extent lost as the down-growing neuraxes pass
through the central wound. The
neuraxes reaching the distal end of the transplant meet with further
rearrangement on passing
through the distal wound. Thus there is no possibility of maintaining
the funicular pattern of a
given nerve regenerated through a nerve transplant. In so far as
1277
has been determined
experimentally, there is no reason to assume that the down-growing
neuraxes manifest any selectivity on reaching the peripheral segment
after bridging (or after a
primary or secondary nerve suture). The neuraxes derived from efferent
neurones no doubt enter
the neurolemma sheaths found in the distal segment of both efferent and
afferent peripheral
nerve fibers and vice versa. It is assumed that chance brings at least
as many branches to
homologous nerve fibers as to heterogenous nerve fibers. A very great
increase in the number of
new neuraxes found in the peripheral end of the central stump permits
many new nerve-fiber
branches to go astray in the scar tissue, the transplant, and in the
peripheral stump and still leave
a sufficient number to admit of structural and functional regeneration.
3.
Experimental observation warrants the conclusion that the placing of a
homogenous-nerve transplant is an operation which is justified. This
operative procedure is made more
available to clinical surgery through the convincing experimental
results obtained with stored
homogenous nerve transplants, and especially with nerve transplants
stored in sterile liquid
petrolatum. The downgrowth of central neuraxes through the funiculi and
the neurolemma
sheaths of nerve fibers of homogenous-nerve transplants stored in
liquid petrolatum is quite as
rapid and very nearly as good as when fresh auto-nerve transplants were
used. The possibility of
thus storing peripheral nerve tissue when opportunity presents itself
makes the operation of
homo-genous-nerve transplantation to bridge nerve defects more
available as a surgical
procedure. This operation obviates the necessity of making a second
wound, as is generally
necessary when it is desired to obtain autogenous nerve tissue. The
method of making a multiple
or cable-homogenous-nerve transplant, of using a number of smaller
nerve bundles rather than
one large nerve, is here suggested; this has not been tested
experimentally but commends itself
when considered in the light of observations on cable-auto-nerve
transplants. The use of
homogenous nerve tissue, stored in 50 per cent alcohol for the purpose
of nerve bridge, deserves
serious consideration. The experimental results obtained are
encouraging. The simplicity of this
method of storage commends itself.
4.
The experimental evidence presented with reference to
heterogenous-nerve transplants
confirms the earlier observations of Huber that regeneration of a
severed nerve with loss of
substance may take place through a heterogenous-nerve transplant. So
far as can be judged on
gross inspection and on study of histologic sections, the source of a
nerve transplant does not
materially influence the fibrous union of the respective end of the
nerve transplant and the
resected nerve. If a satisfactory suture is made with desired
end-to-end approximation of the cut
surfaces the fibroblastic reaction appears essentially the same whether
auto-, homo-, or
heterogenous nerve segments are used to bridge the nerve defects,
suggesting the conclusion that
histogenetically the fibrous tissue of the wound regions is derived
primarily from the parent
nerve and not from the connective tissue elements of the nerve
transplant. The source of the
nerve transplant does not per se appear to influence the extent of
connective tissue proliferation
in the field surrounding the nerve transplant. On gross inspection the
heterogenous-nerve
transplant appears to serve the
1278
purpose of a nerve
bridge quite as satisfactorily as an autogenous- or homogenous-nerve
transplant. However, on study of an extended series of microscopic
sections of tissue, removed
in experiments in which heterogeronous-nerve trans-plants were made,
differentially stained for
determination of neuraxes, the conviction grows that while a certain
relatively small per cent of
down-growing central neuraxes may pass through the neurolemma sheaths
of the nerve fibers
found within the funiculi of the transplanted nerve segment, a much
larger per cent of down-growing neuraxes are found in the connective
tissue sheaths of the nerve transplant and in the
immediately surrounding connective tissue. Many of these extrafunicular
down-growing
neuraxes, found in the connective tissue either as single fibers or as
small bundles of fibers,
reach the region of the distal wound and through it bring about
neurotization of the distal
segment of the nerve. So far as may be determined from a study of
pyridine-silver stained
preparations of the extensive series of experimental observations on
nerve transplantation, the
fragmentation of the neuraxes and the myelin, their dissolution, and
removal in the transplanted
nerves no matter whether auto-,homo-, or heterogenous nerve tissue is
considered, is not the
same as in the process of Wallerian degeneration as found concurrent in
the distal segment. The
participation of the sheath cells of the transplanted nerve fibers in
the fragmentation and removal
of the neuraxes and myelin has not been established and seems quite
secondary. The conclusion
seems warranted that neither in auto-, homo-, nor in heterogenous nerve
transplants are the
sheath cells of the transplant of biological significance in the
regeneration of the nerve. The
much more favorable results obtained experimentally on use of
autogenous and homogenous
transplants, even when the latter have been stored for extended periods
before use, than when
heterogenous-nerve tissue is used, can not be attributed to the
behavior of the sheath cells in the
respective experiment, since this difference extends to
heterogenous-nerve transplants stored in
alcohol. The experimental evidence presented argues for the elimination
of the use of
heterogenous-nerve transplants as a surgical procedure.
5.
When sheathing of a nerve is deemed necessary after neurolysis, nerve
suture or nerve
transplantation or other operative procedure on peripheral nerves, the
use of alcoholized Cargile
membrane in double or triple layers deserves consideration as a
surgical procedure.
Experimental observations indicate that it remains in the tissue 5 to 6
months without absorption
and in healthy tissue and aseptic wounds without causing fibrous tissue
proliferation. Alcoholized Cargile membrane is readily prepared, is
easily applied, and is pliable when bathed
in the tissue juices. There was no opportunity for testing
experimentally the behavior of
alcoholized Cargile membrane in the presence of scar tissue. The
several series of experimental
observations in which various substances were used for ensheathing
operated nerves permit the
conclusion that alcoholized Cargile membrane used for the purpose of a
tubular sheath in
peripheral nerve repair is to be given preference over tubular sheaths
prepared from formalized
arterial tubes, auto-fascial sheaths prepared from fascia lata, and a
fat sheath or fat membrane; it
is more readily prepared and applied and incites less connective tissue
proliferation. Cargile
membrane as generally available is useless for this purpose by reason
of its early absorption.
1279
6.
Experimental evidence is at hand to substantiate the view that
regeneration of a
severed nerve with loss of substance can take place through a tubular
suture. The experiments in
which downgrowth of central neuraxes through the lumen of a tubular
suture was obtained offer
convincing evidence in support of the monogenetic view of peripheral
nerve regeneration. The
experiments of tubular suture in the repair of severed nerves with loss
of substance are of
academic interest. While regeneration through a tubular suture is
possible, this method of
operative procedure does not commend itself in surgical practice, since
it is less certain of
favorable results than when auto- or homo- nerve transplants are used.
7.
Experimental observations contraindicate the application of tension
sutures in the
repair of severed peripheral nerves.
8.
Amputation neuromata form at the distal end of the central stump in
aseptic wounds
relatively early after nerve severance, and are regarded as a thwarted
attempt at nerve
regeneration. The injection of absolute alcohol into the nerve about
2.5 cm. above the place of
section in experimental observations prevents neuroma formation.
REFERENCES
(1) Herrick, C. Judson: An Introduction
to
Neurology. W. B. Saunders Co., Philadelphia and London, 1922, 157.
(2) Stoffel, A.: Zum Bau und zur
Chirurgie
der peripheren Nerven. Verhandlungen der deutschen Gesellschaft für
orthopädische Chirurgie, Stuttgart, 1912, xi, 177.
(3) Heinemann, O.: Ueber
Schussverletzungen
der peripheren Nerven. Nebst anatomischen Untersuchungen über
den inneren Bau der grossen Nervenstämme. Archiv fur klinische Chirurgie, Berlin, 1916, cviii, No. 1, 107.
(4) Borchardt, M., and Wjasmenski: Der
Nervus
medianus. Beiträdge zur klinischen Chirurgie,
Tilbingen,
1917, cvii, No. 5, 553 .
(5) Langley, J. N., and Hashimoto, M.:
On the
Suture of Separate Nerve Bundles in a Nerve Trunk and on Internal
Nerve Plexuses. The Journal of Physiology, London, 1917, li,
Nos. 4 and 5, 318.
(6) Compton, A. T.: The Intrinsic
Anatomy of
the Large Nerve Trunks of Limbs. The Journal of Anatomy and
Physiology, London, 1916-17, li, 103.
(7) Dustin, A. P.: La fasciculation des
nerfs, son importance dans le diagnostic, le prognostic et le
traitement
des lesions nerveuses. Traraux de ambülance de l'ocean, Masson
et cie., Paris, Vol. ii, 1918.
(8) Künzel: Zur Prognose der
Nervenschussverletzungen. Beiträdge zur klinischen Chirurgie, Tübingen, 1918, cvii, 583.
(9) Stookey, B.: Surgical and Mechanical
Treatment of Peripheral Nerves, with a Chapter on Nerve Degeneration
and Regeneration by G. Carl Huber. WV. B. Saunders Co., Philadelphia
and London, 1922, 475.
(10) Doinikow, von Boris: Beiträge zur
Histologie und Histopathologic der periphercn Nerven. Nissl-Alzheimer,
histologische und histopathologische Arbeiten ueber die Grosshirnrinde,
Jena, 1911, iv, 445.
(11) Nemiloff, A.: Ueber die Beziehung
der
sog. "Zellen der Schwannschen Scheide," Zurn Myelin in der
Nervenfasern von Saugetieren. Archiv für mikroskopische Anatomic,
Bonn, 1910, lxxvi, No. 2, 329.
(12) His, W.: Histogenese und
Zusammenhang
der Nervenelemente, Archiv für Anatomic und Physiologie Supplement-Band, Leipzig, 1890, 95 .
(13) Harrison, R. G.: Observations on
the
Living Developing Nerve Fiber. (Proc. Soc. Exp. Biol. and Med., iv,
1907.) The Anatomical Record, Baltimore, 1906-8, i, No. 5, 116.
(14) Balfour, F. M.: On the Development
of
Spinal Nerves in Elasmobranch Fishes. Philosophical
Transactions, London, 1876;, clxvi, 175.
(15) Dohrn: Die Schwainnscheni Kernie,
ihire
Herkunft und Bedeutug. Mitteilungen der Zoologischen Station.
Naples, 1901, xv, Nos. 1- 2, 135 .
(16) Bethc, A.: Allgemeine Anatoime und
Physiologie des Nervensystems, Verlag von Georg Thieme,
Leipzig, 1903.
(17) Hensen, V.: Ueber die Entwickelung
des
Gewebes und der Nerven in Schwanze der Froschlarve. Virchows
Archiv, Berlin, 1864, xxxi, No. 1, 51.
(18) Held, Die Entwicklung des
Nervengewebes
bei den Wirbeltieren. 1909.
(19) Harrison, R. G.: Further
Experiments on
the Development of Peripheral Nerves. The American Journal
of
Anatomy, Baltimore, 1906, v, No. 2, 121.
(20) Streeter, G. L.: The Development of
the
Nervous System. Manual of Human Embryology, Keibel and
Mall, Philadelphia and London, 1912, ii, 1.
(21) Arnemann. Versuche über die
Regeneration an lebenden Tieren. Gottingen, 1787.
(22) Cruikshank, William: Experiments
on
Nerves, Particularly on Their Reproduction and on the Spinal
Marrow of Living Animals. Philosophical Transactions, London, 1795,
Part I, 177.
(23) Haighton, John: An Experimental
Inquiry
Concerning the Reproduction of Nerves. Philosophical
Transactions, London, 1795, Part 1, 190.
(24) Waller, A.: Sur la reproduction des
nerfs et sur la structure et les fonctions des ganglions spinaux. Müller's
Archiv für Anatomie, Physiologie, und Wissenschaftliche Medicin,
Berlin, 1852, 392.
(25) Ranvier, M. L.: Lecons sur
l'histologie
du Système Nerveux, Paris, 1878. Vols. i and ii.
(26) Vanlair, C.: Nouvelles recherches
expérimentales sur la régénération des nerfs. Archives de biologic,
Gand, Liége et Paris, 1885, vi, 127.
(27) Von Büngner, O.: Ueber die
Degenerations und Regenerations-vorgängs am Nerven nach
Verletzungen. Zeigler's Beitrage zur pathologischen Anatomie und zur
allgemeinen Pathologie, Jena, 1891, x, No.
4, 321.
(28) Howell and Huber: A Physiological,
histological, and Clinical Study of the Degeneration and
Regeneration in the Peripheral Nerve Fibers after Severance of their
Connections with the Nerve Centers. Journal of
Physiology, Cambridge, 1892, xiii, 335.
(29) Stroebe, H.: Experimentalle
Untersuchungen über Degeneration and Regeneration peripherer Nerven
nach
Verletzungen. Zeigler's Beiträdge zur pathologischen Anatomie und
zur allgemeinen Pathologic, Jena, 1893, xiii, No.
2, 160.
(30) Huber, G. C.: A Study of the
Operative
Treatment for Loss of Nerve Substance in Peripheral Nerves. Journal of Morphology, Boston, 1895, xi, No. 3, 629.
(31) Galeoti, G. and Levi, G.: Ueber die
Neubildunig des nervösen Elemente in dem wiedererzeugten
Muskelgewebe. Zeigler's Beiträdge zur pathologischen Anatomie und
zur allgemeinen Pathologie, Jena, 1895, xvii, No. 2, 369.
(32) Kennedy, R.: On the Regeneration of
Nerves. Philosophical Transactions, London, 1897, ix, 472.
(33) Weiting, J.: Zur Frage der Regeneration
der peripherischen Nerven. Zeigler's Beiträdge zur pathologischen
Anatomic und zur allgemeinen. Pathologie, Jena, 1898, xxiii, No. 1,
42.
(34) Langley, J. N.
and
Anderson, H. K.: On
Autogenetic Regeneration in the Nerves of the Limbs. The Journal of
Physiology, London, 1904, xxxi, No. 5, 418.
(35) Lugaro, E.: Zur Frage der autogenen
Regeneration der Nervenfasern. Neurologisches Centralblatt, Leipzig,
1905, xxiv, No. 24, 1143.
(36) Perroncito, A.: Die Regeneration
der
Nerven. Zeigler',s Beiträge zur pathologischen Anatomie
und zur
allgemeinen Pathologie, Jena, 1907, xlii, No. 2, 355 .
(37) Poscharissky, J.: Ueber die
histologische Vorgänge an den peripherischen Nerven nach
Kontinuitätstrennung. Zeigler's Beiträdge zur pathologischen
Anatomic und
zur allegmeinen Pathologie, Jena, 1907, xli,
No. 1, 52
(38) Ramón v Cajal, S.:
Nervenregeneration.
Barth. Leipzig, 1908. Regeneracio n de los nervios. La clinica
moderna, Zaragoza, 190S, vii, No. 75, 185
(39) Ranson, S. W.: Degeneration and
Regeneration of Nerve Fibers. The Journal of Comparative
Neurology,
Philadelphia, 1912, xxii, No. 6, 487 .
(40) Boeke. Studicen zur
Nervenregeneration.
No. 1. Die Regeneration der motorischen Nervenelemente, etc. Verhand.
der Kon. Akad. van Wet. Amsterdam, 1916,
Part 18, No. 6.
(41) Boeke. Studien zur
Nervenregeneration,
No. 2. Die Regeneration nach Vereinigung ungleicher Nervenst cke. Verhand.
der Kon. Akad. van Wet., Amsterdam, 1917, Part 19, No. 5.
(42) Dustin. Les lésions
posttrauinatiques
des nerfs. Travaux de ambulance de l’océan, Paris, 1917, No. 2.
(43) Ingebrigtsen, R.: Am
Nerventransplanitation. Christiania, 1918. I. Contribution to the
Biology of Peripheral
Nerves in Transplantation. II.
Life of Peripheral Nerves of Mammals in
Plasina. (From the Laboratories of the
Rockefeller lnstitute for Medical Research, and the
Pathological
Institute of the University Clinic, Christiania.) Journal of Experimental Medicine, New York, 1916, xxiii, No. 2,
251.
(44) Mönkeberg G. and Bethe, A.: Die
degeneration des markhaltigen Nervenfasern der Wirbeltiere. Archiv
für mikroskopische Anatomie, Bonn, 1899, liv, 135.
(45) Huber, G. C.: Ueber das Verhalten
der
Kerne der Schwann'schlen Scheiden bei Nerven- degeneration. Archiv für mikroskopische Anatomie, Bonn, 1892, xl, 409.
(46) Tello, F.: Dégénération et
régénération
des plaques motrices apr s la section des nerfs. Trabajos del
Laboratorio de Investigaciones Biológicas, Madrid, 1907, v, 117.
(47) Kirk, E. G. and Lewis, D. D.:
Regeneration in Peripheral Nerves: An Experimental Study. Johns
Hopkins Hospital Bulletin, Baltimore, 1917, xxviii, No.312, 71.
(48) Huber, G. C.: Observations on the
Degeneration and Regeneration of Motor and Sensory Nerve Endings in
Voluntary Muscles. American Journal of Physiology. Boston,
1900, iii, No. 7, 339.
(49) Huber, G. C.: Operative Treatment
of
Peripheral Nerves after Severance, More Particularly after Loss of
Substance: A Critical Review. The Journal of Laboratory and
Clinical Medicine, St. Louis, 1916-17, ii, 837.
(Prepared for the Committee on Medicine and Hygiene, of the
National
Research Council.)
(50) Stookey, B.: The Futility of
Bridging
Nerve Defects by Means of Nerve Flaps. Surgery, Gynecology
and
Obstetrics, Chicago, 1919, xxix, No. 3, 287.
(51) Hofmeister, von, F.: Ueber doppelte
und mehrfache Nervenpfropfung. (Beitr. z. Klin. Chir. 1915, xcvi, No.
3,
329). Medicinisches Correspondenzblatt des württembergischen
ütztlichen Landesvereins, Stuttgart, 1915,
lxxxv, No. 12, 117.
(52) Huber, G. C.: Transplantation of
Peripheral Nerves. Archives of Neurology and Psychiatry,
Chicago, 1919,
ii, 466 .
(53) Huber, G. C.: Repair of Peripheral
Nerve
Injuries. Surgery, Gynecology and Obstetrics Chicago, 1920,
xxx,
No. 5, 464.
(54) Schlosser: Heilung peripherer
Reizzust
ande sensibler und inotorischer Nerven. Klin. Monat. f. Augenheil.,
Stuttgart, 1903, xli, 244.
(55) Schlosser H.: Erfahrungen in der
Neuralgiebehandlung mit Alkoholeinspritzungen. Verhandlungen des
Kongresses für innere Medizin, Wiesbaden, 1907, xxiv, 49.
(56) Brissaud, Sicard and Tancon. Essais
de
traitement de certain cas . . . par l'alcoolisation locale des trones
nerveux. Revue neurologique, Paris, 1906, xiv, No. 14, 633.
(57) Finkelnburg: Diskussion zur
Neuralgiefrage. Verhandlungen des Kongresses für innere
Medizin,
Wiesbaden, 1907, xxiv, 75.
(58) May, O.: The Functional and
Histological
Effects of Intraneural and Intraganglionic Injections of Alcohol. British Medical Journal, London, August 31, 1912, ii, 465.
(59) Harris, W.: The Alcohol Injection
Treatment for Neuralgia and Spasm. Lancet, London, May 8, 1909,
i, 1310.
(60) Harris, W.: Alcohol Injection of
the
Gasserian Ganglion for Trigeminal Neuralgia. Lancet, London,
January
27, 1912, i, 218.
(61) Patrick, H. T.: The Technic and
Results
of Deep Injection of Alcohol for Trifacial Neuralgia. Journal of
the American Medical Association, Chicago, 1912, lviii, 155
(62) Sicard, J. A.: Traitment des
névrites
douloureuses de guerre (causalgies) par l ‘alcoolisation nerveuse
locale. Presse médicale, Paris, 1916, xxiv, No. :31, 241.
(63) Huber, G. C., and Lewis, D.:
Amputation
Neuromas, Their Development and Prevention. Archives of
Surgery, Chicago, 1920, i, No. 1. 85.
(64) Cone, S. M.: Surgical Pathology of
the
Peripheral Nerves. The British
Journal of Surgery. Bristol, 1917-18, v,
No. 20, 524.
(65) Corner, E. M.: The Surgery of
Painful
Amputation Stumps. Proceedings of
the Royal Society of Medicine, London, 1917-18, xi, 7. The Structure, Forms and Conditions of the Ends
of Divided Nerves. With a Note on
Regeneration Neuromata. British Journal of Surgery, Bristol,
1918-19, vi, 273. Sec also: Marinesco, G.: The
Characteristics of Amputation Neuromata. Proceedings of the Royal
Society of Medicine, London, 1917-1S, xi, 5.
(66) Philipeaux and Vulpian: Note sur
des
essais de greffe d'un troncon du nerf lingual entre les deux fonts du
nerf
hypoglosse, aprés excision d’un segment de ce dernier nerf. Arch. de
Phys. Paris, 1870. iii, No. 5, 618.
(67) Albert E.: Neurom des Nervus
medianus. Berichte
des naturwissenschaftligh-medizinischen Vereines in
Innsbruck, Innsbruck, 1878, ix, 97 .
(68) Stookey, B.: The Technic of Nerve
Suture. Journal of the American Medical Association,
Chicago, 1920,
lxxiv, 1380.
(69) Elsberg, C. A.: Technic of Nerve
Suture
and Nerve Grafting. Journal of the American Medical
Association, Chicago, November 8, 1919, lxxiii, 1422 .
(70) Forssman, J.: Zur Kenntniss des
Neurotropismus. Beiträge zur pathologischer Anatomic und zur
allgemeinen Pathologie, Jena, 1900, xxvii, No. 3, 407.
(71) Merzbacher, L.: Zur Biologie der
Nervendegeneration. Neurologisches Centralblatt, Leipzig, 1905,
xxiv,
No. 4, 150.
(72) Segale, M.: Sulla rigenerazione
delle
fibre nervose. Riforma medica, Naples, June 23, 1906, xxii,
681.
(73) Maccabruni, F.: Der
Degenerationsprozess
der Nerven bei homoplastischen und heteroplastischen
Pfropfungen. Folia Neuro-biologica, Leipzig, 1911, v. No. 6,
598.
(74) Ingebrigtsen, R.: A Contribution to
the
Biology of Peripheral Nerves in Transplantation. The Journal of
Experimental Medicine, Lancaster, 1916, xxiii, No. 2, 251.
(75) Ingebrigtsen, R.: Sur la
transplantation des nerfs. Lyon
chirurgical, Lyon, 1916, xiii, No. 5,
828.
(76) Dujarier, C. and Fratvcois: Stir
vingt
cas de greffe hoimoplastique dans les sections nerveuses. Bulletins et
mèmoires de la Sociètè de chirurgic de Paris, Paris, January 9,
1918, xliv, 43.
(77) Nageotte, J.: Stir line atrophic
musculaire rèflexe prècoce apre s stuture des nerfs par affrontement
et stir les
inconvénients de la greffe nerveuse vivante autoplastique. Comptes rendus hebdomadaires des sèances de la
Sociètè de biologie, Paris, July 20, 1918, lxxxi, 761.
(78)
Morris, R. T.: A Report on Experiments Made with
Cargile Membrane for the Purpose of Determining its Value in Preventing
the Formation of Peritoneal Adhesions. Medical Record, New York, May 17, 1902, lxi, 773.
(79) Craig, A. B., and Ellis, A. G.: An
Experimental and Histological Study of Cargile Membrane with
Reference to (1) its Efficacy in Preventing Adhesions in the Abdominal
and Cranial Cavities and Around Nerves and
Tendons and (2) its Ultimate Fate in the Tissues. Annals of Surgery,
Philadelphia, 1905, xli, No. 6, 801.
(80) Sherren, J.: Some Points in the
Surgery
of the Peripheral Nerves. Edinburgh Medical Journal,
Edinburgh,
1906, xx, ii. s., No. 4, 297 .
(81) Meuriot, H.: Cent observations
d'isolement des nerfs par manchonnage au caoutchoue. Bulletins et
mèmoires de ln Sociètè de chirurgie de Paris, Paris, May 8, 1918,
xliv, 850.
(82) Denk, W.: Ueber
Schussverletzuingeii der
Nerven. Beiträdge zur klinischen
Chirurgie, Tübingen,
1914, xci, Nos. 1 and 2, 217.
(83)
Doepfner: Zur Methodik der Naht and Pripheren Nerven. Münchener,
medizinische Wochenschrift. München,
April 13, 1915, lxii, 526.
(84) Hirschel, G. Erfahrungen über
Schussverletzungen der Nerven. (Deutsch. Zeitschr, f. Chir., cxxxii,
1914-15.) Münchener medizinische Wochenchrift, München,
February 2, 1915, lxii, 159.
(85) Kredel, L.: Ueber das Verhalten der
auf
operierte schussverletztc Nerven über pflanzten Fascienlappen. Zentralblatt für Chirurgie, Leipzig, March 27, 1915, xlii, 201.
(86) Kirk, E. G. and Lewis, D.: Fascial
Tubulization in the Repair of Nerve Defects. Journal of the
American
Medical Association, Chicago, August 7, 1915, lxv, 486.
(87) Lewis, D. D., and Davis, C. B.: The
Repair of Tendons by Fascial Transplantation. Journal of the
American
Medical Association, Chicago, February 21, 1914, lxii, 602.
(88) Foramitti, C.: Zur Technik der
Nervennaht. Archiv für klinische Chirurgie, Berlin, 1904,
lxxiii, No. 3,
643.
(89) Eden, R.: Untersuchungen u ber die
spontane Wiedervereiningung durch trennter Nervem im
stromenden Blut und im leeren Gefässrohr. Archir für klinische
Chirurgie, Berlin, 1917, cviii, No. 3, 344.
(90) Glück: Ueber Transplantation,
Regeneration and entzundliche Neuhildung. Berliner klinische
Wochenschrift, Berlin, 188001, xviii, No. 37, 529.
(91) Wö1fer: Ueber die Nervennaht und
Nervenlosung. Zentrablatt für Chirurgie, Leipzig, 1893.
(92) Payr, E.: Beitr age zur Technik der
Blutgefäss und Nervennaht nebst Mittheillingen über die
Verwendung eines resorbirbaren Metalles in der Chirurgie. Archiv
für klinische Chirurgie, Berlin, 1900, lxii, No. 1,
67.
(93) Lotheisen, G.: Zur Technik der
Nerven
und Sehnennaht. Archiv, für klinische Chirurgie,
Berlin, 1901,
lxiv, No. 2, 310 .
(94) Auerbach, S.: Galalith zur
Tubulisation
der Nervennäch Neurolysen und Nervennähten. Münchener
medizinische Wochenschrift, M unchen, October 26, 1915, lxii, 1457.
(95) Steinthal, H.: Die Deckung
grösserer
Nervendefekte durch Tuibilarnaht. Zentlb. f. Chir. 1917, xliv,
No. 29,
646. Also: Beiträge zur klinischen Chirurgie, Tu bingen, 1916,
xcvi, No. 3, 295.
(96) Edinger, L.: Ueber dieVereinigung
getrennter Nerven; Grundsätzliches und Mitteilung eines Nerven
Verfahrens. Münchener medizinische Wochenschrift, München,
February 15, 1916, 1xiii, 225.
(97) Stracker, O.: Zu den
Ueberbrückungsversuchen von Nervendefekten. Zentralbilatt für Chirurgie,
Leipzig, December 16, 1916, xliii, 985 .
(98) Hohmann und Spielmeyer: Zur Kritik
des
Edingerschien und des Betheschen Verfahrens der Ueberbrückung grösserer
Nervenlücken. Münchener medizinische Wochenschrift, München,
January 6, 1917, lxiv, 97.
(99) Enderlen und Lobenhoffer, W.: Zur
Ueberebrückunig von Nervendefekten. Münchener medizinische
Wochenschrift, München, February 13, 1917, 1xiv, 225
(100) Spitzy, H.:
Bemerkung zur Ueberbrückung
von Nervendefecten. Münchener medizinische
Wochenschrift, München, March 13, 1917, lxiv, 372.
(101) Wollenberg, R.: Das
Edinger-Verfahren
der Nervendefektüberbrücking. Deutsche medizinische
Wochenschrift, Berlin and Leipzig, May 24, 1917, xliii, 641 .
(102) Blencke, A.: Ein weiterer Beitrag
zu
den Ueberbrückungsversuchen von Nervendefekten mit Edinger-Röhrchen. Zentralblatt
für Chirurgie, Leipzig, March 24, 1917,
xliv, 236.
(103) Eden, E.: Sind zur Ueberbrückung
von
Nervendefekten die Verfahren der Tubulization und der
Nerventransplantation zu empfehlen? Zentralblalt für Chirurgie,
Leipzig, February 17, 1917, lxiv, 138.
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