1. METHODS OF EXAMINATION. The spinal cord may be opened anteriorly or posteriorly. The choice of method is largely a matter of convenience or of individual skill in using certain instruments, such as the Brunetti chisels. The method of opening posteriorly is more commonly used in this country, as it requires less skill. It necessitates, however, an additional long skin incision that must be tightly stitched together to prevent leakage of blood and fluids after the restoration of the body. For this reason it is not as clean a method as the anterior opening, which requires only the one main skin-incision. In private practice the latter method is often advisable, as by it an examination of the cord can often be secured when the relatives would not consent to its removal posteriorly, on the ground of undue mutilation of the body. The anterior examination also permits a better inspection and an easier removal of the spinal ganglia and nerves.

Examination of Cord Posteriorly. For the opening of the spinal cord posteriorly the cartilage-knife, bone-forceps, bone-nippers and rhachiotome are necessary; in place of the latter the single saw, double chisel, Brunetti chisels or single chisel may be employed. The posterior examination of the cord should take place at the beginning of the autopsy, after the external inspection of the cadaver, before the thorax and abdomen are examined. The removal of the sternum gives a loss of resistance to the manipulations upon the back of the cadaver, and the turning-over of the body after it has been opened anteriorly is usually an unpleasant procedure because of the dripping of blood and other fluids. When it is found necessary to examine the cord posteriorly after the opening of thorax and abdomen it is better to fill these cavities with tow or excelsior, replace the sternum and sew up the anterior skin-incision before turning the body over.

The cadaver is placed face downwards, with medium-sized blocks beneath the cervical and lumbar regions, the arms being folded underneath the body. With the cartilage-knife an incision is then made through the skin and subcutaneous tissues in the median line, over the spinous processes, beginning above at the occipital prominence and ending at the lower border of the sacrum. The skin and subcutaneous tissues are then dissected back by bold slashing strokes for a distance of a hand’s breadth on both sides of the spine, thus laying bare the muscles of the neck and back. The muscles may be stripped back with the skin, but the heavy flaps thus formed are very likely to fall back and cover the seat of operation. Chain retractors may be used to hold the skin flaps back, particularly in the case of a very fat individual, but usually the separate stripping of the skin and muscles is sufficient. To remove the muscles the cartilage knife is set close against the spinous processes of the uppermost vertebræ and a deep cut made on each side of the spine throughout its entire length, severing the vertebral attachments of all muscles and tendons. About four finger-breadths outside of these cuts there should now be made from above downwards on both sides another deep cut through the muscles parallel with the first two incisions. The bundles of tendons and muscles between these parallel cuts on both sides of the spine are then separated from the bones as cleanly as possible, beginning either above or at the sacral end, severing the muscle-mass at the end at which the separation begins, but leaving it attached at the other end, where it is laid over the side of the body out of the way, and replaced after the examination of the cord is completed; or the two bundles of muscle may be cut off at both ends and disposed of without further trouble. Portions of tissue clinging to the vertebræ should then be scraped or cut away with the chisel or knife.

When the vertebræ are bared the next step is the removal by saw, bone-forceps or chisel of the posterior bony wall of the spinal canal in such a manner as to expose the cord and permit of its removal without causing any damage to it, either from the instruments or from fragments of broken bone. A single-bladed saw with curved ends may be used to saw through the laminæ on both sides of the spinous processes; or even the small bone-saw (Fig. 9) may be used for this purpose. The blade of the saw should be held obliquely against the spinous processes with the sawing edge directed outward so as to cut the laminæ close to the medial borders of the ascending and descending transverse processes. The sawing is complete when the spinous processes become movable. The straight-edged chisel may be used to cut any adhesions left after sawing, and the bone-forceps may be used to cut the atlas and axis. When the laminæ have been cut through on both sides of the spinal column for its entire length, including the sacrum, the posterior ligament between the atlas and occiput is cut with the cartilage knife; and the strip of bone and ligaments loosened by sawing is torn off from above downward by grasping it in the upper cervical region with a pair of bone-nippers and jerking it off forcibly downward toward the sacrum, thus exposing the spinal canal. It may be taken off in the opposite direction by cutting the ligament between the last lumbar vertebra and the sacrum and stripping upward.

The use of the single saw is not advised, however, as it is too time-consuming. The laminæ on both sides of the spinous processes may be cut at the same time by the use of Luer’s rhachiotome (Fig. 11). The blades are separated according to the size of the vertebral arches and are set so as to include the spinous processes and cut the outer border of the laminæ close to the transverse processes in such a manner as not to injure the cord. Since the spinal canal is broader in the cervical and lumbar regions than in the dorsal, the distance between the saw-blades must be regulated accordingly. The dorsal portion is first sawed. The sawing should be in long cuts without too great pressure, the instrument being steadied by placing the left hand on the upright bar. As soon as the spinous processes become movable on slight pressure the sawing should be stopped. Should the blades become caught in the saw-cuts great care should be taken to avoid injuring the cord while releasing them. The straight-edged chisel may be inserted into the cuts and any parts still adherent may be carefully sprung apart. This is necessary particularly in the upper cervical region. The entire posterior wall of the canal may be loosened in this way, the sacrum being also sawed, when it is desired to open this part of the canal. When all the spinous processes are movable the attachments either above or below are cut with the cartilage-knife, and the spinous processes and laminæ torn off by the bone-nippers in one piece, either toward the head or sacrum as is the more convenient.

The laminæ may be cut by a chisel instead of a saw. The straight-edged or curved single chisel, the “tomahawk” chisel, or the double-bladed chisel of Esquirol may be employed. The latter instrument has adjustable chisel-blades that can be set to include the spinous processes. These blades are very strong and short, and have convex cutting edges. The use of a wooden mallet (Fig. 17) is to be preferred to that of the steel hammer in driving chisels of any type. The straight, curved and tomahawk chisels are held with their cutting edges directed slightly outwards. The Amussat rhachiotome is a chisel-knife with a curved metallic handle, the cutting edge running along the length of the chisel. When set at an angle of 45° to the laminæ it is driven through them by means of blows from a wooden mallet delivered upon the chisel-back over the cutting edge. The Brunetti chisels are shown in Fig. 15. In using these to open the spinal cord posteriorly, a block should be placed beneath the abdomen so as to raise the lumbar vertebræ above the level of the dorsal. The intervertebral ligaments of the last lumbar vertebræ are then cut through with the belly of the cartilage-knife held at right angles to the spine. The laminæ and spinous process of the last lumbar vertebra are then cut out with the straight-edged chisel or bone-forceps, exposing the canal. The right and left Brunetti chisels are then alternately used, beginning usually with the “left” chisel, the blunt probe-point being introduced into the canal, while firm pressure downward is made upon the handle, while at the same time the cutting edge is driven through the outer borders of the vertebral arches by blows from a wooden mallet delivered upon the head of the handle. Great care must be taken to keep the cut at the same level throughout. It is better, however, to cut too high rather than too low. In the latter case the cord may be injured, while in the former the bone may later be easily trimmed off sufficiently without causing any damage. The arches of three to four or even more vertebrae may be cut without removing the chisel. The same thing is then done on the other side, using the “right” chisel. The loosened portion of bone and ligaments is then cut or torn off with the bone-forceps or nippers. The cut bone should not be touched with the hands because of the danger of injury and subsequent infection from the sharp spicules and splinters of bone. As the canal is opened the block under the body is pushed towards the head, the object being always to cut down hill and not upward. When the cervical region is reached the head of the cadaver should be firmly held by an assistant so as to give sufficient resistance to the blows of the mallet. The skilful use of the Brunetti chisels is difficult to acquire and a great deal of practice is necessary, but when once the knack is obtained the spinal canal can be opened in this way more quickly than by any other method. In private practice the noise made by the hammer upon the head of the handles of the chisels is unpleasant, and should be avoided by the use of felt or something else on the head of the chisel or mallet to deaden the sound.

Another easy and convenient way of opening the spinal canal posteriorly is the cutting of the laminæ by means of special bone-forceps designed for this purpose. The cutting-edges may engage the laminæ from without or the lower blade may be introduced into the canal as a blunt probe, while the upper blade cuts down upon it through the side of the arch. Such bone-forceps should be very strong and have long handles to give sufficient purchase, as a good deal of force is necessary to cut through the laminæ. With a good instrument the canal can be opened in this way in about 10-15 minutes. It requires much less skill than is needed for good and quick work with the Brunetti chisels, and for that reason is recommended, as is also the use of Luer’s rhachiotome, for the general practitioner.

In the case of marked curvatures of the spine it may be impossible to use either rhachiotome or Brunetti chisels. The straight single chisel and small saw can be used on the concave and convex sides of the curvature respectively. In children and young adults the canal can be easily opened with the bone-forceps.

After the removal of the posterior wall of the spinal canal the peridural adipose tissue and the dural sac are exposed in the canal. The cord may now be removed with dural sac intact, and when the cord is soft this should be done, but in so doing the spinal fluid is likely to be lost; and, as it is very important to obtain a knowledge of the amount and character of this fluid, care should be taken to preserve it. With the block placed under the cervical region to keep the cervical and dorsal vertebræ higher than the lumbar the dural sac may be opened in the median line from above downward. The cervical dura is grasped with a pair of forceps and lifted so that a cut can be made in it with the small bent, probe-pointed shears. The blunt probe-point is then introduced into the subdural space and the dura cut in the median line downward toward the sacrum. With care the arachnoideal sac with its fluid may be preserved intact. What fluid there is in the subdural space will collect in the lumbar region and may be secured while the lumbar dura is cut. The fluid in the subarachnoideal space will likewise collect in the lower portion of the cord, and it is best at this stage of the operation to introduce a sterile pipette through the delicate arachnoid and draw up the fluid, preserving it for bacteriologic and microscopic examination.

The thirty pairs of spinal nerves are now cut from above downward, beginning on the right side. The cut edge of the dura or a dural fold, if the dura is left uncut, is seized with the dissecting forceps and pulled over to the left, so that as much of the nerve can be secured as possible. A long, narrow, sharp-pointed scalpel is inserted, outside of the dura, into the intervertebral foramina, as far as possible, and the nerves are cut while traction is made upon the dura to the opposite side. The same procedure is then carried out upon the left side. When all of the spinal nerves are cut, the scalpel is introduced in the spinal canal upward, as near to the foramen magnum as possible, and the cord and dura are cut transversely. The cord should be held by the dura; direct pressure with forceps or fingers upon the soft substance of the cord should never be made. If the forceps cannot be used to hold the dura with advantage, then the cord enclosed in the dural sac may be gently but firmly held in the palm of the left hand and lifted and drawn downward towards the sacrum with the greatest care. As the cord is removed the fibrous attachments between the dura and the longitudinal fascia of the anterior wall of the canal are cut with the small scalpel by means of oblique cuts upon the bodies of the vertebræ. Any fragments of bone impeding the removal of the cord should be trimmed off with the bone-forceps. The forcing of the cord through a tight aperture in the open canal may ruin that portion of the cord. In some cases it may be better to sever the dura and cord at the sacral end, below the cauda equina, and remove it toward the head, using the same method of holding the dura, and cutting the spinal nerves and peridural tissue. When this is done the importance of saving the spinal fluid should be borne in mind. Some prosectors prefer to sever the dura and cord above before cutting the spinal nerves, and to cut these and the epidural fascia while removing the cord. An experienced operator may save time in this way, but there is greater danger of injuring the cord. The cord may also be removed by severing the spinal nerves and vessels inside of the opened dura and lifting the cord out of the dura, but it is more likely to be damaged by this method. When the brain has been removed before the cord the dural attachments as high as the foramen magnum should be severed and the cord removed up to the point where it was severed from the brain. If it is desired to remove the cord attached to the brain, the cord is first loosened throughout its length from below up to the foramen. It is then carefully protected while the skull is opened; and after the brain-connections have been severed it is drawn up through the foramen as the brain is lifted out of the skull. After its removal from the body the cord is stretched out upon table or board and the dura opened in the median line both anteriorly and posteriorly, if the latter cut was not made before its removal from the body. If it is desired to make sections of both cord and dura for microscopic study the dura may be left uncut or attached to the cord after it has been opened in the median line. It then helps to hold the pieces of cord together after the latter has been cut. Otherwise the dura may be removed from the cord by cutting the nerve-roots and denticulate ligaments on both sides. The cord is now examined by making transverse cuts through it with a clean knife which is dipped into clean water before each cut. The cord is allowed to hang over the index-finger of the left hand while the knife is drawn across it, severing it down to the underlying pin which is left uncut to hold the pieces together. The cuts are usually begun in the cervical region and are made at the level of the spinal nerves. When the dura is left attached to the cord it may be laid back and the cord cut within it, or if it has not been opened, the cuts may be made through it and the cord at the same time, if a very sharp knife is used. Areas of softening should not be cut, but should be preserved intact for examination after fixation and hardening. If the segments of cord are left attached to the dura or pin the cord and membranes may be fixed and hardened en masse so as to permit future orientation.

Examination of Cord Anteriorly. After the complete examination of the neck, thoracic and abdominal organs the spinal column is divested of all remaining tissues, including the psoas muscles. A block is then placed beneath the lumbar vertebræ. With the belly of the cartilage-knife held transversely across the spinal axis the intervertebral disks on both sides of the next-to-the-last lumbar vertebra are cut down to the level of the canal. If the lumbar vertebræ are sufficiently elevated by the block placed beneath the abdomen, the cutting of the disks allows the neighboring vertebræ to spring away, so that the body of the vertebra thus separated can be cut out by the bone-forceps or chisel. The spinal canal is thereby exposed; so that the Brunetti chisels may now be used in cutting the pedicles and stripping off the vertebral bodies. As this stripping progresses upward the block is moved toward the head so that the cutting is always down hill. The chisels are driven through the pedicles of five or six vertebræ at a time; the handle is forced down until the long chisel-blade is nearly parallel with the vertebræ. At the same time the cutting-edge must be sent forward at a uniform level, just high enough to expose the canal. If the cut is too high the chisel will enter the body of the vertebra, if too low the probe-point will be pushed into the cord. When the cervical vertebræ are being cut the head of the cadaver must be steadied by an assistant. As the sections of vertebræ are loosened the intervertebral disks are cut with the cartilage-knife and the pieces of bone pulled away with the bone-nippers. When the canal is fully exposed the examination of the dura and the removal of cord and dura proceed as when the canal is opened posteriorly. The straight chisel and the bone-forceps are also used to open the spinal canal anteriorly, but the Brunetti chisels are especially recommended for this operation.

Examination of Spinal Ganglia. While these may be examined when the canal is opened posteriorly, they can be exposed with less danger of damage in the anterior examination. To expose them in the posterior examination they must either be drawn forcibly through the intervertebral foramina, or the articular processes must be cut away with the chisel.

When it is desired to remove a part of the spinal column for preservation as a specimen, the intervertebral cartilages and the cord above and below the portion to be removed are cut through with the knife, and the ribs severed with a chisel, while the adherent soft parts are cut away. The saw or chisel is then used to complete the disarticulation if necessary and the loosened portion is removed. The entire spine may be removed, if desired; and may be bisected with a band-saw. A stick of wood may be put in the place of the spine and covered with plaster-of-Paris.

After the cord and dura have been removed the inner surface of the canal should be examined. The character of the cut surface of the vertebral bodies is also noted, and the bones examined for pathologic conditions.

2. POINTS TO BE NOTED IN THE EXAMINATION OF THE SPINAL COLUMN.

1. Dorsal Incision. Note color of skin as it is cut, number of bleeding points, moisture, bedsores, amount and character of panniculus, color and blood-content of muscles, hemorrhages, purulent and tuberculous processes (usually infiltrations from diseased vertebræ) trichina in spinal muscles, etc.

2. Vertebrae. Necrosis from bedsores, surfaces smooth or rough, purulent and tuberculous processes (most common anteriorly), exostoses, curvatures, fractures, dislocations, erosions, malformations (spina bifida and supernumerary vertebræ most common), neoplasms (secondary carcinoma, primary sarcoma, myeloma and chloroma most common), actinomycosis, syphilis, rachitis, etc.

3. Dura. Note epidural tissue first, then dura, its thickness, color, translucency, blood-content, intradural pressure, character of inner surface (normally it is grayish-white, smooth and shining). defects, bone-formation, organizing blood-clots, hæmatoma, gumma, neoplasm, etc. Most common pathologic conditions are chronic pachymeningitis, syphilis, tuberculosis, traumatic lesions and secondary carcinoma. Primary tumors (sarcoma) and parasites (echinococcus and cysticercus) are rare. Teratomata occur in sacral and coccygeal regions. A diffuse formation of adipose tissue is common, as is also the development of bony plates in the dura in old chronic pachymeningitis (usually syphilitic). Note character and amount of contents of subdural space (blood, pus, serous exudate, etc.).

4. Inner Meninges. Normally gray, transparent, delicate. Note intrameningeal pressure, contents of subarachnoid space, color, thickness and translucency of arachnoid and pia, blood-vessels, presence of blood, pus, fibrinous exudates, localized thickenings, calcification, etc. Most common pathologic conditions are acute and chronic leptomeningitis, results of trauma, hemorrhage, syphilis, tuberculosis, cerebrospinal meningitis, leprous meningitis, etc. Bony plates (osteomata) are found in the arachnoid of the majority of people over forty-five years of age. In small number and size they have no pathologic significance; they are often large and very numerous in old cases of syphilitic leptomeningitis, sometimes encasing the cord. Primary tumors (fibroma, myxoma and sarcoma) are rare. Teratoid tumors (lipoma, myolipoma, neuroma) are occasionally found in the lumbosacral region, often associated with spina bifida. Secondary carcinoma and sarcoma, and metastases of the so-called glioma of the eye are also rarely found.

5. Cord. Size and form. Average length about 45 cms.; weight, 30 grms.; weight of cord to that of brain, 1:48.

Adhesions to inner meninges, consistence (should be uniform; changes in form and consistence are often the results of postmortem changes), color (gray-white, as seen through the pia), translucency (sclerotic areas in the white matter are firmer, depressed and gray or brownish-gray in color, and more translucent when present in the gray matter), moisture, color and blood-content of cut surface, relation of white and gray matter, symmetry of parts, size of central canal, presence of cavities, areas of softening (soft, yellowish-white, loss of structure), hemorrhages, congestion, anæmia, œdema, gumma, tubercle, tumors, parasites, etc. The normal consistence of the lower portion of the cord is usually somewhat firmer than that of the upper part. The “butterfly-figure” should stand out distinctly on the freshly-cut surface; the outlines between the white and gray matters should be sharp, and the gray matter should be grayish-red in color. Normally the white matter tends to rise above the gray. Inasmuch as the cord is often injured accidentally during its removal it is important to distinguish such artefacts from pathologic softenings. This can be easily done by taking a small portion of the doubtful area and examining in the fresh state under the microscope. In true softening numbers of “fat-granule” cells and also capillary walls showing fat-degeneration are seen.

The pathologic lesions of the cord easily recognized by the naked-eye are areas of sclerosis or gray degeneration, yellow degeneration, hemorrhage, anæmia, œdema, congestion, tabes dorsalis, amyotrophic lateral sclerosis, acute poliomyelitis, syringomyelia, ascending and descending degenerations, glioma, gumma, tubercle, certain malformations, neoplasms and parasites. Other important pathologic conditions are: Malformations (myelocele, hydrorrhachis interna, diastematomyelia, etc.), atrophy, myelitis, sclerosis, effects of trauma, syphilis and intoxications, infections, tuberculosis, etc. Primary tumors are: Glioma, gliosarcoma, gliomyxoma, sarcoma (spindle-cell, myxo-, angiosarcoma, etc.), neuroepithelioma, neuroma, diffuse gliosis, etc. All are rare with the exception of the gliomata. Metastatic carcinoma and sarcoma are relatively rare. Cysticercus and echinococcus are rare.

The thickness, color, consistence and translucence of the spinal ganglia should be noted. Atrophic nerves are smaller, more gray and more translucent.

6. Inner Surface of Vertebrae. The remains of the epidural tissue and the inner surface of the spinal canal should also be carefully examined, noting the consistence of the vertebræ, the character of the ligaments, fascia, periosteum, etc. The anterior wall of the canal should be smooth, the color of the vertebræ grayish-red, that of the intervertebral disks grayish-white. Caries, tuberculosis and syphilis lead to roughening of the bony wall of the canal.