To investigate the causes of false-negative discograms, 181 lower thoracic and lumbar intervertebral discs that had been removed as part of en bloc specimens during thirty autopsies were studied first by discography and then histologically. Comparison of the results of the two methods showed that if fissures and cysts were present in a degenerated anulus fibrosus, but did not establish continuity between the nuclear cavity and the site of a herniation, the discogram was false-negative. Under these circumstances, the inner fiber bundles of the anulus fibrosus were intact and their orientation was often reversed, so that they bulged inward. This finding suggested that a protrusion or a prolapse of tissue from just the anulus fibrosus might have been developing. Ten of the fifty-seven discs that had such changes in the orientation of the fibers had a histologically proved protrusion or prolapse of the anulus fibrosus. However, the discograms showed protrusion in only six of the ten discs and demonstrated a false-negative result in the other four. The cases of seventy-seven patients in whom discography had been performed and a herniation had been subsequently confirmed at operation were also studied. Fifty-nine of the patients had a protrusion and eighteen had a prolapse of the disc. The discograms were falsely interpreted as negative in 32 per cent (nineteen) of the fifty-nine patients who had a protrusion and in 56 per cent (ten) of the eighteen who had a prolapse. Histologically, the prolapses were interpreted as protrusions of a portion of the anulus fibrosus. It was concluded that false-negative discograms are more frequent when a protrusion or a prolapse involves the anulus fibrosus rather than the nucleus pulposus, and that a negative discogram does not exclude the possibility of extensive degeneration of the anulus fibrosus.
Sagittal and horizontal sections of 257 intervertebral discs obtained at autopsy and material obtained from 441 operations for herniation of a disc were examined histologically. In the material that was taken at autopsy, myxomatous degeneration of the annulus fibrosus increased in proportion to the age of the subject. The bundles in the internal layer of the annulus fibrosus reversed their usual direction and showed myxomatous degeneration, sometimes resulting in posterior and anterior convex bulging in the internal layer of the anterior and posterior parts of the annulus fibrosus, respectively. When material from a disc was surgically removed as a single free fragment (as in a complete extrusion or a sequestration type of herniation), annulus fibrosus with myxomatous degeneration was found in most material, while the nucleus pulposus rarely was. These results suggest that, from the standpoint of pathomechanism, a protrusion type of herniation of the annulus fibrosus exists in which only the annulus fibrosus is protruded due to reversal of the bundles of the annulus fibrosus, without involvement of the nucleus pulposus. This type of herniation would be a separate entity from the protrusion type of herniation of the nucleus pulposus that occurs when the nucleus pulposus is protruded through a fissure in the annulus fibrosus.
This study was performed in order to understand the reasons why the metastasis of malignancy into the disc is rare in contrast to the commonly seen vertebral metastasis. By histopathologic studies of 14 vertebral columns with vertebral metastases of various malignant tumors and 616 disc specimens, the authors found three pathways for an intravertebral tumor to invade into the adjacent disc: 1) direct infiltration from the rim of the vertebral body not covered by the cartilagenous plate, 2) infiltration from the side of the vertebral body close to the vertebral corner, through the subspace beneath the longitudinal ligament, and 3) hematogenous invasion via small vessels in the subspace beneath the longitudinal ligament. The authors concluded that the cartilagenous plate between the vertebral body and the disc as well as high intradiscal pressure would be acting as a barrier against tumor invasion from the vertebral body into the disc, and suggests that gradual increase of capillaries in the disc with age may enhance hematogenous invasion into the disc in rare occasions.
Three cases of primary sarcoma of the gallbladder are reported. They consist of autopsy cases of leiomyoearcoma and rhabdomyosarcoma and surgery case of reticulum cell sarcoma, one of which was complicated with cholelithiasls. The number of sarcomas of the gallbladder reported in Japan adding our three cases totalled 14 cases, and 93 cases were reviewed from the world literature. The histological types, morphogenesis, relation to cholelithiasis, distribution of age and sex were discussed.
Three hundred sixty‐eight intervertebral discs (Tll/12‐L5/S1) were obtained at autopsy from 61 individuals (36 male, 25 female) ranging from 25 to 85 years of age, and subsequently examined histopathologically as sagittal‐sectioned specimens with special reference to the cartilaginous plates. The numbers of cartilaginous foci found in Assured and ruptured regions of the plates were found to Increase with age, and were considered to represent a restoration mechanism. Measurement of the cartilaginous plate/intervertebral disc antero‐posterior length ratio showed a decrease with age in intervertebral discs from the same spinal level. Therefore, cartilage cell proliferation in the vertebral body rim was found following rupture of the outer layer of the annulus flbrosus and was thought to be one of the causes of spur formation in spondylosis deformans. When the changes in a cartilaginous plate with aging were accompanied by destructive processes of the vertebrae such as osteoporosis or metastatic cancer, an increase in the height of the disc, or ballooning, developed. On the other hand, when degeneration of the intervertebral disc increased and the nucleus pulposus collapsed, the height of the disc decreased. Thus, although the cartilaginous plate exhibits a restoration mechanism, degeneration with age progresses, resulting in various disc lesions.
To study the relationships between the changes due to aging in lumbar intervertebral discs and the development of protrusion or prolapse, we carried out histological studies on operative specimens of thirty-one discs, of which twenty-two had been protruded and nine, prolapsed. The specimens were obtained during twenty-nine operations for herniation of a lumbar intervertebral disc in patients who were sixty years old or older. Changes in the anulus fibrosus were more extensive in the nine prolapsed discs than in the twenty-two protruded discs. Of the nine prolapsed discs, myxomatous degeneration, fibrosis, and swollen anular fibers were found in all nine, and cysts were seen in five. Of the twenty-two protruded discs, only five showed myxomatous degeneration; ten, fibrosis; one, a cyst; and sixteen, swollen fibers. For comparison, we also studied specimens that had been obtained at operation from twenty-one other patients, twenty to fifty-nine years old, who had a prolapsed disc. The anulus showed myxomatous degeneration in all twenty-one specimens, cysts in eight, and fibrosis in ten. In addition, we examined 368 autopsy specimens from people who had been between twenty-five and eighty-five years old at the time of death. In many of the subjects who had died in the sixth decade of life or later, we found that the orientation of the inner fiber bundles of the anulus fibrosus was reversed, so that they bulged inward. The reversal appeared to be the result of myxomatous degeneration of the middle fibers of the anulus, atrophy of the nucleus, and narrowing of the disc space. These histological findings suggest explanations for the predominance of protrusions of the nucleus pulposus in patients who are less than sixty years old and of prolapse of the anulus fibrosus in the few patients who are more than sixty years old who have herniation of an intervertebral disc.
Six hundred surgical cases of lumber intervertebral disc herniation were evaluated histologically for the presence of blood vessels. These patients ranged in age from 12 to 77 years. Blood vessels were observed in 57 of 101 cases of complete prolapse type of herniated disc (56.4%), 12 of 32 cases of incomplete prolepse type of herniated disc (37.5%), and 53 of 467 cases of protrusion type of intervertebral disc herniation (11.3%). The presence of blood vessels in intervertebral discs was also investigated in postmortem specimens. Blood vessels were observed in 293 of 616 intervertebral discs (T10-L5), in individuals older than 40 years of age from 100 postmortem spines. The specimen age range was 16–89 years. Most of the blood vessels seen in the extruded tissue, exposed to the epidural space in cases of complete and incomplete prolapse type of herniation, are thought to have been newly formed after herniation occurred, As Invasion of the intervertebral disc by blood vessels was found to occur with the advance of age, it is possible that such blood vessels become extruded with the intervertebral disc tissue. The intervertebral disc may herniate posterilorly in three basic patterns. The first pattern Is "protrusion type of herniated disc," in protrusion hernia type there is abnormal posterior bulging of the anulus fibrosus. The disc pathology is predominantly nucleus pulposus, and the peripheral layer of the aulus fibrosus remains attached to the vertebral body bony rim, however. In the second pattern, "incomplete prolapse type of herniated disc," the peripheral anulus fibrosus has become detached from a portion of the vertebral body rim, exposing disc tissue to the epidural space, This tissue is still in continuity with the disc, however. There are no free fragments of disc tissue, and as such, this is considered an incomplete prolapse type of hernlation. The third pattern is "complete prolase type of herniated disc," in which the peripheral anulus fibrosus has become detached from a portion of the posterior vertebral body rim, exposing disc tissue to the epidural space. In this pattern there is free disc tissue that is no longer in continuity with the disc. This is considered extruded tissue. Free specimens of extruded tissue, removed as independent pieces, are found during surgery for complete prolapse type of herniated disc. Frequently most of this tissue is composed of anulus fibrosus. Small blood vessels accompanied by loose fibrous tissue are sometimes observed in the marginal reglons of these free extruded pleces of anulus. The origin of these small blood vessels is unclear. It is possible that pre-existing blood vessels with in the intervertebral disc became extruded together with the herniated tissue, or that newly formed blood vessels after herniation occurred. But blood vessels are not usually observed in the intervertebral disc. If the origin of blood vessels was the intervertebral disc, then their presence with the extruded tissue would provide histologic evidence as to the origin of the herniation. Namely, there is an opinion that blood vessels in the extruded tissue of complete and incomplete prolapse type of herniations are thought to be characteristic of these patients of hernlations, but this study has mentioned that blood vessels could be seen in protrusion type of herniated disc also, and blood vessels in the extruded tissue in cases of prolapse type of hernlations are thought to have been extruded with the intervertebral disc tissue, to have newly formed after hernlation occurred. This study has investigated the significance of these small blood vessels.
Histological examinations were conducted on specimens of 368 intervertebral discs (TU/12‐L5/S1), using X‐ray photography and discography. Specimens were obtained from 61 individuals (36 males and 25 females) whose ages ranged from 25 to 85 years. Fifty‐four Schmol's nodes were found in 28 of the patients (19 males and 9 females), and in 43 discs. In the peripheral regions of Schmorl's nodes, where the vertebral bodies were In contact with the node, growth of cartilaginous cells was seen in many cases. Thickened bone trabeculae were also seen in three nodes accompanied by syncytia. These three nodes were detectable by X‐ray photography of all discs containing Schmorl's nodes, and 35 were subjected to discography. Among these discs, 10 showed a limited form of shadow and 25 showed a diffuse form, and Schmorl's nodes were detected in 11 that showed a diffuse form of shadow. It was possible to detect Schmorl's nodes when they were contiguous with a degenerated annulus flbrosus adjoining the nuclear cavity. Pathogenetically, the presence of Schmorl's nodes in patients of middle and advanced age is interpreted to be one of the symptoms of age‐related changes in the cartilaginous plate.
