Pathological basis of spinal cord cavitation in syringomyelia: analysis of 105 autopsy cases

1995 ◽  
Vol 82 (5) ◽  
pp. 802-812 ◽  
Author(s):  
Thomas H. Milhorat ◽  
Anthony L. Capocelli ◽  
Archinto P. Anzil ◽  
Rene M. Kotzen ◽  
Robert H. Milhorat

✓ This report summarizes neuropathological, clinical, and general autopsy findings in 105 individuals with nonneoplastic syringomyelia. On the basis of detailed histological findings, three types of cavities were distinguished: 1) dilations of the central canal that communicated directly with the fourth ventricle (47 cases); 2) noncommunicating (isolated) dilations of the central canal that arose below a syrinx-free segment of spinal cord (23 cases); and 3) extracanalicular syrinxes that originated in the spinal cord parenchyma and did not communicate with the central canal (35 cases). The incidence of communicating syrinxes in this study reflects an autopsy bias of morbid conditions such as severe birth defects. Communicating central canal syrinxes were found in association with hydrocephalus. The cavities were lined wholly or partially by ependyma and their overall length was influenced by age-related stenosis of the central canal. Noncommunicating central canal syrinxes arose at a variable distance below the fourth ventricle and were associated with disorders that presumably affect cerebrospinal fluid dynamics in the spinal subarachnoid space, such as the Chiari I malformation, basilar impression, and arachnoiditis. These cavities were usually defined rostrally and caudally by stenosis of the central canal and were much more likely than communicating syrinxes to dissect paracentrally into the parenchymal tissues. The paracentral dissections of the central canal syrinxes occurred preferentially into the posterolateral quadrant of the spinal cord. Extracanalicular (parenchymal) syrinxes were found typically in the watershed area of the spinal cord and were associated with conditions that injure spinal cord tissue (for example, trauma, infarction, and hemorrhage). A distinguishing feature of this type of cavitation was its frequent association with myelomalacia. Extracanalicular syrinxes and the paracentral dissections of central canal syrinxes were lined by glial or fibroglial tissue, ruptured frequently into the spinal subarachnoid space, and were characterized by the presence of central chromatolysis, neuronophagia, and Wallerian degeneration. Some lesions extended rostrally into the medulla or pons (syringobulbia). Although clinical information was incomplete, simple dilations of the central canal tended to produce nonspecific neurological findings such as spastic paraparesis, whereas deficits associated with extracanalicular syrinxes and the paracentral dissections of central canal syrinxes included segmental signs that were referable to affected nuclei and tracts. It is concluded that syringomyelia has several distinct cavitary patterns with different mechanisms of pathogenesis that probably determine the clinical features of the condition.

1977 ◽  
Vol 47 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Ansgar Torvik ◽  
V. S. Murthy

✓ In order to study the cause of the great individual variations in kaolin-induced hydrocephalus, the lower brain stem and upper spinal cord were examined histologically in a series of young rabbits that had received injections of kaolin into the cisterna magna. Animals with complete occlusion of the outlets from the fourth ventricle into the subarachnoid space showed only a moderate ventricular dilatation, while cases with marked hydrocephalus also had plugs of kaolin in the caudal part of the fourth ventricle. The intraventricular kaolin was adherent to the roof of the fourth ventricle by strands of connective tissue and it is suggested that the plugs served as valves that initially occluded the opening of the central canal and were then lifted away as the ventricle dilated and the roof moved posteriorly. The animals with marked hydrocephalus also had extensive dilatation of the central canal with cleft formation in the posterior columns. The observations support the concept that in hydrocephalus the central canal may serve as an alternative resorption route for the cerebrospinal fluid through communication with the spinal subarachnoid space.


1974 ◽  
Vol 41 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Howard M. Eisenberg ◽  
James E. McLennan ◽  
Keasley Welch

✓ Cats were made hydrocephalic by cisternal instillation of kaolin. Three to 8 weeks later it was found by perfusion between the ventricular system and the spinal subarachnoid space that communication had been reestablished through a demonstrably dilated central canal of the spinal cord. Absorption of fluid from the ventricular system, measured both by ventriculospinal perfusion and, after ligation of the spinal cord, by perfusion between the lateral ventricles, was found to be indistinguishable from zero over a wide range of ventricular pressure.


1976 ◽  
Vol 45 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Peter V. Hall ◽  
John E. Kalsbeck ◽  
Henry N. Wellman ◽  
Robert L. Campbell ◽  
Sidney Lewis

✓ Kaolin-induced hydrosyringomyelia in dogs has been investigated by radioisotope ventriculography using both cerebrospinal fluid radioassay and scintigraphy. The hydromyelic central canal can be differentiated from the spinal subarachnoid space by scintigraphy. Serial studies show that hydromyelia arises rapidly to decompress the associated hydrocephalus in surviving animals. Syringomyelia, after a delayed onset, originates from the enlarged central canal. Radioisotope ventriculography may be a useful clinical aid in the diagnosis of hydrosyringomyelia.


1973 ◽  
Vol 39 (4) ◽  
pp. 485-492 ◽  
Author(s):  
Donald R. McLean ◽  
Jack D. R. Miller ◽  
Peter B. R. Allen ◽  
S. Ali Ezzeddin

✓ A detailed study of posttraumatic syringomyelia is reported. The interior of the syrinx was outlined by positive contrast and gas myelography. The contrast material entered the syrinx via a communication between the cavity and the subarachnoid space at the site of spinal cord injury. The syrinx also communicated with the fourth ventricle. It is postulated that posttraumatic syringomyelia results from the dissection of cystic remnants of hematomyelia known to be present at the site of serious spinal cord injury. Dissection occurs when pressure within the cyst is increased by elongation of the spinal cord during neck movements, principally flexion. Posttraumatic syringomyelia should be treated by a surgical procedure, which allows permanent drainage of the syrinx into the subarachnoid space.


1983 ◽  
Vol 58 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Shigetoshi Nakamura ◽  
Martin B. Camins ◽  
Gerald M. Hochwald

✓ The resistance to cerebrospinal fluid (CSF) absorption through the alternative CSF absorption pathway in kaolin-induced hydrocephalic cats was measured by the constant infusion-manometric test. The cerebral ventricles were bypassed, and artificial CSF was infused directly into the central canal of the spinal cord. The infusion rates were increased stepwise from 0.022 to 0.168 ml/min when the capacity to absorb CSF was exceeded. There was an initial increase in resistance which was associated with the emergence of infusion fluid through a slit-like opening in the dorsal columns of the lower lumbar spinal cord. The resistance to flow decreased when the infusion rate was greater than 0.086 ml/min. Fluid accumulated in the spinal subarachnoid space when the ability to absorb was exceeded. The diversion of this fluid caused the pressure in the spinal cord central canal to fall rapidly. The results suggest that the CSF absorption deficit in chronic kaolin-induced hydrocephalic cats is probably caused by the restriction of CSF flow from the central canal through the spinal cord and into the spinal subarachnoid space. As a result of kaolin, the central canal is sufficiently dilated to permit, during infusion, the flow of at least five times as much CSF as the hydrocephalic cats produce. It is not clear whether the overloading of the CSF absorption mechanism is due to the restrictions imposed by the size of the subarachnoid space, or to the structures in this space involved with the return of CSF to the blood.


1978 ◽  
Vol 48 (6) ◽  
pp. 970-974 ◽  
Author(s):  
A. Everette James ◽  
William J. Flor ◽  
Gary R. Novak ◽  
Ernst-Peter Strecker ◽  
Barry Burns

✓ The central canal of the spinal cord has been proposed as a significant compensatory alternative pathway of cerebrospinal fluid (CSF) flow in hydrocephalus. Ten dogs were made hydrocephalic by a relatively atraumatic experimental model that simulates the human circumstance of chronic communicating hydrocephalus. The central canal was studied by histopathology and compared with 10 normal control dogs. In both groups the central canal of the spinal cord was normal in size, configuration, and histological appearance. In this experimental model dilatation of the canal and increased movement of CSF does not appear to be a compensatory alternative pathway.


1994 ◽  
Vol 81 (1) ◽  
pp. 103-106 ◽  
Author(s):  
Thomas H. Milhorat ◽  
René M. Kotzen

✓ The central canal of the human spinal cord is partially or completely occluded in the vast majority of individuals by the early years of adult life. The authors describe an experimental lesion following virus-induced ependymitis that bears a striking resemblance to the condition in man. Suckling hamsters were inoculated with 0.06 ml of 10−3 infectivity titer of reovirus type I between the 2nd and 5th days of life. The pathological events consisted of necrotizing ependymitis, healing of the ependyma by gliovascular scarring, and obstruction of narrow bottlenecks such as the central canal. Histological findings were characterized by disorganization of the ependyma, formation of ependymal rosettes and microtubules, subependymal gliovascular scarring, and intracanalicular gliosis. These features are the same as those encountered clinically and provide strong evidence that stenosis of the central canal in man is a pathological lesion involving ependymal injury and scarring.


1972 ◽  
Vol 37 (5) ◽  
pp. 538-542 ◽  
Author(s):  
George J. Dohrmann

✓ Adult dogs were rendered hydrocephalic by the injection of kaolin into the cisterna magna. One group of dogs was sacrificed 1 month after kaolin administration, and ventriculojugular shunts were performed on the other group. Hydrocephalic dogs with shunts were sacrificed 1 day or 1 week after the shunting procedure. All dogs were perfused with formalin at physiological pressure, and the brain stem and cervical spinal cord were examined by light microscopy. Subarachnoid granulomata encompassed the superior cervical spinal cord and dependent surface of the brain stem. Rarefaction of the posterior white columns and clefts or cavities involving the gray matter posterior to the central canal and/or posterior white columns were present in the spinal cords of both hydrocephalic and shunted hydrocephalic dogs. Predominantly in the dogs with shunts, hemorrhages were noted in the spinal cord in association with the clefts or cavities. A mechanism of ischemia followed by reflow of blood is postulated to explain the hemorrhages in the spinal cords of hydrocephalic dogs with shunts.


2001 ◽  
Vol 95 (1) ◽  
pp. 64-73 ◽  
Author(s):  
Metin Tuna ◽  
Sait Polat ◽  
Tahsin Erman ◽  
Faruk Ildan ◽  
A. Iskender Göçer ◽  
...  

Object. The inflammatory cells that accumulate at the damaged site after spinal cord injury (SCI) may secrete interleukin-6 (IL-6), a mediator known to induce the expression of inducible nitric oxide synthase (iNOS). Any increased production of NO by iNOS activity would aggravate the primary neurological damage in SCI. If this mechanism does occur, the direct or indirect effects of IL-6 antagonists on iNOS activity should modulate this secondary injury. In this study, the authors produced spinal cord damage in rats and applied anti—rat IL-6 antibody to neutralize IL-6 bioactivity and to reduce iNOS. They determined the spinal cord tissue activities of Na+-K+/Mg++ adenosine-5′-triphosphatase (ATPase) and superoxide dismutase, evaluated iNOS immunoreactivity, and examined ultrastructural findings to assess the results of this treatment. Methods. Seventy rats were randomly allocated to four groups. Group I (10 rats) were killed to provide normal spinal cord tissue for testing. In Group II 20 rats underwent six-level laminectomy for the effects of total laminectomy alone to be determined. In Group III 20 rats underwent six-level T2–7 laminectomy and SCI was produced by extradural compression of the exposed cord. The same procedures were performed in the 20 Group IV rats, but these rats also received one (2 µg) intraperitoneal injection of anti—rat IL-6 antibody immediately after the injury and a second dose 24 hours posttrauma. Half of the rats from each of Groups II through IV were killed at 2 hours and the other half at 48 hours posttrauma. The exposed cord segments were immediately removed and processed for analysis. Conclusions. The results showed that neutralizing IL-6 bioactivity with anti—rat IL-6 antibody significantly attenuates iNOS activity and reduces secondary structural changes in damaged rat spinal cord tissue.


1979 ◽  
Vol 50 (3) ◽  
pp. 349-352 ◽  
Author(s):  
Alex S. Rivlin ◽  
Charles H. Tator

✓ The effect of papaverine, nitroprusside, or myelotomy on the recovery of spinal cord function was studied in rats after acute cord-compression injury. Spinal cord recovery was measured by a quantitative method of clinical assessment previously developed in our laboratory. Neither papaverine nor nitroprusside improved recovery of cord function. Dorsal midline myelotomy extending anteriorly as far as the central canal did not produce significant improvement (p > 0.05). However, when the myelotomy extended completely through the cord in the anteroposterior plane significant improvement (p < 0.01) was obtained.


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