[An autopsy case of syringomyelia associated with Chiari malformation and basilar impression]

The authors report one autopsy case of syringomyelia associated with Chiari malformation and basilar impression. The pathogenesis of syringomyelia in our case is discussed. This 37-year-old man complained of progressive difficulty in swallowing and walking for two years. He had noticed dysarthria for six months before admission. (Examination) Neurological examination showed dysarthria, down beat nystagmus, disturbance of IXth nerve, Xth nerve and XIth nerve, and cerebellar ataxia. Deep tendon reflexes were hyperactive in the upper and lower extremities. Babinski's sign was positive bilaterally. Neuroradiological examination demonstrated basilar impression and Chiari malformation. (Operation) Suboccipital craniectomy and laminectomy of upper cervical vertebra were performed with dural plasty. Postoperatively he acquired some improvement, but soon after he was worse. He died of respiratory disturbance. (Postmortem examination) Though the central canal was obliterated at the C4 level, the syrinx extended from the C5 to Th7 level. From the C5 to C8, the syrinx was present in the areas of central gray matter, extending into the left dorsal horn, where it communicated with subarachnoid space. Furthermore, the abnormal vessels were noticeable around the syrinx. At the Th2 level, they were also shown in central grey matter where no syrinx existed. (Conclusion) The etiology of syringomyelia in our case was not explained by Gardner's hydrodynamic theory. We suggested that intramedullary abnormal vessels played an important part for the formation of the syringomyelia.