[Pathogenesis and the treatment of secondary syringomyelia].

Six cases with secondary syringomyelia were evaluated clinically and the pathogenesis was discussed. Three cases had the tumors; an ependymoma arising from the conus medullaris and the filum terminale, a foramen magnum meningioma extending to C2 and a thoracic astrocytoma. Two cases had past history of spinal cord injury with L1 and L2 fracture-dislocation, respectively. One case showed hydromyelic symptoms associated with isolated fourth ventricle after post-meningitic hydrocephalus. Clinical symptoms and signs were complex and various in each case due to the association of the original disease and the syrinx. Syringomyelic symptoms were dominant in three cases of which the syrinx extended from the conus to the cervical cord. Initial symptoms of two cases with post-traumatic syringomyelia were tingling pains which began near the site of injury and extended rostrally. Metrizamide myelography revealed complete or incomplete block at the location of the tumors or the injuries. Delayed CT demonstrated the syrinx in all cases. The syrinx was always present near the sites of primary lesions. The communication between the syrinx and the fourth ventricle was suspected in three cases, and the communication of the syrinx and the spinal subarachnoid space was suspected in two cases. All cases underwent the surgical treatments. Total removal of the tumors were completed in two cases and relieved the majority of symptoms. On the other hand, a case with a thoracic astrocytoma underwent biopsy of the tumor and irradiation, followed by poor outcome. Syringo-peritoneal shunts were performed in two cases with post-traumatic syringomyelia and relieved pain, but neurological signs were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)