Ultrastructure of the human posttraumatic syrinx.

Although posttraumatic syringomyelia is a well-established clinicopathological entity, there is a paucity of information on the ultrastructural features of this condition. This study documents the light and electron microscopic features of posttraumatic syringes obtained from two patients who underwent surgical cordectomy. The syringes were lined largely by cell processes of astrocytes. Small regions near the caudal end were lined by flattened ependymal cells that lacked surface specializations. These were thought to represent remnants of the central canal ependyma. The ultrastructural appearance of the syrinx was similar to that of the communicating syringomyelia as well as the periventricular changes that accompany hydrocephalus. The authors conclude that the changes represent the nonspecific sequelae of a distensile force within the syrinx cavity.