POSTTRAUMATIC SYRINGOMYELIA

Study Design. This study retrospectively analyzed patients who develop ed post-traumatic syringomyelia secondary to spinal cord injury. Objec tives. To identify an indicator that would predict the outcome of surg ical treatment for post-traumatic syringomyelia. Summary of Background Data, Syrinx-subarachnoid shunting was chosen as a surgical treatment for posttraumatic syringomyelia. No previous study has been published concerning magnetic resonance imaging findings' ability to predict su rgical results before surgery. Methods. Nine patients diagnosed by mag netic resonance imaging with post-traumatic syringomyelia were the sub jects of this study. The magnetic resonance imaging findings and surgi cal results were analyzed. Results. Neurologic deterioration was found in five patients. Ascending dissociated sensory disturbances and moto r weakness were noticed to occur characteristically above the level of the spinal cord injury. The other four patients complained of a sligh t worsening of numbness without displaying neurologic deterioration. T he five patients with neurologic deterioration were treated with a syr inx-subarachnoid shunting. Two of the five patients experienced sustai ned neurologic improvement after a midline myelotomy, which allowed th e fluid within the syrinx to spout out and cause the expanded spinal c ord to collapse. This was called a ''high-pressure syrinx.'' In these two patients, the preoperative magnetic resonance imaging demonstrated a positive flow-void sign. On the other hand, drainage of the syrinx in the three patients with a negative flow-void sign did not collapse the expanded spinal cord, and the surgical results were considered fai r. This was called a ''low-pressure syrinx.'' Conclusions. Post-trauma tic syringomyelia was classified into two types. A preoperative distin ction could be made based on the presence or absence of the flow-void sign on a T2-weighted magnetic resonance image.