Study design: This study retrospectively analyzed patients who developed post-traumatic syringomyelia secondary to spinal cord injury.
Objectives: To identify an indicator that would predict the outcome of surgical treatment for post-traumatic syringomyelia.
Summary of background data: Syrinx-subarachnoid shunting was chosen as a surgical treatment for post-traumatic syringomyelia. No previous study has been published concerning magnetic resonance imaging findings' ability to predict surgical results before surgery.
Methods: Nine patients diagnosed by magnetic resonance imaging with post-traumatic syringomyelia were the subjects of this study. The magnetic resonance imaging findings and surgical results were analyzed.
Results: Neurologic deterioration was found in five patients. Ascending dissociated sensory disturbances and motor weakness were noticed to occur characteristically above the level of the spinal cord injury. The other four patients complained of a slight worsening of numbness without displaying neurologic deterioration. The five patients with neurologic deterioration were treated with a syrinx-subarachnoid shunting. Two of the five patients experienced sustained neurologic improvement after a midline myelotomy, which allowed the fluid within the syrinx to spout out and cause the expanded spinal cord 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 fair. This was called a "low-pressure syrinx."
Conclusions: Post-traumatic syringomyelia was classified into two types. A preoperative distinction could be made based on the presence or absence of the flow-void sign on a T2-weighted magnetic resonance image.