Idiopathic spinal cord herniation: a treatable cause of the Brown-Sequard syndrome--case report.

Symptomatic herniation of the spinal cord through the dura is an uncommon clinical problem. Since 1989, we have encountered three patients who each presented with an unexplained, longstanding Brown-Sequard syndrome and were found to have idiopathic herniation of the thoracic spinal cord. This report describes the clinical, radiographic, and surgical findings in these three patients and reviews the five previously reported patients with this syndrome. Idiopathic herniation of the spinal cord is a treatable cause of the Brown-Sequard syndrome that may be more common than is currently recognized and should be known to all surgeons managing spinal disorders.