Idiopathic spinal cord herniation: report of three cases and review of the literature.

Abstract

Three case reports and a literature review are presented. To describe characteristic clinical and radiographic findings of idiopathic spinal cord herniation. Idiopathic spinal cord herniation is a rare disease, with only 26 cases reported before the current study. Three cases of idiopathic spinal cord herniation are reported, and previous reports on this subject are reviewed. The responsible regions were in the thoracic spine from T2 to T7. Symptoms were mainly unilateral muscle atrophy in the lower extremity and sensory disturbance below the thoracic level. These symptoms had been progressing gradually. Magnetic resonance imaging demonstrated a unique feature: The spinal cord shifted anteriorly in a few segments. Computed tomographic myelogram showed another distinctive picture: There was no subarachnoid space anterior to the spinal cord. Because idiopathic spinal cord herniation is out of the concept of "compression myelopathy," this condition may be a pitfall in the diagnosis. Idiopathic spinal cord herniation should be recognized as one of the treatable causes for thoracic myelopathy.