Thoracic idiopathic spinal cord herniation at the vertebral body level: a subgroup with a poor prognosis? Case reports and review of the literature.

The authors present two cases of thoracic idiopathic spinal cord herniation (TISCH) occurring at the vertebral body (VB) level in whom adequate surgical reduction failed to reverse symptoms. In the second case, in which TISCH occurred into a VB cavity, presentation was atypical (subacute spinal cord syndrome) and there was persistent postoperative deterioration. In both cases, adequate surgical reduction was achieved via a posterior midthoracic laminectomy, and reduction was maintained by closure of the anterior dural defect by using prosthetic material. Thoracic idiopathic spinal cord herniation occurring at a VB level may be technically well treated by surgical reduction, but the outcome appears less predictable. Herniation that occurs directly into a VB cavity may form a distinct subgroup in which the presentation is atypical and the prognosis worse.