Enhancing transdural lumbar disk herniation.

Transdural migration of an intervertebral disk fragment is accompanied by more severe clinical manifestations than the more common extradural disk herniation. We report on two patients with transdural lumbar disk herniation who had had no previous surgery. In both, there was intense enhancement of the intradural disk material on magnetic resonance imaging. The pathological specimen showed vascularization of the intradural fibrocartilage in one patient.