Neural foramen remodeling caused by a sequestered disk fragment.

A 53-year-old man had had pain for 2 months in the left lower extremity radiating to the thigh . The pain had begun suddenly after he had lifted a heavy object. Clinical examination showed mildly decreased strength in the left leg, normal reflexes, and decreased sensation to pinprick in the left L3 nerve root distribution. A herniated disk at the L3 level was suspected, and myelography and CT of the lumbar spine were performed. The myelogram showed an extradural defect compressing the left lateral and posterior aspects of the thecal sac (Fig . 1 A). The postmyelography CT showed a soft-tissue mass in the left L3-L4 neural foramen. The mass mildly expanded the foramen and eroded the posterior margin of the vertebral body (Fig. 1 B). A neurofibroma was thought to be responsible for the findings, and the patient had surgical exploration. This revealed a tear in the posterior longitudinal ligament, and the mass was extracted in toto. Pathologic examination showed that the mass was composed of benign cartilage surrounded by granulation tissue compatible with a free intervertebral disk fragment.