Intraradicular lumbar disc herniation: case report and review of the literature.

Objective And Importance: Intradural or intraradicular herniation of a lumbar disc is a rare complication of disc disease. The mechanism of the tearing of the dura mater by a herniated disc is not known with certainty. Only six cases of intraradicular disc herniation have been reported. By reporting the seventh case of this rare neurosurgical entity, we emphasize its importance and review the literature on intraradicular disc herniation.

Clinical Presentation: A 41-year-old man was admitted with a 3-year history of low back pain and sciatica. A neurological examination revealed motor weakness during plantar flexion, positive Lasègue's sign, sensory deficit on the S1 dermatoma, and loss of Achilles reflex. Magnetic resonance imaging revealed disc protrusion at the L5-S1 level. Therefore, we decided to operate on the patient having made a diagnosis of lumbar disc disease.

Intervention: The patient underwent a standard hemilaminotomy and foraminotomy for a removal of the L5-S1 disc. There was no disc protrusion or extruded fragment. The left S1 nerve root was observed to be swollen and immobile. A longitudinal incision was made on the radicular sheet of the S1 root, and a free disc fragment, approximately 2 x 1 x 1 cm, was extirpated in one piece.

Conclusion: The patient was immediately relieved of pain and was discharged on the 7th day after the operation with normal muscle strength. It seems probable that in some patients with "failed back syndrome," intraradicular or intradural disc herniation is the cause of failure.