Nerve root compression by a ganglion cyst of the lumbar anulus fibrosus. A case report.

STUDY DESIGN: A case report of a ganglion cyst rising from the anulus pulposus, causing lumbar nerve root compression.

OBJECTIVES: A rare pathologic condition causing sciatica is described. The pathologic anatomy and the magnetic resonance image of the lesion is discussed.

SUMMARY OF BACKGROUND DATA: A 35-year-old man was subjected to an abrupt twisting motion of the torso during a motor vehicle accident. The patient had a L5-S1 discectomy 1 year before the accident. His low back discomfort and right lower extremity pain were clearly exacerbated by the recent trauma.

METHODS: Magnetic resonance imaging revealed enhancing lobulated epidural mass displacing the S1 nerve.

RESULTS: Intraoperative findings were a lobulated cystic mass rising from the degenerated anulus fibrosus, determined on histologic examination to be a ganglion cyst. The patient noted significant relief of the right sciatica after surgery.

CONCLUSION: The appearance and the signal intensity of the epidural mass appear to be important parameters in diagnosing the presence of a ganglion cyst of the anulus fibrous. Excision of the ganglion cyst is indicated in a patient who fails to respond to conservative treatment and where the symptoms correlate with the abnormality seen with magnetic resonance imaging.