Trigeminal neuralgia caused by a fibrous ring around the nerve.

Trigeminal neuralgia is usually caused by compression of the nerve by vessels or a tumor. The authors report a case of trigeminal neuralgia not caused by vessel/tumor compression but by a constricting fibrous band around the trigeminal nerve. A 26-year-old man presented with typical trigeminal neuralgia. Although a gradient echo MR imaging demonstrated no offending vessel or a tumor, the patient agreed to undergo exploratory surgery. Intraoperatively, there were no vessels that could be the cause of the neuralgia; instead, the trigeminal nerve was constricted near the root entry zone. After the fiber was cautiously cut, the nerve expanded slightly. The neuralgia resolved without any neurological deficit, and the postoperative course was uneventful. A fibrous band around the trigeminal nerve can cause trigeminal neuralgia. When the symptom is typical and gradient echo MR imaging shows constriction of the trigeminal nerve, surgery is recommended to release the constricted the trigeminal nerve.