Stereotactic radiosurgery for trigeminal schwannomas

OBJECTIVE: Schwannomas that arise from the trigeminal nerve are rare and are usually managed by surgical resection. The role of radiosurgery in the care of patients with these basal tumors remains to be defined. METHODS: We reviewed the clinical presentation, management, and outcomes for 16 trigeminal schwannoma patients who underwent gamma knife stereotactic radiosurgery. Fifteen of the 16 patients presented with trigeminal sensory dysfunction. Nine patients had tumors in the region of the ganglion, six in the region of the trigeminal nerve root, and one in the region of the mandibular branch. Six patients had undergone one or move previous resections before radiosurgery. Ten underwent radiosurgery as the first procedure. The mean tumor volume was 5.3 cc (range, 1-17.8 cc). The mean tumor margin dose was 15.3 Gy (range, 12-20 Cy). RESULTS: During the average imaging follow-up of 44 months (range, 8-116 mo), the tumor control rate was 100% (regression in nine patients and no further tumor growth in seven patients). Five patients had improvement of clinical symptoms, and 11 remained unchanged. No new cranial nerve deficit developed in any patient. CONCLUSION: As a minimally invasive alternative to microsurgery, gamma knife radiosurgery proved to be an alternative primary or adjuvant strategy that controlled tumor growth, did not cause new deficits, and often improved presenting symptoms.