Gamma Knife radiosurgery of cavernous sinus meningiomas: an institutional review.

INTRODUCTION: Stereotactic radiosurgery offers a unique and effective means of controlling cavernous sinus meningiomas with a low rate of complications. METHODS: We retrospectively reviewed all cavernous sinus meningiomas treated with Gamma Knife (GK) radiosurgery between November 2003 and April 2011 at our institution. RESULTS: Thirty patients were treated, four were lost to follow- up. Presenting symptoms included: headache (9), trigeminal nerve dysesthesias/paresthesias (13), abducens nerve palsy (11), oculomotor nerve palsy (8), Horner's syndrome (2), blurred vision (9), and relative afferent pupillary defect (1). One patient was asymptomatic with documented tumor growth. Treatment planning consisted of MRI and CT in 17 of 30 patients (56.7%), the remainder were planned with MRI alone (44.3%). There were 8 males (26.7%) and 22 females (73.3%). Twelve patients had previous surgical debulking prior to radiosurgery. Average diameter and volume at time of radiosurgery was 3.4 cm and 7.9 cm3 respectively. Average dose at the 50% isodose line was 13.5 Gy. Follow-up was available in 26 patients. Average follow-up was 36.1 months. Mean age 55.1 years. Tumor size post GK decreased in 9 patients (34.6%), remained stable in 15 patients (57.7%), and continued to grow in 2 (7.7%). Minor transient complications occurred in 12 patients, all resolving. Serious permanent complications occurred in 5 patients: new onset trigeminal neuropathic pain (2), frame related occipital neuralgia (1), worsening of pre-GK seizures (1), and panhypopituitarism (1). CONCLUSION: GK offers an effective treatment method for halting meningioma progression in the cavernous sinus, with an acceptable permanent complication rate.