Nonvestibular schwannomas: an evaluation of functional outcome after radiosurgical and microsurgical management

Abstract

Nonvestibular cranial nerve schwannomas (NVCNS) are relatively rare tumors. We evaluated our experience with radiosurgical and microsurgical treatment alone and in combination for the management of NVCNS. The charts of 62 patients with NVCNS who were treated between 1993 and 2005 at our institution were reviewed. Patients diagnosed with neurofibromatosis type 2 were excluded. The patients underwent microsurgery and/or radiosurgery treatment. Trigeminal and jugular foramen schwannomas were the most common NVCNS tumors (n = 47), and the only two groups with sufficient numbers of patients to allow comparison of the three treatment approaches. In these two groups, the mean tumor volume was significantly higher in those who received combined therapy (8.59 +/- 2.29 cc), compared with radiosurgery (4.94 +/- 3.02 cc; p = 0.05) or microsurgery alone (5.38 +/- 3.23; p = 0.027). Patients who underwent radiosurgery alone were significantly older (67.7 +/- 13.3 years; p = 0.019) than those treated with microsurgery (55.3 +/- 13.7 years) or with both modalities (48.7 +/- 12.8 years). The Karnofsky Performance Scale scores were significantly higher (p < or = 0.05) at follow-up compared with baseline for all three treatment approaches. There was no significant change in the Glasgow Outcome scores before and after treatment. Microsurgery and radiosurgery can both be used to manage NVCNS tumors with excellent results. When treatment with either modality alone is not reasonable, tumors can be managed effectively with combined micro- and radiosurgery treatment.