Radiosurgery of vestibular schwannomas: a minimally invasive alternative to microsurgery.

From April 1992 till December 1998 stereotactic radiosurgery (Gamma Knife) was applied to 192 patients with vestibular schwannomas. 56 of them had radiosurgery as primary treatment modality and were followed-up for at least 4 years (48-80 months, median 62). Without fatal complications, control of tumour growth was achieved in all but three cases, useful hearing being preserved in more than one half of the patients (62%). The neurological state improved in 30 patients (54%). Irradiation-associated adverse effects (18%) comprised neurological signs (incomplete facial palsy, four cases (two recovered completely), and mild trigeminal neuropathy, three cases, respectively) and morphological changes (three patients) marked by an enlargement of pre-existing cystic components calling for additional surgical treatment: Microsurgical decompression was performed in two cases, the third patient underwent a shunting procedure because of hydrocephalus formation. Based on the present data, radiosurgery represents an effective treatment for vestibular schwannomas associated with an exceptionally low mortality rate and a good quality of life. With respect to the preservation of cranial nerve function, results are comparable to microsurgical resection. A short duration of hospitalization and a quick return to normal activities constitute further advantages and contribute to cost effectiveness in public health care.