Statistical analysis of a group of 121 patients with acoustic neurinoma treated by gamma knife in our department between 1992–1996 was made. Although the median follow-up was only 2 years, some significant risk factors were detected. Prior microsurgery and the older type of planning system were risk factors for development of complications after radiosurgery. Since 1994 a new planning system Gamma Plan has been used and the risk of the facial and trigeminal neuropathy after radiosurgery decreased, because the quality of the treatment plan had a significant effect on the result of radiosur- gery.

        Key words: acoustic neurinoma, radiosurgery, gamma knife, complications