GAMMA-KNIFE SURGERY IN ACOUSTIC TUMORS

Presentation of the experiences with 254 acoustic neurinomas, treated at the Karolinska Gamma Knife Center from 1969 to 1991, with a minimum follow-up of 12 months. Early loss of contrast enhancement on CT or M RI was seen in 70%. Unilateral tumours showed size decrease in 55%, no change in 33%, and increase in 12%. NF 2 tumours had decrease in 33%, no change in 43%, and increase in 24%. Some degree of facial weakness was seen after 17% of treatments, but always with later improvement o f function. The incidence of trigeminal neuropathy was 19%. Preservati on of hearing was 77%. Gamma knife treatment is as efficient as micros urgery, but without risk of infection, bleeding or CSF leak. It requir es no hospitalisation. The patient can go back to work after a few day s. It therefore should be offered as an alternative to every acoustic neurinoma patient.