Between 1992 and 1996 192 patients with the diagnosis of brain AVM were indicated for Gamma knife treatment. The biggest diameter of the nidus ranged between 0.6 - 5.4 cm, median 2.2 cm. The nidus volume ranged from 0.15 to 28.6 ccm, median 3.9 ccm. Angiographic evaluation has so far been performed in 173 patients. As an expression of the therapeutic result we consider the interval the lower limit of which represents the percentage of the achieved obliteration in the whole patient population and the upper limit the percentage of the obliteration only in the group of patients with angiographic control. The total obliteration of the AVM one year after irradiation was achieved in 19 - 23 % patients, in two years 61 - 64 %, in three years 75 - 76 % and four years after the treatment 77 - 86 % patients. The morbidity of 6 % connected with radiosurgery was caused by the postirradi- ation oedema and resolved after the steroid treatment. Improvement of the symptoms of secondary epilepsy was achieved in 35 % patients, improvement of the neurological status in 50 %. The mortality connected with radiosurgery was zero. The risk of mortality of the patients with AVM treated with the Gamma knife is connected only with the latent period between treatment till complete obliteration. This period takes 1-3 years when the natural risk of the repeated haemorr- hage is the same as in non-treated patient. Re-bleeding occurred in 8 patients, three of them died and five patients are without neurological sequel. If the obliteration does not occur three years after the Gamma knife treatment, reirradiation was indicated. In AVMs with an average diameter up to 3 cm we consider primary microsurgical extirpation or embolization indicated only in the case when the AVM is totally removed and the morbidity and mortality of treatment does not exceed the cumulative risk of the natural course of the disease in the period of three years when the healing process after possible radiosurgery usually occurs. In AVMs with an average diameter bigger than 3 cm, radiosurgery, microsurgery and embolisation are the methods of choice and radical treatment may require an adequate combination of these methods.

        Key words: radiosurgery, cerebral arteriovenous malformation, treatment, results, complications