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Between 1992 and 1996 γ-knife radiosurgery was performed on 192 patients with the diagnosis of brain intracerebral arteriovenous malformations (AVM) at Na Homolce Hospital, Prague. The largest diameter of the nidus ranged between 0.6–5.4 cm, median 2.2 cm. The nidus volume ranged 0.15–28.6 cm2, median 3.9 cm2. Thus far, the angiographic evaluation after radiosurgery was performed in 162 patients. The treatment result reference was defined as follows: the interval with a lower limit represented by the percentage of the complete obliteration in the whole group of patients and the upper limit represented by the percentage of the obliteration only in the group of patients with control angiography. The total obliteration of the AVM 1 year after radiosurgery was reached in 18–32% patients, after 2 years in 59–72%, after 3 years in 69–81%, and 4 years after radiosurgery in 71–93% patients. The morbidity of radiosurgery was 6% and, in a majority of the cases, was caused by the postirradiation edema and resolved after corticotherapy. The improvement of secondary epilepsy was observed in 35% of the patients and the improvement of the neurological status in 50%. The mortality of radiosurgical procedure itself was zero. The risk of mortality of the patients with AVM treated with the γ-knife was related to the latent period from treatment until complete obliteration. This period took between 1–3 years when the natural risk of the repeated hemorrhage was the same as that in the nontreated patient. The rebleeding occurred in eight patients; three of them died and five patients were without neurological sequela. If the obliteration did not occur up to 3 years after the γ-knife radiosurgery, reirradiation was indicated. AVM of Spetzler grade I–III proved to have a high rate of obliteration after γ-knife radiosurgery, while only one-third of patients with Spetzler grade IV obliterated after the first radiosurgery. Radiosurgery was not indicated for AVMs Spetzler grade V. AVMs with an average diameter up to 3 cm were good indications for primary radiosurgery as a noninvasive treatment. In AVMs with the average diameter larger than 3 cm, radiosurgery, microsurgery, and embolization are the methods of choice and the radical treatment may require an adequate combination of these methods.

A review of 217 patients treated with Gamma knife radiosurgery (GKRS), at Hospital Na Homolce, Prague, between October 1992 and January 1998 for arteriovenous malformation (AVM) is presented. Forty-one patients (18.9%) with an AVM and associated aneurysm are the subjects of special interest for this study. The nidus volume in the presence of an aneurysm lying close to the nidus or within it was significantly larger than the nidus volume in cases where the AVMs had no associated aneurysm, suggesting that an increased flow in a larger AVM may be an important factor for aneurysm formation. The association of an arterial aneurysm with an AVM significantly increased the chance of hemorrhage when compared to the group with AVM and no aneurysm. Ten patients out of 14, who had an aneurysm close to or within the nidus, showed a complete obliteration of their AVM and aneurysm, although the latter was not always included within the irradiated volume. Thus, this study indicates that radiosurgery alone could be the method of choice for the treatment of a combination of AVM and aneurysm, if the aneurysm is close to or within the nidus.

We have treated 14 patients with glomus tumor during the 4 years (of 1993 to 1997) using Leksell Gamma Knife radiosurgery. The male: female ratio was 1:3.7, and the mean age 48.6 years (range 22–75 years). The mean tumor volume was 5.5 cm3 (range 0.7–11.3 cm3). The mean maximum dose was 37.4 Gy (range 20–44 Gy). The mean margin dose was 19.4 Gy (range 10–25 Gy). In 3 patients, infrabasal spread of the tumor could not be delineated on peroperative stereotactic CT scans. As a result, this portion of the tumor was treated in 2 patients at a second stage using stereotactic MRI. Follow-up in 11 patients ranged from 6 to 42 months (mean 20.5 months). Hearing on the affected side was further impaired in 3 patients. Tinnitus, vertigo and ataxia improved in 3 patients, headache and nausea in 2 patients. Angiography after radiosurgery was performed in 3 patients. In one patient 12 months after the radiosurgery, pathological vascularisation had completely disappeared. In another patient pathological vascularisation was still present 22 months after the first stage, despite two-stage radiosurgery, although the tumor volume decreased 30%. In the last patient, vascularisation and tumor volume partially decreased 12 months after radiosurgery. The volume of the tumor decreased in 4 patients. No change in tumor volume has been observed in any of the other patients to date. Radiosurgery proves to be a safe treatment for glomus tumor with no acute morbidity. Because of its naturally slow growth rate, up to 10 years follow-up will probably be necessary to establish the therapeutic effectiveness of radiosurgery for glomus tumor.

For 6 years (1992-1998) we have treated 67 patients with cavernous sinus meningioma using the Leksell gamma knife in the Hospital Na Homolce, Prague. The age of the patients ranged between 19-82 years, median 57 years. Radiosurgery was the primary treatment in 64.2% of the patients, in the rest a microsurgical resection preceded. The volume of the tumour ranged from 0.9-31.4 cm3, median 7.8 cm3. The meningioma was distant from the optic tract in 58% of the cases, in 12% of the cases there was a contact with the tumour and the optic tract without its compression and in 30% of the cases there was a compression of the optic tract caused by the meningioma. The dose to the tumour margin ranged from 10-14 Gy, median 12 Gy. The follow up was available in 53 patients, in intervals of 2-60 months, median 19 months. There was no change in the tumour volume in 48% of the cases, in 52% of the cases a decrease of the tumour volume occurred. No increase of the tumour volume was observed. Clinical symptoms and signs improved in 35.8% of the patients, temporary morbidity was 3.8%. The mortality of the treatment was zero. Hitherto, the results of gamma knife radiosurgery of cavernous sinus meningioma have proved its safety and efficiency, although long term experience with a large group of patients is missing. Advances in neuroradiology and radiosurgical technique have allowed us to treat tumours with a closer contact to the optic tract and nerves compared with the past.