Stereotactic radiosurgery for cerebral arteriovenous malformations

Different treatment modalities are being used for cerebral arteriovenous malformations. The authors have evaluated the results of stereotactic radiosurgery on 85 patients (48 females) with median age 34.5 years (range 4 - 70 years) treated at Haukeland University Hospital in Norway in 1989 - 96. Median follow-up time was 7 years 3 months (range 51 144 months). Data were obtained retrospectively from patient files. Haemorrhage was the initial symptom in 72 patients. The majority of lesions were located deep within the brain parenchyma or near critical structures. The minimum dose to the periphery of the malformation was 15 to 33.3 Gy in 30 - 70% isodose line according to the volume and location of the malformation. Complete obliteration was obtained in 65 of 85 malformations (77 %) and in two of five patients who were retreated. 85 % of the malformations smaller than 4 cm3 50% of those larger than 4 cm3 were obliterated after the treatment. The majority of the malformations were obliterated between two and three years after radiation. Radiation-related side effects were observed in six patients. Five patients experienced new bleeding during followup. It is concluded that small and medium-sized arteriovenous malformations are successfully treated with stereotactic radiosurgery with an acceptable rate of radiation-related side effects and latency bleeding