Comparison between adult and pediatric arteriovenous malformations treated by Gamma Knife radiosurgery.

More than 290 cases of cerebral arteriovenous malformation have been treated at our hospital by Gamma Knife radiosurgery since May 1991, of which 99 were followed with angiography for 1 year or more. The results from adult and pediatric age groups were compared. There were 70 adults and 23 children. Previous hemorrhage had occurred in 73.7% of the adults and 91.3% of the children. The mean volume of the nidus was similar in both groups: 4.2 cm3 in adults and 4.8 cm3 in children. In both groups approximately 70% of the cases fell into Spetzler and Martin grade III. The mean margin dose was 20.0 Gy in the adults and 20.5 Gy in the children. Complete nidus occlusion at 1 year occurred in 45% of the adults and 74% of the children. The rates at 2 years were 81 and 94%, respectively. Complications occurred only in adults and consisted of 2 rebleeds, 1 radiation edema and 1 radiation necrosis. Gamma Knife radiosurgery is considered to be safer and have a higher success rate in children than in adults.