Gamma knife radiosurgery for pediatric arteriovenous malformation

Abstract

We retrospectively studied 43 patients with pediatric cerebral arteriovenous malformation, 15 boys and 28 girls aged 4 to 15 years (mean 11.7 years), who underwent gamma knife radiosurgery (GKS) at our hospital. The mean nidus volume was 4.5 ml (0.1-17 ml), and the mean prescription dose at the nidus margin was 19.9 Gy (12-25 Gy). The actuarial obliteration rate was 50.0% at 3 years and 80.0% at 5 years, based on angiography in 24 patients and magnetic resonance (MR) imaging in 4 patients. The delivered peripheral dose tended to be correlated with obliteration rate (p = 0.09). Fourteen of the 43 patients developed radiation-induced change in the brain tissue on follow-up MR imaging, and 4 of these 14 patients were symptomatic. Eight of the 14 patients with edema of the brain tissue required steroid therapy. None suffered permanent neurological complication. Three of the 43 patients suffered postradiosurgical hemorrhage. No patient developed long-term complication such as cyst formation or chronic encapsulated expanding hematoma. These findings suggest that GKS is effective for the treatment of pediatric cerebral arteriovenous malformation, especially if located in deep or eloquent areas. In contrast, we recommend direct surgery for cerebral arteriovenous malformation in surgical accessible regions because of the relatively high rate of radiation-induced change of brain tissue on follow-up MR imaging.