OBJECT: The purpose of this study was to evaluate the safety and efficacy of gamma knife surgery (GKS) for the treatment of arteriovenous malformations (AVMs) involving the corpus callosum. METHODS: Thirty-two patients aged from 7 to 65 years (median 25 years) with AVMs of the corpus callosum underwent GKS between 1990 and 2002. The maximum AVM diameter was more than 3 cm in 11 patients (34%). The AVM volume ranged from 0.1 to 19.1 cm3 (median 1.6 cm3). The median dose to the AVM margin was 20 Gy (range 17-28 Gy). Patients were followed for 1 to 12 years (median 9 years). The angiographically confirmed actuarial obliteration rate was 64% and 74% at 4 and 6 years, respectively. Younger patient age (p < 0.05) and lower radiosurgery-based grading score (calculated from the patient age and AVM volume; p < 0.01) were the significant factors affecting successful AVM obliteration. No patient suffered a hemorrhage after GKS, although 28 patients (88%) had a history of hemorrhage from their AVMs. Radiation-induced neurological deficit was observed only in one patient (3%) who had undergone previous radiotherapy (50 Gy). No patient experienced complications of occlusion or stenosis of the normal vascular structures adjacent to the AVM. CONCLUSIONS: Gamma knife surgery is a safe and effective treatment for selected patients with AVMs involving the corpus callosum, and it carries a low risk of damaging adjacent critical vascular structures. Even ruptured AVMs with relatively large diameter can be successfully treated, especially in younger patients, with minimal morbidity and a low risk of repeated hemorrhage.
OBJECT: The purpose of this study was to evaluate the safety and efficacy of gamma knife surgery (GKS) for the treatment of arteriovenous malformations (AVMs) involving the corpus callosum. METHODS: Thirty-two patients aged from 7 to 65 years (median 25 years) with AVMs of the corpus callosum underwent GKS between 1990 and 2002. The maximum AVM diameter was more than 3 cm in 11 patients (34%). The AVM volume ranged from 0.1 to 19.1 cm3 (median 1.6 cm3). The median dose to the AVM margin was 20 Gy (range 17-28 Gy). Patients were followed for 1 to 12 years (median 9 years). The angiographically confirmed actuarial obliteration rate was 64% and 74% at 4 and 6 years, respectively. Younger patient age (p < 0.05) and lower radiosurgery-based grading score (calculated from the patient age and AVM volume; p < 0.01) were the significant factors affecting successful AVM obliteration. No patient suffered a hemorrhage after GKS, although 28 patients (88%) had a history of hemorrhage from their AVMs. Radiation-induced neurological deficit was observed only in one patient (3%) who had undergone previous radiotherapy (50 Gy). No patient experienced complications of occlusion or stenosis of the normal vascular structures adjacent to the AVM. CONCLUSIONS: Gamma knife surgery is a safe and effective treatment for selected patients with AVMs involving the corpus callosum, and it carries a low risk of damaging adjacent critical vascular structures. Even ruptured AVMs with relatively large diameter can be successfully treated, especially in younger patients, with minimal morbidity and a low risk of repeated hemorrhage.