title: Gamma knife surgery for arteriovenous malformations involving the corpus callosum.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan. kskmarutky@umin.ac.jp
authors.forename: Keisuke
authors.initials: K
authors.lastname: Maruyama
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shin
authors.forename: Masao
authors.initials: M
authors.lastname: Tago
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kurita
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kawamoto
authors.forename: Akio
authors.initials: A
authors.lastname: Morita
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kirino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002533:Cerebral Angiography; D002648:Child; D003337:Corpus Callosum / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000295:instrumentation*