title: Gamma Knife surgery for arteriovenous malformations within or adjacent to the ventricles.
abstract: OBJECTIVE
  The outcomes of stereotactic radiosurgery for arteriovenous malformations (AVMs) within or adjacent to the ventricular system are largely unknown. This study assessed the long-term outcomes and hemorrhage risks for patients with AVMs within this region who underwent Gamma Knife surgery (GKS) at the University of Pittsburgh.
  
  
  METHODS
  The authors retrospectively identified 188 patients with ventricular-region AVMs who underwent a single-stage GKS procedure during a 22-year interval. The median patient age was 32 years (range 3-80 years), the median target volume was 4.6 cm(3) (range 0.1-22 cm(3)), and the median marginal dose was 20 Gy (range 13-27 Gy).
  
  
  RESULTS
  Arteriovenous malformation obliteration was confirmed by MRI or angiography in 89 patients during a median follow-up of 65 months (range 2-265 months). The actuarial rates of total obliteration were 32% at 3 years, 55% at 4 years, 60% at 5 years, and 64% at 10 years. Higher rates of AVM obliteration were obtained in the 26 patients with intraventricular AVMs. Twenty-five patients (13%) sustained a hemorrhage during the initial latency interval after GKS, indicating an annual hemorrhage rate of 3.4% prior to AVM obliteration. No patient experienced a hemorrhage after AVM obliteration was confirmed by imaging. Permanent neurological deficits due to adverse radiation effects developed in 7 patients (4%).
  
  
  CONCLUSIONS
  Although patients in this study demonstrated an elevated hemorrhage risk that remained until complete obliteration, GKS still proved to be a generally safe and effective treatment for patients with these high-risk intraventricular and periventriclar AVMs.
authors.affiliation: Departments of Neurological Surgery and.
authors.forename: Greg
authors.initials: G
authors.lastname: Bowden
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.forename: Huai-Che
authors.initials: HC
authors.lastname: Yang
authors.forename: Ajay
authors.initials: A
authors.lastname: Niranjan
authors.forename: John
authors.initials: J
authors.lastname: Flickinger
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002543:Cerebral Hemorrhage / Q000209:etiology; D002552:Cerebral Ventricles / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000601:surgery*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods*; D012086:Reoperation; D012189:Retrospective Studies; D018570:Risk Assessment; D020521:Stroke / Q000209:etiology; D016896:Treatment Outcome; D055815:Young Adult
keywords: AVM = arteriovenous malformation; GKS = Gamma Knife surgery; arteriovenous malformation; hemorrhage; stereotactic radiosurgery; vascular disorders; ventricle