title: Is repeated radiosurgery an alternative to staged radiosurgery for very large brain arteriovenous malformations?
abstract: OBJECTIVE
  The results of a novel radiosurgical approach to treat large arteriovenous malformations (AVMs) with repeated radiosurgery are presented and discussed.
  
  
  METHODS
  The outcome was studied following repeated Gamma Knife surgery (GKS) for large AVMs, defined as a nidus volume of 9 ml or more. The philosophy was to treat the whole AVM with a low dose of radiation (> or = 10 Gy), and to repeat the treatment if the AVM shrank but was not obliterated. The study included 133 patients with AVMs treated at one of three different institutions. Clinical information was available for all patients, and complete radiological follow-up was available in 89 patients after the first treatment, and in 19 after the second treatment.
  
  
  RESULTS
  The estimated obliteration rate following repeated GKS was 62%. Four patients (3%) developed neurological deficits caused by the radiation, whereas five others (4%) developed cystic changes. The annual incidence of hemorrhage was high (7%), of which 35% occurred within the 1st year after the first treatment.
  
  
  CONCLUSIONS
  Repeated radiosurgery seems to be a viable option for some AVMs considered to be too large for conventional radiosurgical treatment. The incidence of posttreatment hemorrhages seems to be a larger clinical problem than radiation-induced complications.
authors.affiliation: Department of Neurosurgery, West Virginia University, Morgantown, West Virginia 26506, USA. nykuttram@yahoo.se
authors.forename: Bengt
authors.initials: B
authors.lastname: Karlsson
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Jokura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Michael
authors.initials: M
authors.lastname: Söderman
authors.forename: Ingmar
authors.initials: I
authors.lastname: Lax
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002543:Cerebral Hemorrhage / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D002538:Intracranial Arteriovenous Malformations / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D011829:Radiation Dosage; D016634:Radiosurgery / Q000379:methods* / Q000706:statistics & numerical data; D012086:Reoperation / Q000379:methods* / Q000706:statistics & numerical data; D012307:Risk Factors; D016896:Treatment Outcome