title: Optimal timing for Gamma Knife surgery after hemorrhage from brain arteriovenous malformations.
abstract: OBJECTIVE
  Optimal timing of Gamma Knife surgery (GKS) after hemorrhage from brain arteriovenous malformations (AVMs) is unclear and of concern to neurosurgeons because GKS is usually performed after absorption of the hematoma. The authors investigated whether waiting for hematoma absorption is beneficial and aimed to clarify the optimal treatment timing.
  
  
  METHODS
  The authors retrospectively studied 211 patients with AVMs who presented with hemorrhage and underwent GKS as the initial treatment. Patients were categorized into 3 groups according to the interval between the time of first hemorrhage and GKS, as follows: Group 1, 0-3 months (70 patients); Group 2, 3-6 months (62 patients); and Group 3, > 6 months (79 patients). The obliteration rates, number of hemorrhages before and after GKS, and complication rates were compared between these 3 groups. The authors also analyzed a subgroup of 127 patients who presented with intracerebral hemorrhage (ICH) to identify the influence of ICH on outcome.
  
  
  RESULTS
  After a median follow-up of 6.3 years, the rates of obliteration, hemorrhage after treatment, and complication were not significantly different between the 3 groups even though the patients with a longer interval before GKS (Group 3) had more AVMs in eloquent areas and neurological deficits. However, the numbers of patients with preoperative hemorrhage in the interval before GKS was significantly higher in Group 3 (1, 3, and 20 patients in Group 1, 2, and 3, respectively). These results were similar in the analyses of 127 patients presenting with ICH.
  
  
  CONCLUSIONS
  No benefit was detected in waiting for hematoma absorption until GKS after hemorrhage from AVM. Because of higher hemorrhagic risk until GKS > 6 months after hemorrhage, the authors recommend GKS within 6 months after hemorrhage.
authors.affiliation: Departments of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan. kskmarutky@umin.ac.jp
authors.forename: Keisuke
authors.initials: K
authors.lastname: Maruyama
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Koga
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shin
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Igaki
authors.forename: Masao
authors.initials: M
authors.lastname: Tago
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Saito
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006406:Hematoma / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000601:surgery*; D020300:Intracranial Hemorrhages / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D008297:Male; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome