title: Combined management of intracranial arteriovenous malformations with embolization and gamma knife radiosurgery: comparative evaluation of the long-term results.
abstract: BACKGROUND
  Volume reduction of large AVMs attained with endovascular embolization can be potentially helpful for their subsequent radiosurgical management. The objective of the present retrospective analysis was comparative evaluation of the long-term outcome after GKR for intracranial AVM performed with and without initial embolization of the nidus.
  
  
  METHODS
  The long-term outcome in 15 patients with intracranial AVM treated with initial embolization and subsequent GKR was evaluated and compared with the series of 237 patients treated during the same period solely with GKR. All patients were followed at least 2 years after radiosurgery.
  
  
  RESULTS
  Mean reductions of the nidus volume and score of the radiosurgery-based grading system for AVMs after embolization constituted 6.9 +/- 2.4 mL and 0.7 +/- 0.2, respectively (P < .001). Complete obliteration of the nidus after GKR was marked in 10 cases (67%). It was attained in 9 (90%) of 10 AVMs with postembolization nidus volume less than 12 mL, and in 1 (20%) of 5 with postembolization nidus volume more than 12 mL (P < .05). Delayed cyst formation was met once (7%). Obliteration and long-term morbidity rates did not differ significantly in patients treated with and without preradiosurgical nidus embolization, whereas nidus volume was seemingly larger in the former cohort.
  
  
  CONCLUSIONS
  Combined management with embolization and GKR may be effective for selected cases of large intracranial AVM. Radiosurgery preceded by partial nidus embolization does not associate with increased rate of long-term complications.
authors.affiliation: Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University, Tokyo 162-8666, Japan. mizawa@nij.twmu.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Izawa
authors.forename: Mikhail
authors.initials: M
authors.lastname: Chernov
authors.forename: Motohiro
authors.initials: M
authors.lastname: Hayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iseki
authors.forename: Tomokatsu
authors.initials: T
authors.lastname: Hori
authors.forename: Kintomo
authors.initials: K
authors.lastname: Takakura
mesh_terms: D000328:Adult; D002533:Cerebral Angiography; D004621:Embolization, Therapeutic / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult