title: Combined endovascular embolization and stereotactic radiosurgery in the treatment of large arteriovenous malformations.
abstract: OBJECTIVE
  Large cerebral arteriovenous malformations (AVMs) are often not amenable to direct resection or stereotactic radiosurgery (SRS) treatment. An alternative treatment strategy is staged endovascular embolization followed by SRS (Embo/SRS). The object of this study was to examine the experience at Washington University in St. Louis with Embo/SRS for large AVMs and review the results in earlier case series.
  
  
  METHODS
  Twenty-one cases involving patients with large AVMs treated with Embo/SRS between 1994 and 2006 were retrospectively evaluated. The AVM size (before and after embolization), procedural complications, radiological outcome, and neurological outcome were examined. Radiological success was defined as AVM obliteration as demonstrated by catheter angiography, CT angiography, or MR angiography. Radiological failure was defined as residual AVM as demonstrated by catheter angiography, CT angiography, or MR angiography performed at least 3 years after SRS.
  
  
  RESULTS
  The maximum diameter of all AVMs in this series was > 3 cm (mean 4.2 cm); 12 (57%) were Spetzler-Martin Grade IV or V. Clinical follow-up was available in 20 of 21 cases; radiological follow-up was available in 19 of 21 cases (mean duration of follow-up 3.6 years). Forty-three embolization procedures were performed; 8 embolization-related complications occurred, leading to transient neurological deficits in 5 patients (24%), minor permanent neurological deficits in 3 patients (14%), and major permanent neurological deficits in none (0%). Twenty-one SRS procedures were performed; 1 radiation-induced complication occurred (5%), leading to a permanent minor neurological deficit. Of the 20 patients with clinical follow-up, none experienced cerebral hemorrhage. In the 19 patients with radiological follow-up, AVM obliteration was confirmed by catheter angiography in 13, MR angiography in 2, and CT angiography in 1. Residual nidus was found in 3 patients. In patients with follow-up catheter angiography, the AVM obliteration rate was 81% (13 of 16 cases).
  
  
  CONCLUSIONS
  Staged endovascular embolization followed by SRS provides an effective means of treating large AVMs not amenable to standard surgical or SRS treatment. The outcomes and complication rates reported in this series compare favorably to the results of other reported therapeutic strategies for this very challenging patient population.
authors.affiliation: Department of Neurosurgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: Spiros L
authors.initials: SL
authors.lastname: Blackburn
authors.forename: William W
authors.initials: WW
authors.lastname: Ashley
authors.forename: Keith M
authors.initials: KM
authors.lastname: Rich
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Simpson
authors.forename: Robert E
authors.initials: RE
authors.lastname: Drzymala
authors.forename: Wilson Z
authors.initials: WZ
authors.lastname: Ray
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Moran
authors.forename: DeWitte T
authors.initials: DT
authors.lastname: Cross
authors.forename: Michael R
authors.initials: MR
authors.lastname: Chicoine
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Dacey
authors.forename: Colin P
authors.initials: CP
authors.lastname: Derdeyn
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Zipfel
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography; D003131:Combined Modality Therapy; D004621:Embolization, Therapeutic / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000601:surgery / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome