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Original research
Onyx embolization prior to stereotactic radiosurgery for brain arteriovenous malformations: a single-center treatment algorithm
  1. John D Nerva1,
  2. Jason Barber1,
  3. Michael R Levitt1,2,3,
  4. Jason K Rockhill1,4,
  5. Danial K Hallam1,2,
  6. Basavaraj V Ghodke1,2,
  7. Laligam N Sekhar1,2,
  8. Louis J Kim1,2
  1. 1Department of Neurological Surgery, University of Washington, Washington, USA
  2. 2Department of Radiology, University of Washington, Washington, USA
  3. 3Department of Mechanical Engineering, University of Washington, Washington, USA
  4. 4Department of Radiation Oncology, University of Washington, Washington, USA
  1. Correspondence to Louis J Kim, University of Washington, Chief of Neurological Surgery, Harborview Medical Center, Seattle, WA 98104, USA; ljkim1{at}


Background Embolization before stereotactic radiosurgery (SRS) for brain arteriovenous malformations (BAVMs) is controversial.

Objective To compare clinical and radiographic outcomes in patients undergoing pre-SRS embolization with ethylene copolymer (Onyx) with outcomes in patients undergoing SRS alone.

Methods Seventy consecutive patients with BAVMs who underwent SRS were retrospectively reviewed. Univariate and multivariate analyses were performed to assess the factors associated with radiographic obliteration and complication.

Results Forty-one (59%) patients presented without BAVM rupture and 29 (41%) patients presented with rupture. Pre-SRS embolization was used in 20 patients (28.6%; 7 unruptured and 13 ruptured). Twenty-five of 70 (36%) patients sustained a complication from treatment, including 6 (9%) patients with a post-SRS latency period hemorrhage. Ten (14%) patients had persistent neurological deficits after treatment. Functional outcome (as modified Rankin Scale), complication rate, and radiographic obliteration at last follow-up were not significantly different between embolized and non-embolized groups in both unruptured and ruptured BAVMs. For unruptured BAVMs, 3- and 5-year rates of radiographic obliteration were 23% and 73% for non-embolized patients and 20% and 60% for embolized patients, respectively. For ruptured BAVMs, 3- and 5-year rates of radiographic obliteration were 45% and 72% for non-embolized patients and 53% and 82% for embolized patients, respectively.

Conclusion Pre-SRS embolization with Onyx was not associated with worse clinical or radiographic outcomes than SRS treatment without embolization. Pre-SRS embolization has a low complication rate and can safely be used to target high-risk BAVM features in carefully selected patients destined for SRS.

  • Embolization
  • Intracranial arteriovenous malformation
  • Radiosurgery

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  • Contributors All authors made substantial contributions to the conception or design of the work, or the acquisition, analysis, or interpretation of data for the work; and drafting the work or revising it critically for important intellectual content; and approved the final version to be published; and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Competing interests LJK is a consultant for Aesculap and Covidien and a shareholder of Spi Surgical. BVG is a consultant for Covidien and Viket Medical. LNS is a consultant for Viket Medical and a shareholder in Spi Surgical.

  • Ethics approval University of Washington Institutional Review Board Human Subjects Division.

  • Provenance and peer review Not commissioned; externally peer reviewed.