title: Effect of Prior Embolization on Cerebral Arteriovenous Malformation Radiosurgery Outcomes: A Case-Control Study.
abstract: BACKGROUND
  Embolization before stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVM) has been shown to negatively affect obliteration rates, but its impact on the risks of radiosurgery-induced complications and latency period hemorrhage is poorly defined.
  
  
  OBJECTIVE
  To determine, in a case-control study, the effect of prior embolization on AVM SRS outcomes.
  
  
  METHODS
  We evaluated a database of AVM patients who underwent SRS. Propensity score analysis was used to match the case (embolized nidi) and control (nonembolized nidi) cohorts. AVM angioarchitectural complexity was defined as the sum of the number of major feeding arteries and draining veins to the nidus. Multivariate Cox proportional hazards regression analyses were performed on the overall study population to determine independent predictors of obliteration and radiation-induced changes.
  
  
  RESULTS
  The matching process yielded 242 patients in each cohort. The actuarial obliteration rates were significantly lower in the embolized (31%, 49% at 5, 10 years, respectively) compared with the nonembolized (48%, 64% at 5, 10 years, respectively) cohort (P = .003). In the multivariate analysis for obliteration, lower angioarchitectural complexity (P < .001) and radiologically evident radiation-induced changes (P = .016) were independent predictors, but embolization was not significant (P = .744). In the multivariate analysis for radiologic radiation-induced changes, lack of prior embolization (P = .009) and fewer draining veins (P = .011) were independent predictors.
  
  
  CONCLUSIONS
  The effect of prior embolization on AVM obliteration after SRS may be significantly confounded by nidus angioarchitectural complexity. Additionally, embolization could reduce the risk of radiation-induced changes. Thus, combined embolization and SRS may be warranted for appropriately selected nidi.
authors: *Mount Sinai Health System, Department of Neurosurgery, New York City, New York; ‡University of Virginia, Department of Neurosurgery, Charlottesville, Virginia; §New York University Langone Medical Center, Department of Neurosurgery, New York City, New York.
authors: Eric K
authors: EK
authors: Oermann
authors: Dale
authors: D
authors: Ding
authors: Chun-Po
authors: CP
authors: Yen
authors: Robert M
authors: RM
authors: Starke
authors: Joshua B
authors: JB
authors: Bederson
authors: Douglas
authors: D
authors: Kondziolka
authors: Jason P
authors: JP
authors: Sheehan
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D016208:Databases, Factual; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery*; D008297:Male; D016634:Radiosurgery; D016896:Treatment Outcome; D055815:Young Adult