title: Radiosurgery for Cerebral Arteriovenous Malformations with Associated Arterial Aneurysms.
abstract: OBJECTIVE
  The radiosurgical outcomes for cerebral arteriovenous malformations (AVM) with AVM-associated arterial aneurysms (AAA) are poorly understood, because many AAAs are embolized before nidal intervention. The aim of this retrospective case-control study is to determine the effect of AAAs on AVM radiosurgery outcomes.
  
  
  METHODS
  We evaluated an institutional AVM radiosurgery database from 1989 to 2013. AAAs were classified as intranidal (type I) or prenidal (type II). The case cohort comprised AVMs with patent type I or II AAAs. The control cohort comprised AVMs without AAAs and matched 2:1 to the case cohort.
  
  
  RESULTS
  The case cohort comprised 51 AVMs, including 23 with type I and 28 with type II AAAs. The control cohort comprised 102 AVMs without AAAs. The cumulative AVM obliteration, annual postradiosurgery hemorrhage, and radiologically evident radiation-induced changes rates were 67%, 3.3%, and 28%, respectively, for the case cohort, compared with 70%, 2.0%, and 35%, respectively, for the control cohort. The presence of an AAA was not significantly associated with obliteration (P = 0.293), postradiosurgery hemorrhage (P = 0.209), or radiation-induced changes (P = 0.323). The rates of type II AAA occlusion at 3, 5, and 10 years were 46%, 77%, and 95%, respectively. The type II AAA occlusion rate was significantly higher in obliterated AVMs (P = 0.002).
  
  
  CONCLUSIONS
  Patent intranidal or prenidal AAAs do not significantly affect AVM radiosurgical outcomes. Occlusion of distal prenidal AAAs commonly occurs after radiosurgery. These findings may support a more conservative stance for embolization before radiosurgery for AVMs with AAAs.
authors.affiliation: Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: Dale
authors.initials: D
authors.lastname: Ding
authors.affiliation: Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Starke
authors.affiliation: Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: Chun-Po
authors.initials: CP
authors.lastname: Yen
authors.affiliation: Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: Han-Hsun
authors.initials: HH
authors.lastname: Shih
authors.affiliation: Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Buell
authors.affiliation: Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA. Electronic address: jps2f@virginia.edu.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Sheehan
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D004621:Embolization, Therapeutic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000628:therapy*; D002538:Intracranial Arteriovenous Malformations / Q000150:complications* / Q000601:surgery*; D020300:Intracranial Hemorrhages / Q000209:etiology / Q000517:prevention & control; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D016634:Radiosurgery / Q000009:adverse effects; D012189:Retrospective Studies; D012640:Seizures / Q000209:etiology / Q000517:prevention & control; D016896:Treatment Outcome
keywords: Gamma knife; Intracranial aneurysm; Intracranial arteriovenous malformation; Intracranial hemorrhages; Radiosurgery; Stroke; Vascular malformations