title: Failure in radiosurgery treatment of cerebral arteriovenous malformations.
abstract: OBJECTIVE
  The aim of this study was to retrospectively analyze the reasons for the failure of radiosurgical treatment of cerebral arteriovenous malformations (AVMs).
  
  
  METHODS
  Seventeen cases of noncured AVMs were reviewed 3 years after radiosurgical treatment. Follow-up ranged from 33 to 54 months (mean, 44.3 mo). Lesion dimensions varied from 9 to 55 mm (mean, 29.2 mm). The lesions were located in critical or near-critical brain regions. Angiography was performed under Talairach's stereotactic conditions. Two large AVMs bled 36 and 39 months after receiving irradiation, respectively. These two AVMs had been incompletely irradiated.
  
  
  RESULTS
  Retrospectively, in four cases (23.5%) we observed errors in determining AVM target shape and size because of inaccurate definition of the nidus and/or because of stereoangiographic incompleteness (absence of external carotid artery injections). In five large and/or irregularly shaped AVMs (29.4%), a strategy of partial volume irradiation had been used. In one patient (5.8%), we observed the recanalization of previously embolized AVMs. In another case (5.8%), the target had been partially missed. The AVMs in one case (5.8%) had been treated with an ineffective peripheral dose. In one (5.8%), the failure occurred because of the lesion angio-architecture. In four cases (23.5%), no evident reasons for failure were determined.
  
  
  CONCLUSIONS
  The results of this study suggest the necessity of complete irradiation of the nidus. The strategy of partial volume irradiation might be avoided, even if it necessitates lowering the doses to treat large AVMs. Accuracy in the target determination is required, and complete stereoangiography is necessary.
authors.affiliation: Department of Neurosurgery, S. Anne Hospital, Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Gallina
authors.forename: L
authors.initials: L
authors.lastname: Merienne
authors.forename: J F
authors.initials: JF
authors.lastname: Meder
authors.forename: M
authors.initials: M
authors.lastname: Schlienger
authors.forename: D
authors.initials: D
authors.lastname: Lefkopoulos
authors.forename: J J
authors.initials: JJ
authors.lastname: Merland
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography; D002543:Cerebral Hemorrhage / Q000209:etiology / Q000601:surgery; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods; D012189:Retrospective Studies; D017211:Treatment Failure