title: Analysis of treatment failure after radiosurgery for arteriovenous malformations.
abstract: OBJECTIVE
  The aim of this study was to evaluate the causes of treatment failure in patients with arteriovenous malformations (AVMs) who underwent radiosurgery, which is increasingly used as a treatment method for selected, surgically high-risk AVMs. Unfortunately, radiosurgical treatment fails in a small but significant percentage of patients. In the time period covered in this study, 72 patients attained angiographically confirmed cures after radiosurgery and 36 were retreated after the initial radiosurgical treatment failed.
  
  
  METHODS
  Using a computerized image fusion technique, the initial radiosurgical dosimetry plan was superimposed on the remaining AVM nidus at the time of retreatment. Twenty-six percent of the retreated cases were found to have AVM niduses outside the original treatment isodose line, which means that targeting error was a factor. The retreated group was also statistically compared with the cured group.
  
  
  CONCLUSIONS
  Multivariate analysis revealed that the following factors were statistically significant predictors of treatment failure: increasing AVM size, decreasing treatment dose, and increasing Spetzler-Martin grade.
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville 32610, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Ellis
authors.forename: W A
authors.initials: WA
authors.lastname: Friedman
authors.forename: F J
authors.initials: FJ
authors.lastname: Bova
authors.forename: P S
authors.initials: PS
authors.lastname: Kubilis
authors.forename: J M
authors.initials: JM
authors.lastname: Buatti
mesh_terms: D002533:Cerebral Angiography; D005069:Evaluation Studies as Topic; D005260:Female; D005544:Forecasting; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D012372:ROC Curve; D016634:Radiosurgery; D011879:Radiotherapy Dosage; D012074:Remission Induction; D019233:Retreatment; D012680:Sensitivity and Specificity; D013813:Therapy, Computer-Assisted; D017211:Treatment Failure; D016896:Treatment Outcome