title: The Risk of Seizure Following Surgery for Brain Arteriovenous Malformation: A Prospective Cohort Study.
abstract: BACKGROUND
  The evidence for the risk of seizures following surgery for brain arteriovenous malformations (bAVM) is limited.
  
  
  OBJECTIVE
  To determine the risk of seizures after discharge from surgery for supratentorial bAVM.
  
  
  METHODS
  A prospectively collected cohort database of 559 supratentorial bAVM patients (excluding patients where surgery was not performed with the primary intention of treating the bAVM) was analyzed. Cox proportional hazards regression models (Cox regression) were generated assessing risk factors, a Receiver Operator Characteristic curve was generated to identify a cut-point for size and Kaplan-Meier life table curves created to identify the cumulative freedom from postoperative seizure.
  
  
  RESULTS
  Preoperative histories of more than 2 seizures and increasing maximum diameter (size, cm) of bAVM were found to be significantly (P < .01) associated with the development of postoperative seizures and remained significant in the Cox regression (size as continuous variable: P = .01; hazard ratio: 1.2; 95% confidence interval: 1.0-1.3; more than 2 seizures: P = .02; hazard ratio: 2.1; 95% confidence interval: 1.1-3.8). The cumulative risk of first seizure after discharge from hospital following resection surgery for all patients with bAVM was 5.8% and 18% at 12 mo and 7 yr, respectively. The 7-yr risk of developing postoperative seizures ranged from 11% for patients with bAVM ≤4 cm and with 0 to 2 preoperative seizures, to 59% for patients with bAVM >4 cm and with >2 preoperative.
  
  
  CONCLUSIONS
  The risk of seizures after discharge from hospital following surgery for bAVM increases with the maximum diameter of the bAVM and a patient history of more than 2 preoperative seizures.
authors.affiliation: Department of Clinical Medicine, Macquarie University, Sydney NSW, Australia.
authors.forename: Joan Margaret
authors.initials: JM
authors.lastname: O'Donnell
authors.affiliation: Department of Clinical Medicine, Macquarie University, Sydney NSW, Australia.
authors.forename: Michael Kerin
authors.initials: MK
authors.lastname: Morgan
authors.affiliation: Department of Statistics, Macquarie University, Sydney NSW, Australia.
authors.forename: Gillian Z
authors.initials: GZ
authors.lastname: Heller
mesh_terms: D000328:Adult; D001164:Arteriovenous Fistula / Q000473:pathology / Q000601:surgery*; D001921:Brain / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D012640:Seizures / Q000453:epidemiology / Q000209:etiology*
keywords: Arteriovenous malformation; Brain; Cox regression; Kaplan–Meier; Seizure; Surgery