title: Resective focal epilepsy surgery - Has selection of candidates changed? A systematic review.
abstract: OBJECTIVE
  No standard, widely accepted criteria exist to determine who should be referred for an epilepsy surgical evaluation. As a result, indications for epilepsy surgery evaluation vary significantly between centers. We review the literature to assess what criteria have been used to select patients for resective epilepsy surgery and examine whether these have changed since the publication of the first epilepsy surgery randomized controlled trial in 2001.
  
  
  METHODS
  A systematic review was conducted using PubMed and EMBASE, bibliographies of reviews and book chapters identifying focal epilepsy resective series. Abstract, full text review and data abstraction (i.e. indications for surgery) were performed independently by two reviewers. Descriptive historical analysis was done to examine indications over time.
  
  
  RESULTS
  Out of 5061 articles related to epilepsy surgery, 384 articles met all eligibility criteria. Most common criteria for selecting patients for evaluation for resective surgery were: AED resistance (n=303, most commonly >2 AEDs=46), epilepsy duration (n=53, most commonly >1 year=42) and seizure frequency (most commonly at least one seizure/month, n=29). Out of the prospective studies the most notable change over time (pre-2000 vs. post-2000) was failure of ≥2 AEDs (8% vs. 43% respectively, p<0.001).
  
  
  CONCLUSIONS
  Important variations between studies make it difficult to identify consistent criteria to guide surgical candidacy or changes in indications over time. With increasing evidence that earlier surgery is associated with better outcomes, it is recommended that patients be evaluated as soon as they have failed two AEDs, consistent with the new definition of drug resistant epilepsy. Furthermore, low seizure frequency should not be a barrier to epilepsy surgery. Anyone with drug resistant epilepsy should be promptly evaluated for possible surgery, regardless of seizure frequency.
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA. Electronic address: churlsu.kwon@gmail.com.
authors.forename: Churl-Su
authors.initials: CS
authors.lastname: Kwon
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA. Electronic address: jonbneal@gmail.com.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Neal
authors.affiliation: Department of Neurology, University of Saskatchewan, Saskatoon, Canada. Electronic address: jose.tellez@usask.ca.
authors.forename: Jose
authors.initials: J
authors.lastname: Telléz-Zenteno
authors.affiliation: Department of Obstetrics and Gynecology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada. Electronic address: amy.metcalfe@albertahealthservices.ca.
authors.forename: Amy
authors.initials: A
authors.lastname: Metcalfe
authors.affiliation: Harvard School of Public Health, Boston, MA, USA. Electronic address: katefitzgrld@gmail.com.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Fitzgerald
authors.affiliation: Department of Neurology, University of Saskatchewan, Saskatoon, Canada. Electronic address: liztellez33@hotmail.com.
authors.forename: Lizbeth
authors.initials: L
authors.lastname: Hernandez-Ronquillo
authors.affiliation: Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Alberta, Canada. Electronic address: walter.hader@albertahealthservices.ca.
authors.forename: Walter
authors.initials: W
authors.lastname: Hader
authors.affiliation: Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Alberta, Canada; Department of Community Health Sciences, O'Brien Institute for Public Health, University of Calgary, Alberta, Canada. Electronic address: swiebe@ucalgary.ca.
authors.forename: Samuel
authors.initials: S
authors.lastname: Wiebe
authors.affiliation: Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Alberta, Canada; Department of Community Health Sciences, O'Brien Institute for Public Health, University of Calgary, Alberta, Canada. Electronic address: Nathalie.jette@albertahealthservices.ca.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jetté
mesh_terms: D004828:Epilepsies, Partial / Q000601:surgery*; D006801:Humans; D019635:Neurosurgical Procedures / Q000379:methods*; D018579:Patient Selection
keywords: Epilepsy surgery; Extra-temporal lobe epilepsy; Systematic review; Temporal lobe epilepsy