title: The evolution of epilepsy surgery between 1991 and 2011 in nine major epilepsy centers across the United States, Germany, and Australia.
abstract: OBJECTIVE
  Epilepsy surgery is the most effective treatment for select patients with drug-resistant epilepsy. In this article, we aim to provide an accurate understanding of the current epidemiologic characteristics of this intervention, as this knowledge is critical for guiding educational, academic, and resource priorities.
  
  
  METHODS
  We profile the practice of epilepsy surgery between 1991 and 2011 in nine major epilepsy surgery centers in the United States, Germany, and Australia. Clinical, imaging, surgical, and histopathologic data were derived from the surgical databases at various centers.
  
  
  RESULTS
  Although five of the centers performed their highest number of surgeries for mesial temporal sclerosis (MTS) in 1991, and three had their highest number of MTS surgeries in 2001, only one center achieved its peak number of MTS surgeries in 2011. The most productive year for MTS surgeries varied then by center; overall, the nine centers surveyed performed 48% (95% confidence interval [CI] -27.3% to -67.4%) fewer such surgeries in 2011 compared to either 1991 or 2001, whichever was higher. There was a parallel increase in the performance of surgery for nonlesional epilepsy. Further analysis of 5/9 centers showed a yearly increase of 0.6 ± 0.07% in the performance of invasive electroencephalography (EEG) without subsequent resections. Overall, although MTS was the main surgical substrate in 1991 and 2001 (proportion of total surgeries in study centers ranging from 33.3% to 70.2%); it occupied only 33.6% of all resections in 2011 in the context of an overall stable total surgical volume.
  
  
  CONCLUSIONS
  These findings highlight the major aspects of the evolution of epilepsy surgery across the past two decades in a sample of well-established epilepsy surgery centers, and the critical current challenges of this treatment option in addressing complex epilepsy cases requiring detailed evaluations. Possible causes and implications of these findings are discussed.
authors.affiliation: Department of Neurology, Cleveland Clinic, Cleveland, Ohio, U.S.A.
authors.forename: Lara
authors.initials: L
authors.lastname: Jehi
authors.affiliation: Department of Neurology, New York University, New York, New York, U.S.A.
authors.forename: Daniel
authors.initials: D
authors.lastname: Friedman
authors.affiliation: Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A.
authors.forename: Chad
authors.initials: C
authors.lastname: Carlson
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, U.S.A.
authors.forename: Gregory
authors.initials: G
authors.lastname: Cascino
authors.affiliation: Department of Neurology, University of California-Los Angeles, Los Angeles, California, U.S.A.
authors.forename: Sandra
authors.initials: S
authors.lastname: Dewar
authors.affiliation: Department of Neurology, University of Bonn, Bonn, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Elger
authors.affiliation: Department of Neurology, University of California-Los Angeles, Los Angeles, California, U.S.A.
authors.forename: Jerome
authors.initials: J
authors.lastname: Engel
authors.affiliation: Department of Neurology, University of California-San Francisco, San Francisco, California, U.S.A.
authors.forename: Robert
authors.initials: R
authors.lastname: Knowlton
authors.affiliation: Department of Neurology, New York University, New York, New York, U.S.A.
authors.forename: Ruben
authors.initials: R
authors.lastname: Kuzniecky
authors.affiliation: The Department of Medicine, The Royal Melbourne and Austin Hospitals, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: McIntosh
authors.affiliation: The Department of Medicine, The Royal Melbourne and Austin Hospitals, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Terence J
authors.initials: TJ
authors.lastname: O'Brien
authors.affiliation: Department of Neurology, Yale University, New Haven, Connecticut, U.S.A.
authors.forename: Dennis
authors.initials: D
authors.lastname: Spencer
authors.affiliation: Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sperling
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, U.S.A.
authors.forename: Gregory
authors.initials: G
authors.lastname: Worrell
authors.affiliation: Department of Neurology, Cleveland Clinic, Cleveland, Ohio, U.S.A.
authors.forename: Bill
authors.initials: B
authors.lastname: Bingaman
authors.affiliation: Department of Neurology, Cleveland Clinic, Cleveland, Ohio, U.S.A.
authors.forename: Jorge
authors.initials: J
authors.lastname: Gonzalez-Martinez
authors.affiliation: Department of Neurology, New York University, New York, New York, U.S.A.
authors.forename: Werner
authors.initials: W
authors.lastname: Doyle
authors.affiliation: Department of Neurology, New York University, New York, New York, U.S.A.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: French
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia; D004827:Epilepsy / Q000601:surgery*; D005260:Female; D005858:Germany; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014481:United States; D055815:Young Adult
keywords: Epilepsy surgery; Invasive EEG; Mesial temporal sclerosis; Neocortical epilepsy