title: Derivation and initial validation of a surgical grading scale for the preliminary evaluation of adult patients with drug-resistant focal epilepsy.
abstract: Presently, there is no simple method at initial presentation for identifying a patient's likelihood of progressing to surgery and a favorable outcome. The Epilepsy Surgery Grading Scale (ESGS) is a three-tier empirically derived mathematical scale with five categories: magnetic resonance imaging (MRI), electroencephalography (EEG), concordance (between MRI and EEG), semiology, and IQ designed to stratify patients with drug-resistant focal epilepsy based on their likelihood of proceeding to resective epilepsy surgery and achieving seizure freedom.
  
  
  
  In this cross-sectional study, we abstracted data from the charts of all patients admitted to the New York University Langone Medical Center (NYULMC) for presurgical evaluation or presented in surgical multidisciplinary conference (MDC) at the NYU Comprehensive Epilepsy Center (CEC) from 1/1/2007 to 7/31/2008 with focal epilepsy, who met minimal criteria for treatment resistance. We classified patients into ESGS Grade 1 (most favorable), Grade 2 (intermediate), and Grade 3 (least favorable candidates). Three cohorts were evaluated: all patients, patients presented in MDC, and patients who had resective surgery. The primary outcome measure was proceeding to surgery and seizure freedom.
  
  
  
  Four hundred seven patients met eligibility criteria; 200 (49.1%) were presented in MDC and 113 (27.8%) underwent surgery. A significant difference was observed between Grades 1 and 3, Grades 1 and 2, and Grades 2 and 3 for all presurgical patients, and those presented in MDC, with Grade 1 patients having the highest likelihood of both having surgery and becoming seizure-free. There was no difference between Grades 1 and 2 among patients who had resective surgery.
  
  
  
  These results demonstrate that by systematically using basic information available during initial assessment, patients with drug-resistant epilepsy may be successfully stratified into clinically meaningful groups with varied prognosis. The ESGS may improve communication, facilitate decision making and early referral to a CEC, and allow patients and physicians to better manage expectations.
authors.affiliation: Department of Neurology, New York University Langone Medical Center, New York, New York, U.S.A.
authors.forename: Patricia
authors.initials: P
authors.lastname: Dugan
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 Clinical Neurosciences and Hotchkiss Brain Institute, Department of Community Health Sciences and O'Brien Institute for Public Health, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jetté
authors.affiliation: Department of Clinical Neurosciences and Hotchkiss Brain Institute, Department of Community Health Sciences and O'Brien Institute for Public Health, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Samuel
authors.initials: S
authors.lastname: Wiebe
authors.affiliation: Department of Neurology, Albany Medical Center, Albany, New York, U.S.A.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Bunch
authors.affiliation: Department of Neurology, New York University Langone Medical Center, New York, New York, U.S.A.
authors.forename: Ruben
authors.initials: R
authors.lastname: Kuzniecky
authors.affiliation: Department of Neurology, New York University Langone Medical Center, New York, New York, U.S.A.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: French
mesh_terms: D000328:Adult; D000465:Algorithms; D000927:Anticonvulsants / Q000009:adverse effects / Q000627:therapeutic use*; D015331:Cohort Studies; D000069279:Drug Resistant Epilepsy / Q000145:classification* / Q000175:diagnosis / Q000188:drug therapy / Q000601:surgery*; D004569:Electroencephalography; D020938:Epilepsy, Partial, Motor / Q000145:classification* / Q000175:diagnosis / Q000188:drug therapy / Q000601:surgery*; D005260:Female; D006801:Humans; D007360:Intelligence; D016013:Likelihood Functions; D008279:Magnetic Resonance Imaging; D008297:Male; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D011379:Prognosis; D012017:Referral and Consultation / Q000706:statistics & numerical data; D018570:Risk Assessment / Q000706:statistics & numerical data; D013702:Temporal Lobe / Q000601:surgery
chemical_list: D000927:Anticonvulsants
keywords: Drug-resistant epilepsy; Epilepsy surgery; Grading scale