title: Seizure freedom score: a new simple method to predict success of epilepsy surgery.
abstract: OBJECTIVE
  We aim to develop a new scale that predicts seizure outcomes after resective epilepsy surgery.
  
  
  METHODS
  We retrospectively reviewed patients who underwent surgery for medically refractory epilepsy at our center between 1999 and 2012. Four predictive outcome indicators were selected: preoperative seizure frequency, history of generalized tonic-clonic seizures, brain magnetic resonance imaging (MRI), and epilepsy duration. A score of 0 or 1 was given if the indicator was associated with poor or good outcome, respectively. A seizure freedom score (SFS) was calculated by adding these four categories (total score ranged from 0 to 4). A modified SFS (m-SFS) was then calculated with two additional outcome indicators: invasive electroencephalography (EEG) evaluation (IEI) (performed or not performed) and lobe of resection (temporal vs. extratemporal), for a score ranging from 0 to 6. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom in the overall group. Statistical significance was tested using the log-rank test and comparison of 95% confidence intervals (CIs).
  
  
  RESULTS
  The study population included 466 patients with 244 (52%) male. Seizure freedom rates were directly correlated with the SFS score: at 10 years, 36.9% of patients with SFS of 0 were seizure-free, as opposed to 45% for SFS = 1, 60% for SFS = 2, 72% for SFS 3 or above (p = 0.002). When calculated including the IEI and the localization, the score's performance improved: 24% of patients with a m-SFS of 0 were seizure-free at 10 years, as opposed to 38-59% for m-SFS = 1-3, and 75-79% for m-SFS of 4-6 (p < 0.001).
  
  
  CONCLUSIONS
  An easily measurable seizure freedom score could be a reliable tool to synthesize multiple seizure outcome predictors into a single simple score to predict postoperative seizure freedom. This tool will help with patient and family counseling and estimation of surgical candidacy at both early (SFS) and advanced (m-SFS) stages of a surgical evaluation.
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.
authors.forename: Camilo
authors.initials: C
authors.lastname: Garcia Gracia
authors.forename: Ruta
authors.initials: R
authors.lastname: Yardi
authors.forename: Michael W
authors.initials: MW
authors.lastname: Kattan
authors.forename: Dileep
authors.initials: D
authors.lastname: Nair
authors.forename: Ajay
authors.initials: A
authors.lastname: Gupta
authors.forename: Imad
authors.initials: I
authors.lastname: Najm
authors.forename: William
authors.initials: W
authors.lastname: Bingaman
authors.forename: Jorge
authors.initials: J
authors.lastname: Gonzalez-Martinez
authors.forename: Lara
authors.initials: L
authors.lastname: Jehi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004827:Epilepsy / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D053208:Kaplan-Meier Estimate; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011237:Predictive Value of Tests; D011859:Radiography; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome; D055815:Young Adult
keywords: Epilepsy surgery; Outcomes