title: Late seizures in patients initially seizure free after epilepsy surgery.
abstract: OBJECTIVE
  Surgery for medically intractable epilepsy is currently the most effective means of achieving seizure control. Although relatively few long-term outcome studies have been performed, evidence is mounting that the possibility of late seizure recurrence exists, even after an early seizure-free period. No published reports document the rate and predictors of late recurrence in a large series of patients undergoing surgery in the magnetic resonance imaging (MRI) era.
  
  
  METHODS
  We retrospectively queried the databases of two epilepsy surgery centers. Patients eligible for study had preoperative MRI scans, were seizure free for 1 year after surgery, and had a minimal follow-up period of 3 years. Patients with tumors or vascular lesions were excluded. We performed log-rank comparison of Kaplan-Meier product limit estimates for categoric variables and used a Cox proportional hazards model for continuous variables. Variables that were significant (p<0.05) on a univariate screen were entered into a multivariate forward step-wise Cox regression.
  
  
  RESULTS
  The study included 285 patients, 254 with medial temporal lobe (MTLE) and 31 with neocortical epilepsy. The probability of having a single seizure after being seizure free for 1 year was 18.3% at 5 years and 32.7% at 10 years. However, only 13% were not seizure free at the last follow-up. Predictors of late recurrences on both uni- and multivariate analysis were the presence of preoperative generalized tonic-clonic (GTC) seizures in patients with neocortical epilepsy and late age at surgery in patients with MTLE. MRI results and location of surgery were not predictive.
  
  
  CONCLUSIONS
  Although the risk of at least one recurrent seizure after initially successful epilepsy surgery is relatively high, the rate of recurrent intractability is low. The finding that late age at surgery and presence of preoperative GTC seizures are predictors of late recurrence indicates the importance of patient selection and early surgery for persistent seizure control.
authors.affiliation: Neurological Surgery, Weill Cornell Medical College, and New York Presbyterian Hospital, New York, NY 10021, USA. schwarh@med.cornell.edu
authors.forename: Theodore H
authors.initials: TH
authors.lastname: Schwartz
authors.forename: Lara
authors.initials: L
authors.lastname: Jeha
authors.forename: Adrianna
authors.initials: A
authors.lastname: Tanner
authors.forename: William
authors.initials: W
authors.lastname: Bingaman
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sperling
mesh_terms: D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D002540:Cerebral Cortex / Q000601:surgery*; D018572:Disease-Free Survival; D004827:Epilepsy / Q000601:surgery*; D004833:Epilepsy, Temporal Lobe / Q000601:surgery; D004830:Epilepsy, Tonic-Clonic / Q000453:epidemiology / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D019579:Neocortex / Q000601:surgery; D018579:Patient Selection; D011184:Postoperative Period; D011300:Preoperative Care; D011336:Probability; D016016:Proportional Hazards Models; D012008:Recurrence; D012189:Retrospective Studies; D016896:Treatment Outcome