title: Predicting seizure frequency after epilepsy surgery.
abstract: OBJECTIVE
  To identify clinical features related to seizure frequency after epilepsy surgery in patients with recurrent seizures.
  
  
  BACKGROUND
  No studies have examined the differences between patients who have rare seizures and patients who experience frequent seizures after epilepsy surgery. Since seizure frequency correlates with morbidity and quality of life, it is desirable to know which preoperative clinical features predict postoperative seizure frequency.
  
  
  METHODS
  Patients with recurrent seizures were placed in two categories: rare postoperative seizures (< or =2 per year) and frequent postoperative seizures (> or =12 per year) using seizure frequency in the second postoperative year. Variables included preoperative seizure frequency, age of first risk, age at first seizure, epilepsy duration, age at surgery, history of febrile convulsions, tonic-clonic seizures, status epilepticus, or family history, IQ, magnetic resonance imaging (MRI), and positron emission tomography (PET). Variables were analyzed using non-parametric tests to assess relationship to postoperative seizure frequency.
  
  
  RESULTS
  Of 475 patients who had epilepsy surgery, 111 had rare or frequent seizures in the second postoperative year. After anterior temporal lobectomy (ATL), age of first risk< or =5 years and presence of mesial temporal sclerosis on MRI were associated with rare seizures (66% of patients), whereas lack of these risk factors was associated with frequent seizures (75% of patients) (p<0.03). For non-ATL operations, preoperative seizure frequency of > or =20 seizures per month was associated with frequent postoperative seizures (p=0.03). No other variables influenced outcome.
  
  
  CONCLUSIONS
  Some preoperative clinical features correlate with postoperative seizure frequency in patients with recurrent seizures after epilepsy surgery. This has implications for the surgical decision making process and early postoperative management.
authors.affiliation: Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Khoury
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Winokur
authors.forename: Joseph I
authors.initials: JI
authors.lastname: Tracy
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sperling
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D038481:Anterior Temporal Lobectomy; D002648:Child; D002675:Child, Preschool; D006259:Craniocerebral Trauma / Q000150:complications / Q000453:epidemiology; D004828:Epilepsies, Partial / Q000453:epidemiology; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology / Q000601:surgery*; D004830:Epilepsy, Tonic-Clonic / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019635:Neurosurgical Procedures; D049268:Positron-Emission Tomography; D011184:Postoperative Period; D012307:Risk Factors; D012598:Sclerosis; D012640:Seizures / Q000453:epidemiology* / Q000473:pathology; D003294:Seizures, Febrile / Q000453:epidemiology; D013226:Status Epilepticus / Q000453:epidemiology; D013702:Temporal Lobe / Q000473:pathology / Q000601:surgery