title: Randomized controlled trial of 2.5-cm versus 3.5-cm mesial temporal resection in temporal lobe epilepsy--Part 1: intent-to-treat analysis.
abstract: BACKGROUND
  Only one prospective randomized study on the extent of mesial resection in surgery for temporal lobe epilepsy (TLE) exists. This randomized controlled trial (RCT) examines whether 3.5-cm mesial resection is leading to a better seizure outcome than a 2.5-cm resection.
  
  
  METHODS
  Three epilepsy surgery centers using similar MRI protocols, neuropsychological tests, and resection types for TLE surgery included 207 patients in a RCT with pre- and postoperative volumetrics. One hundred and four patients were randomized into a 2.5-cm resection group and 103 patients into a 3.5-cm resection group, i.e., an intended minimum resection length of 25 versus 35 mm for the hippocampus and parahippocampus. Primary outcome measure was seizure freedom Engel class I throughout the first year. The study was powered to detect a 20% difference in class I outcome. Seizure outcome was available for 207 patients, complete volumetric results for 179 patients. Outcome analysis was restricted to control of successful randomization and an intent-to-treat analysis of seizure outcome.
  
  
  RESULTS
  The mean true resection volumes were significantly different for the 2.5-cm and 3.5-cm resection groups; thus, the randomization was successful. Median resection volume in the 2.5-cm group was 72.86% of initial volume and 83.44% in the 3.5-cm group. At 1 year, seizure outcome Engel class I was 74% in the 2.5-cm and 72.8% in the 3.5-cm resection group.
  
  
  CONCLUSIONS
  The primary intent-to-treat analysis did not show a different seizure freedom rate for the more posteriorly reaching 3.5-cm resection group. It appears possible that not maximal volume resection but adequate volume resection leads to good seizure freedom.
authors.affiliation: Department of Neurosurgery, University of Bonn, Germany. Johannes.Schramm@ukb.uni-bonn.de
authors.forename: Johannes
authors.initials: J
authors.lastname: Schramm
authors.forename: T N
authors.initials: TN
authors.lastname: Lehmann
authors.forename: J
authors.initials: J
authors.lastname: Zentner
authors.forename: C A
authors.initials: CA
authors.lastname: Mueller
authors.forename: J
authors.initials: J
authors.lastname: Scorzin
authors.forename: R
authors.initials: R
authors.lastname: Fimmers
authors.forename: H J
authors.initials: HJ
authors.lastname: Meencke
authors.forename: A
authors.initials: A
authors.lastname: Schulze-Bonhage
authors.forename: C E
authors.initials: CE
authors.lastname: Elger
mesh_terms: D000328:Adult; D038481:Anterior Temporal Lobectomy / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011446:Prospective Studies; D012307:Risk Factors; D013702:Temporal Lobe / Q000473:pathology / Q000601:surgery*