title: Long-term outcomes after nonlesional extratemporal lobe epilepsy surgery.
abstract: OBJECTIVE
  A focal lesion detected by use of magnetic resonance imaging (MRI) is a favorable prognostic finding for epilepsy surgery. Patients with normal MRI findings and extratemporal lobe epilepsy have less favorable outcomes. Most studies investigating the outcomes of patients with normal MRI findings who underwent (nonlesional) extratemporal epilepsy surgery are confined to a highly select group of patients with limited follow-up.
  
  
  OBJECTIVE
  To evaluate noninvasive diagnostic test results and their association with excellent surgical outcomes (defined using Engel classes I-IIA of surgical outcomes) in a group of patients with medically resistant nonlesional extratemporal epilepsy.
  
  
  METHODS
  A retrospective study.
  
  
  METHODS
  Mayo Clinic, Rochester, Minnesota.
  
  
  METHODS
  From 1997 through 2002, we identified 85 patients with medically resistant extratemporal lobe epilepsy who had normal MRI findings. Based on a standardized presurgical evaluation and review at a multidisciplinary epilepsy surgery conference, some of these patients were selected for intracranial electroencephalographic (EEG) monitoring and epilepsy surgery.
  
  
  METHODS
  Nonlesional extratemporal lobe epilepsy surgery.
  
  
  METHODS
  The results of noninvasive diagnostic tests and the clinical variables potentially associated with excellent surgical outcome were examined in patients with a minimum follow-up of 1 year (mean follow-up, 9 years).
  
  
  RESULTS
  Based on the noninvasive diagnostic test results, a clear hypothesis for seizure origin was possible for 47 of the 85 patients (55%), and 31 of these 47 patients (66%) proceeded to intracranial EEG monitoring. For 24 of these 31 patients undergoing long-term intracranial EEG (77%), a seizure focus was identified and surgically resected. Of these 24 patients, 9 (38%) had an excellent outcome after resective epilepsy surgery. All patients with an excellent surgical outcome had at least 10 years of follow-up. Univariate analysis showed that localized interictal epileptiform discharges on scalp EEGs were associated with an excellent surgical outcome.
  
  
  CONCLUSIONS
  Scalp EEG was the most useful test for identifying patients with normal MRI findings and extratemporal lobe epilepsy who were likely to have excellent outcomes after epilepsy surgery. Extending outcome analysis beyond the resective surgery group to the entire group of patients who were evaluated further highlights the challenge that these patients pose. Although 9 of 24 patients undergoing resective surgery (38%) had excellent outcomes, only 9 of 31 patients undergoing intracranial EEG (29%) and only 9 of 85 patient with nonlesional extratemporal lobe epilepsy (11%) had long-term excellent outcomes.
authors.affiliation: Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Noe
authors.forename: Vlastimil
authors.initials: V
authors.lastname: Sulc
authors.forename: Lily
authors.initials: L
authors.lastname: Wong-Kisiel
authors.forename: Elaine
authors.initials: E
authors.lastname: Wirrell
authors.forename: Jamie J
authors.initials: JJ
authors.lastname: Van Gompel
authors.forename: Nicholas
authors.initials: N
authors.lastname: Wetjen
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Britton
authors.forename: Elson
authors.initials: E
authors.lastname: So
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Cascino
authors.forename: W Richard
authors.initials: WR
authors.lastname: Marsh
authors.forename: Fredric
authors.initials: F
authors.lastname: Meyer
authors.forename: Daniel
authors.initials: D
authors.lastname: Horinek
authors.forename: Caterina
authors.initials: C
authors.lastname: Giannini
authors.forename: Robert
authors.initials: R
authors.lastname: Watson
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Brinkmann
authors.forename: Matt
authors.initials: M
authors.lastname: Stead
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Worrell
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000503:physiopathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007223:Infant; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome; D055815:Young Adult