title: The value of intraoperative electrocorticography in surgical decision making for temporal lobe epilepsy with normal MRI.
abstract: OBJECTIVE
  We hypothesized that acute intraoperative electrocorticography (ECoG) might identify a subset of patients with magnetic resonance imaging (MRI)-negative temporal lobe epilepsy (TLE) who could proceed directly to standard anteromesial resection (SAMR), obviating the need for chronic electrode implantation to guide resection.
  
  
  METHODS
  Patients with TLE and a normal MRI who underwent acute ECoG prior to chronic electrode recording of ictal onsets were evaluated. Intraoperative interictal spikes were classified as mesial (M), lateral (L), or mesial/lateral (ML). Results of the acute ECoG were correlated with the ictal-onset zone following chronic ECoG. Onsets were also classified as "M,""L," or "ML." Positron emission tomography (PET), scalp-EEG (electroencephalography), and Wada were evaluated as adjuncts.
  
  
  RESULTS
  Sixteen patients fit criteria for inclusion. Outcomes were Engel class I in nine patients, Engel II in two, Engel III in four, and Engel IV in one. Mean postoperative follow-up was 45.2 months. Scalp EEG and PET correlated with ictal onsets in 69% and 64% of patients, respectively. Wada correlated with onsets in 47% of patients. Acute intraoperative ECoG correlated with seizure onsets on chronic ECoG in all 16 patients. All eight patients with "M" pattern ECoG underwent SAMR, and six (75%) experienced Engel class I outcomes. Three of eight patients with "L" or "ML" onsets (38%) had Engel class I outcomes.
  
  
  CONCLUSIONS
  Intraoperative ECoG may be useful in identifying a subset of patients with MRI-negative TLE who will benefit from SAMR without chronic implantation of electrodes. These patients have uniquely mesial interictal spikes and can go on to have improved postoperative seizure-free outcomes.
authors.affiliation: Department of Neurological Surgery, Weill Cornell Medical College, New York, New York 10065, USA.
authors.forename: Neal
authors.initials: N
authors.lastname: Luther
authors.forename: Elayna
authors.initials: E
authors.lastname: Rubens
authors.forename: Nitin
authors.initials: N
authors.lastname: Sethi
authors.forename: Padmaja
authors.initials: P
authors.lastname: Kandula
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Labar
authors.forename: Cynthia
authors.initials: C
authors.lastname: Harden
authors.forename: Kenneth
authors.initials: K
authors.lastname: Perrine
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Christos
authors.forename: J Bryan
authors.initials: JB
authors.lastname: Iorgulescu
authors.forename: Guido
authors.initials: G
authors.lastname: Lancman
authors.forename: Neil S
authors.initials: NS
authors.lastname: Schaul
authors.forename: Dmitriy V
authors.initials: DV
authors.lastname: Kolesnik
authors.forename: Shahin
authors.initials: S
authors.lastname: Nouri
authors.forename: Andrew
authors.initials: A
authors.lastname: Dawson
authors.forename: Apostolos J
authors.initials: AJ
authors.lastname: Tsiouris
authors.forename: Theodore H
authors.initials: TH
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D003657:Decision Making; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods* / Q000706:statistics & numerical data; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000523:psychology / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D019635:Neurosurgical Procedures / Q000379:methods* / Q000592:standards; D016896:Treatment Outcome