title: Uncovered primary seizure foci in Lennox-Gastaut syndrome after corpus callosotomy.
abstract: OBJECTIVE
  Corpus callosotomy (CC) is a palliative surgical procedure to control atonic, tonic, or generalized tonic-clonic seizure in Lennox-Gastaut syndrome (LGS). Here, we report patients with LGS who underwent resective surgery, following CC better delineating the presumed seizure foci localized in one hemisphere.
  
  
  METHODS
  We retrospectively reviewed seven patients with LGS who underwent CC and subsequent cortical resection. The median follow-up duration after lobectomy was 20 months (range, 15-54 months) and three patients had follow-up periods over 24 months. The findings of video electroencephalography (EEG) monitoring, structural and functional neuroimagings were compared between pre- and post-CC.
  
  
  RESULTS
  Four patients had Engel class I and one patient had Engel class II outcomes following cortical resection; post-CC, compared to pre-CC, showed better localized ictal/interictal epileptiform discharges in the unilateral frontal area in two patients, in the unilateral parieto-temporo-occipital areas in one patient and in the unilateral fronto-temporal areas in the remaining two patients. Two patients had Engel Class III outcome following cortical resection; post-CC EEG continued to show multifocal epileptiform discharges but predominantly arising from a unilateral frontal area. Following CC, positron emission tomography showed localized glucose hypometabolism of which location was concordant with post-CC EEG abnormalities in all patient. Similarly, ictal/interictal single photon emission computed tomography also showed localized abnormalities concordant with post-CC EEG abnormalities in five of the six patients. Pathological assessment revealed cortical dysplasia in six patients, whereas no pathological abnormality was found in the remaining patient, who obtained Engel Class I outcome following cortical resection.
  
  
  CONCLUSIONS
  CC could change EEG findings, glucose metabolisms and cerebral blood flows, and it is sometimes helpful in delineating the primary seizure focus in patients with LGS.
authors.affiliation: Department of Pediatrics, Haeundae Paik Hospital, Inje University College of Medicine, Pusan, Republic of Korea.
authors.forename: Yun Jung
authors.initials: YJ
authors.lastname: Hur
authors.forename: Hoon-Chul
authors.initials: HC
authors.lastname: Kang
authors.forename: Dong Seok
authors.initials: DS
authors.lastname: Kim
authors.forename: Sae Rom
authors.initials: SR
authors.lastname: Choi
authors.forename: Heung Dong
authors.initials: HD
authors.lastname: Kim
authors.forename: Joon Soo
authors.initials: JS
authors.lastname: Lee
mesh_terms: D002648:Child; D002675:Child, Preschool; D003337:Corpus Callosum / Q000601:surgery*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D065768:Lennox Gastaut Syndrome; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies; D012640:Seizures / Q000503:physiopathology / Q000601:surgery*; D013036:Spasms, Infantile / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*