title: Minimally resective epilepsy surgery in MRI-negative children.
abstract: OBJECTIVE
  Performing epilepsy surgery on children with non-lesional brain MRI often results in large lobar or multilobar resections. The aim of this study was to determine if smaller resections result in a comparable rate of seizure freedom.
  
  
  METHODS
  We reviewed 25 children who had undergone focal corticectomies restricted to one aspect of a single lobe or the insula at our institution within a 5.5-year period. Data collected in the comprehensive non-invasive pre-surgical evaluation (including scalp video-EEG, volumetric MRI, functional MRI, EEG source localization, and SPECT and PET), as well as from invasive recordings performed in each patient, was reviewed. Data from each functional modality was identified as convergent or divergent with the epileptogenic zone using image coregistration. Specific biomarkers (from extra-operative and invasive testing) previously indicated to be indicative of focal epileptogenicity were used to further tailor each resection to an epileptogenic epicentre. Tissue pathology and postoperative outcomes were obtained from all 25 patients.
  
  
  RESULTS
  Two years postoperatively, 15/25 (60%) children were seizure-free, three (12%) experienced >90% reduction in seizure frequency, two (8%) had a 50-90% reduction in seizure frequency, and the remaining five (20%) had no change in seizure burden. There was no significant difference in outcome based on numerous pre- and postoperative factors including location of resection, the number of preoperative functional tests providing convergent data, and tissue pathology.
  
  
  CONCLUSIONS
  In MRI-negative children with focal epilepsy, an epileptogenic epicentre within a larger epileptogenic zone can be identified when specific biomarkers are recognized on non-invasive and invasive testing. When such children undergo resection of a small, well-defined epileptogenic epicentre, favourable outcomes can be achieved.
authors: Department of Neurology, Miami Children's Hospital.
authors: Ann
authors: A
authors: Hyslop
authors: Department of Neurology, Miami Children's Hospital.
authors: Ian
authors: I
authors: Miller
authors: Department of Neurosurgery, Miami Children's Hospital, Department of Neurosurgery, Miller School of Medicine, University of Miami.
authors: Sanjiv
authors: S
authors: Bhatia
authors: Department of Neurology, Miami Children's Hospital, Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA.
authors: Trevor
authors: T
authors: Resnick
authors: Department of Neurology, Miami Children's Hospital, Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA.
authors: Michael
authors: M
authors: Duchowny
authors: Department of Neurology, Miami Children's Hospital.
authors: Prasanna
authors: P
authors: Jayakar
mesh_terms: D000293:Adolescent; D015415:Biomarkers; D002540:Cerebral Cortex / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D000069280:Electrocorticography; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods*; D017063:Outcome Assessment, Health Care
chemical_list: D015415:Biomarkers
keywords: ECoG; EEG; MRI-negative; PET; SPECT; epilepsy surgery; focal epilepsy; seizure freedom