title: Characterizing magnetic spike sources by using magnetoencephalography-guided neuronavigation in epilepsy surgery in pediatric patients.
abstract: OBJECTIVE
  The authors sought to validate magnetoencephalography spike sources (MEGSSs) in neuronavigation during epilepsy surgery in pediatric patients.
  
  
  METHODS
  The distributions of MEGSSs in 16 children were defined and classified as clusters (Class I), greater than or equal to 20 MEGSSs with 1 cm or less between MEGSSs; small clusters (Class II), 6 to 19 with 1 cm or less between; and scatters (Class III), less than 6 or greater than 1 cm between spike sources. Using neuronavigation, the MEGSSs were correlated to epileptic zones from intra- and extraoperative electrocorticography (ECoG), surgical procedures, disease entities, and seizure outcomes. Thirteen patients underwent MEGSSs: nine had clusters; two had small clusters, one with and one without clusters; and three had scatters alone. All 13 had scatters. Clusters localized within and extended from areas of cortical dysplasia and at margins of tumors or cystic lesions. All clusters were colocalized to ECoG-defined epileptic zones. Four of 10 patients with clusters and/or small clusters underwent complete excisions, and six underwent partial excision with or without multiple subpial transections. In the three patients with scatters alone, ECoG revealed epileptic zones buried within MEGSS areas; these regions of scatters were completely excised and treated with multiple subpial transections. Coexisting scatters were left untreated in nine of 10 patients. Postoperatively, nine of 13 patients were seizure free; the four patients with residual seizures had clusters in unresected eloquent cortex. Three patients in whom no MEGSSs were demonstrated underwent lesionectomies and were seizure free.
  
  
  CONCLUSIONS
  Magnetoencephalography spike source clusters indicate an epileptic zone requiring complete excision. Coexisting scatters remote from clusters are nonepileptogenic and do not require excision. Scatters alone, however, should be examined by ECoG; an epileptic zone may exist within these distributions.
authors.affiliation: Division of Neurology, The Hospital for Sick Children and University of Toronto, Ontario, Canada.
authors.forename: Koji
authors.initials: K
authors.lastname: Iida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
authors.forename: Yuuri
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Ayako
authors.initials: A
authors.lastname: Ochi
authors.forename: Makoto
authors.initials: M
authors.lastname: Oishi
authors.forename: Stephanie
authors.initials: S
authors.lastname: Holowka
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Pang
authors.forename: Irene
authors.initials: I
authors.lastname: Elliott
authors.forename: Shelly K
authors.initials: SK
authors.lastname: Weiss
authors.forename: Sylvester H
authors.initials: SH
authors.lastname: Chuang
authors.forename: O Carter
authors.initials: OC
authors.lastname: Snead
authors.forename: James T
authors.initials: JT
authors.lastname: Rutka
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004827:Epilepsy / Q000601:surgery*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007430:Intraoperative Care; D015225:Magnetoencephalography; D008297:Male; D038361:Neuronavigation / Q000295:instrumentation*; D019635:Neurosurgical Procedures / Q000379:methods*; D011182:Postoperative Care; D011300:Preoperative Care; D016896:Treatment Outcome