title: Prospective and "live" fast ripple detection and localization in the operating room: Impact on epilepsy surgery outcomes in children.
abstract: Fast ripples (FR, 250-500Hz) are proposed biomarkers of the epileptogenic zone on the basis of several retrospective reports linking postoperative seizure freedom to their complete resection. There are no clinical trials or prospective reports validating the use of FR as characterized by electrocorticography (ECoG), to guide the scope of epilepsy surgery, and to inform prognosis thereafter. We set out to prospectively evaluate the utility of FR resection to predict postoperative epilepsy outcomes, and examine the feasibility of "live" intraoperative FR ascertainment.
  
  
  
  FR were prospectively reviewed in 30 consecutive pediatric cases including 11 reviewed "live" during surgery. Intraoperative ECoG studies were recorded at 2000Hz sampling rate, interpreted conventionally to guide surgical resection, and visually inspected for FR. Seizure outcome was tallied for all 30 children.
  
  
  
  Median age at surgery was 9.1 years (interquartile range [IQR] 4.7-13.2), median ECoG duration was 10.5min (IQR 8.0-13.2), and median postoperative follow-up was 58.4 months (IQR 25.7-79.0). FR were identified in 24 of 30 ECoG studies. The incomplete resection of FR was strongly linked to postoperative seizures (hazard ratio 11.6, p=0.005). "Live" ECoG review in the operating room to ascertain FR proved feasible and did not differ from conventional FR ascertainment.
  
  
  
  In a prospective fashion, including "live" review, FR were detected in 80% of pediatric ECoG studies, and incomplete resection of FR cortex predicted postoperative seizures. These findings extend the notion that interictal FR are surrogate markers of the epileptogenic zone, and that their intraoperative localization could be used to inform prognosis and guide surgical resections in children.
authors.affiliation: Division of Pediatric Neurology, Mattel Children's Hospital UCLA, Los Angeles, CA, United States.
authors.forename: Shaun A
authors.initials: SA
authors.lastname: Hussain
authors.affiliation: Departments of Neurosurgery and Psychiatry & BioBehavioral Sciences, Los Angeles, CA, United States; The Brain Research Institute, and The Intellectual and Developmental Disabilities Research Center, Los Angeles, CA, United States.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Mathern
authors.affiliation: Division of Pediatric Neurology, Mattel Children's Hospital UCLA, Los Angeles, CA, United States; Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States.
authors.forename: Raman
authors.initials: R
authors.lastname: Sankar
authors.affiliation: Division of Pediatric Neurology, Mattel Children's Hospital UCLA, Los Angeles, CA, United States. Electronic address: joycewu@mednet.ucla.edu.
authors.forename: Joyce Y
authors.initials: JY
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D000069279:Drug Resistant Epilepsy / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D000069280:Electrocorticography; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring; D053208:Kaplan-Meier Estimate; D008297:Male; D009873:Operating Rooms; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012640:Seizures / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome
keywords: EEG; Epilepsy surgery; High frequency oscillation; Intraoperative electrocorticography; Seizure outcome