title: Predicting seizure freedom after two or more chronic invasive evaluations in patients with intractable epilepsy.
abstract: OBJECTIVE
  In patients with intractable epilepsy, failure to localize and/or resect the epileptic focus after invasive monitoring is multifactorial. Rarely do these patients return for a second invasive evaluation, and their outcome is not clearly characterized. This study aims to determine the seizure outcome after a second invasive electroencephalographic (EEG) evaluation, and its possible predictors.
  
  
  METHODS
  We retrospectively reviewed 30 patients who underwent two or more invasive evaluations at Cleveland Clinic between 1980 and 2007. Clinical, surgical, imaging, and pathology information was analyzed using a multivariate regression model. A favorable outcome was defined as complete seizure freedom, allowing for auras and seizures restricted to the first postoperative week.
  
  
  RESULTS
  Ten patients (33%) became seizure free after the second operation (mean follow-up duration 3.13 years [range 6 months-17 years]). Seizure freedom was more likely in patients reporting fewer seizures per month preoperatively (mean 19 seizures/mo), and in those with a predominantly regional/lateralized scalp EEG ictal pattern (32% seizure free), as opposed to those with higher seizure frequency (mean 70 seizures/month; P = 0.02) or diffuse ictal EEGs (0% seizure free; P = 0.04). There was a significant association between acute postoperative seizures and failure of repeat surgery (P = 0.0083). In 17 of 30 patients, at least one complication was reported (57%) after the second invasive evaluation compared with a complication rate of 23% after the first invasive evaluation.
  
  
  CONCLUSIONS
  A second invasive evaluation may lead to seizure freedom in one-third of patients. However, this must be weighed against the increased complication rate with reoperation.
authors: Department of Neuroscience, MetroHealth Medical Center, Cleveland, Ohio, USA. seanjnagel@gmail.com
authors: Sean J
authors: SJ
authors: Nagel
authors: Lara E
authors: LE
authors: Jehi
authors: Rebecca
authors: R
authors: O'Dwyer
authors: Dani
authors: D
authors: Bidros
authors: Girish K
authors: GK
authors: Hiremath
authors: William E
authors: WE
authors: Bingaman
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D054220:Malformations of Cortical Development / Q000150:complications; D009422:Nervous System Diseases / Q000209:etiology; D059906:Neuroimaging; D011183:Postoperative Complications / Q000453:epidemiology; D011184:Postoperative Period; D012044:Regression Analysis; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D012640:Seizures / Q000453:epidemiology / Q000601:surgery*; D017211:Treatment Failure; D016896:Treatment Outcome; D055815:Young Adult