title: Predictors of seizure freedom after surgery for malformations of cortical development.
abstract: OBJECTIVE
  Malformations of cortical development (MCDs) are a major cause of medically refractory epilepsy. Our aim was to examine a surgical series of patients with cortical malformations to determine the prognostic factors associated with long-term seizure control.
  
  
  METHODS
  We conducted a retrospective review of 143 patients with MCD who underwent resective surgery for medically refractory epilepsy. Demographic, imaging, histopathologic, and surgical variables were analyzed for potential association with seizure freedom. Preoperative magnetic resonance imaging (MRI) was evaluated in a blind fashion and classified according to a new imaging/embryologic MCD classification system.
  
  
  RESULTS
  Gray-white blurring on MRI, smaller lesions, complete resection of structural lesions, complete resection of abnormal electrocorticographic areas, and locally confined electrocorticographic abnormalities are favorable prognosticators of seizure freedom on univariate analysis. Imaging features consistent with abnormal proliferation (Barkovich class I) were associated with better outcome compared to those related to abnormal neuronal migration (class II) or abnormal cortical organization (class III). Multivariate logistic regression revealed complete resection of tissue manifesting electrocorticographic and/or MRI anatomic abnormalities as the main independent predictor of seizure freedom. Other histopathologic or demographic factors were not associated with seizure control. Long-term follow-up of patients demonstrated sustained overall rates of seizure control (72% at 2 years, 65% at 5 years, and 67% at 10 years).
  
  
  CONCLUSIONS
  Surgery for MCDs can result in high rates of seizure freedom. Complete resection of electrocorticographic and anatomic abnormalities appears to be most predictive of long-term seizure control.
authors.affiliation: Northern California Comprehensive Epilepsy Center, San Francisco, San Francisco, CA 94143, USA. changed@neurosurg.ucsf.edu
authors.forename: Edward F
authors.initials: EF
authors.lastname: Chang
authors.forename: Doris D
authors.initials: DD
authors.lastname: Wang
authors.forename: A James
authors.initials: AJ
authors.lastname: Barkovich
authors.forename: Tarik
authors.initials: T
authors.lastname: Tihan
authors.forename: Kurtis I
authors.initials: KI
authors.lastname: Auguste
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Sullivan
authors.forename: Paul A
authors.initials: PA
authors.lastname: Garcia
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Barbaro
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D004827:Epilepsy / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012640:Seizures / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult