title: Surgical management of medically refractory epilepsy in patients with polymicrogyria.
abstract: OBJECTIVE
  Polymicrogyria (PMG) is a malformation of cortical development characterized by formation of an excessive number of small gyri. Sixty percent to 85% of patients with PMG have epilepsy that is refractory to medication, but surgical options are usually limited. We characterize a cohort of patient with polymicrogyria who underwent epilepsy surgery and document seizure outcomes.
  
  
  METHODS
  A retrospective study of all patients with PMG who underwent epilepsy surgery (focal seizure foci resection and/or hemispherectomy) at our center was performed by review of all clinical data related to their treatment.
  
  
  RESULTS
  We identified 12 patients (7 males and 5 female) with mean age of 18 (ranging from 3 months to 44 years) at time of surgery. Mean age at seizure onset was 8 years, with the majority (83%) having childhood onset. Six patients had focal, five had multifocal, and one patient had diffuse PMG. Perisylvian PMG was the most common pattern seen on magnetic resonance imaging (MRI). Eight patients had other cortical malformations including hemimegalencephaly and cortical dysplasia. Scalp electroencephalography (EEG) often showed diffuse epileptic discharges that poorly lateralized but were focal on intracranial electrocorticography (ECoG). Eight patients underwent seizure foci resection and four underwent hemispherectomy. Mean follow-up was 7 years (ranging from one to 19 years). Six patients (50%) were seizure-free at last follow-up. One patient had rare seizures (Engel class II). Three patients were Engel class III, having either decreased seizure frequency or severity, and two patients were Engel class IV. Gross total resection of the PMG cortex trended toward good seizure control.
  
  
  CONCLUSIONS
  Our study shows that even in patients with extensive or bilateral PMG malformations, some may still be good candidates for surgery because the epileptogenic zone may involve only a portion of the malformation. Intracranial ECoG can provide additional localizing information compared to scalp EEG in guiding resection of epileptogenic foci.
authors.affiliation: Department of Neurological Surgery, UCSF Comprehensive Epilepsy Center, University of California, San Francisco, California, U.S.A.
authors.forename: Doris D
authors.initials: DD
authors.lastname: Wang
authors.affiliation: Department of Neurology, University of California, San Francisco, California, U.S.A.
authors.forename: Renatta
authors.initials: R
authors.lastname: Knox
authors.affiliation: Department of Neurological Surgery, UCSF Comprehensive Epilepsy Center, University of California, San Francisco, California, U.S.A.
authors.forename: John D
authors.initials: JD
authors.lastname: Rolston
authors.affiliation: Department of Neurological Surgery, UCSF Comprehensive Epilepsy Center, University of California, San Francisco, California, U.S.A.
authors.forename: Dario J
authors.initials: DJ
authors.lastname: Englot
authors.affiliation: Department of Radiology, University of California, San Francisco, California, U.S.A.
authors.forename: A James
authors.initials: AJ
authors.lastname: Barkovich
authors.affiliation: Department of Pathology, University of California, San Francisco, California, U.S.A.
authors.forename: Tarik
authors.initials: T
authors.lastname: Tihan
authors.affiliation: Department of Neurological Surgery, UCSF Comprehensive Epilepsy Center, University of California, San Francisco, California, U.S.A.|Benioff Children's Hospital, University of California, San Francisco, California, U.S.A.
authors.forename: Kurtis I
authors.initials: KI
authors.lastname: Auguste
authors.affiliation: Department of Neurology, University of California, San Francisco, California, U.S.A.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Knowlton
authors.affiliation: Department of Neurology, University of California, San Francisco, California, U.S.A.
authors.forename: Susannah B
authors.initials: SB
authors.lastname: Cornes
authors.affiliation: Department of Neurological Surgery, UCSF Comprehensive Epilepsy Center, University of California, San Francisco, California, U.S.A.
authors.forename: Edward F
authors.initials: EF
authors.lastname: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D000069279:Drug Resistant Epilepsy / Q000150:complications* / Q000601:surgery*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods*; D065706:Polymicrogyria / Q000150:complications* / Q000601:surgery*; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Cortical dysplasia; Cortical malformation; Hemimegalencephaly; Hemispherectomy; Malformation of cortical development; Polymicrogyria; Refractory epilepsy; Schizencephaly; Seizure outcome; Surgical treatment