title: Surgery for Nontumoral Insular Epilepsy Explored by Stereoelectroencephalography.
abstract: Hidden by the perisylvian operculi, insular cortex has long been underexplored in the context of epilepsy surgery. Recent studies advocated stereoelectroencephalography (SEEG) as a reliable tool to explore insular cortex and its involvement in intractable epilepsy and suggested that insular seizures could be an underestimated entity. However, the results of insular resection to treat pharmacoresistant epilepsy are rarely reported.
  
  
  
  We report 6 consecutive cases of right insular resection performed based on anatomoelectroclinical correlations provided by SEEG.
  
  
  
  Six right-handed patients (3 male, 3 female) with drug-resistant epilepsy underwent comprehensive presurgical evaluation. Based on video electroencephalographic recordings, they all underwent SEEG evaluation with bilateral (n = 4) or unilateral right (n = 2) insular depth electrode placement. All patients had both orthogonal and oblique (1 anterior, 1 posterior) insular electrodes (n = 4-6 electrodes). Preoperative magnetic resonance imaging findings were normal in 4 patients, 1 patient had right insular focal cortical dysplasia, and 1 patient had a right opercular postoperative scar (cavernous angioma). All patients underwent right partial insular corticectomy via the subpial transopercular approach.
  
  
  
  Intracerebral recordings demonstrated an epileptogenic zone confined to the right insula in all patients. After selective insular resection, 5 of 6 patients were seizure free (Engel class I) with a mean follow-up of 36.2 months (range, 18-68 months). Histological findings revealed focal cortical dysplasia in 5 patients and a gliosis scar in 1 patient. All patients had minor transient neurological deficit (eg, facial paresis, dysarthria).
  
  
  
  Insular resection based on SEEG findings can be performed safely with a significant chance of seizure freedom.
  
  
  
  EEG, electroencephalographyEZ, epileptic zoneFCD, focal cortical dysplasiaILE, insular lobe epilepsySEEG, stereoelectroencephalography.
authors.affiliation: *INSERM U1216, Grenoble Institut des Neurosciences, Grenoble, France; ‡Département de Neurochirurgie, Hôpital Gui de Chauliac, Centre Hospitalier Universitaire, Montpellier, France; §Clinique de Neurologie, Centre Hospitalier Universitaire, Grenoble, France; ¶Clinique de Neurochirurgie, Centre Hospitalier Universitaire, Grenoble, France; ‖Clinique de Neuroradiologie, Centre Hospitalier Universitaire, Grenoble, France; #University Grenoble Alpes, Grenoble, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Gras-Combe
authors.forename: Lorella
authors.initials: L
authors.lastname: Minotti
authors.forename: Dominique
authors.initials: D
authors.lastname: Hoffmann
authors.forename: Alexandre
authors.initials: A
authors.lastname: Krainik
authors.forename: Philippe
authors.initials: P
authors.lastname: Kahane
authors.forename: Stephan
authors.initials: S
authors.lastname: Chabardes
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000601:surgery*; D000069279:Drug Resistant Epilepsy / Q000601:surgery*; D004566:Electrodes; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*