title: Stereotactic Electroencephalography Is a Safe Procedure, Including for Insular Implantations.
abstract: BACKGROUND
  In some cases of drug-resistant focal epilepsy, noninvasive presurgical investigation may be insufficient to identify the ictal onset zone and the eloquent cortical areas. In such situations, invasive investigations are proposed using either stereotactic electroencephalography (SEEG) or subdural grid electrodes. Meta-analysis suggests that SEEG is safer than subdural grid electrodes, but insular implantation of SEEG electrodes has been thought to carry an additional risk of intraparenchymal hemorrhagic complications. Our objectives were to determine whether an insular SEEG trajectory is a risk factor for intracranial hematoma and to report the global safety of the procedure and provide some guidelines to prevent and detect complications.
  
  
  METHODS
  In a retrospective analysis of a surgical series of 525 consecutive procedures between 1995 and 2015, all electrodes were classified according to their insular or extrainsular trajectory. All complications were classified as major or minor according to their potential consequences regarding patient neurologic status.
  
  
  RESULTS
  Four intraparenchymal hematomas, all related to extrainsular electrodes (4/4974; 0.08%) were reported; no hematoma was found along insular electrodes (0/1042; 0%). There were 8 major complications (1.52%): 7 intracranial hematomas (1.33%) and 1 case of meningitis. Two patients had long-term neurologic impairment (0.38%), and 1 death (not directly related to the procedure) occurred (0.19%). Eleven minor complications (2.09%) were encountered, including broken electrode (1.52%), acute pneumocephalus (0.38%), and local cutaneous infection (0.19%).
  
  
  CONCLUSIONS
  SEEG is a safe procedure. Insular trajectories cannot be considered an additional risk of intracranial bleeding.
authors.affiliation: Department of Neurosurgery, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France; Université Claude Bernard, University of Lyon, Lyon, France; Université Pierre et Marie Curie, Sorbonne University, Paris, France; Brain and Spine Institute, INSERM U1127, CNRS, UMR7225, Paris France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Bourdillon
authors.affiliation: CHUV, Department of Clinical Neurosciences, Lausanne, Switzerland; Neuroscience Research Center of Lyon, INSERM U1028, CNRS 5292, Lyon, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ryvlin
authors.affiliation: Neuroscience Research Center of Lyon, INSERM U1028, CNRS 5292, Lyon, France; Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Isnard
authors.affiliation: Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France; Department of Sleep, Epilepsy and Pediatric Clinical Neurophysiology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Montavont
authors.affiliation: Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Catenoix
authors.affiliation: Université Claude Bernard, University of Lyon, Lyon, France; Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.
authors.forename: François
authors.initials: F
authors.lastname: Mauguière
authors.affiliation: Université Claude Bernard, University of Lyon, Lyon, France; Neuroscience Research Center of Lyon, INSERM U1028, CNRS 5292, Lyon, France; Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Rheims
authors.affiliation: Department of Sleep, Epilepsy and Pediatric Clinical Neurophysiology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Ostrowsky-Coste
authors.affiliation: Department of Neurosurgery, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France; Université Claude Bernard, University of Lyon, Lyon, France; Neuroscience Research Center of Lyon, INSERM U1028, CNRS 5292, Lyon, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Guénot
mesh_terms: D000293:Adolescent; D000328:Adult; D015901:Angiography, Digital Subtraction; D002540:Cerebral Cortex; D002648:Child; D000069279:Drug Resistant Epilepsy / Q000175:diagnosis* / Q000601:surgery; D000069280:Electrocorticography / Q000379:methods*; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D006407:Hematoma, Epidural, Cranial / Q000453:epidemiology; D046648:Hematoma, Subdural, Intracranial / Q000453:epidemiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D025321:Surgery, Computer-Assisted; D055815:Young Adult
keywords: Drug-resistant; Epilepsy; Epilepsy surgery; Focal epilepsy; Postoperative complications; Stereotactic surgery