title: Intracerebral depth electrode monitoring in partial epilepsy: the morbidity and efficacy of placement using magnetic resonance image-guided stereotactic surgery.
abstract: OBJECTIVE
  To determine the indications for, efficacy of, and safety of depth electrode placement using magnetic resonance imaging (MRI)-guided stereotactic surgery in patients with intractable epilepsy.
  
  
  METHODS
  We analyzed retrospectively the results of depth electrode usage in 50 consecutive patients at the University of Michigan Hospitals studied in the years 1991 through 1994, using MRI-guided stereotactic implantation, in conjunction with simultaneous subdural strip electrode recordings.
  
  
  RESULTS
  There were no deaths, no infections, and no new neurological deficits. One small subdural hematoma adjacent to a subdural strip electrode was evacuated to prevent interference with ictal recording. Two cylindrical subdural electrodes were found to be intraparenchymal, as revealed by postoperative MRI, and were removed. One patient was unintentionally left alone briefly, and he pulled out the electrodes while confused postictally, requiring a subsequent operation for replacement. Ictal onset zones were successfully localized in 47 patients.
  
  
  CONCLUSIONS
  We have found intracerebral electrode placement to be as safe as subdural strip electrode placement and have found combined depth and strip electrode monitoring to be highly effective in localizing the onset zones of complex partial seizures. Intracranial monitoring was particularly useful in the detection of a single ictal onset zone in the absence of neuroimaging abnormality and in the definitive diagnosis of bilateral independent ictal onset zones in the temporal lobe epilepsy syndrome. The specific technical aspects of the procedure that contribute to a successful outcome are reviewed. A comparison with earlier reported series suggests that MRI-guided stereotaxy and pial inspection may reduce complications of depth electrode placement.
authors.affiliation: Department of Surgery (Section of Neurosurgery), University of Michigan Medical Center, Ann Arbor, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Ross
authors.forename: J A
authors.initials: JA
authors.lastname: Brunberg
authors.forename: I
authors.initials: I
authors.lastname: Drury
authors.forename: T R
authors.initials: TR
authors.lastname: Henry
mesh_terms: D001931:Brain Mapping / Q000295:instrumentation*; D004292:Dominance, Cerebral / Q000502:physiology; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000295:instrumentation*; D004828:Epilepsies, Partial / Q000503:physiopathology / Q000601:surgery*; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology / Q000601:surgery; D004869:Equipment Safety; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D011612:Psychosurgery; D012086:Reoperation; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013238:Stereotaxic Techniques / Q000295:instrumentation*; D016896:Treatment Outcome