Journal article
Intracranial EEG for seizure focus localization: evolving techniques, outcomes, complications, and utility of combining surface and depth electrodes
Journal of neurosurgery, Vol.130(4), pp.1-13
05/2018
DOI: 10.3171/2018.1.JNS171808
PMID: 29799342
Abstract
OBJECTIVEIntracranial electroencephalography (iEEG) provides valuable information that guides clinical decision-making in patients undergoing epilepsy surgery, but it carries technical challenges and risks. The technical approaches used and reported rates of complications vary across institutions and evolve over time with increasing experience. In this report, the authors describe the strategy at the University of Iowa using both surface and depth electrodes and analyze outcomes and complications.METHODSThe authors performed a retrospective review and analysis of all patients who underwent craniotomy and electrode implantation from January 2006 through December 2015 at the University of Iowa Hospitals and Clinics. The basic demographic and clinical information was collected, including electrode coverage, monitoring results, outcomes, and complications. The correlations between clinically significant complications with various clinical variables were analyzed using multivariate analysis. The Fisher exact test was used to evaluate a change in the rate of complications over the study period.RESULTSNinety-one patients (mean age 29 ± 14 years, range 3–62 years), including 22 pediatric patients, underwent iEEG. Subdural surface (grid and/or strip) electrodes were utilized in all patients, and depth electrodes were also placed in 89 (97.8%) patients. The total number of electrode contacts placed per patient averaged 151 ± 58. The duration of invasive monitoring averaged 12.0 ± 5.1 days. In 84 (92.3%) patients, a seizure focus was localized by ictal onset (82 cases) or inferred based on interictal discharges (2 patients). Localization was achieved based on data obtained from surface electrodes alone (29 patients), depth electrodes alone (13 patients), or a combination of both surface and depth electrodes (42 patients). Seventy-two (79.1%) patients ultimately underwent resective surgery. Forty-seven (65.3%) and 18 (25.0%) patients achieved modified Engel class I and II outcomes, respectively. The mean follow-up duration was 3.9 ± 2.9 (range 0.1–10.5) years. Clinically significant complications occurred in 8 patients, including hematoma in 3 (3.3%) patients, infection/osteomyelitis in 3 (3.3%) patients, and edema/compression in 2 (2.2%) patients. One patient developed a permanent neurological deficit (1.1%), and there were no deaths. The hemorrhagic and edema/compression complications correlated significantly with the total number of electrode contacts (p = 0.01), but not with age, a history of prior cranial surgery, laterality, monitoring duration, and the number of each electrode type. The small number of infectious complications precluded multivariate analysis. The number of complications decreased from 5 of 36 cases (13.9%) to 3 of 55 cases (5.5%) during the first and last 5 years, respectively, but this change was not statistically significant (p = 0.26).CONCLUSIONSAn iEEG implantation strategy that makes use of both surface and depth electrodes is safe and effective at identifying seizure foci in patients with medically refractory epilepsy. With experience and iterative refinement of technical surgical details, the risk of complications has decreased over time.
Details
- Title: Subtitle
- Intracranial EEG for seizure focus localization: evolving techniques, outcomes, complications, and utility of combining surface and depth electrodes
- Creators
- Yasunori Nagahama - Departments of 1Neurosurgery andAlan J Schmitt - 2Neurology, University of Iowa Hospitals and Clinics, Iowa CityDaichi Nakagawa - Departments of 1Neurosurgery andAdam S Vesole - 3Carver College of Medicine, University of Iowa Hospitals and Clinics, Iowa City; andJanina Kamm - 2Neurology, University of Iowa Hospitals and Clinics, Iowa CityChristopher K Kovach - Departments of 1Neurosurgery andDavid Hasan - Departments of 1Neurosurgery andMark Granner - 2Neurology, University of Iowa Hospitals and Clinics, Iowa CityBrian J Dlouhy - Departments of 1Neurosurgery and, 4Pappajohn Biomedical Institute, University of Iowa Carver College of Medicine, Iowa City, IowaMatthew A Howard - Departments of 1Neurosurgery and, 4Pappajohn Biomedical Institute, University of Iowa Carver College of Medicine, Iowa City, IowaHiroto Kawasaki - Departments of 1Neurosurgery and
- Resource Type
- Journal article
- Publication Details
- Journal of neurosurgery, Vol.130(4), pp.1-13
- DOI
- 10.3171/2018.1.JNS171808
- PMID
- 29799342
- ISSN
- 0022-3085
- eISSN
- 1933-0693
- Language
- English
- Date published
- 05/2018
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Neurology; Stead Family Department of Pediatrics; Iowa Neuroscience Institute; Neurosurgery; Otolaryngology
- Record Identifier
- 9984014019002771
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