Clinical utility of intraoperative electrocorticography for epilepsy surgery: A systematic review and meta-analysis

Keshav Goel; Valérie Pek; Nathan A Shlobin; Jia-Shu Chen; Andrew Wang; George M Ibrahim; Aristides Hadjinicolaou; Karl Roessler; Roy W Dudley; Dang K Nguyen; Riëm El-Tahry; Aria Fallah; Alexander G Weil

doi:10.1111/epi.17472

Clinical utility of intraoperative electrocorticography for epilepsy surgery: A systematic review and meta-analysis

Epilepsia. 2023 Feb;64(2):253-265. doi: 10.1111/epi.17472. Epub 2022 Dec 12.

Authors

Keshav Goel¹, Valérie Pek², Nathan A Shlobin³, Jia-Shu Chen⁴, Andrew Wang^{1

5}, George M Ibrahim⁶, Aristides Hadjinicolaou^{7

8}, Karl Roessler⁹, Roy W Dudley¹⁰, Dang K Nguyen¹¹, Riëm El-Tahry^{12

13}, Aria Fallah^{1

14}, Alexander G Weil^{8

15

16

17}

Affiliations

¹ David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California, USA.
² Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada.
³ Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
⁴ Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA.
⁵ College of Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, Los Angeles, California, USA.
⁶ Division of Neurosurgery, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
⁷ Division of Neurology, Department of Pediatrics, Sainte-Justine University Hospital Centre, Montreal, Quebec, Canada.
⁸ Brain and Development Research Axis, Sainte-Justine Research Centre, Montreal, Quebec, Canada.
⁹ Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.
¹⁰ Division of Pediatric Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada.
¹¹ Department of Neurology, University of Montreal Hospital Centre, Montreal, Quebec, Canada.
¹² Saint Luc University Hospital, Brussels, Belgium.
¹³ Institute of Neuroscience, Neurology pole, Catholic University of Louvain, Brussels, Belgium.
¹⁴ Department of Neurosurgery, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California, USA.
¹⁵ Division of Neurosurgery, Department of Surgery, Sainte-Justine University Hospital Centre, Montreal, Quebec, Canada.
¹⁶ Division of Neurosurgery, Department of Surgery, University of Montreal Hospital Centre, Montreal, Quebec, Canada.
¹⁷ Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada.

PMID: 36404579
DOI: 10.1111/epi.17472

Abstract

Despite the widespread use of intraoperative electrocorticography (iECoG) during resective epilepsy surgery, there are conflicting data on its overall efficacy and inability to predict benefit per pathology. Given the heterogeneity of iECoG use in resective epilepsy surgery, it is important to assess the utility of interictal-based iECoG. This individual patient data (IPD) meta-analysis seeks to identify the benefit of iECoG during resective epilepsy surgery in achieving seizure freedom for various pathologies. Embase, Scopus, and PubMed were searched from inception to January 31, 2021 using the following terms: "ecog", "electrocorticography", and "epilepsy". Articles were included if they reported seizure freedom at ≥12-month follow-up in cohorts with and without iECoG for epilepsy surgery. Non-English articles, noncomparative iECoG cohorts, and studies with <10% iECoG use were excluded. This meta-analysis followed the PRISMA 2020 guidelines. The primary outcome was seizure freedom at last follow-up and time to seizure recurrence, if applicable. Forest plots with random effects modeling assessed the relationship between iECoG use and seizure freedom. Cox regression of IPD was performed to identify predictors of longer duration of seizure freedom. Kaplan-Meier curves with log-rank test were created to visualize differences in time to seizure recurrence. Of 7504 articles identified, 18 were included for study-level analysis. iECoG was not associated with higher seizure freedom at the study level (relative risk = 1.09, 95% confidence interval [CI] = 0.96-1.23, p = .19, I² = 64%), but on IPD (n = 7 studies, 231 patients) iECoG use was independently associated with more favorable seizure outcomes (hazard ratio = 0.47, 95% CI = .23-.95, p = .037). In Kaplan-Meier analysis of specific pathologies, iECoG use was significantly associated with longer seizure freedom only for focal cortical dysplasia (FCD; p < .001) etiology. Number needed to treat for iECoG was 8.8, and for iECoG in FCD it was 4.7. We show iECoG seizure freedom is not achieved uniformly across centers. iECoG is particularly beneficial for FCD etiology in improving seizure freedom.

Keywords: clinical utility; epilepsy surgery; intraoperative electrocorticography; meta-analysis.

Publication types

Meta-Analysis
Systematic Review
Review

MeSH terms

Electrocorticography*
Epilepsy* / etiology
Epilepsy* / surgery
Follow-Up Studies
Humans
Retrospective Studies
Seizures / etiology
Treatment Outcome