Predictors of Outcomes after Surgery for Medically Intractable Insular Epilepsy: A Systematic Review and Individual Participant Data Meta-Analysis

Sami Obaid, Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada.
Jia-Shu Chen, The Warren Alpert Medical School of Brown University, Providence, RI, USA.
George M. Ibrahim, Division of Neurosurgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Alain Bouthillier, Division of Neurosurgery, University of Montreal Hospital Center, Montreal, QC, Canada.
Evan Dimentberg, Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada.
Werner Surbeck, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, Zurich, Switzerland.
Elena Guadagno, Harvey E. Beardmore Division of Pediatric Surgery, McGill University Health Centre, Quebec, Canada.
Tristan Brunette-Clément, Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada.
Nathan A. Shlobin, Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
Aidan Shulkin, Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada.
Andrew T. Hale, Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA.
Luke D. Tomycz, The Epilepsy Institute of New Jersey, Jersey City, NJ, USA.
Marec Von Lehe, Department of Neurosurgery, Brandenburg Medical School, Neuruppin, Germany.
M Scott Perry, Comprehensive Epilepsy Program, Jane and John Justin Neuroscience Center, Cook Children's Medical Center, Fort Worth, TX, USA.
Francine Chassoux, Service de neurochirurgie, GHU Paris Psychiatrie et Neurosciences, Université Paris-Descartes Paris, France.
Viviane Bouilleret, Université Paris Saclay-APHP, Unité de Neurophysiologie Clinique et d'Épileptologie(UNCE), Le Kremlin Bicêtre, France.
Delphine Taussig, Université Paris Saclay-APHP, Unité de Neurophysiologie Clinique et d'Épileptologie(UNCE), Le Kremlin Bicêtre, France.
Martine Fohlen, Pediatric Neurosurgery Department, Rothschild Foundation Hospital, Paris, France.
Georg Dorfmuller, Pediatric Neurosurgery Department, Rothschild Foundation Hospital, Paris, France.
Koichi Hagiwara, Epilepsy and Sleep Center, Fukuoka Sanno Hospital, Fukuoka, Japan.
Jean Isnard, Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Hospital for Neurology and Neurosurgery, Lyon, France.
Chima O. Oluigbo, Department of Neurosurgery, Children's National Medical Center, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA.
Naoki Ikegaya, Departments of Neurosurgery, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
Dang K. Nguyen, Division of Neurology, University of Montreal Hospital Center, Montreal, QC, Canada.
Aria Fallah, Department of Neurosurgery and Pediatrics, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA.
Alexander G. Weil, Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Montreal, Quebec, Canada.

Document Type

Journal Article

Publication Date

10-19-2022

Journal

Epilepsia open

DOI

10.1002/epi4.12663

Keywords

epilepsy; epilepsy surgery; insula; insular epilepsy; insulectomy; surgical outcome

Abstract

Insular epilepsy (IE) is an increasingly recognized cause of drug-resistant epilepsy amenable to surgery. However, concerns of suboptimal seizure control and permanent neurological morbidity hamper widespread adoption of surgery for IE. We performed a systematic review and individual participant data meta-analysis to determine the efficacy and safety profile of surgery for IE and identify predictors of outcomes. Of 2,483 unique citations, 24 retrospective studies reporting on 312 participants were eligible for inclusion. The median follow-up duration was 2.58 years (range, 0-17 years), and 206 (66.7%) patients were seizure free at last follow-up. Younger age at surgery (≤18 years) (HR=1.70, 95% CI=1.09-2.66, p=0.022) and invasive EEG monitoring (HR=1.97, 95% CI=1.04-3.74, p=0.039) were significantly associated with shorter time to seizure recurrence. Performing MR-guided laser ablation or radiofrequency ablation instead of open resection (OR=2.05, 95% CI=1.08-3.89, p=0.028) was independently associated with suboptimal or poor seizure outcome (Engel II-IV) at last follow-up. Postoperative neurological complications occurred in 42.5% of patients, most commonly motor deficits (29.9%). Permanent neurological complications occurred in 7.8% of surgeries, including a 5% and 1.4% rate of permanent motor deficits and dysphasia respectively. Resection of the frontal operculum was independently associated with greater odds of motor deficits (OR=2.75, 95% CI=1.46-5.15, p=0.002). Dominant-hemisphere resections were independently associated with dysphasia (OR=13.09, 95% CI=2.22-77.14, p=0.005) albeit none of the observed language deficits were permanent. Surgery for IE is associated with a good efficacy/safety profile. Most patients experience seizure freedom, and neurological deficits are predominantly transient. Pediatric patients and those requiring invasive monitoring or undergoing stereotactic ablation procedures experience lower rates of seizure freedom. Transgression of the frontal operculum should be avoided if it is not deemed part of the epileptogenic zone. Well-selected candidates undergoing dominant-hemisphere resection are more likely to exhibit transient language deficits; however, the risk of permanent deficit is very low.

Department

Neurological Surgery

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