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Obaid S, Chen JS, Ibrahim GM, Bouthillier A, Dimentberg E, Surbeck W, Guadagno E, Brunette-Clément T, Shlobin NA, Shulkin A, Hale AT, Tomycz LD, Von Lehe M, Perry MS, Chassoux F, Bouilleret V, Taussig D, Fohlen M, Dorfmuller G, Hagiwara K, Isnard J, Oluigbo CO, Ikegaya N, Nguyen DK, Fallah A, Weil AG. Predictors of outcomes after surgery for medically intractable insular epilepsy: A systematic review and individual participant data meta-analysis. Epilepsia Open 2023; 8:12-31. [PMID: 36263454 PMCID: PMC9978079 DOI: 10.1002/epi4.12663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 09/28/2022] [Indexed: 11/11/2022] Open
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 2483 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 = .022) and invasive EEG monitoring (HR = 1.97, 95% CI = 1.04-3.74, P = .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 = .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 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 = .002). Dominant-hemisphere resections were independently associated with dysphasia (OR = 13.09, 95% CI = 2.22-77.14, P = .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.
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Affiliation(s)
- Sami Obaid
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Quebec, Montreal, Canada.,Division of Neurosurgery, University of Montreal Hospital Center, Montreal, Quebec, Canada
| | - Jia-Shu Chen
- The Warren Alpert Medical School of Brown University, Providence, Rhode Island, 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, Quebec, Canada
| | - Evan Dimentberg
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Quebec, Montreal, Canada.,Faculty of Medicine, Université Laval, Quebec City, 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, Montreal, Quebec, Canada
| | - Tristan Brunette-Clément
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Quebec, Montreal, Canada.,Division of Neurosurgery, University of Montreal Hospital Center, Montreal, Quebec, Canada
| | - Nathan A Shlobin
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Aidan Shulkin
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Quebec, Montreal, Canada
| | - Andrew T Hale
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Luke D Tomycz
- The Epilepsy Institute of New Jersey, Jersey City, New Jersey, USA
| | - Marec Von Lehe
- Department of Neurosurgery, Brandenburg Medical School, Neuruppin, Germany
| | - Michael Scott Perry
- Comprehensive Epilepsy Program, Jane and John Justin Neuroscience Center, Cook Children's Medical Center, Fort Worth, Texas, USA
| | - Francine Chassoux
- Service de Neurochirurgie, GHU Paris Psychiatrie et Neurosciences, Université Paris-Descartes Paris, 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.,Pediatric Neurosurgery Department, Rothschild Foundation Hospital, Paris, 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, Quebec, Canada
| | - Aria Fallah
- Department of Neurosurgery and Pediatrics, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA
| | - Alexander G Weil
- Division of Pediatric Neurosurgery, Department of Surgery, Sainte Justine Hospital, University of Montreal, Quebec, Montreal, Canada.,Division of Neurosurgery, University of Montreal Hospital Center, Montreal, Quebec, Canada.,Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
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Solanki C, Williams J, Andrews C, Fayed I, Wu C. Insula in epilepsy - "untying the gordian knot": A systematic review. Seizure 2023; 106:148-161. [PMID: 36878050 DOI: 10.1016/j.seizure.2023.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 02/23/2023] [Accepted: 02/25/2023] [Indexed: 03/02/2023] Open
Abstract
PURPOSE Despite significant advances in epileptology, there are still many uncertainties about the role of the insula in epilepsy. Until recently, most insular onset seizures were wrongly attributed to the temporal lobe. Further, there are no standardised approaches to the diagnosis and treatment of insular onset seizures. This systematic review gathers the available information about insular epilepsy and synthesizes current knowledge as a basis for future research. METHOD Adhering to the PRISMA guidelines, studies were meticulously extracted from the PubMed database. The empirical data pertaining to the semiology of insular seizures, insular networks in epilepsy, techniques of mapping the insula, and the surgical intricacies of non-lesional insular epilepsy were reviewed from published studies. The corpus of information available was then subjected to a process of concise summarization and astute synthesis. RESULTS Out of 235 studies identified for full-text review, 86 studies were included in the systematic review. The insula emerges as a brain region with a number of functional subdivisions. The semiology of insular seizures is diverse and depends on the involvement of particular subdivisions. The semiological heterogeneity of insular seizures is explained by the extensive connectivity of the insula and its subdivisions with all four lobes of the brain, deep grey matter structures, and remote brainstem areas. The mainstay of the diagnosis of seizure onset in the insula is stereoelectroencephalography (SEEG). The surgical resection of the insular epileptogenic zone (when possible) is the most effective treatment. Open surgery on the insula is challenging but magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) also holds promise. CONCLUSION The physiological and functional roles of the insula in epilepsy have remained obfuscated. The dearth of precisely defined diagnostic and therapeutic protocols acts as an impediment to scientific advancement. This review could potentially facilitate forthcoming research endeavours by establishing a foundational framework for uniform data collection protocols, thereby enhancing the feasibility of comparing findings across future studies and promoting progress in this domain.
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Affiliation(s)
- Chirag Solanki
- Consultant Neurosurgeon, Department of Neurosurgery, Sterling Hospital, Ahmedabad, Gujarat, India.
| | - Justin Williams
- Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, United States.
| | - Carrie Andrews
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, United States.
| | - Islam Fayed
- Stereotactic and Functional Neurosurgery, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, United States.
| | - Chengyuan Wu
- Associate Professor of Neurosurgery and Radiology, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, United States.
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Tran TPY, Pouliot P, Assi EB, Rainville P, Myers KA, Robert M, Bouthillier A, Keezer MR, Nguyen DK. Heart Rate Variability in Insulo-Opercular Epilepsy. Brain Sci 2021; 11:brainsci11111505. [PMID: 34827504 PMCID: PMC8615554 DOI: 10.3390/brainsci11111505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022] Open
Abstract
Background: We aimed to evaluate heart rate variability (HRV) changes in insulo-opercular epilepsy (IOE) and after insulo-opercular surgery. Methods: We analyzed 5-min resting HRV of IOE patients before and after surgery. Patients’ SUDEP-7 risk inventory scores were also calculated. Results were compared with age- and sex-matched patients with temporal lobe epilepsy (TLE) and healthy individuals. Results: There were no differences in HRV measurements between IOE, TLE, and healthy control groups (and within each IOE group and TLE group) in preoperative and postoperative periods. In IOE patients, the SUDEP-7 score was positively correlated with pNN50 (percentage of successive RR intervals that differ by more than 50 ms) (p = 0.008) and RMSSD (root mean square of successive RR interval differences) (p = 0.019). We stratified IOE patients into those whose preoperative RMSSD values were below (Group 1a = 7) versus above (Group 1b = 9) a cut-off threshold of 31 ms (median value of a healthy population from a previous study). In group 1a, all HRV values significantly increased after surgery. In group 1b, time-domain parameters significantly decreased postoperatively. Conclusions: Our results suggest that in IOE, HRV may be either decreased in parasympathetic tone or increased globally in both sympathetic and parasympathetic tones. We found no evidence that insulo-opercular surgeries lead to major autonomic dysfunction when a good seizure outcome is reached. The increase in parasympathetic tone observed preoperatively may be of clinical concern, as it was positively correlated with the SUDEP-7 score.
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Affiliation(s)
- Thi Phuoc Yen Tran
- CHUM Research Center, University of Montreal, Montreal, QC H2X 0A9, Canada; (T.P.Y.T.); (E.B.A.); (M.R.); (M.R.K.)
| | - Philippe Pouliot
- Safe Engineering Services and Technologies, Laval, QC H7L 6E8, Canada;
- Labeo Technologies, Montreal, QC H3V 1A2, Canada
| | - Elie Bou Assi
- CHUM Research Center, University of Montreal, Montreal, QC H2X 0A9, Canada; (T.P.Y.T.); (E.B.A.); (M.R.); (M.R.K.)
| | - Pierre Rainville
- Department of Somatology, University of Montreal, Montreal, QC H3T 1J7, Canada;
- Research Centre of Institut Universitaire de Gériatrie de Montréal, Montreal, QC H3C 3J7, Canada
| | - Kenneth A. Myers
- Research Institute of the McGill University Medical Centre, Montreal, QC H3H 2R9, Canada;
- Division of Neurology, Department of Pediatrics, Montreal Children’s Hospital, McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Manon Robert
- CHUM Research Center, University of Montreal, Montreal, QC H2X 0A9, Canada; (T.P.Y.T.); (E.B.A.); (M.R.); (M.R.K.)
| | - Alain Bouthillier
- Division of Neurosurgery, CHUM, University of Montreal, Montreal, QC H2X 0C1, Canada;
| | - Mark R. Keezer
- CHUM Research Center, University of Montreal, Montreal, QC H2X 0A9, Canada; (T.P.Y.T.); (E.B.A.); (M.R.); (M.R.K.)
- Division of Neurology, CHUM, University of Montreal, Montreal, QC H2X 0C1, Canada
| | - Dang Khoa Nguyen
- CHUM Research Center, University of Montreal, Montreal, QC H2X 0A9, Canada; (T.P.Y.T.); (E.B.A.); (M.R.); (M.R.K.)
- Division of Neurology, CHUM, University of Montreal, Montreal, QC H2X 0C1, Canada
- Correspondence:
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Obaid S, Rheault F, Edde M, Guberman GI, St-Onge E, Sidhu J, Bouthillier A, Daducci A, Ghaziri J, Bojanowski MW, Nguyen DK, Descoteaux M. Structural Connectivity Alterations in Operculo-Insular Epilepsy. Brain Sci 2021; 11:1041. [PMID: 34439659 DOI: 10.3390/brainsci11081041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/27/2021] [Accepted: 08/02/2021] [Indexed: 11/17/2022] Open
Abstract
Operculo-insular epilepsy (OIE) is an under-recognized condition that can mimic temporal and extratemporal epilepsies. Previous studies have revealed structural connectivity changes in the epileptic network of focal epilepsy. However, most reports use the debated streamline-count to quantify ‘connectivity strength’ and rely on standard tracking algorithms. We propose a sophisticated cutting-edge method that is robust to crossing fibers, optimizes cortical coverage, and assigns an accurate microstructure-reflecting quantitative conectivity marker, namely the COMMIT (Convex Optimization Modeling for Microstructure Informed Tractography)-weight. Using our pipeline, we report the connectivity alterations in OIE. COMMIT-weighted matrices were created in all participants (nine patients with OIE, eight patients with temporal lobe epilepsy (TLE), and 22 healthy controls (HC)). In the OIE group, widespread increases in ‘connectivity strength’ were observed bilaterally. In OIE patients, ‘hyperconnections’ were observed between the insula and the pregenual cingulate gyrus (OIE group vs. HC group) and between insular subregions (OIE vs. TLE). Graph theoretic analyses revealed higher connectivity within insular subregions of OIE patients (OIE vs. TLE). We reveal, for the first time, the structural connectivity distribution in OIE. The observed pattern of connectivity in OIE likely reflects a diffuse epileptic network incorporating insular-connected regions and may represent a structural signature and diagnostic biomarker.
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Abstract
Focal epilepsy originating from the insular cortex is rare. One reason is the small amount of cortical tissue compared with other lobes of the brain. However, the incidence of insular epilepsy might be underestimated because of diagnostic difficulties. The semiology and the surface EEG are often not meaningful or even misleading, and elaborated imaging might be necessary. The close connections of the insular cortex with other potentially epileptogenic areas, such as the temporal lobe or frontal/central cortex, is increasingly recognized as possible reason for failure of epilepsy surgery for temporal or extratemporal seizures. Therefore, some centers consider invasive EEG recording of the insular cortex not only in case of insular epilepsy but also in other focal epilepsies with nonconclusive results from the presurgical work-up. The surgical approach to and resection of insular cortex is challenging because of its deep location and proximity to highly eloquent brain structures. Over the last decades, technical adjuncts like navigation tools, electrophysiological monitoring and intraoperative imaging have improved the outcome after surgery. Nevertheless, there is still a considerable rate of postoperative transient or permanent deficits, in some cases as unavoidable and calculated deficits. In most of the recent series, seizure outcome was favorable and comparable with extratemporal epilepsy surgery or even better. Up to now, the data volume concerning long-term follow-up is limited. This review focusses on the surgical challenges of resections to treat insular epilepsy, on prognostic factors concerning seizure outcome, on postoperative deficits and complications. Moreover, less invasive surgical techniques to treat epilepsy in this highly eloquent area are summarized.
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Aitouche Y, Gibbs SA, Gilbert G, Boucher O, Bouthillier A, Nguyen DK. Proton MR Spectroscopy in Patients with Nonlesional Insular Cortex Epilepsy Confirmed by Invasive EEG Recordings. J Neuroimaging 2017; 27:517-523. [PMID: 28318128 DOI: 10.1111/jon.12436] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 02/10/2017] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Recent studies suggest that a nonnegligible proportion of drug-resistant epilepsy surgery candidates have an epileptogenic zone that involves the insula. We aimed to examine the value of proton magnetic resonance spectroscopy (1 H-MRS) in identifying patients with insular cortex epilepsy. METHODS Patients with possible nonlesional drug-refractory insular epilepsy underwent a voxel-based 1 H-MRS study prior to an intracranial electroencephalographic (EEG) study. Patients were then divided into two groups based on invasive EEG findings: the insular group with evidence of insular seizures and the noninsular group with no evidence of insular seizures. Sixteen age-matched healthy controls were also scanned for normative data. RESULTS Twenty-two epileptic patients were recruited, 12 with insular seizures and 10 with extra-insular seizures. Ipsilateral and contralateral insular N-acetyl-aspartate concentrations ([NAA]) and NAA/Cr ratios were found to be similar in both patient groups. No significant differences in [NAA] or NAA/Cr ratios were found between the insular group, noninsular group, and healthy controls. [NAA] and NAA/Cr asymmetry indices correctly lateralized the seizure focus in only 16.7% and 0% of patients, respectively. CONCLUSIONS Our preliminary findings suggest that 1 H-MRS fares poorly in identifying patients with nonlesional insular epilepsy.
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Affiliation(s)
| | - Steve A Gibbs
- Department of Neurosciences, Université de Montréal, Canada.,Division of Neurology, Hôpital du Sacré-Cœur de Montréal, Université de Montréal, Canada
| | - Guillaume Gilbert
- MR Clinical Science, Philips Healthcare, Canada.,Department of Radiology, CHUM Notre-Dame, Université de Montréal, Canada
| | | | - Alain Bouthillier
- Division of Neurosurgery, CHUM Notre-Dame, Université de Montréal, Canada
| | - Dang Khoa Nguyen
- Department of Neurosciences, Université de Montréal, Canada.,Division of Neurology, CHUM Notre-Dame, Université de Montréal, Canada
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