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Ong S, Kullmann A, Mertens S, Rosa D, Diaz-Botia CA. Electrochemical Testing of a New Polyimide Thin Film Electrode for Stimulation, Recording, and Monitoring of Brain Activity. MICROMACHINES 2022; 13:1798. [PMID: 36296151 PMCID: PMC9611492 DOI: 10.3390/mi13101798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
Subdural electrode arrays are used for monitoring cortical activity and functional brain mapping in patients with seizures. Until recently, the only commercially available arrays were silicone-based, whose thickness and lack of conformability could impact their performance. We designed, characterized, manufactured, and obtained FDA clearance for 29-day clinical use (510(k) K192764) of a new thin-film polyimide-based electrode array. This study describes the electrochemical characterization undertaken to evaluate the quality and reliability of electrical signal recordings and stimulation of these new arrays. Two testing paradigms were performed: a short-term active soak with electrical stimulation and a 29-day passive soak. Before and after each testing paradigm, the arrays were evaluated for their electrical performance using Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV) and Voltage Transients (VT). In all tests, the impedance remained within an acceptable range across all frequencies. The different CV curves showed no significant changes in shape or area, which is indicative of stable electrode material. The electrode polarization remained within appropriate limits to avoid hydrolysis.
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Gonzalez-Martinez JA, Abou-Al-Shaar H, Mallela AN, McDowell MM, Henry L, Fernandes Cabral DT, Sweat J, Urban A, Fong J, Barot N, Castellano JF, Rajasekaran V, Bagic A, Snyderman CH, Gardner PA. The endoscopic anterior transmaxillary temporal pole approach for mesial temporal lobe epilepsies: a feasibility study. J Neurosurg 2022; 138:992-1001. [PMID: 36087323 DOI: 10.3171/2022.7.jns221062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/15/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE In mesial temporal lobe epilepsy (MTLE), the ideal surgical approach to achieve seizure freedom and minimize morbidity is an unsolved question. Selective approaches to mesial temporal structures often result in suboptimal seizure outcomes. The authors report the results of a pilot study intended to evaluate the clinical feasibility of using an endoscopic anterior transmaxillary (eATM) approach for minimally invasive management of MTLEs. METHODS The study is a prospectively collected case series of four consecutive patients who underwent the eATM approach for the treatment of MTLE and were followed for a minimum of 12 months. All participants underwent an epilepsy workup and surgical care at a tertiary referral comprehensive epilepsy center and had medically refractory epilepsy. The noninvasive evaluations and intracranial recordings of these patients confirmed the presence of anatomically restricted epileptogenic zones located in the mesial temporal structures. Data on seizure freedom at 1 year, neuropsychological outcomes, diffusion tractography, and adverse events were collected and analyzed. RESULTS By applying the eATM technique and approaching the far anterior temporal lobe regions, mesial-basal resections of the temporal polar areas and mesial temporal structures were successfully achieved in all patients (2 with left-sided approaches, 2 with right-sided approaches). No neurological complications or neuropsychological declines were observed. All 4 patients achieved Engel class Ia outcome up to the end of the follow-up period (19, 15, 14, and 12 months). One patient developed hypoesthesia in the left V2 distribution but there were no other adverse events. The low degree of white matter injury from the eATM approach was analyzed using high-definition fiber tractography in 1 patient as a putative mechanism for preserving neuropsychological function. CONCLUSIONS The described series demonstrates the feasibility and potential safety profile of a novel approach for medically refractory MTLE. The study affirms the feasibility of performing efficacious mesial temporal lobe resections through an eATM approach.
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Affiliation(s)
- Jorge A Gonzalez-Martinez
- 1Epilepsy Center, University of Pittsburgh Medical Center, Pittsburgh.,Departments of3Neurological Surgery
| | | | | | | | | | | | | | - Alexandra Urban
- 1Epilepsy Center, University of Pittsburgh Medical Center, Pittsburgh.,4Neurology, and
| | - Joanna Fong
- 1Epilepsy Center, University of Pittsburgh Medical Center, Pittsburgh.,4Neurology, and
| | - Niravkumar Barot
- 1Epilepsy Center, University of Pittsburgh Medical Center, Pittsburgh.,4Neurology, and
| | - James F Castellano
- 1Epilepsy Center, University of Pittsburgh Medical Center, Pittsburgh.,4Neurology, and
| | | | - Anto Bagic
- 1Epilepsy Center, University of Pittsburgh Medical Center, Pittsburgh.,4Neurology, and
| | - Carl H Snyderman
- 2Skull Base Center, University of Pittsburgh Medical Center, Pittsburgh; and.,5Otorhinolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Paul A Gardner
- 2Skull Base Center, University of Pittsburgh Medical Center, Pittsburgh; and.,Departments of3Neurological Surgery
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Kullmann A, Kridner D, Mertens S, Christianson M, Rosa D, Diaz-Botia CA. First Food and Drug Administration Cleared Thin-Film Electrode for Intracranial Stimulation, Recording, and Monitoring of Brain Activity—Part 1: Biocompatibility Testing. Front Neurosci 2022; 16:876877. [PMID: 35573282 PMCID: PMC9100917 DOI: 10.3389/fnins.2022.876877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/28/2022] [Indexed: 11/16/2022] Open
Abstract
Subdural strip and grid invasive electroencephalography electrodes are routinely used for surgical evaluation of patients with drug-resistant epilepsy (DRE). Although these electrodes have been in the United States market for decades (first FDA clearance 1985), their fabrication, materials, and properties have hardly changed. Existing commercially available electrodes are made of silicone, are thick (>0.5 mm), and do not optimally conform to brain convolutions. New thin-film polyimide electrodes (0.08 mm) have been manufactured to address these issues. While different thin-film electrodes are available for research use, to date, only one electrode is cleared by Food and Drug Administration (FDA) for use in clinical practice. This study describes the biocompatibility tests that led to this clearance. Biocompatibility was tested using standard methods according to International Organization for Standardization (ISO) 10993. Electrodes and appropriate control materials were bent, folded, and placed in the appropriate extraction vehicles, or implanted. The extracts were used for in vitro and in vivo tests, to assess the effects of any potential extractable and leachable materials that may be toxic to the body. In vitro studies included cytotoxicity tested in L929 cell line, genotoxicity tested using mouse lymphoma assay (MLA) and Ames assay, and hemolysis tested in rabbit whole blood samples. The results indicated that the electrodes were non-cytotoxic, non-mutagenic, non-clastogenic, and non-hemolytic. In vivo studies included sensitization tested in guinea pigs, irritation tested in rabbits, acute systemic toxicity testing in mice, pyrogenicity tested in rabbits, and a prolonged 28-day subdural implant in sheep. The results indicated that the electrodes induced no sensitization and irritation, no weight loss, and no temperature increase. Histological examination of the sheep brain tissue showed no or minimal immune cell accumulation, necrosis, neovascularization, fibrosis, and astrocyte infiltration, with no differences from the control material. In summary, biocompatibility studies indicated that these new thin-film electrodes are appropriate for human use. As a result, the electrodes were cleared by the FDA for use in clinical practice [510(k) K192764], making it the first thin-film subdural electrode to progress from research to clinic. Its readiness as a commercial product ensures availability to all patients undergoing surgical evaluation for DRE.
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Jehi L, Morita-Sherman M, Love TE, Bartolomei F, Bingaman W, Braun K, Busch RM, Duncan J, Hader WJ, Luan G, Rolston JD, Schuele S, Tassi L, Vadera S, Sheikh S, Najm I, Arain A, Bingaman J, Diehl B, de Tisi J, Rados M, Van Eijsden P, Wahby S, Wang X, Wiebe S. Comparative Effectiveness of Stereotactic Electroencephalography Versus Subdural Grids in Epilepsy Surgery. Ann Neurol 2021; 90:927-939. [PMID: 34590337 DOI: 10.1002/ana.26238] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 09/28/2021] [Accepted: 09/28/2021] [Indexed: 01/08/2023]
Abstract
OBJECTIVE The aim was to compare the outcomes of subdural electrode (SDE) implantations versus stereotactic electroencephalography (SEEG), the 2 predominant methods of intracranial electroencephalography (iEEG) performed in difficult-to-localize drug-resistant focal epilepsy. METHODS The Surgical Therapies Commission of the International League Against Epilepsy created an international registry of iEEG patients implanted between 2005 and 2019 with ≥1 year of follow-up. We used propensity score matching to control exposure selection bias and generate comparable cohorts. Study endpoints were: (1) likelihood of resection after iEEG; (2) seizure freedom at last follow-up; and (3) complications (composite of postoperative infection, symptomatic intracranial hemorrhage, or permanent neurological deficit). RESULTS Ten study sites from 7 countries and 3 continents contributed 2,012 patients, including 1,468 (73%) eligible for analysis (526 SDE and 942 SEEG), of whom 988 (67%) underwent subsequent resection. Propensity score matching improved covariate balance between exposure groups for all analyses. Propensity-matched patients who underwent SDE had higher odds of subsequent resective surgery (odds ratio [OR] = 1.4, 95% confidence interval [CI] 1.05, 1.84) and higher odds of complications (OR = 2.24, 95% CI 1.34, 3.74; unadjusted: 9.6% after SDE vs 3.3% after SEEG). Odds of seizure freedom in propensity-matched resected patients were 1.66 times higher (95% CI 1.21, 2.26) for SEEG compared with SDE (unadjusted: 55% seizure free after SEEG-guided resections vs 41% after SDE). INTERPRETATION In comparison to SEEG, SDE evaluations are more likely to lead to brain surgery in patients with drug-resistant epilepsy but have more surgical complications and lower probability of seizure freedom. This comparative-effectiveness study provides the highest feasible evidence level to guide decisions on iEEG. ANN NEUROL 2021.
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Affiliation(s)
- Lara Jehi
- Cleveland Clinic Epilepsy Center, Cleveland, OH
| | | | - Thomas E Love
- Departments of Medicine and Population & Quantitative Health Sciences, CWRU and Population Health Research Institute, The MetroHealth System, and Center for Health Care Research and Policy, CWRU - MetroHealth, Cleveland, OH
| | - Fabrice Bartolomei
- Epileptology Department, Aix Marseille University, APHM, INSERM, INS, Institut National de la Sante et de la Recherche Medicale, Timone Hospital, Marseille, France
| | | | - Kees Braun
- Department of Child Neurology, Brain Center Rudolf Magnus, UMC Utrecht, Utrecht, The Netherlands
| | | | - John Duncan
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Walter J Hader
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Guoming Luan
- Department of Neurosurgery, Comprehensive Epilepsy Center, Sanbo Brain Hospital, Capital Medical University; Beijing Key Laboratory of Epilepsy; Epilepsy Institution, Beijing Institute for Brain Disorders, Beijing, China
| | - John D Rolston
- Department of Neurosurgery, University of Utah, Salt Lake City, UT
| | - Stephan Schuele
- Department of Neurology, Northwestern University, Chicago, IL
| | - Laura Tassi
- "C. Munari" Epilepsy Surgery Center, Niguarda Hospital, Milano, Italy
| | - Sumeet Vadera
- Department of Neurosurgery, University of California, Irvine, CA
| | | | - Imad Najm
- Cleveland Clinic Epilepsy Center, Cleveland, OH
| | - Amir Arain
- Department of Neurology, University of Utah, Salt Lake City, UT
| | | | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Jane de Tisi
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Matea Rados
- Department of Child Neurology, Brain Center Rudolf Magnus, UMC Utrecht, Utrecht, The Netherlands
| | - Pieter Van Eijsden
- Department of Child Neurology, Brain Center Rudolf Magnus, UMC Utrecht, Utrecht, The Netherlands
| | - Sandra Wahby
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Xiongfei Wang
- Department of Neurosurgery, Comprehensive Epilepsy Center, Sanbo Brain Hospital, Capital Medical University; Beijing Key Laboratory of Epilepsy; Epilepsy Institution, Beijing Institute for Brain Disorders, Beijing, China
| | - Samuel Wiebe
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Remick M, Ibrahim GM, Mansouri A, Abel TJ. Patient phenotypes and clinical outcomes in invasive monitoring for epilepsy: An individual patient data meta-analysis. Epilepsy Behav 2020; 102:106652. [PMID: 31770717 DOI: 10.1016/j.yebeh.2019.106652] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 10/16/2019] [Accepted: 10/17/2019] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Invasive monitoring provides valuable clinical information in patients with drug-resistant epilepsy (DRE). However, there is no clear evidence indicating either stereoelectroencephalography (SEEG) or subdural electrodes (SDE) as the optimal method. Our goal was to examine differences in postresection seizure freedom rates between SEEG- and SDE-informed resective epilepsy surgeries. Additionally, we aimed to determine potential clinical indicators for SEEG or SDE monitoring in patients with drug-resistant epilepsy. METHODS A systematic literature review was performed in which we searched for primary articles using keywords such as "electroencephalography", "intracranial grid", and "epilepsy." Only studies containing individual patient data (IPD) were included for analysis. A one-stage IPD meta-analysis was performed to determine differences in rates of seizure freedom (International League Against Epilepsy (ILAE) guidelines and Engel classification) and resection status between SEEG and SDE patients. A Cox proportional-hazards regression was performed to determine the effect of time on seizure freedom status. Additionally, a principal component analysis was performed to investigate primary drivers of variance between these two groups. RESULTS This IPD meta-analysis compared differences between SEEG and SDE invasive monitoring techniques in 595 patients from 33 studies. Our results demonstrate that while there was no difference in seizure freedom rates regardless of resection (p = 0.0565), SEEG was associated with a lower rate of resection compared with SDE (82.00% SEEG, 92.74% SDE, p = 0.0002). Additionally, while SDE was associated with a higher rate of postresection seizure freedom (54.04% SEEG, 64.32% SDE, p = 0.0247), the difference between seizure freedom rates following SEEG- or SDE-informed resection decreased with long-term follow-up. A principal component analysis showed that cases resulting in SEEG were associated with lower risk of morbidity than SDE cases, which were strongly collinear with multiple subpial transections, anterior temporal lobectomy, amygdalectomy, and hippocampectomy. SIGNIFICANCE In this IPD meta-analysis of SEEG and SDE invasive monitoring techniques, SEEG and SDE were associated with similar rates of seizure freedom at latest follow-up. The former was associated with lower rates of resection. Furthermore, the clinical phenotypes of patients undergoing SEEG monitoring was associated with lower rates of complications. Future long-term prospective registries of IPD are promising options for clarifying the differences in these intracranial monitoring techniques as well as the unique patient phenotypes that may be associated with their indication.
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Affiliation(s)
- Madison Remick
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - George M Ibrahim
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada; Division of Neurosurgery, Hospital for Sick Children, Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, Canada
| | - Alireza Mansouri
- Department of Neurosurgery, Penn State University, Hershey, PA, USA
| | - Taylor J Abel
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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