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Kaoutzani L, Goldman LV, Piper K, Kumar M, Vale FL. Revision and removal of vagus nerve stimulation systems: twenty-five years' experience. Acta Neurochir (Wien) 2023; 165:3913-3920. [PMID: 37957310 DOI: 10.1007/s00701-023-05875-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/24/2023] [Indexed: 11/15/2023]
Abstract
BACKGROUND Epilepsy, a disease characterized by recurrent seizures, is a common chronic neurologic condition. Antiepileptic drugs (AED) are the mainstay of treatment for epilepsy. Vagus nerve stimulation (VNS) surgery is an adjuvant therapy for the treatment of drug refractory epilepsy (DRE). VNS revision and implant removal surgeries remain common. METHODS Using a single neurosurgeon data registry for epilepsy surgery, we retrospectively analyzed a total of 824 VNS surgeries. Patients were referred to two Level IV Comprehensive Epilepsy centers (from 08/1997 to 08/2022) for evaluation. Patients were divided into four groups: new device placement, revision surgery, removal surgery, and battery replacement for end-of-life of the generator. The primary endpoint was to analyze the reasons that led patients to undergo revision and removal surgeries. The time period from the index surgery to the removal surgery was also calculated. RESULTS The median age of patients undergoing any type of surgery was 34 years. The primary reason for revision surgeries was device malfunction, followed by patients' cosmetic dissatisfaction. There was no statistical sex-difference in revision surgeries. The median age and body mass index (BMI) of patients who underwent revision surgery were 38 years and 26, respectively. On the other hand, the primary reason for removal was lack of efficacy, followed again by cosmetic dissatisfaction. The survival analysis showed that 43% of VNS device remained in place for 5 years and 50% of the VNS devices were kept for 1533 days or 4.2 years. CONCLUSIONS VNS therapy is safe and well-tolerated. VNS revision and removal surgeries occur in less than 5% of cases. More importantly, attention to detail and good surgical technique at the time of the index surgery can increase patient satisfaction, minimize the need for further surgeries, and improve acceptance of the VNS technology.
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Affiliation(s)
- Lydia Kaoutzani
- Department of Neurosurgery, Medical College of Georgia, Augusta University (MCG-AU), Augusta, GA, USA
| | - Liam V Goldman
- Department of Neurosurgery, Medical College of Georgia, Augusta University (MCG-AU), Augusta, GA, USA
| | - Keaton Piper
- Department of Neurosurgery, University of South Florida (USF), Tampa, USA
| | - Manish Kumar
- Department of Neurosurgery, Medical College of Georgia, Augusta University (MCG-AU), Augusta, GA, USA
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Fernando L Vale
- Department of Neurosurgery, Medical College of Georgia, Augusta University (MCG-AU), Augusta, GA, USA.
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Saba ES, Rivero A. Pediatric vagal nerve stimulator explantation: A comprehensive literature review and tertiary care experience. Int J Pediatr Otorhinolaryngol 2023; 170:111603. [PMID: 37267661 DOI: 10.1016/j.ijporl.2023.111603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/08/2023] [Accepted: 05/18/2023] [Indexed: 06/04/2023]
Abstract
OBJECTIVE Patients with medically-refractory epilepsy who undergo vagal nerve stimulator (VNS) implantation to reduce seizure burden sometimes require device removal. Complete explantation refers to the removal of both the generator and vagal nerve leads, and is uncommonly performed by otolaryngologists due to the perceived risk associated with lead removal. This comprehensive literature review and case series studies safety outcomes among pediatric patients undergoing complete VNS explantation. STUDY DESIGN/SETTING Literature review and tertiary care case series. METHODS PubMed, Embase, Web of Science, and Google Scholar were searched to identify all articles involving VNS explantation prior to January 2023. A retrospective review of pediatric patients undergoing complete VNS explantation from 2009 to 2023 at our tertiary center was also conducted. RESULTS After screening, 36 articles were retained involving 399 patients (139 confirmed children) who underwent complete VNS explantation. 26 patients (6.5%) experienced 1+ peri/post-operative complications. These included temporary VF paresis or dysphonia (n = 14; 3.6%), permanent vocal fold (VF) paralysis/paresis (n = 6; 1.5%), internal jugular vein injury (n = 4; 1.0%), temporary dysphagia (n = 2; 0.50%), and cable-bowstring phenomenon (n = 1; 0.25%). Data from our tertiary care center revealed eight patients (6 M: 2 F) with a mean age of 11.4 ± 6.2 years. Devices were removed for clinical ineffectiveness (n = 2), infection (n = 2), lead failures (n = 2), and increased lead impedance (n = 2). Mean total length of implantation was 44.4 ± 40.3 months. Mean follow-up was 44.8 ± 35.2 months. No complications were identified. CONCLUSIONS Complete VNS device removal in pediatric patients is technically feasible with low reported complications. Working alongside neurosurgery, otolaryngologists offer unique expertise in dissection along the vagus nerve and may thus add value to the practice of VNS surgery.
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Affiliation(s)
- Elias S Saba
- Kaiser Permanente Oakland Medical Center, 3600 Broadway, Oakland, CA, 94611, USA.
| | - Alexander Rivero
- Kaiser Permanente Oakland Medical Center, 3600 Broadway, Oakland, CA, 94611, USA
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LoPresti MA, Huang J, Shlobin NA, Curry DJ, Weiner HL, Lam SK. Vagus nerve stimulator revision in pediatric epilepsy patients: a technical note and case series. Childs Nerv Syst 2023; 39:435-441. [PMID: 36434283 DOI: 10.1007/s00381-022-05769-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/16/2022] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Vagus nerve stimulation (VNS) is an adjunctive treatment in children with intractable epilepsy. When lead replacement becomes necessary, the old leads are often truncated and retained and new leads are implanted at a newly exposed segment of the nerve. Direct lead removal and replacement are infrequently described, with outcomes poorly characterized. We aimed to describe our experience with feasibility of VNS lead removal and replacement in pediatric patients. METHODS Retrospective review examined 14 patients, at a single, tertiary-care, children's hospital, who underwent surgery to replace VNS leads, with complete removal of the existing lead from the vagus nerve and placement of a new lead on the same segment of the vagus nerve, via blunt and sharp dissection without use of electrocautery. Preoperative characteristics, stimulation parameters, and outcomes were collected. RESULTS Mean age at initial VNS placement was 7.6 years (SD 3.5, range 4.5-13.4). Most common etiologies of epilepsy were genetic (5, 36%) and cryptogenic (4, 29%). Lead replacement was performed at a mean of 6.0 years (SD 3.8, range 2.1-11.7) following initial VNS placement. Reasons for revision included VNS lead breakage or malfunction. There were no perioperative complications, including surgical site infection, voice changes, dysphagia, or new deficits postoperatively. Stimulation parameters after replacement surgery at last follow-up were similar compared to preoperatively, with final stimulation parameters ranging from 0.25 mA higher to 1.5 mA lower to maintain baseline seizure control. The mean length of follow-up was 7.9 years (SD 3.5, range 3.1-13.7). CONCLUSION Removal and replacement of VNS leads are feasible and can be safely performed in children. Further characterization of surgical technique, associated risk, impact on stimulation parameters, and long-term outcomes are needed to inform best practices in VNS revision.
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Affiliation(s)
- Melissa A LoPresti
- Division of Pediatric Neurosurgery, Texas Children's Hospital; Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA.,Division of Pediatric Neurosurgery, Lurie Children's Hospital; Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jonathan Huang
- Division of Pediatric Neurosurgery, Lurie Children's Hospital; Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Nathan A Shlobin
- Division of Pediatric Neurosurgery, Lurie Children's Hospital; Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Daniel J Curry
- Division of Pediatric Neurosurgery, Texas Children's Hospital; Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
| | - Howard L Weiner
- Division of Pediatric Neurosurgery, Texas Children's Hospital; Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
| | - Sandi K Lam
- Division of Pediatric Neurosurgery, Lurie Children's Hospital; Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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Al Omari AI, Nuseir A, Kanaan Y, Al-Ashqar R, Alzoubi F. The feasibility of vagal nerve stimulation revision surgery and surgical techniques: a retrospective review. Acta Otolaryngol 2021; 141:719-723. [PMID: 34003719 DOI: 10.1080/00016489.2021.1916588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND With the large number of VNS implants performed worldwide, the need for removal or replacement of the device in selected cases is emerging, this removal or replacement of VNS can be challenging. AIMS/OBJECTIVE To describe the feasibility and safety of revising vagal nerve stimulation surgery in terms of the indications, surgical techniques, and outcomes. MATERIALS AND METHODS A retrospective study, a series of eight cases with VNS implants that needed revision surgery have been reviewed, four devices were completely removed and four were only revised. The revision surgery was performed after a range of 7 months to 6 years, due to different reasons. Initial surgeries and revisions were performed at the otolaryngology department in a major tertiary center. CONCLUSIONS AND SIGNIFICANCE We concluded that the previously implanted vagal nerve stimulation electrodes can be completely removed without any significant sequelae on the nerve. It may also be re-implanted safely at the previously used segment of the vagus nerve with a similar outcome in seizure control as the initial implantation.
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Affiliation(s)
- Ahmad I. Al Omari
- Otolaryngology Department, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Amjad Nuseir
- Otolaryngology Department, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Yazan Kanaan
- Otolaryngology Department, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Ra’ed Al-Ashqar
- Otolaryngology Department, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Firas Alzoubi
- Otolaryngology Department, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
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Hamdi H, Spatola G, Lagarde S, McGonigal A, Paz-Paredes A, Bizeau A, Bartolomei F, Carron R. Use of Polyvinyl Alcohol Sponge Cubes for Vagal Nerve Stimulation: A Suggestion for the Wrapping Step. Technical Note and Step-by-Step Operative Technique. Oper Neurosurg (Hagerstown) 2021; 18:487-495. [PMID: 31386756 PMCID: PMC7594176 DOI: 10.1093/ons/opz227] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 05/29/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Vagal nerve stimulation (VNS) is an approved treatment for epilepsy and depression. Wrapping the helical electrodes around the nerve can prove technically challenging. However, a quick and efficient method to slightly elevate the nerve can highly facilitate this part of the procedure. OBJECTIVE To provide useful surgical tips to facilitate the procedure. METHODS Based on experience of more than 150 adult cases for mainly epilepsy (primary lead implant), the authors share their surgical technique to provide the experienced surgeons or newcomers to the field of VNS with some useful tips. All patients signed informed consent according to the local ethics committee guidelines. RESULTS The article consists of a detailed step-by-step description of the whole procedure illustrated through high-resolution colored photographs of the surgical field. Special reference is made to the usefulness of polyvinyl alcohol (PVA) sponge cubes to elevate the nerve instead of the commonly used silicon vessel loops. CONCLUSION The use of surgical microscope and PVA sponge cubes to elevate the nerve constitute key points to make VNS an easy surgery.
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Affiliation(s)
- Hussein Hamdi
- Department of Functional and Stereotactic Neurosurgery, Timone University Hospital, Marseille, France.,Aix Marseille Univ, APHM, INSERM, INS, Inst Neurosci Syst, Timone Hospital, Marseille, France.,Functional Neurosurgery and Stereotaxy Unit, Neurological Surgery Department, Tanta University, Egypt
| | - Giorgio Spatola
- Department of Functional and Stereotactic Neurosurgery, Timone University Hospital, Marseille, France.,Aix Marseille Univ, APHM, INSERM, INS, Inst Neurosci Syst, Timone Hospital, Marseille, France
| | - Stanislas Lagarde
- Epileptology Department, Aix Marseille Univ, APHM, INSERM, INS, Inst Neurosci Syst, Timone Hospital, Marseille, France
| | - Aileen McGonigal
- Epileptology Department, Aix Marseille Univ, APHM, INSERM, INS, Inst Neurosci Syst, Timone Hospital, Marseille, France
| | - Armando Paz-Paredes
- Department of Functional and Stereotactic Neurosurgery, Timone University Hospital, Marseille, France
| | - Alain Bizeau
- Department of Cervico-Facial Surgery, Sainte Musse Hospital, Toulon, France
| | - Fabrice Bartolomei
- Epileptology Department, Aix Marseille Univ, APHM, INSERM, INS, Inst Neurosci Syst, Timone Hospital, Marseille, France
| | - Romain Carron
- Department of Functional and Stereotactic Neurosurgery, Timone University Hospital, Marseille, France.,Aix Marseille Univ, APHM, INSERM, INS, Inst Neurosci Syst, Timone Hospital, Marseille, France
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Fetzer S, Ortler M. A simple electrical approach to diagnosing a suspected lead break in patients with implanted vagus nerve stimulators - Technical note. Clin Neurol Neurosurg 2021; 206:106707. [PMID: 34053806 DOI: 10.1016/j.clineuro.2021.106707] [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: 03/19/2021] [Revised: 05/15/2021] [Accepted: 05/17/2021] [Indexed: 12/01/2022]
Abstract
PURPOSE Vagus nerve stimulation (VNS) is an effective adjunctive treatment for patients with drug-resistant epilepsy (DRE) or difficult-to-treat depression (DTD). The implanted system consists of a titanium-cased generator and a lead with platinum electrodes, placed around the cervical vagus nerve. In rare cases a lead may break, causing the patient to receive insufficient therapy or no therapy at all, with potentially dangerous consequences. In order to confirm a suspected lead breakage, physicians have the option to perform x-rays. However, x-rays often do not show a clear, unmistakable lead break. In this technical note an additional method to verify lead integrity electrophysiological is described in detail to provide the highest degree of certainty on the integrity of the lead when a broken lead is suspected before proceeding to revision surgery. METHODS When patients introduce themselves with symptoms indicating a suspected lead breakage, a systematic lead break management is required. This includes, beside the clinical anamneses, performing VNS Therapy® System Diagnostics (SD). If an unacceptable HIGH lead impedance is observed, performing x-rays (anteroposterior and lateral views) may help to confirm a lead breakage. Additionally, EMG recording equipment can be used to analyse the VNS stimulus waveform from the neck for verification of an electrical discontinuity. RESULTS A differentiated VNS waveform with narrowed pulses or no waveform at all can confirm lead discontinuity. CONCLUSION This Technical Note describes an easy but underused electrophysiological procedure to be included in the standardized protocol for identifying VNS lead breakage.
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Affiliation(s)
- Steffen Fetzer
- LivaNova Deutschland GmbH, Medical Affairs Department, a LivaNova PLC-owned Subsidiary, Lindberghstraße 25, 80939 Munich, Germany.
| | - Martin Ortler
- Department of Neurosurgery, Landstrasse Municipal Hospital, Vienna Health Care Network, Vienna, Austria and Department of Neurosurgery, Innsbruck Medical University, Innsbruck, Austria
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Entezami P, German JW, Adamo MA. High lead impedances requiring revision during vagal nerve stimulator generator replacement. Acta Neurochir (Wien) 2021; 163:1365-1368. [PMID: 32970237 DOI: 10.1007/s00701-020-04585-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/15/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Vagal nerve stimulation (VNS) therapy is among the growing options in the treatment of intractable epilepsy. The phenomenon of surprise lead impedance issues found at the time of surgery resulting in unplanned lead revision is a challenge with this type of device. We reviewed our experience with VNS revisions. MATERIAL AND METHODS We retrospectively reviewed the records of all adult and pediatric patients between January 2009 and September 2018 who underwent surgery for VNS therapy, including revision surgery. Office and operative notes were reviewed to obtain the indications and operative details for VNS placement. RESULTS A total of 570 operations were reviewed. The indication was intractable epilepsy in all cases. Primary implantation was performed in 232 patients, while the remaining 338 cases were revision cases of various natures. Surprise high lead impedance was found in 10 (3%) of these cases, resulting in a significantly increased complexity of surgery in those instances. CONCLUSION Lead impedance issues can be caused by disconnection, electrode fracture, hardware failure, or tissue scarring but ultimately require a more extended surgery than may be initially planned. Anticipating the potential for a more extensive operation than a simple generator replacement may prevent perioperative frustrations on both sides.
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Affiliation(s)
- Pouya Entezami
- Department of Neurosurgery, Albany Medical College, 47 New Scotland Ave, MC-10, Albany, NY, 12208-3479, USA.
| | - John W German
- Department of Neurosurgery, Albany Medical College, 47 New Scotland Ave, MC-10, Albany, NY, 12208-3479, USA
| | - Matthew A Adamo
- Department of Neurosurgery, Albany Medical College, 47 New Scotland Ave, MC-10, Albany, NY, 12208-3479, USA
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Entezami P, German JW, Adamo MA. Does One Week of Postoperative Antibiotic Prophylaxis Reduce the Rate of Infection After Vagus Nerve Stimulator Surgery? World Neurosurg 2021; 149:e546-e548. [PMID: 33549927 DOI: 10.1016/j.wneu.2021.01.140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Vagus nerve stimulation (VNS) therapy is an increasingly popular treatment for medically intractable epilepsy. During a review of our cases, we noted that one of the senior authors give patients 1 week of antibiotic prophylaxis after VNS surgery while the other does not. We reviewed our experience with postoperative antibiotic prophylaxis after VNS surgery. METHODS We retrospectively reviewed the records of patients from January 2009 to September 2018 who had undergone surgery for VNS therapy, including generator replacement. The office and operative notes were reviewed to obtain the indications and operative details for VNS placement. RESULTS A total of 570 operations were reviewed, 232 of which were primary implantations and 338 were revisions. The indication was intractable epilepsy in all cases. A total of 5 infections occurred, 4 in the group with postoperative antibiotic prophylaxis and 1 in the group without. The difference was not statistically significant. CONCLUSION Just as with any hardware implantation, infection of the hardware can lead to significant morbidity. However, the use of postoperative oral antibiotic prophylaxis did not show benefit in reducing the infection rate.
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Affiliation(s)
- Pouya Entezami
- Department of Neurosurgery, Albany Medical College, Albany, New York, USA.
| | - John W German
- Department of Neurosurgery, Albany Medical College, Albany, New York, USA
| | - Matthew A Adamo
- Department of Neurosurgery, Albany Medical College, Albany, New York, USA
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Levine YA, Faltys M, Chernoff D. Harnessing the Inflammatory Reflex for the Treatment of Inflammation-Mediated Diseases. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a034330. [PMID: 30833463 DOI: 10.1101/cshperspect.a034330] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Treating diseases nonpharmacologically, using targeted neurostimulation instead of systemic drugs, is a hallmark of the burgeoning field of bioelectronic medicine. In this review, we provide a brief overview of the discovery and function of the prototypical neuroimmune reflex, the "inflammatory reflex." We discuss various biomarkers developed and used to translate early physiological discoveries into dosing parameters used in experimental settings, from the treatment of animal models of disease through a proof-of-concept clinical study in rheumatoid arthritis (RA). Finally, we relate how unique aspects of this form of therapy enabled the design of a next-generation implanted pulse generator using integrated electrodes, currently under evaluation in a U.S.-based clinical study for patients with drug refractory RA.
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Zhou H, Liu Q, Zhao C, Ma J, Ye X, Xu J. Lead Failure After Vagus Nerve Stimulation Implantation: Radiographic Examination and Revision Surgery. World Neurosurg 2018; 124:S1878-8750(18)32893-6. [PMID: 30593965 DOI: 10.1016/j.wneu.2018.12.070] [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: 10/06/2018] [Revised: 12/06/2018] [Accepted: 12/07/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVE The present study assessed the most common types of lead failures, identified the causes, and discussed the potential procedures for revision surgery after vagus nerve stimulator implantation in patients with epilepsy. METHODS In a retrospective study during an 8-year period, 13 patients had undergone revision surgery because of lead failure. Lead failure was classified as either lead intrinsic damage or lead pin disengagement from the generator header. On the radiographic image, we defined a rear lead connector (RC) ratio that represented the portion of the rear lead connector in the header receptacle. It was used to quantitatively evaluate the mechanical failure of the lead-header interface. The optimal procedures to identify and manage lead failure were established. RESULTS All 13 patients presented with high lead impedance of ≥9 kOhms at the time of revision. Of 10 patients with lead damage, 7 had presented with an increased seizure frequency after a period of seizure remission. In contrast to lead damage occurring relatively late (>15 months), lead pin disengagement was usually found within the early months after device implantation. A significant association was found between an elevated RC ratio (≥35%) and lead pin disengagement. The microsurgical technique permitted removal or replacement of the lead without adverse effects. CONCLUSIONS The method of measuring the RC ratio developed in the present study is feasible for identifying lead disengagement at the generator level. Lead revision was an effective and safe procedure for patients experiencing lead failure.
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Affiliation(s)
- Hongyu Zhou
- Department of Functional Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Qiangqiang Liu
- Department of Functional Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chenjie Zhao
- Department of Functional Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Junfeng Ma
- Department of Functional Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaolai Ye
- Department of Functional Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jiwen Xu
- Department of Functional Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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Gigliotti MJ, Mao G, Dupré DA, Wilberger J. Vagal Nerve Stimulation: Indications for Revision in Adult Refractory Epilepsy. World Neurosurg 2018; 120:e1047-e1053. [DOI: 10.1016/j.wneu.2018.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/31/2018] [Accepted: 09/02/2018] [Indexed: 11/26/2022]
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Kozai TDY. The History and Horizons of Microscale Neural Interfaces. MICROMACHINES 2018; 9:E445. [PMID: 30424378 PMCID: PMC6187275 DOI: 10.3390/mi9090445] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 08/27/2018] [Accepted: 09/03/2018] [Indexed: 12/29/2022]
Abstract
Microscale neural technologies interface with the nervous system to record and stimulate brain tissue with high spatial and temporal resolution. These devices are being developed to understand the mechanisms that govern brain function, plasticity and cognitive learning, treat neurological diseases, or monitor and restore functions over the lifetime of the patient. Despite decades of use in basic research over days to months, and the growing prevalence of neuromodulation therapies, in many cases the lack of knowledge regarding the fundamental mechanisms driving activation has dramatically limited our ability to interpret data or fine-tune design parameters to improve long-term performance. While advances in materials, microfabrication techniques, packaging, and understanding of the nervous system has enabled tremendous innovation in the field of neural engineering, many challenges and opportunities remain at the frontiers of the neural interface in terms of both neurobiology and engineering. In this short-communication, we explore critical needs in the neural engineering field to overcome these challenges. Disentangling the complexities involved in the chronic neural interface problem requires simultaneous proficiency in multiple scientific and engineering disciplines. The critical component of advancing neural interface knowledge is to prepare the next wave of investigators who have simultaneous multi-disciplinary proficiencies with a diverse set of perspectives necessary to solve the chronic neural interface challenge.
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Affiliation(s)
- Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15213, USA.
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261, USA.
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15212, USA.
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA 15260, USA.
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Bettinger CJ. Recent advances in materials and flexible electronics for peripheral nerve interfaces. Bioelectron Med 2018; 4:6. [PMID: 32232082 PMCID: PMC7098226 DOI: 10.1186/s42234-018-0007-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/03/2018] [Indexed: 11/10/2022] Open
Abstract
Peripheral nerve interfaces are a central technology in advancing bioelectronic medicines because these medical devices can record and modulate the activity of nerves that innervate visceral organs. Peripheral nerve interfaces that use electrical signals for recording or stimulation have advanced our collective understanding of the peripheral nervous system. Furthermore, devices such as cuff electrodes and multielectrode arrays of various form factors have been implanted in the peripheral nervous system of humans in several therapeutic contexts. Substantive advances have been made using devices composed of off-the-shelf commodity materials. However, there is also a demand for improved device performance including extended chronic reliability, enhanced biocompatibility, and increased bandwidth for recording and stimulation. These aspirational goals manifest as much needed improvements in device performance including: increasing mechanical compliance (reducing Young's modulus and increasing extensibility); improving the barrier properties of encapsulation materials; reducing impedance and increasing the charge injection capacity of electrode materials; and increasing the spatial resolution of multielectrode arrays. These proposed improvements require new materials and novel microfabrication strategies. This mini-review highlights selected recent advances in flexible electronics for peripheral nerve interfaces. The foci of this mini-review include novel materials for flexible and stretchable substrates, non-conventional microfabrication techniques, strategies for improved device packaging, and materials to improve signal transduction across the tissue-electrode interface. Taken together, this article highlights challenges and opportunities in materials science and processing to improve the performance of peripheral nerve interfaces and advance bioelectronic medicine.
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Affiliation(s)
- Christopher J. Bettinger
- Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 USA
- Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 USA
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Wellman SM, Eles JR, Ludwig KA, Seymour JP, Michelson NJ, McFadden WE, Vazquez AL, Kozai TDY. A Materials Roadmap to Functional Neural Interface Design. ADVANCED FUNCTIONAL MATERIALS 2018; 28:1701269. [PMID: 29805350 PMCID: PMC5963731 DOI: 10.1002/adfm.201701269] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Advancement in neurotechnologies for electrophysiology, neurochemical sensing, neuromodulation, and optogenetics are revolutionizing scientific understanding of the brain while enabling treatments, cures, and preventative measures for a variety of neurological disorders. The grand challenge in neural interface engineering is to seamlessly integrate the interface between neurobiology and engineered technology, to record from and modulate neurons over chronic timescales. However, the biological inflammatory response to implants, neural degeneration, and long-term material stability diminish the quality of interface overtime. Recent advances in functional materials have been aimed at engineering solutions for chronic neural interfaces. Yet, the development and deployment of neural interfaces designed from novel materials have introduced new challenges that have largely avoided being addressed. Many engineering efforts that solely focus on optimizing individual probe design parameters, such as softness or flexibility, downplay critical multi-dimensional interactions between different physical properties of the device that contribute to overall performance and biocompatibility. Moreover, the use of these new materials present substantial new difficulties that must be addressed before regulatory approval for use in human patients will be achievable. In this review, the interdependence of different electrode components are highlighted to demonstrate the current materials-based challenges facing the field of neural interface engineering.
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Affiliation(s)
- Steven M Wellman
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - James R Eles
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Kip A Ludwig
- Department of Neurologic Surgery, 200 First St. SW, Rochester, MN 55905
| | - John P Seymour
- Electrical & Computer Engineering, 1301 Beal Ave., 2227 EECS, Ann Arbor, MI 48109
| | - Nicholas J Michelson
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - William E McFadden
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Alberto L Vazquez
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Takashi D Y Kozai
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
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Cozzens JW. The Surgical Technique of Vagus Nerve Stimulator Implantation. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00042-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Oliveira TVHFD, Francisco AN, Demartini Junior Z, Stebel SL. The role of vagus nerve stimulation in refractory epilepsy. ARQUIVOS DE NEURO-PSIQUIATRIA 2017; 75:657-666. [DOI: 10.1590/0004-282x20170113] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 06/07/2017] [Indexed: 11/22/2022]
Abstract
ABSTRACT Vagus nerve stimulation is an adjunctive therapy used to treat patients with refractory epilepsy who are not candidates for resective surgery or had poor results after surgical procedures. Its mechanism of action is not yet fully comprehended but it possibly involves modulation of the locus coeruleus, thalamus and limbic circuit through noradrenergic and serotonergic projections. There is sufficient evidence to support its use in patients with focal epilepsy and other seizure types. However, it should be recognized that improvement is not immediate and increases over time. The majority of adverse events is stimulation-related, temporary and decreases after adjustment of settings. Future perspectives to improve efficacy and reduce side effects, such as different approaches to increase battery life, transcutaneous stimulation and identification of prognostic factors, should be further investigated.
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Giordano F, Zicca A, Barba C, Guerrini R, Genitori L. Vagus nerve stimulation: Surgical technique of implantation and revision and related morbidity. Epilepsia 2017; 58 Suppl 1:85-90. [DOI: 10.1111/epi.13678] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Flavio Giordano
- Department of Neurosurgery; Anna Meyer Hospital; University of Firenze; Firenze Italy
| | - Anna Zicca
- Department of Neuroanaesthesiology; Anna Meyer Hospital; University of Firenze; Firenze Italy
| | - Carmen Barba
- Pediatric Neurology Unit; Anna Meyer Hospital; University of Firenze; Firenze Italy
| | - Renzo Guerrini
- Pediatric Neurology Unit; Anna Meyer Hospital; University of Firenze; Firenze Italy
| | - Lorenzo Genitori
- Department of Neurosurgery; Anna Meyer Hospital; University of Firenze; Firenze Italy
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Trezza A, Landi A, Grioni D, Pirillo D, Fiori L, Giussani C, Sganzerla EP. Adverse Effects and Surgical Complications in Pediatric Patients Undergoing Vagal Nerve Stimulation for Drug-Resistant Epilepsy. ACTA NEUROCHIRURGICA. SUPPLEMENT 2017; 124:43-47. [PMID: 28120051 DOI: 10.1007/978-3-319-39546-3_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Vagal nerve stimulation (VNS) is an effective treatment for drug-resistant epilepsy that is not suitable for resective surgery, both in adults and in children. Few reports describe the adverse effects and complications of VNS. The aim of our study was to present a series of 33 pediatric patients who underwent VNS for drug-resistant epilepsy and to discuss the adverse effects and complications through a review of the literature.The adverse effects of VNS are usually transient and are dependent on stimulation of the vagus and its efferent fibers; surgical complications of the procedure may be challenging and patients sometimes require further surgery; generally these complications affect VNS efficacy; in addition, hardware complications also have to be taken into account.In our experience and according to the literature, adverse effects and surgical and hardware complications are uncommon and can usually be managed definitely. Careful selection of patients, particularly from a respiratory and cardiac point of view, has to be done before surgery to limit the incidence of some adverse effects.
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Affiliation(s)
- A Trezza
- Neurosurgery, Department of Surgery and Translational Medicine, Milan Center for Neuroscience, San Gerardo Hospital, University of Milano Bicocca, via Pergolesi 33, 20900, Monza, Italy.
| | - A Landi
- Neurosurgery, Department of Surgery and Translational Medicine, Milan Center for Neuroscience, San Gerardo Hospital, University of Milano Bicocca, via Pergolesi 33, 20900, Monza, Italy
| | - D Grioni
- Unit of Pediatric Neurophysiology, Child Neuropsychiatric Clinic, San Gerardo Hospital, University of Milano Bicocca, via Pergolesi 33, 20900, Monza, Italy
| | - D Pirillo
- Neurosurgery, Department of Surgery and Translational Medicine, Milan Center for Neuroscience, San Gerardo Hospital, University of Milano Bicocca, via Pergolesi 33, 20900, Monza, Italy
| | - L Fiori
- Neurosurgery, Department of Surgery and Translational Medicine, Milan Center for Neuroscience, San Gerardo Hospital, University of Milano Bicocca, via Pergolesi 33, 20900, Monza, Italy
| | - C Giussani
- Neurosurgery, Department of Surgery and Translational Medicine, Milan Center for Neuroscience, San Gerardo Hospital, University of Milano Bicocca, via Pergolesi 33, 20900, Monza, Italy
| | - E P Sganzerla
- Neurosurgery, Department of Surgery and Translational Medicine, Milan Center for Neuroscience, San Gerardo Hospital, University of Milano Bicocca, via Pergolesi 33, 20900, Monza, Italy
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Champeaux C, Landré E, Chassoux F, Mann MW, Devaux B, Turak B. Vagus Nerve Stimulation Removal or Replacement Involving the Lead and the Electrode: Surgical Technique, Institutional Experience and Outcome. World Neurosurg 2016; 99:275-281. [PMID: 28012885 DOI: 10.1016/j.wneu.2016.11.103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 01/26/2023]
Abstract
OBJECTIVE To analyze the outcome of epileptic patients who had redo surgery involving the vagus nerve stimulation's lead. METHODS We reviewed the clinical and surgical records of all patients who had a complete vagus nerve stimulation (VNS) removal or replacement or any redo surgical procedure involving the system lead at Sainte-Anne Hospital in Paris, France. RESULTS Between the years 1999 and 2016, 41 redo surgical procedures involving the lead or electrode were achieved, of which 23 were complete VNS explantations, 12 were complete system replacements, 5 were lead changes only, and 1 was isolated lead removal. 41% of the surgical procedures were achieved in female patients. This population has a median age at VNS implantation of 33.6 years (interquartile range [IQR], [21.4-38.6]. Median time between the VNS implantation and the redo surgery involving the lead was 4.9 years (IQR, 2.9-8). The reason for VNS removal was mainly a lack of clinical effectiveness. No preoperative or postoperative complications occurred after complete VNS system removal or lead replacement. The effectiveness of the VNS therapy remained unchanged after lead replacement. No vagus nerve injury was reported, nor did symptoms suggest that it was disabled. CONCLUSIONS Complete removal or replacement of the VNS system including the lead and the electrode is feasible and safe. These procedures should be offered to patients who would no longer benefit from the VNS or when only a lead change is needed.
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Affiliation(s)
| | | | | | | | - Bertrand Devaux
- Department of Neurosurgery, Sainte-Anne Hospital, Paris, France
| | - Baris Turak
- Department of Neurosurgery, Sainte-Anne Hospital, Paris, France
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Kumar R, Winston KR, Folzenlogen Z. Removal of Vagus Nerve Stimulator Leads and Reuse of Same Site for Reimplantation: Technique and Experience. World Neurosurg 2016; 91:190-4. [PMID: 27062916 DOI: 10.1016/j.wneu.2016.03.085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 10/22/2022]
Abstract
OBJECTIVE This report describes the authors' experience and technique in removing vagus nerve stimulator leads, including coils, and reuse of the same site on the vagus nerve for implantation of new coils. METHODS The charts of all patients who underwent complete removal by the authors of vagus nerve stimulator leads between 1 September 2001 and 1 July 2015 were retrospectively reviewed. RESULTS Thirty patients underwent 31 surgeries for removal of vagus nerve stimulator leads. Complete removal, including proximal coils around the vagus nerve, was achieved in all cases. Reimplantation was performed immediately at the same location in 24 patients, delayed in 1 patient, and never replaced in 6. Long-term vocal cord paralysis followed 2 of 9 surgeries performed with sharp dissection and followed one of 22 surgeries in which dissection was performed with monopolar microneedle electrocautery. CONCLUSIONS Vagus nerve stimulator coils can be removed from the vagus nerve, via monopolar microneedle electrocautery, and the same site reused for immediate reimplantation with relative safety.
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Affiliation(s)
- Ramesh Kumar
- Department of Neurosurgery of the University of Colorado School of Medicine, Aurora, Colorado, USA; Denver Health and Hospitals, Denver, Colorado, USA; University Hospital Colorado, Aurora, Colorado, USA; Children's Hospital Colorado, Aurora, Colorado, USA.
| | - Ken R Winston
- Department of Neurosurgery of the University of Colorado School of Medicine, Aurora, Colorado, USA; Denver Health and Hospitals, Denver, Colorado, USA; University Hospital Colorado, Aurora, Colorado, USA; Children's Hospital Colorado, Aurora, Colorado, USA
| | - Zach Folzenlogen
- Department of Neurosurgery of the University of Colorado School of Medicine, Aurora, Colorado, USA; University Hospital Colorado, Aurora, Colorado, USA; Children's Hospital Colorado, Aurora, Colorado, USA
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Vagus nerve stimulation lead removal or replacement: surgical technique, institutional experience, and literature overview. Acta Neurochir (Wien) 2015; 157:1917-24. [PMID: 26335753 PMCID: PMC4604497 DOI: 10.1007/s00701-015-2547-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/07/2015] [Indexed: 11/18/2022]
Abstract
Background With the growing use of vagus nerve stimulation (VNS) as a treatment for refractory epilepsy, there is a growing demand for complete removal or replacement of the VNS system. We evaluate the safety and efficacy of complete removal or replacement of the VNS system and provide an extensive description of our surgical technique. Methods We retrospectively reviewed our patient registry for all VNS surgeries performed between January 2007 (the year of our first complete removal) and May 2014. In order to assess patient satisfaction, a written questionnaire was sent to patients or their caregivers. Additionally, we reviewed all literature on this topic. Results The VNS system was completely removed in 22 patients and completely replaced in 13 patients. There were no incomplete removals. Revision surgery was complicated by a small laceration of the jugular vein in two patients and by vocal cord paralysis in one patient. Seizure frequency was unaltered or improved after revision surgery. Electrode-related side effects all improved after revision surgery. Twenty-one studies reported a total of 131 patients in whom the VNS system was completely removed. In 95 patients, the system was subsequently replaced. The most frequently reported side effect was vocal cord paresis, which occurred in four patients. Conclusions Complete removal or replacement of the VNS system including lead and coils is feasible and safe. Although initial results seem promising, further research and longer follow-up are needed to assess whether lead replacement may affect VNS effectiveness. Electronic supplementary material The online version of this article (doi:10.1007/s00701-015-2547-9) contains supplementary material, which is available to authorized users.
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Waseem H, Raffa SJ, Benbadis SR, Vale FL. Lead revision surgery for vagus nerve stimulation in epilepsy: outcomes and efficacy. Epilepsy Behav 2014; 31:110-3. [PMID: 24389021 DOI: 10.1016/j.yebeh.2013.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 11/29/2013] [Accepted: 12/02/2013] [Indexed: 11/17/2022]
Abstract
We present, to our knowledge, the first published analysis of vagus nerve stimulation (VNS) lead revisions to incorporate quality of life, clinical response, and antiepileptic drug (AED) burden in postrevision clinical outcomes. Ten patients were followed and had no postoperative complications. Seven patients had improvement in quality of life, and three experienced no change. Eight patients noted a restoration of clinical response comparable with initial VNS implantation. Seven patients reported 30-60% improvement in seizure reduction, two experienced >60%, and one noted <30%. Six patients had no change in AED burden. Vagus nerve stimulation lead revision should be considered a safe option for patients with VNS lead failure and medically intractable epilepsy.
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Affiliation(s)
- Hena Waseem
- Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, 2 Tampa General Circle, USF Health, 7th Floor, Tampa, FL 33606, USA.
| | - Scott J Raffa
- Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, 2 Tampa General Circle, USF Health, 7th Floor, Tampa, FL 33606, USA.
| | - Selim R Benbadis
- Department of Neurology, Morsani College of Medicine, University of South Florida, 2 Tampa General Circle, USF Health, 6th Floor, Tampa, FL 33606, USA.
| | - Fernando L Vale
- Department of Neurosurgery and Brain Repair, Morsani College of Medicine, University of South Florida, 2 Tampa General Circle, USF Health, 7th Floor, Tampa, FL 33606, USA.
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Complications of vagal nerve stimulation for drug-resistant epilepsy: a single center longitudinal study of 143 patients. Seizure 2013; 22:827-33. [PMID: 23867218 DOI: 10.1016/j.seizure.2013.06.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 06/19/2013] [Accepted: 06/25/2013] [Indexed: 01/07/2023] Open
Abstract
PURPOSE To longitudinally study surgical and hardware complications to vagal nerve stimulation (VNS) treatment in patients with drug-resistant epilepsy. METHODS In a longitudinal retrospective study, we analyzed surgical and hardware complications in 143 patients (81 men and 62 women) who between 1994 and 2010 underwent implantation of a VNS-device for drug-resistant epilepsy. The mean follow-up time was 62 ± 46 months and the total number of patient years 738. RESULTS 251 procedures were performed on 143 patients. 16.8% of the patients were afflicted by complications related to surgery and 16.8% suffered from hardware malfunctions. Surgical complications were: superficial infection in 3.5%, deep infection needing explantation in 3.5%, vocal cord palsy in 5.6%, which persisted in at least 0.7% for over one year, and other complications in 5.6%. Hardware-related complications were: lead fracture in 11.9% of patients, disconnection in 2.8%, spontaneous turn-off in 1.4% and stimulator malfunction in 1.4%. We noted a tendency to different survival times between the two most commonly used lead models as well as a tendency to increased infection rate with increasing number of stimulator replacements. CONCLUSION In this series we report on surgical and hardware complications from our 16 years of experience with VNS treatment. Infection following insertion of the VNS device and vocal cord palsy due to damage to the vagus nerve are the most serious complications related to the surgery. Avoiding unnecessary reoperations in order to reduce the appearances of these complications are of great importance. It is therefore essential to minimize technical malfunctions that will lead to additional surgery. Further studies are needed to evaluate the possible superiority of the modified leads.
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Giulioni M, Martinoni M, Naldi I, Bisulli F, Pozzati E, Tinuper P. Successful removal and reimplant of vagal nerve stimulator device after 10 years. Ann Indian Acad Neurol 2012; 15:128-9. [PMID: 22566727 PMCID: PMC3345590 DOI: 10.4103/0972-2327.94997] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 11/05/2010] [Indexed: 11/15/2022] Open
Abstract
The number of implanted vagal nerve stimulators is growing and the need for removal or revision of the devices will become even more frequent. A significant concern about Vagus Nerve Stimulation (VNS) therapy is the presence of the spiral stimulating electrodes, wrapped around the nerve, once treatment is considered ineffective or is no longer desired. Our purpose is to demonstrate the feasibility of complete removal and replacement of the vagal nerve stimulator electrodes using microsurgical technique even after a long period, without damaging the nerve. We attempted removal and replacement of spiral stimulating electrodes from a patient who received a 10-year long VNS therapy for drug-resistant epilepsy. Our results indicate that the spiral electrodes may be safely removed from the vagus nerve, even after several years. The reversibility of lead implantation may enhance the attractiveness of VNS therapy. Furthermore, with a correct microsurgical technique, it is possible to respect the normal anatomy and functionality of vagal nerve and to reimplant a new VNS system with all its components, maintaining the same therapeutic efficacy after many years.
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Affiliation(s)
- Marco Giulioni
- Department of Neurosurgery, Bellaria Hospital, Bologna, Italy
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Lead breakage and vocal cord paralysis following blunt neck trauma in a patient with vagal nerve stimulator. J Neurol Sci 2012; 304:132-5. [PMID: 21397256 DOI: 10.1016/j.jns.2011.02.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 02/10/2011] [Accepted: 02/16/2011] [Indexed: 11/20/2022]
Abstract
Patients with medically intractable seizures who are not candidates for epilepsy surgery are left with few options. Vagal nerve stimulation therapy is often a viable alternative for these patients and can have a positive impact on quality of life. Rarely complications may occur. We report a case of mild blunt neck trauma resulting in VNS malfunction and delayed vocal cord paralysis. A systematic review of the literature on VNS malfunction, self-inflicted injuries, vagal nerve injury, and common side effects including voice changes was performed. Only a handful of relevant publications were found. Symptoms following VNS dysfunction include pain, dyspnea, and dysphonia. These symptoms are usually nonspecific, and in many cases, do not help differentiate from vagal nerve traction, lead breakage, or pulse generator malfunction. In our case, lead fracture and visible traction injury to the left vagus nerve were seen during surgical exploration. The vocal cord function completely recovered after revision of the leads. Prompt medical attention including appropriate diagnostic studies and early surgical exploration is necessary in cases of delayed vocal cord dysfunction and can help prevent long-term complications such as neuroma formation. The authors present a unique case of reversible vocal cord injury from blunt neck trauma leading to left vagus nerve damage.
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Dlouhy BJ, Viljoen SV, Kung DK, Vogel TW, Granner MA, Howard MA, Kawasaki H. Vagus nerve stimulation after lead revision. Neurosurg Focus 2012; 32:E11. [DOI: 10.3171/2012.1.focus11333] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Vagus nerve stimulation (VNS) has demonstrated benefit in patients with medically intractable partial epilepsy. As in other therapies with mechanical devices, hardware failure occurs, most notably within the VNS lead, requiring replacement. However, the spiral-designed lead electrodes wrapped around the vagus nerve are often encased in dense scar tissue hampering dissection and removal. The objective in this study was to characterize VNS lead failure and lead revision surgery and to examine VNS efficacy after placement of a new electrode on the previously used segment of vagus nerve.
Methods
The authors reviewed all VNS lead revisions performed between October 2001 and August 2011 at the University of Iowa Hospitals and Clinics. Twenty-four patients underwent 25 lead revisions. In all cases, the helical electrodes were removed, and a new lead was placed on the previously used segment of vagus nerve. All inpatient and outpatient records of the 25 lead revisions were retrospectively reviewed.
Results
Four cases were second lead revisions, and 21 cases were first lead revisions. The average time to any revision was 5 years (range 1.8–11.1 years), with essentially no difference between a first and second lead revision. The most common reason for a revision was intrinsic lead failure resulting in high impedance (64%), and the most common symptom was increased seizure frequency (72%). The average duration of surgery for the initial implantation in the 15 patients whose VNS system was initially implanted at the authors' institution was much shorter (94 minutes) than the average duration of lead revision surgery (173 minutes). However, there was a significant trend toward shorter surgical times as more revision surgeries were performed. Sixteen of the 25 cases of lead revision were followed up for more than 3 months. In 15 of these 16 cases, the revision was as effective as the previous VNS lead. In most of these cases, both the severity and frequency of seizures were decreased to levels similar to those following the previous implantation procedure. Only 1 complication occurred, and there were no postoperative infections.
Conclusions
Lead revision surgery involving the placement of a new electrode at the previously used segment of vagus nerve is effective at decreasing the seizure burden to an extent similar to that obtained following the initial VNS implantation. Even with multiple lead revisions, patients can obtain VNS efficacy similar to that following the initial lead implantation. There is a learning curve with revision surgery, and overall the duration of surgery is longer than for the initial implantation. Note, however, that complications and infection are rare.
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Affiliation(s)
| | | | | | | | - Mark A. Granner
- 2Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
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O'Neill BR, Wilberger JE. Revision of vagal nerve stimulator electrodes through a posterior cervical triangle approach: technical note. Neurosurgery 2011; 67:457-60. [PMID: 21099572 DOI: 10.1227/neu.0b013e3181f825a3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND We describe an approach to vagal nerve stimulator (VNS) lead replacement through the posterior cervical triangle. Scar around the structures of the carotid sheath is avoided and new leads are placed on a pristine section of the vagus nerve proximal to the original site. CLINICAL PRESENTATION Skin incision from the implantation surgery is incorporated and extended to allow access to the posterior border of the sternocleidomastoid muscle (SCM). Dissection proceeds along the posterior border of the SCM. The SCM and jugular vein are retracted anterior to expose a fresh segment of the vagal nerve immediately superficial to the carotid artery and proximal to the original electrode site. Once the nerve is adequately exposed, electrode placement proceeds in the standard fashion. Dysfunctional electrodes are left in place, and the lead wire is cut as near the electrodes as can be easily accessed. Three patients have undergone lead revision with this approach. Lead placement was successful and free from complications in all cases. CONCLUSION The posterior cervical triangle approach provides a virgin dissection plane for VNS revision.
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Affiliation(s)
- Brent R O'Neill
- Division of Pediatric Neurosurgery, The Children's Hospital, University of Colorado, Aurora, Colorado, USA.
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Abstract
Patients with medically intractable epilepsy who are not candidates for epilepsy surgery could benefit from neurostimulation. At this time, vagus nerve stimulation (VNS) therapy is the only Food and Drug Administation-approved neurostimulation modality; it has been shown to be efficacious and just as well tolerated in children and adolescents as in adults. Notwithstanding the initial cost of the device and implantation, VNS therapy has been shown to be a cost-effective treatment, reducing direct medical costs and improving health-related quality of life measures. Deep brain stimulation of various brain regions, especially the anterior nucleus of the thalamus and responsive neurostimulation, also appear effective but are not yet approved for clinical use. Repetitive transcranial magnetic stimulation, which is also in early clinical development, is promising and could become available in the not too distant future.
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Agarwal G, Wilfong AA, Edmonds JL. Surgical Revision of Vagus Nerve Stimulation Electrodes in Children. Otolaryngol Head Neck Surg 2010; 144:123-4. [DOI: 10.1177/0194599810390896] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Use of vagus nerve stimulation (VNS) has increased in the past decade, resulting in frequent revision cases for device failure. The authors report their series of children who underwent reimplantation of the VNS device after removal of old electrodes and leads. Patients with medically refractory seizures who underwent revision of VNS electrodes were included (n = 23). Twenty patients had high lead impedance and underwent removal of the device and replacement of the VNS electrodes during the same procedure. In 3 patients, electrodes and the device had been removed previously at an outside institution because of infection. None of the patients experienced any major complications. Mean operative time was 2.3 ± 0.9 hours. The reimplanted device worked well in all patients, and seizure control was similar to or better than that reported with the previous device. Thus, implantation of the VNS electrodes is reversible, and it appears that the electrodes can be removed or replaced safely if the device is not functioning properly.
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Affiliation(s)
- Garima Agarwal
- University of Texas Medical School at Houston, Houston, Texas, USA
| | | | - Joseph L. Edmonds
- University of Texas Medical School at Houston, Houston, Texas, USA
- Baylor College of Medicine, Houston, Texas, USA
- Texas Children’s Hospital, Houston, Texas, USA
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Spuck S, Tronnier V, Orosz I, Schönweiler R, Sepehrnia A, Nowak G, Sperner J. Operative and Technical Complications of Vagus Nerve Stimulator Implantation. Oper Neurosurg (Hagerstown) 2010; 67:489-94. [DOI: 10.1227/neu.0b013e3181f88867] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
ABSTRACT
BACKGROUND:
The treatment of refractory epilepsy by vagus nerve stimulation (VNS) is a well-established therapy option for patients not suitable for epilepsy surgery and therapy refractory depressions.
OBJECTIVE:
To analyze surgical and technical complications after implantation of left-sided VNS in patients with therapy-refractory epilepsy and depression.
METHODS:
One hundred five patients receiving a VNS or VNS-related operations (n = 118) from 1999 to 2008 were investigated retrospectively.
RESULTS:
At the time of operation, 84 patients were younger than 18 years, with a mean age of 10.5 years. Twenty (19%) patients had technical problems or complications. In 6 (5.7%) patients these problems were caused by the operation. The device was removed in 8 cases. The range of surgically and technically induced complications included electrode fractures, early and late onset of deep wound infections, transient vocal cord palsy, cardiac arrhythmia under test stimulation, electrode malfunction, and posttraumatic dysfunction of the stimulator.
CONCLUSION:
VNS therapy is combined with a wide spread of possible complications. Technical problems are to be expected, including electrode fracture, dislocation, and generator malfunction. The major complication in younger patients is the electrode fracture, which might be induced by growth during adolescence. Surgically induced complications of VNS implantation are comparably low. Cardiac symptoms and recurrent nerve palsy need to be taken into consideration.
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Affiliation(s)
- Sebastian Spuck
- Department of Neurosurgery, Medical University of Luebeck, Luebeck, Germany
| | - Volker Tronnier
- Department of Neurosurgery, Medical University of Luebeck, Luebeck, Germany
| | - Iren Orosz
- Department of Neuropediatrics, Medical University of Luebeck, Luebeck, Germany
| | - Rainer Schönweiler
- Department of Phoniatrics and Pediatric Audiology, Medical University of Luebeck, Luebeck, Germany
| | | | - Georg Nowak
- Department of Neurosurgery, Medical University of Luebeck, Luebeck, Germany
| | - Jürgen Sperner
- Department of Neuropediatrics, Medical University of Luebeck, Luebeck, Germany
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Ng WH, Donner E, Go C, Abou-Hamden A, Rutka JT. Revision of vagal nerve stimulation (VNS) electrodes: review and report on use of ultra-sharp monopolar tip. Childs Nerv Syst 2010; 26:1081-4. [PMID: 20225085 DOI: 10.1007/s00381-010-1121-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 02/22/2010] [Indexed: 11/30/2022]
Abstract
PURPOSE As a result of the increasingly popularity of vagal nerve stimulation (VNS) for intractable seizures, neurosurgeons not uncommonly encounter cases which require electrode revision. We examine our experience of VNS revision and reports the use of the ultra-sharp monopolar tip for safe dissection and removal of the electrode from the vagus nerve. METHODS A retrospective review was performed from January 2000 to Dec 2009 reviewed eight cases of VNS revision. RESULTS The indications for VNS revision were device malfunction manifesting with increased seizures or increased impedance of the device and infection. The time from initial VNS implantation to revision ranged from 6 to 108 months (mean: 38 months). The entire VNS electrode system, was removed in seven cases and the helical coils were left in-situ in one case who did not derive any benefit from VNS and it was deemed unnecessary to subject the patient to the additional risk of vagal nerve injury. One case had dislodgement of the lower two coils and three cases had dense scarring to the vagus nerve causing high impedance and malfunction. The other three cases demonstrated no fibrotic scar tissue between the helical coils and the vagus nerve. Four cases had replacement of new VNS system but the case of infected VNS stimulator was not replaced as there was no benefit from the device. CONCLUSION VNS revision is normally performed in cases of device malfunction or infection and can be safely performed using a combination of ultra-sharp monopolar coagulation and sharp dissection.
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Affiliation(s)
- Wai Hoe Ng
- Division of Neurosurgery, Suite 1503, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, ON, Canada
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Ortler M, Unterhofer C, Dobesberger J, Haberlandt E, Trinka E. Complete removal of vagus nerve stimulator generator and electrodes. J Neurosurg Pediatr 2010; 5:191-4. [PMID: 20121370 DOI: 10.3171/2009.9.peds0810] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Vagus nerve stimulation has become widely used in the palliative treatment of refractory epilepsy. Removal of a vagus nerve stimulator may be desirable or even necessary due to lack of efficacy, intolerable side effects, signs of infection, or failure of the device. Unless the lead or the helical electrodes are defective, only the generator is explanted and the electrodes are usually left behind for fear of damaging nerve or surrounding structures. The authors review their experience with complete removal of the stimulating electrodes and pacemaker-like generator device in 9 consecutive patients, 3 of whom were children. Using microsurgical techniques, the authors were able to completely remove the stimulator, including electrodes in all patients. All nerves remained morphologically intact. One case of temporary and one of permanent clinically silent ipsilateral vocal cord paresis were observed.
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Affiliation(s)
- Martin Ortler
- Clinical Department of Neurosurgery, Innsbruck Medical University, Innsbruck, Austria.
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Boon P, Raedt R, de Herdt V, Wyckhuys T, Vonck K. Electrical stimulation for the treatment of epilepsy. Neurotherapeutics 2009; 6:218-27. [PMID: 19332313 PMCID: PMC5084197 DOI: 10.1016/j.nurt.2008.12.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Accepted: 12/31/2008] [Indexed: 01/24/2023] Open
Abstract
Despite the advent of new pharmacological treatments and the high success rate of many surgical treatments for epilepsy, a substantial number of patients either do not become seizure-free or they experience major adverse events (or both). Neurostimulation-based treatments have gained considerable interest in the last decade. Vagus nerve stimulation (VNS) is an alternative treatment for patients with medically refractory epilepsy, who are unsuitable candidates for conventional epilepsy surgery, or who have had such surgery without optimal outcome. Although responder identification studies are lacking, long-term VNS studies show response rates between 40% and 50% and long-term seizure freedom in 5% to 10% of patients. Surgical complications and perioperative morbidity are low. Research into the mechanism of action of VNS has revealed a crucial role for the thalamus and cortical areas that are important in the epileptogenic process. Acute deep brain stimulation (DBS) in various thalamic nuclei and medial temporal lobe structures has recently been shown to be efficacious in small pilot studies. There is little evidence-based information on rational targets and stimulation parameters. Amygdalohippocampal DBS has yielded a significant decrease of seizure counts and interictal EEG abnormalities during long-term follow-up. Data from pilot studies suggest that chronic DBS for epilepsy may be a feasible, effective, and safe procedure. Further trials with larger patient populations and with controlled, randomized, and closed-loop designs should now be initiated. Further progress in understanding the mechanism of action of DBS for epilepsy is a necessary step to making this therapy more efficacious and established.
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Affiliation(s)
- Paul Boon
- Reference Center for Refractory Epilepsy and Laboratory for Clinical and Experimental Neurophysiology (LCEN), Department of Neurology, Ghent University Hospital, Ghent, Belgium.
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Vonck K, De Herdt V, Boon P. Vagal nerve stimulation--a 15-year survey of an established treatment modality in epilepsy surgery. Adv Tech Stand Neurosurg 2009; 34:111-46. [PMID: 19368083 DOI: 10.1007/978-3-211-78741-0_5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Neurostimulation is an emerging treatment for neurological diseases. Electrical stimulation of the tenth cranial nerve or vagus nerve stimulation (VNS) has become a valuable option in the therapeutic armamentarium for patients with refractory epilepsy. It is indicated in patients with refractory epilepsy who are unsuitable candidates for epilepsy surgery or who have had insufficient benefit from such a treatment. Vagus nerve stimulation reduces seizure frequency with > 50% in 1/3 of patients and has a mild side effects profile. Research to elucidate the mechanism of action of vagus nerve stimulation has shown that effective stimulation in humans is primarily mediated by afferent vagal A- and B-fibers. Crucial brainstem and intracranial structures include the locus coeruleus, the nucleus of the solitary tract, the thalamus and limbic structures. Neurotransmitters playing a role may involve the major inhibitory neurotransmitter GABA but also serotoninergic and adrenergic systems. This manuscript reviews the clinical studies investigating efficacy and side effects in patients and the experimental studies aiming to elucidate the mechanims of action.
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Affiliation(s)
- K Vonck
- Department of Neurology, Ghent University Hospital, Gent, Belgium
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Cozzens JW. Surgical Technique for Vagus Nerve Stimulator Implantation. Neuromodulation 2009. [DOI: 10.1016/b978-0-12-374248-3.00092-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Stimulation chronique du nerf vague dans le traitement del’épilepsie pharmacorésistante. Neurochirurgie 2008; 54:332-9. [DOI: 10.1016/j.neuchi.2008.02.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Accepted: 02/26/2008] [Indexed: 11/19/2022]
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García-March G, Sánchez-Ledesma M, Broseta J. Estimulación eléctrica vagal en el tratamiento de la epilepsia rebelde. Situación actual. Neurocirugia (Astur) 2008. [DOI: 10.1016/s1130-1473(08)70208-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Ishizuka K, Oaklander AL, Chiocca EA. A retrospective analysis of reasons for reoperation following initially successful peripheral nerve stimulation. J Neurosurg 2007; 106:388-90. [PMID: 17367060 DOI: 10.3171/jns.2007.106.3.388] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The authors investigated the causes for surgical reexploration in patients with complex regional pain syndrome Type II who received initial relief of pain from implantation of a peripheral nerve stimulator (PNS).
Methods
The authors reviewed the charts of 11 consecutive patients who underwent a total of 27 PNS-related operations at one institution. Duration of follow up ranged from 5 days to more than 24 months. Of 11 patients who received PNS implants, seven (64%) required one or more additional surgeries to relocate the PNS because initial pain relief following stimulation was lost and not restored by changing pulse generator settings. Loss of analgesia was attributed to migration of the sutured electrode strip paddle (nine [33%] of 27 surgeries), infection (four [15%] of 27), and the need for placement in an alternative location (three [11%] of 27).
Conclusions
Although infection is attributable to surgical technique, most complications requiring repeated surgery (nine [33%] of 27) are caused by equipment design. Changes in PNS design or in implantation technique might substantially reduce the need for reoperation after PNS implantation.
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Affiliation(s)
- Kelly Ishizuka
- Department of Neurological Surgery, The Ohio State University Medical Center, Columbus, Ohio 43210, USA
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Sakas DE, Korfias S, Nicholson CL, Panourias IG, Georgakoulias N, Gatzonis S, Jenkins A. Vagus nerve stimulation for intractable epilepsy: outcome in two series combining 90 patients. ACTA NEUROCHIRURGICA. SUPPLEMENT 2007; 97:287-91. [PMID: 17691315 DOI: 10.1007/978-3-211-33081-4_32] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Vagus nerve stimulation (VNS) is the most widely used non-pharmacological treatment for medically intractable epilepsy and has been in clinical use for over a decade. It is indicated in patients who are refractory to medical treatment or who experience intolerable side effects, and who are not candidates for resective surgery. VNS used in the acute setting can both abort seizures and have an acute prophylactic effect. This effect increases over time in chronic treatment to a maximum at around 18 months. The evidence base supporting the efficacy of VNS is strong, but its exact mechanism of action remains unknown. A vagus nerve stimulator consists of two electrodes embedded in a silastic helix that is wrapped around the cervical vagus nerve. The stimulator is always implanted on the left vagus nerve in order to reduce the likelihood of adverse cardiac effects. The electrodes are connected to an implantable pulse generator (IPG) which is positioned subcutaneously either below the clavicle or in the axilla. The IPG is programmed by computer via a wand placed on the skin over it. In addition, extra pulses of stimulation triggered by a hand-held magnet may help to prevent or abort seizures. VNS is essentially a palliative treatment and the number of patients who become seizure free is very small. A significant reduction in the frequency and severity of seizures can be expected in about one third of patients and efficacy tends to improve with time. Vagus nerve stimulation is well tolerated and has few significant side effects. We describe our experience on the use of VNS on drug-resistant epilepsy in 90 patients treated in two departments (in Athens, Greece and Newcastle, England).
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Affiliation(s)
- D E Sakas
- Department of Neurosurgery, University of Athens, Evangelismos General Hospital, Athens, Greece.
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Labiner DM, Ahern GL. Vagus nerve stimulation therapy in depression and epilepsy: therapeutic parameter settings. Acta Neurol Scand 2007; 115:23-33. [PMID: 17156262 DOI: 10.1111/j.1600-0404.2006.00732.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vagus nerve stimulation (VNS) therapy is an effective adjunctive treatment for chronic or recurrent treatment-resistant depression in adults, and for pharmacoresistant epilepsy in adults and adolescents. VNS therapy is administered through an implanted pulse generator that delivers programmed electrical pulses through an implanted lead to the left vagus nerve. Programmable pulse parameters include output current, frequency, pulse width, and ON/OFF times. Within a range of typical values, individual patients respond best to different combinations of parameter settings. The physician must identify the optimum settings for each patient while balancing the goals of maximizing efficacy, minimizing side effects, and preserving battery life. Output current is gradually increased from 0.25 mA to the maximum tolerable level (maximum, 3.5 mA); typical therapeutic settings range from 1.0 to 1.5 mA. Greater output current is associated with increased side effects, including voice alteration, cough, a feeling of throat tightening, and dyspnea. Frequency is typically programmed at 20 Hz in depression and 30 Hz in epilepsy. Pulse width is typically 250 or 500 micros. The recommended initial ON time is 30 s, followed by 5 min OFF; OFF time > ON time is recommended. As with pharmacotherapy, VNS therapy must be adjusted in a gradual, systematic fashion to individualize therapy for each patient.
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Affiliation(s)
- David M Labiner
- Department of Neurology, University of Arizona Health Sciences Center, Tucson, AZ, USA.
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Rychlicki F, Zamponi N, Cesaroni E, Corpaci L, Trignani R, Ducati A, Scerrati M. Complications of vagal nerve stimulation for epilepsy in children. Neurosurg Rev 2006; 29:103-7. [PMID: 16518639 DOI: 10.1007/s10143-005-0005-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Revised: 06/10/2005] [Accepted: 08/29/2005] [Indexed: 12/26/2022]
Abstract
Vagal nerve stimulation (VNS) is a surgical option to treat drug-resistant epilepsy. A few side effects have been described, mainly as anecdotal reports. We analysed our material concerning a juvenile population to identify the most common and most important complications, discussing them with the literature. Thirty-six patients were studied (18 months-18 years old). The children were assessed before the VNS implant and 3, 6, 12, 24 and 36 months after surgery. The mean follow-up was 30 months. Four patients required a second surgery: two for changing the device 3 years after implant; one for revision of an imperfect implant; one for removing a non-functioning device. In one patient a transient vocal cord paralysis was observed. Hoarseness was the main complaint (38.8%). More infrequent was mild sleep apnoea (8.3%), sternocleidomastoid muscle spasm, drooling and snoring in one patient each. Skin scars were reported with a different frequency according to the surgical technique. At variance with the literature reports, we did not observe infections. Side effects of VNS can be minimised, but not avoided completely, with a correct technical procedure, which in turn depends upon a thorough knowledge of vagus nerve anatomy.
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Affiliation(s)
- F Rychlicki
- Neurosurgical Department, Ospedali Riuniti Umberto I-GM Lancisi-G. Salesi, Università Politecnica delle Marche, Ancona, Italy
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Vassilyadi M, Strawsburg RH. Delayed onset of vocal cord paralysis after explantation of a vagus nerve stimulator in a child. Childs Nerv Syst 2003; 19:261-3. [PMID: 12715196 DOI: 10.1007/s00381-003-0722-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2002] [Revised: 09/25/2002] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Vagus nerve stimulation for the management of intractable seizure disorders is increasingly being used, especially in younger children. Although complications such as infection or vocal cord paralysis are uncommon, some may be unreported. CLINICAL PRESENTATION A 3.5-year-old boy with intractable complex partial and generalized seizures had a left vagus nerve stimulator (VNS) successfully implanted. Two weeks later, the cervical incision showed signs of infection, antibiotics were started, and the VNS generator and leads were explanted. Three weeks later the child's mother noted a change in the voice of her son, as well as increased coughing and gagging. Flexible laryngoscopy identified a left vocal cord paralysis, which eventually resolved after 6 months. CONCLUSION Infection requiring explantation of a VNS is uncommon. The risk is higher in younger children, especially in those who are developmentally delayed. These children may continuously drool, with saliva or food soiling the fresh incision, or even pick at the incision to the point of twisting or even pulling out the electrodes. Less common is a vocal cord paralysis, especially occurring in a delayed fashion.
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Affiliation(s)
- M Vassilyadi
- Division of Neurosurgery and Neurology, Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.
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Abstract
The purpose of this open retrospective study was to analyze the efficacy and tolerability of vagal nerve stimulation (VNS) in a Norwegian cohort of referral patients with refractory epileptic seizures. A total of 47 patients have been assessed after a mean follow-up time of 2.7 years. Mean age was 34.4 years, mean duration of epilepsy was 25.3 years. Forty-two patients (89%) had localization-related epilepsy, 36 patients (77%) had daily seizures. The patients had tried on average 9.5 antiepileptic drugs, and 12 patients (26%) had undergone epilepsy surgery. Sixteen patients (34%) had >50% reduction of seizure frequency with VNS, of which one patient became seizure free. The stimulation was generally well tolerated, but three patients requested the device removed because of troublesome side effects. We conclude that VNS is an efficacious and safe mode of treatment that should be offered to patients with medically and surgically refractory seizures.
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Frost M, Gates J, Helmers SL, Wheless JW, Levisohn P, Tardo C, Conry JA. Vagus nerve stimulation in children with refractory seizures associated with Lennox-Gastaut syndrome. Epilepsia 2001; 42:1148-52. [PMID: 11580762 DOI: 10.1046/j.1528-1157.2001.23900.x] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Vagus nerve stimulation (VNS) is approved for use for refractory partial seizures. Nevertheless, information regarding VNS therapy for special populations, including Lennox-Gastaut syndrome (LGS) is limited. We discuss the effectiveness, tolerability, and safety of VNS therapy in patients with LGS. METHODS A six-center, retrospective study evaluated the effectiveness of VNS therapy in patients with LGS at 3 and 6 months and compared preimplant and postimplant seizure frequency. Adverse effects and quality of life (QOL) were included as secondary measures. RESULTS Fifty patients, median age 13 years, with medically refractory epilepsy, were implanted. Median age at onset of seizures was 1.4 years, and a median of nine anticonvulsants (AEDs) had been tried before implantation. Data-collection forms were designed for retrospectively gathering data on each patient's preimplant history, seizures, implants, device settings, QOL, and adverse events. Median reductions in total seizures were 42% at 1 month, 58.2% at 3 months, and 57.9% at 6 months. The most common adverse events reported were voice alteration and coughing during stimulation. Other uncommon adverse events included increased drooling and behavioral changes. Investigators noted that QOL had improved for some patients in the study. CONCLUSIONS VNS is an effective treatment for medically refractory epilepsy in LGS. This treatment is well tolerated, safe, and may improve QOL.
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Affiliation(s)
- M Frost
- Minnesota Epilepsy Group, P.A., United and Children's Hospitals, St. Paul, Minnesota 55102, USA.
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Abstract
Vagus nerve stimulation (VNS) is a neurophysiological treatment for patients with medically or surgically refractory epilepsy. Since the first human implant in 1989, more than 10 000 patients have been treated with VNS. Two randomized controlled studies have shown a statistically significant decrease in seizure frequency during a 12-week treatment period versus a baseline period when 'high stimulation' mode was compared with 'low stimulation' mode. The efficacy appears to increase over time. In general, one third of the patients show a >50% reduction of seizure frequency; one third show a 30-50% seizure reduction, and one third of patients show no response. Few patients become seizure-free. Side effects during stimulation are mainly voice alteration, coughing, throat paraesthesia and discomfort. When studied on a long-term basis, VNS is an efficacious, safe and cost-effective treatment not only in adults but also in children and the elderly. The precise mechanism of action remains to be elucidated. In recent years much progress has been made through neurophysiological, neuroanatomical, neurochemical and cerebral blood flow studies in animals and patients treated with VNS. Further elucidation of the mechanism of action of VNS may increase its clinical efficacy and our general understanding of some physiopathological aspects of epilepsy. Finally, VNS may become an alternative treatment for other conditions such as depression and pain.
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Affiliation(s)
- P Boon
- Reference Centre for Refractory Epilepsy, Department of Neurology, Ghent University Hospital, Belgium
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Vonck K, Van Laere K, Dedeurwaerdere S, Caemaert J, De Reuck J, Boon P. The mechanism of action of vagus nerve stimulation for refractory epilepsy: the current status. J Clin Neurophysiol 2001; 18:394-401. [PMID: 11709643 DOI: 10.1097/00004691-200109000-00002] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Vagus nerve stimulation (VNS) is a neurophysiologic treatment for patients with medically or surgically refractory epilepsy. Since the first human implant in 1989, more than 10,000 patients have been treated with VNS. The precise mechanism of action remains to be elucidated. Animal experiments with VNS were initially performed to demonstrate efficacy and safety preceding the clinical trials in human patients. Mechanism of action research involving animal experiments can provide essential clues. Animal experiments are often labor-intensive even in the hands of experienced researchers, however, and the results remain only a reflection of the complicated pathophysiologic systems of the human brain. Mechanism of action research in human patients treated with VNS is particularly challenging because of safety concerns, the large number of patients required, and the heterogeneous nature of various small patient series. This study provides an overview of the progress that has been made in the past 10 years through neurophysiologic, neuroanatomic, neurochemical, and cerebral blood flow studies in animals and patients treated with VNS. Further elucidation of the mechanism of action of VNS may increase its clinical efficacy. It may also provide inspiration for the development of new therapeutic modalities for refractory epilepsy.
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Affiliation(s)
- K Vonck
- Epilepsy Monitoring Unit, Department of Neurology, Ghent University Hospital, Ghent, Belgium.
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Ortler M, Luef G, Kofler A, Bauer G, Twerdy K. Deep wound infection after vagus nerve stimulator implantation: treatment without removal of the device. Epilepsia 2001; 42:133-5. [PMID: 11207797 DOI: 10.1046/j.1528-1157.2001.23800.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Effective treatment of deep wound infection without removal of a previously implanted foreign body is difficult. The Neurocybernetic Prosthesis (NCP) System (Cyberonics Inc., Webster, TX, U.S.A.), implanted for vagus nerve stimulation in patients with medically refractory epilepsy, uses coil-like electrodes placed around the left vagus nerve after exposure of the nerve in the carotid sheath. Infection within this compartment endangers the contained structures and makes removal of the system hazardous. We report the case of one patient implanted with the NCP who underwent successful open wound treatment without removal of the system. A 35-year-old man had local signs of wound infection 5 weeks after implantation of a vagus nerve stimulator. Systemic signs of infection were absent. C-reactive protein was slightly elevated, but all other laboratory values were normal. After open wound debridement and thorough rinsing with bacitracin-containing solution, the wound was packed with 3% iodoformized gauze. The NCP was left in place. Systemic antibiotic therapy with fosfomycin and cefmenoxim was started. Cultures confirmed an infection with Staphylococcus aureus. The wound was rinsed daily with 3% hydrogen peroxide solution and 5% saline until cultures were sterile and granulation tissue started to fill the wound. Delayed primary closure was performed 2 weeks later. Wound healing was accomplished without removal of the device. No signs of recurrent infection were observed during a follow-up of 1 year. Open wound treatment without removal of the implanted vagus nerve stimulator is feasible in cases of deep cervical wound infection and can be an alternative if removal of the device appears hazardous.
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Affiliation(s)
- M Ortler
- Universitätskliniken für Neurochirurgie and Neurologie, 35, Innsbruck 6020, Austria
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