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Lee G, Ray E, Yoon HJ, Genovese S, Choi YS, Lee MK, Şahin S, Yan Y, Ahn HY, Bandodkar AJ, Kim J, Park M, Ryu H, Kwak SS, Jung YH, Odabas A, Khandpur U, Ray WZ, MacEwan MR, Rogers JA. A bioresorbable peripheral nerve stimulator for electronic pain block. SCIENCE ADVANCES 2022; 8:eabp9169. [PMID: 36197971 PMCID: PMC9534494 DOI: 10.1126/sciadv.abp9169] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 08/18/2022] [Indexed: 05/31/2023]
Abstract
Local electrical stimulation of peripheral nerves can block the propagation of action potentials, as an attractive alternative to pharmacological agents for the treatment of acute pain. Traditional hardware for such purposes, however, involves interfaces that can damage nerve tissue and, when used for temporary pain relief, that impose costs and risks due to requirements for surgical extraction after a period of need. Here, we introduce a bioresorbable nerve stimulator that enables electrical nerve block and associated pain mitigation without these drawbacks. This platform combines a collection of bioresorbable materials in architectures that support stable blocking with minimal adverse mechanical, electrical, or biochemical effects. Optimized designs ensure that the device disappears harmlessly in the body after a desired period of use. Studies in live animal models illustrate capabilities for complete nerve block and other key features of the technology. In certain clinically relevant scenarios, such approaches may reduce or eliminate the need for use of highly addictive drugs such as opioids.
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Affiliation(s)
- Geumbee Lee
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
- Precision Biology Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Emily Ray
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Hong-Joon Yoon
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Sabrina Genovese
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Yeon Sik Choi
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Min-Kyu Lee
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Samet Şahin
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
- Department of Bioengineering, Bilecik Şeyh Edebali University, 11230 Bilecik, Merkez/Bilecik, Turkey
| | - Ying Yan
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Hak-Young Ahn
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Amay J. Bandodkar
- Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, NC 27606, USA
- Center for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST), North Carolina State University, Raleigh, NC 27606, USA
| | - Joohee Kim
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Minsu Park
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Hanjun Ryu
- Department of Advanced Materials Engineering, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Sung Soo Kwak
- Center for Bionics, Biomedical Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Yei Hwan Jung
- Department of Electronic Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Arman Odabas
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
- Department of Internal Medicine, Stanford University Medical Center, Stanford, CA 94305, USA
| | - Umang Khandpur
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Wilson Z. Ray
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Matthew R. MacEwan
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - John A. Rogers
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Muzquiz MI, Mintch L, Horn MR, Alhawwash A, Bashirullah R, Carr M, Schild JH, Yoshida K. A Reversible Low Frequency Alternating Current Nerve Conduction Block Applied to Mammalian Autonomic Nerves. SENSORS 2021; 21:s21134521. [PMID: 34282758 PMCID: PMC8271881 DOI: 10.3390/s21134521] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/23/2021] [Accepted: 06/28/2021] [Indexed: 11/30/2022]
Abstract
Electrical stimulation can be used to modulate activity within the nervous system in one of two modes: (1) Activation, where activity is added to the neural signalling pathways, or (2) Block, where activity in the nerve is reduced or eliminated. In principle, electrical nerve conduction block has many attractive properties compared to pharmaceutical or surgical interventions. These include reversibility, localization, and tunability for nerve caliber and type. However, methods to effect electrical nerve block are relatively new. Some methods can have associated drawbacks, such as the need for large currents, the production of irreversible chemical byproducts, and onset responses. These can lead to irreversible nerve damage or undesirable neural responses. In the present study we describe a novel low frequency alternating current blocking waveform (LFACb) and measure its efficacy to reversibly block the bradycardic effect elicited by vagal stimulation in anaesthetised rat model. The waveform is a sinusoidal, zero mean(charge balanced), current waveform presented at 1 Hz to bipolar electrodes. Standard pulse stimulation was delivered through Pt-Black coated PtIr bipolar hook electrodes to evoke bradycardia. The conditioning LFAC waveform was presented either through a set of CorTec® bipolar cuff electrodes with Amplicoat® coated Pt contacts, or a second set of Pt Black coated PtIr hook electrodes. The conditioning electrodes were placed caudal to the pulse stimulation hook electrodes. Block of bradycardic effect was assessed by quantifying changes in heart rate during the stimulation stages of LFAC alone, LFAC-and-vagal, and vagal alone. The LFAC achieved 86.2±11.1% and 84.3±4.6% block using hook (N = 7) and cuff (N = 5) electrodes, respectively, at current levels less than 110 µAp (current to peak). The potential across the LFAC delivering electrodes were continuously monitored to verify that the blocking effect was immediately reversed upon discontinuing the LFAC. Thus, LFACb produced a high degree of nerve block at current levels comparable to pulse stimulation amplitudes to activate nerves, resulting in a measurable functional change of a biomarker in the mammalian nervous system.
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Affiliation(s)
- M. Ivette Muzquiz
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (M.I.M.); (M.R.H.); (J.H.S.)
| | | | - M. Ryne Horn
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (M.I.M.); (M.R.H.); (J.H.S.)
| | - Awadh Alhawwash
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA;
- Biomedical Technology Department, King Saud University, Riyadh 11362, Saudi Arabia
| | - Rizwan Bashirullah
- Galvani Bioelectronics Inc., Collegeville, PA 19426, USA; (R.B.); (M.C.)
| | - Michael Carr
- Galvani Bioelectronics Inc., Collegeville, PA 19426, USA; (R.B.); (M.C.)
| | - John H. Schild
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (M.I.M.); (M.R.H.); (J.H.S.)
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA;
| | - Ken Yoshida
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (M.I.M.); (M.R.H.); (J.H.S.)
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA;
- Correspondence:
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Muzquiz MI, Richardson L, Vetter C, Smolik M, Alhawwash A, Goodwill A, Bashirullah R, Carr M, Yoshida K. In-vivo application of low frequency alternating currents on porcine cervical vagus nerve evokes reversible nerve conduction block. Bioelectron Med 2021; 7:9. [PMID: 34187586 PMCID: PMC8243469 DOI: 10.1186/s42234-021-00072-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This paper describes a method to reversibly block nerve conduction through direct application of a 1 Hz sinusoidal current waveform delivered through a bipolar nerve cuff electrode. This low frequency alternating current (LFAC) waveform was previously shown to reversibly block the effects of vagal pulse stimulation evoked bradycardia in-vivo in the anaesthetised rat model (Mintch et al. 2019). The present work measured the effectiveness of LFAC block on larger caliber myelinated vagal afferent fibers in human sized nerve bundles projecting to changes in breathing rate mediated by the Hering-Breuer (HB) reflex in anaesthetized domestic swine (n=5). METHODS Two bipolar cuff electrodes were implanted unilaterally to the left cervical vagus nerve, which was crushed caudal to the electrodes to eliminate cardiac effects. A tripolar recording cuff electrode was placed rostral to the bipolar stimulating electrodes on the same nerve to measure changes in the compound nerve action potentials (CNAP) elicited by the vagal pulse stimulation and conditioned by the LFAC waveform. Standard pulse stimulation was applied at a sufficient level to induce a reduction in breathing rate through the HB reflex. If unblocked, the HB reflex would cause breathing to slow down and potentially halt completely. Block was quantified by the ability of LFAC to reduce the effect of the HB reflex by monitoring the respiration rate during LFAC alone, LFAC and vagal stimulation, and vagal stimulation alone. RESULTS LFAC achieved 87.2 ±8.8% block (n=5) at current levels of 1.1 ±0.3 mAp (current to peak), which was well within the water window of the working electrode. CNAP showed changes that directly correlated to the effectiveness of LFAC block, which manifested itself as the slowing and amplitude reduction of components of the CNAP. CONCLUSION These novel findings suggest that LFAC is a potential alternative or complementary method to other electrical blocking techniques in clinical applications.
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Affiliation(s)
- Maria Ivette Muzquiz
- Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, USA.
| | - Lindsay Richardson
- Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, USA
| | - Christian Vetter
- Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, USA
| | - Macallister Smolik
- Department of Biology, Indiana University - Purdue University Indianapolis, Indianapolis, USA
| | - Awadh Alhawwash
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, USA.,Biomedical Technology Department, King Saud University, Riyadh, Saudi Arabia
| | - Adam Goodwill
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, USA
| | | | - Michael Carr
- Galvani Bioelectronics, Glaxo Smith Kline, GSK, King of Prussia, USA
| | - Ken Yoshida
- Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, USA.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, USA
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Dewberry LS, Dru A, Gravenstine M, Nguyen B, Anderson J, Vaziri S, Hoh D, Allen K, Otto KJ. Partial high frequency nerve block decreases neuropathic signaling following chronic sciatic nerve constriction injury. J Neural Eng 2020; 18. [PMID: 33027782 DOI: 10.1088/1741-2552/abbf03] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 10/07/2020] [Indexed: 11/11/2022]
Abstract
OBJECTIVE High frequency (HF) block can quickly and reversibly stop nerve conduction. We hypothesized HF block at the sciatic nerve would minimize nociception by preventing neuropathic signals from reaching the central nervous system. APPROACH Lewis rats were implanted with a constriction cuff and a distal cuff electrode around their right sciatic nerve. Tactile sensitivity was evaluated using the 50% paw withdrawal threshold determined using Chaplan's method for von Frey monofilaments. Over the course of 49 days, the 50% paw withdrawal threshold was measured 1) before HF block, 2) during HF block (50 kHz, 3 Vpp), and 3) after HF block. Gait was observed and scored before and during block. At end point, HF block efficacy was directly evaluated using additional cuff electrodes to elicit and record compound neural action potentials across the HF blocking cuff. MAIN RESULTS At days 7 and 14 days post-operation, tactile sensitivity was significantly lower during HF block compared to before and after block (p < 0.005). Additionally, an increase in gait disability was not visually observed during HF block. SIGNIFICANCE HF block can reduce tactile sensitivity in a limb with a neuropthic injury in a rapidly reversible fashion.
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Affiliation(s)
- Lauren Savannah Dewberry
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Biomedical Sciences Building JG56, Gainesville, FL 32611-6131, Gainesville, Florida, 32611-7011, UNITED STATES
| | - Alexander Dru
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, Florida, UNITED STATES
| | - Maxwell Gravenstine
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, UNITED STATES
| | - Brian Nguyen
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, UNITED STATES
| | - James Anderson
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, UNITED STATES
| | - Sasha Vaziri
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, Florida, UNITED STATES
| | - Daniel Hoh
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, Florida, UNITED STATES
| | - Kyle Allen
- Department of Biomedical Engineering, University of Florida, P.O. Box 116131, USA, Gainesville, Florida, 32611-6131, UNITED STATES
| | - Kevin J Otto
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, 32611-7011, UNITED STATES
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Avendano-Coy J, Serrano-Munoz D, Taylor J, Goicoechea-Garcia C, Gomez-Soriano J. Peripheral Nerve Conduction Block by High-Frequency Alternating Currents: A Systematic Review. IEEE Trans Neural Syst Rehabil Eng 2018; 26:1131-1140. [DOI: 10.1109/tnsre.2018.2833141] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bhadra N, Vrabec TL, Bhadra N, Kilgore KL. Reversible conduction block in peripheral nerve using electrical waveforms. BIOELECTRONICS IN MEDICINE 2018; 1:39-54. [PMID: 29480897 PMCID: PMC5811084 DOI: 10.2217/bem-2017-0004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/15/2017] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Electrical nerve block uses electrical waveforms to block action potential propagation. MATERIALS & METHODS Two key features that distinguish electrical nerve block from other nonelectrical means of nerve block: block occurs instantly, typically within 1 s; and block is fully and rapidly reversible (within seconds). RESULTS Approaches for achieving electrical nerve block are reviewed, including kilohertz frequency alternating current and charge-balanced polarizing current. We conclude with a discussion of the future directions of electrical nerve block. CONCLUSION Electrical nerve block is an emerging technique that has many significant advantages over other methods of nerve block. This field is still in its infancy, but a significant expansion in the clinical application of this technique is expected in the coming years.
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Affiliation(s)
- Niloy Bhadra
- Department of Physical Medicine & Rehabilitation, MetroHealth Medical Center, Cleveland, OH 44109, USA
| | - Tina L Vrabec
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Narendra Bhadra
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kevin L Kilgore
- Department of Orthopaedics, MetroHealth Medical Center & Case Western Reserve University, Cleveland, OH 44109, USA
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA
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Kilgore KL, Bhadra N. Reversible nerve conduction block using kilohertz frequency alternating current. Neuromodulation 2013; 17:242-54; discussion 254-5. [PMID: 23924075 DOI: 10.1111/ner.12100] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/04/2013] [Accepted: 06/21/2013] [Indexed: 01/25/2023]
Abstract
OBJECTIVES The features and clinical applications of balanced-charge kilohertz frequency alternating currents (KHFAC) are reviewed. Preclinical studies of KHFAC block have demonstrated that it can produce an extremely rapid and reversible block of nerve conduction. Recent systematic analysis and experimentation utilizing KHFAC block have resulted in a significant increase in interest in KHFAC block, both scientifically and clinically. MATERIALS AND METHODS We review the history and characteristics of KHFAC block, the methods used to investigate this type of block, the experimental evaluation of block, and the electrical parameters and electrode designs needed to achieve successful block. We then analyze the existing clinical applications of high-frequency currents, comparing the early results with the known features of KHFAC block. RESULTS Although many features of KHFAC block have been characterized, there is still much that is unknown regarding the response of neural structures to rapidly fluctuating electrical fields. The clinical reports to date do not provide sufficient information to properly evaluate the mechanisms that result in successful or unsuccessful treatment. CONCLUSIONS KHFAC nerve block has significant potential as a means of controlling nerve activity for the purpose of treating disease. However, early clinical studies in the use of high-frequency currents for the treatment of pain have not been designed to elucidate mechanisms or allow direct comparisons to preclinical data. We strongly encourage the careful reporting of the parameters utilized in these clinical studies, as well as the development of outcome measures that could illuminate the mechanisms of this modality.
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Affiliation(s)
- Kevin L Kilgore
- Department of Orthopaedics, MetroHealth Medical Center, Cleveland, OH, USA; Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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Ackermann DM, Bhadra N, Gerges M, Thomas PJ. Dynamics and sensitivity analysis of high-frequency conduction block. J Neural Eng 2011; 8:065007. [PMID: 22056338 PMCID: PMC3417344 DOI: 10.1088/1741-2560/8/6/065007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The local delivery of extracellular high-frequency stimulation (HFS) has been shown to be a fast acting and quickly reversible method of blocking neural conduction and is currently being pursued for several clinical indications. However, the mechanism for this type of nerve block remains unclear. In this study, we investigate two hypotheses: (1) depolarizing currents promote conduction block via inactivation of sodium channels and (2) the gating dynamics of the fast sodium channel are the primary determinate of minimal blocking frequency. Hypothesis 1 was investigated using a combined modeling and experimental study to investigate the effect of depolarizing and hyperpolarizing currents on high-frequency block. The results of the modeling study show that both depolarizing and hyperpolarizing currents play an important role in conduction block and that the conductance to each of three ionic currents increases relative to resting values during HFS. However, depolarizing currents were found to promote the blocking effect, and hyperpolarizing currents were found to diminish the blocking effect. Inward sodium currents were larger than the sum of the outward currents, resulting in a net depolarization of the nodal membrane. Our experimental results support these findings and closely match results from the equivalent modeling scenario: intra-peritoneal administration of the persistent sodium channel blocker ranolazine resulted in an increase in the amplitude of HFS required to produce conduction block in rats, confirming that depolarizing currents promote the conduction block phenomenon. Hypothesis 2 was investigated using a spectral analysis of the channel gating variables in a single-fiber axon model. The results of this study suggested a relationship between the dynamical properties of specific ion channel gating elements and the contributions of corresponding conductances to block onset. Specifically, we show that the dynamics of the fast sodium inactivation gate are too slow to track the high-frequency changes in membrane potential during HFS, and that the behavior of the fast sodium current was dominated by the low-frequency depolarization of the membrane. As a result, in the blocked state, only 5.4% of nodal sodium channels were found to be in the activatable state in the node closest to the blocking electrode, resulting in conduction block. Moreover, we find that the corner frequency for the persistent sodium channel activation gate corresponds to the frequency below which high-frequency stimuli of arbitrary amplitude are incapable of inducing conduction block.
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Affiliation(s)
| | - Niloy Bhadra
- Dept. of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- MetroHealth Medical Center, Cleveland, OH, USA
| | | | - Peter J. Thomas
- Depts. of Mathematics, Biology and Cognitive Science, Case Western Reserve University, Cleveland, OH, USA
- Dept. of Neuroscience, Oberlin College, Oberlin, OH, USA
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Ackermann DM, Ethier C, Foldes EL, Oby ER, Tyler D, Bauman M, Bhadra N, Miller L, Kilgore KL. Electrical conduction block in large nerves: high-frequency current delivery in the nonhuman primate. Muscle Nerve 2011; 43:897-9. [PMID: 21607972 PMCID: PMC3101373 DOI: 10.1002/mus.22037] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent studies have made significant progress toward the clinical implementation of high-frequency conduction block (HFB) of peripheral nerves. However, these studies were performed in small nerves, and questions remain regarding the nature of HFB in large-diameter nerves. This study in nonhuman primates shows reliable conduction block in large-diameter nerves (up to 4.1 mm) with relatively low-threshold current amplitude and only moderate nerve discharge prior to the onset of block.
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Affiliation(s)
- D Michael Ackermann
- Cleveland FES Center, Hamman 601, 2500 MetroHealth Drive, Cleveland, Ohio 44109, USA.
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Ackermann DM, Bhadra N, Foldes EL, Wang XF, Kilgore KL. Effect of nerve cuff electrode geometry on onset response firing in high-frequency nerve conduction block. IEEE Trans Neural Syst Rehabil Eng 2010; 18:658-65. [PMID: 20813650 PMCID: PMC3467702 DOI: 10.1109/tnsre.2010.2071882] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The delivery of high-frequency alternating currents has been shown to produce a focal and reversible conduction block in whole nerve and is a potential therapeutic option for various diseases and disorders involving pathological or undesired neurological activity. However, delivery of high-frequency alternating current to a nerve produces a finite burst of neuronal firing, called the onset response, before the nerve is blocked. Reduction or elimination of the onset response is very important to moving this type of nerve block into clinical applications since the onset response is likely to result in undesired muscle contraction and pain. This paper describes a study of the effect of nerve cuff electrode geometry (specifically, bipolar contact separation distance), and waveform amplitude on the magnitude and duration of the onset response. Electrode geometry and waveform amplitude were both found to affect these measures. The magnitude and duration of the onset response showed a monotonic relationship with bipolar separation distance and amplitude. The duration of the onset response varied by as much as 820% on average for combinations of different electrode geometries and waveform amplitudes. Bipolar electrodes with a contact separation distance of 0.5 mm resulted in the briefest onset response on average. Furthermore, the data presented in this study provide some insight into a biophysical explanation for the onset response. These data suggest that the onset response consists of two different phases: one phase which is responsive to experimental variables such as electrode geometry and waveform amplitude, and one which is not and appears to be inherent to the transition to the blocked state. This study has implications for nerve block electrode and stimulation parameter selection for clinical therapy systems and basic neurophysiology studies.
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Affiliation(s)
- D Michael Ackermann
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
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Gerges M, Foldes EL, Ackermann DM, Bhadra N, Bhadra N, Kilgore KL. Frequency- and amplitude-transitioned waveforms mitigate the onset response in high-frequency nerve block. J Neural Eng 2010; 7:066003. [PMID: 20966536 DOI: 10.1088/1741-2560/7/6/066003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
High-frequency alternating currents (HFAC) have proven to be a reversible and rapid method of blocking peripheral nerve conduction, holding promise for treatment of disorders associated with undesirable neuronal activity. The delivery of HFAC is characterized by a transient period of neural firing at its inception, termed the 'onset response'. The onset response is minimized for higher frequencies and higher amplitudes, but requires larger currents. However, the complete block can be maintained at lower frequencies and amplitudes, using lower currents. In this in vivo study on whole mammalian peripheral nerves, we demonstrate a method to minimize the onset response by initiating the block using a stimulation paradigm with a high frequency and large amplitude, and then transitioning to a low-frequency and low-amplitude waveform, reducing the currents required to maintain the conduction block. In five of six animals, it was possible to transition from a 30 kHz to a 10 kHz waveform without inducing any transient neural firing. The minimum transition time was 0.03 s. Transition activity was minimized or eliminated with longer transition times. The results of this study show that this method is feasible for achieving a nerve block with minimal onset responses and current amplitude requirements.
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Conduction block of whole nerve without onset firing using combined high frequency and direct current. Med Biol Eng Comput 2010; 49:241-51. [PMID: 20890673 DOI: 10.1007/s11517-010-0679-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 09/11/2010] [Indexed: 10/19/2022]
Abstract
This study investigates a novel technique for blocking a nerve using a combination of direct and high frequency alternating currents (HFAC). HFAC can produce a fast acting and reversible conduction block, but cause intense firing at the onset of current delivery. We hypothesized that a direct current (DC) block could be used for a very brief period in combination with HFAC to block the onset firing, and thus establish a nerve conduction block which does not transmit onset response firing to an end organ. Experiments were performed in rats to evaluate (1) nerve response to anodic and cathodic DC of various amplitudes, (2) degree of nerve activation to ramped DC, (3) a method of blocking onset firing generated by high frequency block with DC, and (4) prolonged non-electrical conduction failure caused by DC delivery. The results showed that cathodic currents produced complete block of the sciatic nerve with a mean block threshold amplitude of 1.73 mA. Ramped DC waveforms allowed for conduction block without nerve activation; however, down ramps were more reliable than up ramps. The degree of nerve activity was found to have a non-monotonic relationship with up ramp time. Block of the onset response resulting from 40 kHz current using DC was achieved in each of the six animals in which it was attempted; however, DC was found to produce a prolonged conduction failure that likely resulted from nerve damage.
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