1
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Madden LR, Graham RD, Lempka SF, Bruns TM. Multiformity of extracellular microelectrode recordings from Aδ neurons in the dorsal root ganglia: a computational modeling study. J Neurophysiol 2024; 131:261-277. [PMID: 38169334 PMCID: PMC11305647 DOI: 10.1152/jn.00385.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/18/2023] [Accepted: 01/02/2024] [Indexed: 01/05/2024] Open
Abstract
Microelectrodes serve as a fundamental tool in electrophysiology research throughout the nervous system, providing a means of exploring neural function with a high resolution of neural firing information. We constructed a hybrid computational model using the finite element method and multicompartment cable models to explore factors that contribute to extracellular voltage waveforms that are produced by sensory pseudounipolar neurons, specifically smaller A-type neurons, and that are recorded by microelectrodes in dorsal root ganglia. The finite element method model included a dorsal root ganglion, surrounding tissues, and a planar microelectrode array. We built a multicompartment neuron model with multiple trajectories of the glomerular initial segment found in many A-type sensory neurons. Our model replicated both the somatic intracellular voltage profile of Aδ low-threshold mechanoreceptor neurons and the unique extracellular voltage waveform shapes that are observed in experimental settings. Results from this model indicated that tortuous glomerular initial segment geometries can introduce distinct multiphasic properties into a neuron's recorded waveform. Our model also demonstrated how recording location relative to specific microanatomical components of these neurons, and recording distance from these components, can contribute to additional changes in the multiphasic characteristics and peak-to-peak voltage amplitude of the waveform. This knowledge may provide context for research employing microelectrode recordings of pseudounipolar neurons in sensory ganglia, including functional mapping and closed-loop neuromodulation. Furthermore, our simulations gave insight into the neurophysiology of pseudounipolar neurons by demonstrating how the glomerular initial segment aids in increasing the resistance of the stem axon and mitigating rebounding somatic action potentials.NEW & NOTEWORTHY We built a computational model of sensory neurons in the dorsal root ganglia to investigate factors that influence the extracellular waveforms recorded by microelectrodes. Our model demonstrates how the unique structure of these neurons can lead to diverse and often multiphasic waveform profiles depending on the location of the recording contact relative to microanatomical neural components. Our model also provides insight into the neurophysiological function of axon glomeruli that are often present in these neurons.
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Affiliation(s)
- Lauren R Madden
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States
- Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, United States
| | - Robert D Graham
- Department of Anesthesiology, Washington University, St. Louis, Missouri, United States
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States
- Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, United States
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Tim M Bruns
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States
- Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan, United States
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2
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Giannotti A, Musco S, Miragliotta V, Lazzarini G, Pirone A, Briganti A, Verardo C, Bernini F, Del Popolo G, Micera S. Swine Pudendal Nerve as a Model for Neuromodulation Studies to Restore Lower Urinary Tract Dysfunction. Int J Mol Sci 2024; 25:855. [PMID: 38255927 PMCID: PMC10815560 DOI: 10.3390/ijms25020855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Lower urinary tract dysfunction, such as incontinence or urinary retention, is one of the leading consequences of neurological diseases. This significantly impacts the quality of life for those affected, with implications extending not only to humans but also to clinical veterinary care. Having motor and sensory fibers, the pudendal nerve is an optimal candidate for neuromodulation therapies using bidirectional intraneural prostheses, paving the way towards the restoration of a more physiological urination cycle: bladder state can be detected from recorded neural signals, then an electrical current can be injected to the nerve based on the real-time need of the bladder. To develop such prostheses and investigate this novel approach, animal studies are still required since the morphology of the target nerve is fundamental to optimizing the prosthesis design. This study aims to describe the porcine pudendal nerve as a model for neuromodulation studies aiming at restoring lower urinary tract dysfunction. Five male farm pigs were involved in the study. First, a surgical procedure to access the porcine pudendal nerve without muscle resection was developed. Then, an intraneural interface was implanted to confirm the presence of fibers innervating the external urethral sphincter by measuring its electromyographic activity. Finally, the morphophysiology of the porcine pudendal nerve at the level of surgical exposure was described by using histological and immunohistochemical characterization. This analysis confirmed the fasciculate nature of the nerve and the presence of mixed fibers with a spatial and functional organization. These achievements pave the way for further pudendal neuromodulation studies by using a clinically relevant animal model with the potential for translating the findings into clinical applications.
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Affiliation(s)
- Alice Giannotti
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant’Anna, 56127 Pisa, Italy; (A.G.); (C.V.)
| | - Stefania Musco
- Neuro-Urology Department, Careggi University Hospital, 50134 Firenze, Italy; (S.M.); (G.D.P.)
| | - Vincenzo Miragliotta
- Department of Veterinary Sciences, University of Pisa, 56124 Pisa, Italy; (V.M.); (G.L.); (A.P.); (A.B.)
| | - Giulia Lazzarini
- Department of Veterinary Sciences, University of Pisa, 56124 Pisa, Italy; (V.M.); (G.L.); (A.P.); (A.B.)
| | - Andrea Pirone
- Department of Veterinary Sciences, University of Pisa, 56124 Pisa, Italy; (V.M.); (G.L.); (A.P.); (A.B.)
| | - Angela Briganti
- Department of Veterinary Sciences, University of Pisa, 56124 Pisa, Italy; (V.M.); (G.L.); (A.P.); (A.B.)
| | - Claudio Verardo
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant’Anna, 56127 Pisa, Italy; (A.G.); (C.V.)
| | - Fabio Bernini
- BioMedLab, Scuola Superiore Sant’Anna, 56127 Pisa, Italy;
| | - Giulio Del Popolo
- Neuro-Urology Department, Careggi University Hospital, 50134 Firenze, Italy; (S.M.); (G.D.P.)
| | - Silvestro Micera
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant’Anna, 56127 Pisa, Italy; (A.G.); (C.V.)
- Bertarelli Foundation Chair in Translational NeuroEngineering, Center for Neuroprosthetics and Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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3
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Giannotti A, Lo Vecchio S, Musco S, Pollina L, Vallone F, Strauss I, Paggi V, Bernini F, Gabisonia K, Carlucci L, Lenzi C, Pirone A, Giannessi E, Miragliotta V, Lacour S, Del Popolo G, Moccia S, Micera S. Decoding bladder state from pudendal intraneural signals in pigs. APL Bioeng 2023; 7:046101. [PMID: 37811476 PMCID: PMC10558243 DOI: 10.1063/5.0156484] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 09/11/2023] [Indexed: 10/10/2023] Open
Abstract
Neuroprosthetic devices used for the treatment of lower urinary tract dysfunction, such as incontinence or urinary retention, apply a pre-set continuous, open-loop stimulation paradigm, which can cause voiding dysfunctions due to neural adaptation. In the literature, conditional, closed-loop stimulation paradigms have been shown to increase bladder capacity and voiding efficacy compared to continuous stimulation. Current limitations to the implementation of the closed-loop stimulation paradigm include the lack of robust and real-time decoding strategies for the bladder fullness state. We recorded intraneural pudendal nerve signals in five anesthetized pigs. Three bladder-filling states, corresponding to empty, full, and micturition, were decoded using the Random Forest classifier. The decoding algorithm showed a mean balanced accuracy above 86.67% among the three classes for all five animals. Our approach could represent an important step toward the implementation of an adaptive real-time closed-loop stimulation protocol for pudendal nerve modulation, paving the way for the design of an assisted-as-needed neuroprosthesis.
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Affiliation(s)
- A. Giannotti
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - S. Lo Vecchio
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - S. Musco
- Neuro-Urology Department, Careggi University Hospital, Firenze, Italy
| | - L. Pollina
- Bertarelli Foundation Chair in Translational NeuroEngineering, Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - F. Vallone
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - I. Strauss
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering–IMTEK, IMBIT//NeuroProbes BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany
| | - V. Paggi
- Bertarelli Foundation Chair in Microengineering and Bioengineering, Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - F. Bernini
- BioMedLab, Scuola Superiore Sant'Anna, Pisa, Italy
| | - K. Gabisonia
- BioMedLab, Scuola Superiore Sant'Anna, Pisa, Italy
| | - L. Carlucci
- BioMedLab, Scuola Superiore Sant'Anna, Pisa, Italy
| | - C. Lenzi
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | - A. Pirone
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | - E. Giannessi
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | - V. Miragliotta
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | - S. Lacour
- Bertarelli Foundation Chair in Microengineering and Bioengineering, Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - G. Del Popolo
- Neuro-Urology Department, Careggi University Hospital, Firenze, Italy
| | - S. Moccia
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - S. Micera
- Author to whom correspondence should be addressed:
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4
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Steins H, Mierzejewski M, Brauns L, Stumpf A, Kohler A, Heusel G, Corna A, Herrmann T, Jones PD, Zeck G, von Metzen R, Stieglitz T. A flexible protruding microelectrode array for neural interfacing in bioelectronic medicine. MICROSYSTEMS & NANOENGINEERING 2022; 8:131. [PMID: 36568135 PMCID: PMC9772315 DOI: 10.1038/s41378-022-00466-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/23/2022] [Accepted: 07/07/2022] [Indexed: 05/31/2023]
Abstract
Recording neural signals from delicate autonomic nerves is a challenging task that requires the development of a low-invasive neural interface with highly selective, micrometer-sized electrodes. This paper reports on the development of a three-dimensional (3D) protruding thin-film microelectrode array (MEA), which is intended to be used for recording low-amplitude neural signals from pelvic nervous structures by penetrating the nerves transversely to reduce the distance to the axons. Cylindrical gold pillars (Ø 20 or 50 µm, ~60 µm height) were fabricated on a micromachined polyimide substrate in an electroplating process. Their sidewalls were insulated with parylene C, and their tips were optionally modified by wet etching and/or the application of a titanium nitride (TiN) coating. The microelectrodes modified by these combined techniques exhibited low impedances (~7 kΩ at 1 kHz for Ø 50 µm microelectrode with the exposed surface area of ~5000 µm²) and low intrinsic noise levels. Their functionalities were evaluated in an ex vivo pilot study with mouse retinae, in which spontaneous neuronal spikes were recorded with amplitudes of up to 66 µV. This novel process strategy for fabricating flexible, 3D neural interfaces with low-impedance microelectrodes has the potential to selectively record neural signals from not only delicate structures such as retinal cells but also autonomic nerves with improved signal quality to study neural circuits and develop stimulation strategies in bioelectronic medicine, e.g., for the control of vital digestive functions.
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Affiliation(s)
- Helen Steins
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Michael Mierzejewski
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Lisa Brauns
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Angelika Stumpf
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Alina Kohler
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Gerhard Heusel
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Andrea Corna
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Institute of Biomedical Electronics, TU Wien, Vienna, Austria
| | - Thoralf Herrmann
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Peter D. Jones
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Günther Zeck
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Institute of Biomedical Electronics, TU Wien, Vienna, Austria
| | - Rene von Metzen
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Thomas Stieglitz
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
- Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
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5
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Sperry ZJ, Na K, Jun J, Madden LR, Socha A, Yoon E, Seymour JP, Bruns TM. High-density neural recordings from feline sacral dorsal root ganglia with thin-film array. J Neural Eng 2021; 18. [PMID: 33545709 DOI: 10.1088/1741-2552/abe398] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 02/05/2021] [Indexed: 12/26/2022]
Abstract
Objective. Dorsal root ganglia (DRG) are promising sites for recording sensory activity. Current technologies for DRG recording are stiff and typically do not have sufficient site density for high-fidelity neural data techniques.Approach. In acute experiments, we demonstrate single-unit neural recordings in sacral DRG of anesthetized felines using a 4.5µm thick, high-density flexible polyimide microelectrode array with 60 sites and 30-40µm site spacing. We delivered arrays into DRG with ultrananocrystalline diamond shuttles designed for high stiffness affording a smaller footprint. We recorded neural activity during sensory activation, including cutaneous brushing and bladder filling, as well as during electrical stimulation of the pudendal nerve and anal sphincter. We used specialized neural signal analysis software to sort densely packed neural signals.Main results. We successfully delivered arrays in five of six experiments and recorded single-unit sensory activity in four experiments. The median neural signal amplitude was 55μV peak-to-peak and the maximum unique units recorded at one array position was 260, with 157 driven by sensory or electrical stimulation. In one experiment, we used the neural analysis software to track eight sorted single units as the array was retracted ∼500μm.Significance. This study is the first demonstration of ultrathin, flexible, high-density electronics delivered into DRG, with capabilities for recording and tracking sensory information that are a significant improvement over conventional DRG interfaces.
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Affiliation(s)
- Zachariah J Sperry
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Kyounghwan Na
- Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States of America
| | - James Jun
- Flatiron Institute, Simons Foundation, New York City, NY, United States of America
| | - Lauren R Madden
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Alec Socha
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America.,Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States of America
| | - Eusik Yoon
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States of America.,Center for Nanomedicine, Institute for Basic Science (IBS) and Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul, Republic of Korea
| | - John P Seymour
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States of America.,University of Texas Health Science Center, Department of Neurosurgery, Houston, TX, United States of America.,Department of Electrical and Computer Engineering, Rice University, Houston, TX, United States of America
| | - Tim M Bruns
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
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6
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Yousefpour A, Erfanian A. A general framework for automatic closed-loop control of bladder voiding induced by intraspinal microstimulation in rats. Sci Rep 2021; 11:3424. [PMID: 33564019 PMCID: PMC7873267 DOI: 10.1038/s41598-021-82933-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/27/2021] [Indexed: 12/13/2022] Open
Abstract
Individuals with spinal cord injury or neurological disorders have problems in voiding function due to the dyssynergic contraction of the urethral sphincter. Here, we introduce a closed-loop control of intraspinal microstimulation (ISMS) for efficient bladder voiding. The strategy is based on asynchronous two-electrode ISMS with combined pulse-amplitude and pulse-frequency modulation without requiring rhizotomy, neurotomy, or high-frequency blocking. Intermittent stimulation is alternately applied to the two electrodes that are implanted in the S2 lateral ventral horn and S1 dorsal gray commissure, to excite the bladder motoneurons and to inhibit the urethral sphincter motoneurons. Asynchronous stimulation would lead to reduce the net electric field and to maximize the selective stimulation. The proposed closed-loop system attains a highly voiding efficiency of 77.2-100%, with an average of 91.28 ± 8.4%. This work represents a promising approach to the development of a natural and robust motor neuroprosthesis device for restoring bladder functions.
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Affiliation(s)
- Abolhasan Yousefpour
- Department of Biomedical Engineering, School of Electrical Engineering, Iran Neural Technology Research Center, Iran University of Science and Technology (IUST), Tehran, Iran
| | - Abbas Erfanian
- Department of Biomedical Engineering, School of Electrical Engineering, Iran Neural Technology Research Center, Iran University of Science and Technology (IUST), Tehran, Iran.
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7
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Jiman AA, Ratze DC, Welle EJ, Patel PR, Richie JM, Bottorff EC, Seymour JP, Chestek CA, Bruns TM. Multi-channel intraneural vagus nerve recordings with a novel high-density carbon fiber microelectrode array. Sci Rep 2020; 10:15501. [PMID: 32968177 PMCID: PMC7511947 DOI: 10.1038/s41598-020-72512-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/27/2020] [Indexed: 01/03/2023] Open
Abstract
Autonomic nerves convey essential neural signals that regulate vital body functions. Recording clearly distinctive physiological neural signals from autonomic nerves will help develop new treatments for restoring regulatory functions. However, this is very challenging due to the small nature of autonomic nerves and the low-amplitude signals from their small axons. We developed a multi-channel, high-density, intraneural carbon fiber microelectrode array (CFMA) with ultra-small electrodes (8-9 µm in diameter, 150-250 µm in length) for recording physiological action potentials from small autonomic nerves. In this study, we inserted CFMA with up to 16 recording carbon fibers in the cervical vagus nerve of 22 isoflurane-anesthetized rats. We recorded action potentials with peak-to-peak amplitudes of 15.1-91.7 µV and signal-to-noise ratios of 2.0-8.3 on multiple carbon fibers per experiment, determined conduction velocities of some vagal signals in the afferent (0.7-4.4 m/s) and efferent (0.7-8.8 m/s) directions, and monitored firing rate changes in breathing and blood glucose modulated conditions. Overall, these experiments demonstrated that CFMA is a novel interface for in-vivo intraneural action potential recordings. This work is considerable progress towards the comprehensive understanding of physiological neural signaling in vital regulatory functions controlled by autonomic nerves.
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Affiliation(s)
- Ahmad A Jiman
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - David C Ratze
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Elissa J Welle
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Paras R Patel
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Julianna M Richie
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Elizabeth C Bottorff
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - John P Seymour
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
- Department of Neurosurgery, University of Texas Health Science Center, Houston, TX, USA
| | - Cynthia A Chestek
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Tim M Bruns
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA.
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.
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8
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Estimation of Bladder Pressure and Volume from the Neural Activity of Lumbosacral Dorsal Horn Using a Long-Short-Term-Memory-based Deep Neural Network. Sci Rep 2019; 9:18128. [PMID: 31792247 PMCID: PMC6889392 DOI: 10.1038/s41598-019-54144-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/09/2019] [Indexed: 12/30/2022] Open
Abstract
In this paper, we propose a deep recurrent neural network (DRNN) for the estimation of bladder pressure and volume from neural activity recorded directly from spinal cord gray matter neurons. The model was based on the Long Short-Term Memory (LSTM) architecture, which has emerged as a general and effective model for capturing long-term temporal dependencies with good generalization performance. In this way, training the network with the data recorded from one rat could lead to estimating the bladder status of different rats. We combined modeling of spiking and local field potential (LFP) activity into a unified framework to estimate the pressure and volume of the bladder. Moreover, we investigated the effect of two-electrode recording on decoding performance. The results show that the two-electrode recordings significantly improve the decoding performance compared to single-electrode recordings. The proposed framework could estimate bladder pressure and volume with an average normalized root-mean-squared (NRMS) error of 14.9 ± 4.8% and 19.7 ± 4.7% and a correlation coefficient (CC) of 83.2 ± 3.2% and 74.2 ± 6.2%, respectively. This work represents a promising approach to the real-time estimation of bladder pressure/volume in the closed-loop control of bladder function using functional electrical stimulation.
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9
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A review for the peripheral nerve interface designer. J Neurosci Methods 2019; 332:108523. [PMID: 31743684 DOI: 10.1016/j.jneumeth.2019.108523] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 12/11/2022]
Abstract
Informational density and relative accessibility of the peripheral nervous system make it an attractive site for therapeutic intervention. Electrode-based electrophysiological interfaces with peripheral nerves have been under development since the 1960s and, for several applications, have seen widespread clinical implementation. However, many applications require a combination of neural target resolution and stability which has thus far eluded existing peripheral nerve interfaces (PNIs). With the goal of aiding PNI designers in development of devices that meet the demands of next-generation applications, this review seeks to collect and present practical considerations and best practices which emerge from the literature, including both lessons learned during early PNI development and recent ideas. Fundamental and practical principles guiding PNI design are reviewed, followed by an updated and critical account of existing PNI designs and strategies. Finally, a brief survey of in vitro and in vivo PNI characterization methods is presented.
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10
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Zhang T, Yu J, Huang Z, Wang G, Zhang R. Electroacupuncture improves neurogenic bladder dysfunction through activation of NGF/TrkA signaling in a rat model. J Cell Biochem 2018; 120:9900-9905. [PMID: 30592331 DOI: 10.1002/jcb.28272] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 11/19/2018] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To observe the effect of electroacupuncture on the morphological change of the bladder tissue and the protein expression levels of NGF, TrkA, p-TrkA, AKT, and p-AKT in the bladder tissue of rats with neurogenic bladder after suprasacral spinal cord injury and to preliminarily explore its partial mechanism of action. METHODS Eighty female Sprague-Dawley rats were randomly divided into blank group, model group, electroacupuncture group, model/siNGF group, and electroacupuncture/siNGF group according to random number table method with 16 rats in each group. Eighty Neurogenic bladder models after suprasacral spinal cord injury were established by adopting a modified spinal cord transection method. Electroacupuncture intervention was conducted on the 19th day after modeling. The bladder function was detected by bladder weight, urine output, serum BUN, and urine protein. After treatment for 7 consecutive days, the rats were killed and the bladder tissues were removed rapidly for microscopic observation of morphological change after hematoxylin and eosin stain and for determination of the protein expression levels of NGF, TrkA, p-TrkA, AKT, and p-AKT via Western blot analysis. The transcription of NGF was measured by reverse-transcription polymerase chain reaction. RESULTS After treatment, compared with the blank group, the bladder weight of model and electroacupuncture groups were significantly increased (P < 0.05). Compared with the model group, the bladder weight of the electroacupuncture group was decreased (P > 0.05). Compared with the blank group, the urine output of the model group was increased ( P < 0.05). Compared with the blank group, the urine output of the electroacupuncture group was increased ( P > 0.05). Compared with the blank group, the serum BUN of the model group was increased ( P < 0.05). Compared with the blank group, the serum BUN of the electroacupuncture group was increased ( P > 0.05). Compared with the blank group, the urine protein of the model group was increased ( P < 0.05). Compared with the blank group, the urine protein of the electroacupuncture group was increased ( P > 0.05). The expression of NGF, p-TrkA, and p-AKT in the model and electroacupuncture groups was obviously higher than that in the blank group ( P < 0.05). The expression of NGF, p-TrkA, and p-AKT in the electroacupuncture group was higher than that in the model group. The expression of TrkA and AKT were unchanged in blank, model, and electroacupuncture groups ( P > 0.05). After tail vein injection with siNGF lentivirus, the expression of NGF in the model/siNGF group and electroacupuncture/siNGF group was significantly decreased ( P < 0.05). And the protein level of p-AKT and p-TrkA was significantly lower than that of the model and electroacupuncture groups ( P < 0.05). CONCLUSION Sacral electroacupuncture therapy can improve the expression of both NGF/TrkA signaling and AKT signaling in the local nerve of the damaged spinal cord, inhibit apoptosis of the damaged spinal cord, protect nerve cells, and promote the recovery of the damaged nerve. At the same time, electroacupuncture can promote the coordination of micturition reflex and improve neurogenic bladder function after the spinal cord injury.
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Affiliation(s)
- Tong Zhang
- Department of Rehabilitation, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jiafeng Yu
- Department of Rehabilitation, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zongqiang Huang
- Department of Rehabilitation, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Gang Wang
- Department of Rehabilitation, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Runhe Zhang
- Department of Rehabilitation, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Byun D, Cho SJ, Lee BH, Min J, Lee JH, Kim S. Recording nerve signals in canine sciatic nerves with a flexible penetrating microelectrode array. J Neural Eng 2018; 14:046023. [PMID: 28612758 DOI: 10.1088/1741-2552/aa7493] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Previously, we presented the fabrication and characterization of a flexible penetrating microelectrode array (FPMA) as a neural interface device. In the present study, we aim to prove the feasibility of the developed FPMA as a chronic intrafascicular recording tool for peripheral applications. APPROACH For recording from the peripheral nerves of medium-sized animals, the FPMA was integrated with an interconnection cable and other parts that were designed to fit canine sciatic nerves. The uniformity of tip exposure and in vitro electrochemical properties of the electrodes were characterized. The capability of the device to acquire in vivo electrophysiological signals was evaluated by implanting the FPMA assembly in canine sciatic nerves acutely as well as chronically for 4 weeks. We also examined the histology of implanted tissues to evaluate the damage caused by the device. MAIN RESULTS Throughout recording sessions, we observed successful multi-channel recordings (up to 73% of viable electrode channels) of evoked afferent and spontaneous nerve unit spikes with high signal quality (SNR > 4.9). Also, minor influences of the device implantation on the morphology of nerve tissues were found. SIGNIFICANCE The presented results demonstrate the viability of the developed FPMA device in the peripheral nerves of medium-sized animals, thereby bringing us a step closer to human applications. Furthermore, the obtained data provide a driving force toward a further study for device improvements to be used as a bidirectional neural interface in humans.
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Affiliation(s)
- Donghak Byun
- School of Mechanical Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
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12
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Zhen G, Chen H, Tsai SY, Zhang J, Chen T, Jia X. Long-term feasibility and biocompatibility of directly microsurgically implanted intrafascicular electrodes in free roaming rabbits. J Biomed Mater Res B Appl Biomater 2018; 107:435-444. [PMID: 29675920 DOI: 10.1002/jbm.b.34135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 02/22/2018] [Accepted: 03/23/2018] [Indexed: 11/08/2022]
Abstract
Novel neural interfaces capable of reliably capturing electrical signals are crucial for the development of prostheses. Longitudinal intrafascicular electrodes (LIFEs) have been proposed as a promising technology, and their feasibility and biocompatibility need to be investigated for long-term implantation. In this study, custom-designed 95%Pt-5%Ir intrafascicular electrodes were implanted into the sciatic nerves of 14 rabbits using our novel direct microsurgical technique. The biocompatibility and their ability to record electrophysiological signals were serially investigated up to 9 months after implantation. Nerve tissues were examined using light and transmitted electron microscopy, and axon diameters were quantified, evaluated over time, and compared with sham-control (N = 4). Selective stimulation and stable recording properties of electrical signals were achieved by intrafascicular electrodes along the experimental period. While electrophysiological signal amplitude decreased by as early as 1 month after implantation (p < 0.05), the signal strength recovered to baseline levels by 3-5 months (p > 0.05). Axon diameter results showed a similar trend of initial decline (10.8% reduction, p < 0.01) followed by gradual recovery by 6 months (p > 0.05). Microstructural and ultrastructural analysis revealed modest tissue damage at the implantation site after implantation with gradual normalization over time. Intrafascicular electrodes implanted with direct microsurgical techniques demonstrated good biocompatibility and have great potential for long-term implantation and electrophysiological recordings. Though subtle tissue damage impaired ability to capture electrophysiological signals in the first 2 months, this damage gradually normalized after 3 months, and was fully normalized by 6 months. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 435-444, 2019.
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Affiliation(s)
- Gehua Zhen
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205
| | - Huanwen Chen
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, 21201
| | - Shin-Yi Tsai
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205
| | - Jian Zhang
- Department of Orthopedic Surgery, Zhong Shan Hospital, Fudan University, Shanghai, China
| | - Tongyi Chen
- Department of Orthopedic Surgery, Zhong Shan Hospital, Fudan University, Shanghai, China
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, 21201.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205.,Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205.,Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, 21201.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, 21201
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13
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Li T, Feng X, Lv J, Cai T, Wang S. Short-term Clinical Efficacy of Electric Pudendal Nerve Stimulation on Neurogenic Lower Urinary Tract Disease: A Pilot Research. Urology 2018; 112:69-73. [DOI: 10.1016/j.urology.2017.10.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/25/2017] [Accepted: 10/30/2017] [Indexed: 10/18/2022]
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14
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The effect of electroacupuncture on the protein expression levels of Cyt-C, Caspase-3 and Caspase-9 in the bladder tissue of rats with neurogenic bladder after suprasacral spinal cord injury. WORLD JOURNAL OF ACUPUNCTURE-MOXIBUSTION 2017. [DOI: 10.1016/s1003-5257(17)30140-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Khurram A, Ross SE, Sperry ZJ, Ouyang A, Stephan C, Jiman AA, Bruns TM. Chronic monitoring of lower urinary tract activity via a sacral dorsal root ganglia interface. J Neural Eng 2017; 14:036027. [PMID: 28322213 DOI: 10.1088/1741-2552/aa6801] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Our goal is to develop an interface that integrates chronic monitoring of lower urinary tract (LUT) activity with stimulation of peripheral pathways. APPROACH Penetrating microelectrodes were implanted in sacral dorsal root ganglia (DRG) of adult male felines. Peripheral electrodes were placed on or in the pudendal nerve, bladder neck and near the external urethral sphincter. Supra-pubic bladder catheters were implanted for saline infusion and pressure monitoring. Electrode and catheter leads were enclosed in an external housing on the back. Neural signals from microelectrodes and bladder pressure of sedated or awake-behaving felines were recorded under various test conditions in weekly sessions. Electrodes were also stimulated to drive activity. MAIN RESULTS LUT single- and multi-unit activity was recorded for 4-11 weeks in four felines. As many as 18 unique bladder pressure single-units were identified in each experiment. Some channels consistently recorded bladder afferent activity for up to 41 d, and we tracked individual single-units for up to 23 d continuously. Distension-evoked and stimulation-driven (DRG and pudendal) bladder emptying was observed, during which LUT sensory activity was recorded. SIGNIFICANCE This chronic implant animal model allows for behavioral studies of LUT neurophysiology and will allow for continued development of a closed-loop neuroprosthesis for bladder control.
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Affiliation(s)
- Abeer Khurram
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI, United States of America. Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
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16
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Powell CR. Conditional Electrical Stimulation in Animal and Human Models for Neurogenic Bladder: Working Toward a Neuroprosthesis. CURRENT BLADDER DYSFUNCTION REPORTS 2016; 11:379-385. [PMID: 27920880 PMCID: PMC5134915 DOI: 10.1007/s11884-016-0388-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Sacral neuromodulation has had a tremendous impact on the treatment of urinary incontinence and lower urinary tract symptoms for patients with neurologic conditions. This stimulation does not use real-time data from the body or input from the patient. Incorporating this is the goal of those pursuing a neuroprosthesis to enhance bladder function for these patients. Investigators have demonstrated the effectiveness of conditional (also called closed-loop) feedback in animal models as well as limited human studies. Dorsal genital nerve, pudendal nerve, S3 afferent nerve roots, S1 and S2 ganglia have all been used as targets for stimulation. Most of these have also been used as sources of afferent nerve information using sophisticated nerve electrode arrays and filtering algorithms to detect significant bladder events and even to estimate the fullness of the bladder. There are problems with afferent nerve sensing, however. Some of these include sensor migration and low signal to noise ratios. Implantable pressure sensors have also been investigated that have their own unique challenges, such as erosion and sensor drift. As technology improves, an intelligent neuroprosthesis with the ability to sense significant bladder events and stimulate as needed will evolve.
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Affiliation(s)
- C R Powell
- Indiana University School of Medicine, Department of Urology, 535 Barnhill Dr., Suite 420, Indianapolis, IN 46202, USA,
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17
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Normann RA, Fernandez E. Clinical applications of penetrating neural interfaces and Utah Electrode Array technologies. J Neural Eng 2016; 13:061003. [PMID: 27762237 DOI: 10.1088/1741-2560/13/6/061003] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This paper briefly describes some of the recent progress in the development of penetrating microelectrode arrays and highlights the use of two of these devices, Utah electrode arrays and Utah slanted electrode arrays, in two therapeutic interventions: recording volitional skeletal motor commands from the central nervous system, and recording motor commands and evoking somatosensory percepts in the peripheral nervous system (PNS). The paper also briefly explores other potential sites for microelectrode array interventions that could be profitably pursued and that could have important consequences in enhancing the quality of life of patients that has been compromised by disorders of the central and PNSs.
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Affiliation(s)
- Richard A Normann
- Departments of Bioengineering and Ophthalmology, University of Utah, Salt Lake City, UT 84112, USA
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18
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Ross SE, Sperry ZJ, Mahar CM, Bruns TM. Hysteretic behavior of bladder afferent neurons in response to changes in bladder pressure. BMC Neurosci 2016; 17:57. [PMID: 27520434 PMCID: PMC4983075 DOI: 10.1186/s12868-016-0292-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/01/2016] [Indexed: 01/16/2023] Open
Abstract
Background Mechanosensitive afferents innervating the bladder increase their firing rate as the bladder fills and pressure rises. However, the relationship between afferent firing rates and intravesical pressure is not a simple linear one. Firing rate responses to pressure can differ depending on prior activity, demonstrating hysteresis in the system. Though this hysteresis has been commented on in published literature, it has not been quantified. Results Sixty-six bladder afferents recorded from sacral dorsal root ganglia in five alpha-chloralose anesthetized felines were identified based on their characteristic responses to pressure (correlation coefficient ≥ 0.2) during saline infusion (2 ml/min). For saline infusion trials, we calculated a maximum hysteresis ratio between the firing rate difference at each pressure and the overall firing rate range (or Hmax) of 0.86 ± 0.09 (mean ± standard deviation) and mean hysteresis ratio (or Hmean) of 0.52 ± 0.13 (n = 46 afferents). For isovolumetric trials in two experiments (n = 33 afferents) Hmax was 0.72 ± 0.14 and Hmean was 0.40 ± 0.14. Conclusions A comprehensive state model that integrates these hysteresis parameters to determine the bladder state may improve upon existing neuroprostheses for bladder control.
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Affiliation(s)
- Shani E Ross
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,, NCRC-B20-104W, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Zachariah J Sperry
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,, NCRC-B20-111WD, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Colin M Mahar
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,, NCRC-B20-111WD, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Tim M Bruns
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA. .,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA. .,, NCRC-B10-A169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA.
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Emhardt E, Siegel J, Hoffman L. Anatomic variation and orgasm: Could variations in anatomy explain differences in orgasmic success? Clin Anat 2016; 29:665-72. [PMID: 26916103 DOI: 10.1002/ca.22703] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 02/16/2016] [Accepted: 02/16/2016] [Indexed: 01/18/2023]
Abstract
Though the public consciousness is typically focused on factors such as psychology, penis size, and the presence of the "G-spot," there are other anatomical and neuro-anatomic differences that could play an equal, or more important, role in the frequency and intensity of orgasms. Discovering these variations could direct further medical or procedural management to improve sexual satisfaction. The aim of this study is to review the available literature of anatomical sexual variation and to explain why this variation may predispose some patients toward a particular sexual experience. In this review, we explored the available literature on sexual anatomy and neuro-anatomy. We used PubMed and OVID Medline for search terms, including orgasm, penile size variation, clitoral variation, Grafenberg spot, and benefits of orgasm. First we review the basic anatomy and innervation of the reproductive organs. Then we describe several anatomical variations that likely play a superior role to popular known variation (penis size, presence of g-spot, etc). For males, the delicate play between the parasympathetic and sympathetic nervous systems is vital to achieve orgasm. For females, the autonomic component is more complex. The clitoris is the primary anatomical feature for female orgasm, including its migration toward the anterior vaginal wall. In conclusions, orgasms are complex phenomena involving psychological, physiological, and anatomic variation. While these variations predispose people to certain sexual function, future research should explore how to surgically or medically alter these. Clin. Anat. 29:665-672, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- E Emhardt
- Class of 2016, Indiana University School of Medicine, Indianapolis, Indiana, 46220
| | - J Siegel
- Department of Neurology, Mayo Clinic, Jacksonville, Florida, 32224
| | - L Hoffman
- Department of Anatomy, Indiana University School of Medicine, Fort Wayne, Indiana, 46805
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20
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Translational approaches to the treatment of benign urologic conditions in elderly women. Curr Opin Urol 2016; 26:184-92. [PMID: 26814884 DOI: 10.1097/mou.0000000000000261] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Stress urinary incontinence, overactive bladder, interstitial cystitis/painful bladder syndrome, and underactive bladder are highly prevalent among elderly women, and have significant impact on quality of life; however, existing treatments are limited and are not always successful for all patients. Researchers are investigating a multitude of new therapies to treat these conditions. This review will summarize the recent literature on investigative therapies for these conditions. RECENT FINDINGS Multiple new treatments are being developed for lower urinary tract dysfunction. Some of these treatments, including balloon therapy and muscle-derived stem cells for stress urinary incontinence, could provide alternatives to existing therapies. Others require further research before being used in patients, such as pudendal nerve stimulation for overactive bladder and intravesical liposomes for drug delivery in interstitial cystitis/painful bladder syndrome. SUMMARY Multiple new therapies are being investigated that could provide clinicians with additional tools to treat lower urinary tract disorders in millions of elderly women.
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Christensen MB, Wark HA, Hutchinson DT. A histological analysis of human median and ulnar nerves following implantation of Utah slanted electrode arrays. Biomaterials 2016; 77:235-42. [DOI: 10.1016/j.biomaterials.2015.11.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 01/30/2023]
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Abstract
Neuromodulation approaches to treating lower urinary tract dysfunction could be substantially improved by a sensor able to detect when the bladder is full. A number of approaches to this problem have been proposed, but none has been found entirely satisfactory. Electrical plethysmography approaches attempt to relate the electrical impedance of the bladder to its volume, but have previously focused only on the amplitudes of the measured signals. We investigated whether the phase relationships between sinusoidal currents applied through a pair of stimulating electrodes and measured through a pair of recording electrodes could provide information about bladder volume. Acute experiments in a rabbit model were used to investigate how phase-to-volume or amplitude-to-volume regression models could be used to predict bladder volumes in future recordings, with and without changes to the saline conductivity. Volume prediction errors were found to be 6.63 ± 1.12 mL using the phase information and 8.32 ± 3.88 mL using the amplitude information (p = 0.44 when comparing the phase and amplitude results, n = 6), where the volume of the filled bladder was about 25 mL. When a full/empty binary decision rule was applied based on the regression model, the difference between the actual threshold that would result from this rule and the desired threshold was found to be 4.24 ± 0.65 mL using the phase information and 106.92 ± 189.82 mL using the amplitude information (p = 0.03, n = 6). Our results suggest that phase information can form the basis for more effective and robust electrical plethysmography approaches to bladder volume measurement.
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Emerging neural stimulation technologies for bladder dysfunctions. Int Neurourol J 2015; 19:3-11. [PMID: 25833475 PMCID: PMC4386488 DOI: 10.5213/inj.2015.19.1.3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 03/10/2015] [Indexed: 01/16/2023] Open
Abstract
In the neural engineering field, physiological dysfunctions are approached by identifying the target nerves and providing artificial stimulation to restore the function. Neural stimulation and recording technologies play a central role in this approach, and various engineering devices and stimulation techniques have become available to the medical community. For bladder control problems, electrical stimulation has been used as one of the treatments, while only a few emerging neurotechnologies have been used to tackle these problems. In this review, we introduce some recent developments in neural stimulation technologies including microelectrode array, closed-loop neural stimulation, optical stimulation, and ultrasound stimulation.
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Wark HAC, Black SR, Mathews KS, Cartwright PC, Gustafson KJ, Normann RA. Restoration from acute urinary dysfunction using Utah electrode arrays implanted into the feline pudendal nerve. Neuromodulation 2014; 18:317-23. [PMID: 25430001 DOI: 10.1111/ner.12259] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 09/22/2014] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To investigate intrafascicular pudendal nerve stimulation in felines as a means to restore urinary function in acute models of urinary incontinence, overactive bladder, and underactive bladder. MATERIALS AND METHODS Felines were anesthetized, and high-electrode-count (48 electrodes; 25 electrodes/mm(2) ) electrode arrays were implanted intrafascicularly into the pudendal nerve trunk. Electrodes were mapped for their ability to selectively or nonselectively excite the external anal sphincter, external urethral sphincter, and the detrusor bladder muscle. Statistical analysis was carried out to quantify reflexive voiding efficiencies, mean impedances of the microelectrodes used in this study, and to determine what differences, if any, in bladder contraction amplitudes were evoked by different electrode configurations. RESULTS Multielectrode arrays implanted into the pudendal nerve trunk were able to selectively and nonselectively excite genitourinary muscles. After inducing urinary incontinence with bilateral pudendal nerve transections (proximal to the implants), electrical stimulation delivered through certain microelectrodes was able to significantly reduce leaking (p = 0.008). Electrical stimulation delivered through detrusor selective electrodes was able to inhibit reflexive bladder contractions and excite bladder contractions, depending on the stimulation frequency. Specific electrode configurations were able to drive significantly (p < 0.001) larger bladder contractions than other electrode configurations, depending on the preparation. Successful reflexively or electrically driven bladder contractions were achieved in 46% and 38% of the preparations, respectively, an observation that has not been noted in previously published feline pudendal stimulation studies. CONCLUSIONS Multielectrode arrays implanted intrafascicularly into the pudendal nerve trunk may provide a promising new clinical neuromodulation therapy for the restoration of urinary function.
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Affiliation(s)
| | - Shana R Black
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | | | - Patrick C Cartwright
- Department of Urology and Urological Surgery, University of Utah, Salt Lake City, UT, USA
| | - Kenneth J Gustafson
- Department of Bioengineering, Case Western Reserve University, Cleveland, OH, USA
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