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Grossman RG, Tang X, Horner PJ. Stereotaxic Atlas of the Human Lumbar-Sacral Spinal Cord. World Neurosurg 2022; 166:e460-e468. [PMID: 35840094 DOI: 10.1016/j.wneu.2022.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 12/15/2022]
Abstract
OBJECTIVE A Stereotaxic Atlas of the Human Lumbar-Sacral Spinal Cord has been created to provide an anatomical basis for radiologic and ultrasonic imaging and electrophysiological examination, which are used to target the placement of lumbar-sacral epidural stimulating electrodes and cellular transplantation in order to restore movement in individuals with sustained spinal cord injury or a degenerative disorder of the spinal cord. Through the availability of an atlas that exhibits axial images of the cytoarchitecture of each cord segment with a stereotaxic millimeter grid of dorsal-ventral depth from the midline dorsal surface of the cord and right-left distances from the midline of the cord, neuromodulation, and cellular therapy would undoubtedly be made not only more precise but also safer for patients. METHODS The atlas is based upon dimension measurements and subsequent serial sectioning, staining and high-resolution digital imaging of the lumbar-sacral enlargement of 20 adult human spinal cords. RESULTS Nissl stained cross-sections from cord segments L1-S3 illustrate the cytoarchitecture and stereotactic coordinates. CONCLUSIONS The atlas provides an anatomical basis for radiologic and physiologic confirmation of target localization in the lumbar-sacral spinal cord.
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Affiliation(s)
- Robert G Grossman
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, Texas, USA
| | - Xiufeng Tang
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, Texas, USA
| | - Philip J Horner
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, Texas, USA.
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Tawakol O, Mushahwar VK, Troyk PR. The Use of Digital Image Correlation for Measurement of Strain Fields in a Novel Wireless Intraspinal Microstimulation Interface. Artif Organs 2022; 46:2066-2072. [PMID: 35747905 DOI: 10.1111/aor.14349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/13/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Intraspinal microstimulation (ISMS) has emerged as a promising neuromodulation technique for restoring standing and overground walking in individuals with spinal cord injury. Current and emerging ISMS implant designs connect the electrodes to the stimulator through lead wires that cross the dura mater. To reduce possible complications associated with transdural leads such as tethering and leakage of cerebrospinal fluid, we aim to develop a wireless, fully intradural ISMS implant based upon our prior work in the cortex with the Wireless Floating Microelectrode Array (WFMA). Although we have extensive data about WFMA cortical stability, its mechanical and electrical stability in the spinal cord remain unknown. One of the quantifiable metrics to assess long-term implant stability is mechanical strain. OBJECTIVE The aim of the current work is to develop a method to assess implant stability by measuring strain fields in a surrogate of the human spinal cord. METHODS A physical model of the spinal cord was studied using an electromechanical testing apparatus, simulating typical spinal cord motion. Strain fields were digitally analyzed using an optical method known as digital image correlation (DIC). RESULTS Displacement and strain were visualized using contour plots. The strain values in the vicinity of each WFMA device were significantly different from the strain values in the same locations in the control surrogate spinal cord. CONCLUSION The results demonstrate that DIC can be used for in-vitro screening of intraspinal implants. Accurate optical strain measurements will enable researchers to optimize implant design over a wide range of motion conditions.
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Affiliation(s)
- Omar Tawakol
- Department of Biomedical Engineering, Illinois Institute of Technology, United States
| | - Vivian K Mushahwar
- Department of Medicine and Neuroscience & Mental Health Institute, University of Alberta, Canada.,Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Canada
| | - Philip R Troyk
- Department of Biomedical Engineering, Illinois Institute of Technology, United States.,Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Canada
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3
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Mirkiani S, Roszko DA, O'Sullivan C, Faridi P, Hu DS, Fang D, Everaert DG, Toossi A, Konrad PE, Robinson K, Mushahwar VK. Overground gait kinematics and muscle activation patterns in the Yucatan mini pig. J Neural Eng 2022; 19. [PMID: 35172283 DOI: 10.1088/1741-2552/ac55ac] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/16/2022] [Indexed: 11/12/2022]
Abstract
Objective The objectives of this study were to assess gait biomechanics and the effect of overground walking speed on gait parameters, kinematics, and electromyographic (EMG) activity in the hindlimb muscles of Yucatan Minipigs (YMPs). Approach Nine neurologically-intact, adult YMPs were trained to walk overground in a straight line. Whole-body kinematics and EMG activity of hindlimb muscles were recorded and analyzed at 6 different speed ranges (0.4-0.59, 0.6-0.79, 0.8-0.99, 1.0-1.19, 1.2-1.39, and 1.4-1.6 m/s). A MATLAB program was developed to detect strides and gait events automatically from motion-captured data. The kinematics and EMG activity were analyzed for each stride based on the detected events. Main results Significant decreases in stride duration, stance and swing times and an increase in stride length were observed with increasing speed. A transition in gait pattern occurred at the 1.0m/s walking speed. Significant increases in the range of motion of the knee and ankle joints were observed at higher speeds. Also, the points of minimum and maximum joint angles occurred earlier in the gait cycle as the walking speed increased. The onset of EMG activity in the biceps femoris muscle occurred significantly earlier in the gait cycle with increasing speed. Significance YMPs are becoming frequently used as large animal models for preclinical testing and translation of novel interventions to humans. A comprehensive characterization of overground walking in neurologically-intact YMPs is provided in this study. These normative measures set the basis against which the effects of future interventions on locomotor capacity in YMPs can be compared.
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Affiliation(s)
- Soroush Mirkiani
- Neuroscience & Mental Health Institute and Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz Building, University of Alberta, Edmonton, Alberta, T6G 2R3, CANADA
| | - David A Roszko
- Neuroscience & Mental Health Institute and Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz Building, Edmonton, Alberta, T6G 2R3, CANADA
| | - Carly O'Sullivan
- Neuroscience & Mental Health Institute and Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz, Building, Edmonton, Alberta, T6G 2R3, CANADA
| | - Pouria Faridi
- Neuroscience & Mental Health Institute and Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz Building, Edmonton, Alberta, T6G 2R3, CANADA
| | - David S Hu
- Department of Medicine and Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz Building, Edmonton, Alberta, T6G 2R3, CANADA
| | - Daniel Fang
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz Building, Edmonton, Alberta, T6G 2R3, CANADA
| | - Dirk G Everaert
- Department of Medicine and Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz Building, Edmonton, Alberta, T6G 2R3, CANADA
| | - Amirali Toossi
- Neuroscience & Mental Health Institute and Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz Building, Edmonton, Alberta, T6G 2R3, CANADA
| | - Peter E Konrad
- Department of Neurosurgery, West Virginia University, PO Box 9183, Morgantown, West Virginia, 26506, UNITED STATES
| | - Kevin Robinson
- School of Physical Therapy, Belmont University, 341 McWhorter Hall, Nashville, Tennessee, 37212, UNITED STATES
| | - Vivian K Mushahwar
- Department of Medicine and Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, 5005 Katz Building, University of Alberta, Edmonton, Alberta, T6G 2R3, CANADA
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Flores Á, López-Santos D, García-Alías G. When Spinal Neuromodulation Meets Sensorimotor Rehabilitation: Lessons Learned From Animal Models to Regain Manual Dexterity After a Spinal Cord Injury. FRONTIERS IN REHABILITATION SCIENCES 2021; 2:755963. [PMID: 36188826 PMCID: PMC9397786 DOI: 10.3389/fresc.2021.755963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/16/2021] [Indexed: 12/22/2022]
Abstract
Electrical neuromodulation has strongly hit the foundations of spinal cord injury and repair. Clinical and experimental studies have demonstrated the ability to neuromodulate and engage spinal cord circuits to recover volitional motor functions lost after the injury. Although the science and technology behind electrical neuromodulation has attracted much of the attention, it cannot be obviated that electrical stimulation must be applied concomitantly to sensorimotor rehabilitation, and one would be very difficult to understand without the other, as both need to be finely tuned to efficiently execute movements. The present review explores the difficulties faced by experimental and clinical neuroscientists when attempting to neuromodulate and rehabilitate manual dexterity in spinal cord injured subjects. From a translational point of view, we will describe the major rehabilitation interventions employed in animal research to promote recovery of forelimb motor function. On the other hand, we will outline some of the state-of-the-art findings when applying electrical neuromodulation to the spinal cord in animal models and human patients, highlighting how evidences from lumbar stimulation are paving the path to cervical neuromodulation.
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Affiliation(s)
- África Flores
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Diego López-Santos
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Guillermo García-Alías
- Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
- Institut Guttmann de Neurorehabilitació, Badalona, Spain
- *Correspondence: Guillermo García-Alías
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Hogan MK, Barber SM, Rao Z, Kondiles BR, Huang M, Steele WJ, Yu C, Horner PJ. A wireless spinal stimulation system for ventral activation of the rat cervical spinal cord. Sci Rep 2021; 11:14900. [PMID: 34290260 PMCID: PMC8295294 DOI: 10.1038/s41598-021-94047-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 06/24/2021] [Indexed: 11/09/2022] Open
Abstract
Electrical stimulation of the cervical spinal cord is gaining traction as a therapy following spinal cord injury; however, it is difficult to target the cervical motor region in a rodent using a non-penetrating stimulus compared with direct placement of intraspinal wire electrodes. Penetrating wire electrodes have been explored in rodent and pig models and, while they have proven beneficial in the injured spinal cord, the negative aspects of spinal parenchymal penetration (e.g., gliosis, neural tissue damage, and obdurate inflammation) are of concern when considering therapeutic potential. We therefore designed a novel approach for epidural stimulation of the rat spinal cord using a wireless stimulation system and ventral electrode array. Our approach allowed for preservation of mobility following surgery and was suitable for long term stimulation strategies in awake, freely functioning animals. Further, electrophysiology mapping of the ventral spinal cord revealed the ventral approach was suitable to target muscle groups of the rat forelimb and, at a single electrode lead position, different stimulation protocols could be applied to achieve unique activation patterns of the muscles of the forelimb.
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Affiliation(s)
- Matthew K Hogan
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA.
| | - Sean M Barber
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA
| | | | - Bethany R Kondiles
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA.,International Collaboration on Repair Discovories, University of British Columbia, Vancouver, Canada
| | - Meng Huang
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA
| | - William J Steele
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA
| | | | - Philip J Horner
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, USA
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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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Zholudeva LV, Abraira VE, Satkunendrarajah K, McDevitt TC, Goulding MD, Magnuson DSK, Lane MA. Spinal Interneurons as Gatekeepers to Neuroplasticity after Injury or Disease. J Neurosci 2021; 41:845-854. [PMID: 33472820 PMCID: PMC7880285 DOI: 10.1523/jneurosci.1654-20.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/15/2022] Open
Abstract
Spinal interneurons are important facilitators and modulators of motor, sensory, and autonomic functions in the intact CNS. This heterogeneous population of neurons is now widely appreciated to be a key component of plasticity and recovery. This review highlights our current understanding of spinal interneuron heterogeneity, their contribution to control and modulation of motor and sensory functions, and how this role might change after traumatic spinal cord injury. We also offer a perspective for how treatments can optimize the contribution of interneurons to functional improvement.
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Affiliation(s)
| | - Victoria E Abraira
- Department of Cell Biology & Neuroscience, Rutgers University, The State University of New Jersey, New Jersey, 08854
| | - Kajana Satkunendrarajah
- Departments of Neurosurgery and Physiology, Medical College of Wisconsin, Wisconsin, 53226
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin, 53295
| | - Todd C McDevitt
- Gladstone Institutes, San Francisco, California, 94158
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California, 94143
| | | | - David S K Magnuson
- University of Louisville, Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, 40208
| | - Michael A Lane
- Department of Neurobiology and Anatomy, and the Marion Murray Spinal Cord Research Center, Drexel University, Philadelphia, Pennsylvania, 19129
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8
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Toossi A, Bergin B, Marefatallah M, Parhizi B, Tyreman N, Everaert DG, Rezaei S, Seres P, Gatenby JC, Perlmutter SI, Mushahwar VK. Comparative neuroanatomy of the lumbosacral spinal cord of the rat, cat, pig, monkey, and human. Sci Rep 2021; 11:1955. [PMID: 33479371 PMCID: PMC7820487 DOI: 10.1038/s41598-021-81371-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/28/2020] [Indexed: 02/06/2023] Open
Abstract
The overall goal of this work was to create a high-resolution MRI atlas of the lumbosacral enlargement of the spinal cord of the rat (Sprague-Dawley), cat, domestic pig, rhesus monkey, and human. These species were chosen because they are commonly used in basic and translational research in spinal cord injuries and diseases. Six spinal cord specimens from each of the studied species (total of 30 specimens) were fixed, extracted, and imaged. Sizes of the spinal cord segments, cross-sectional dimensions, and locations of the spinal cord gray and white matter were quantified and compared across species. The lumbar enlargement spans spinal cord levels L3-S1 in rats, L4-S1 in cats, L3-S1 in pigs, L2/L3-L7/S1 in monkeys, and T12/L1-S1/S2 in humans. The enlargements in pigs and humans are largest and most similar in size (length and cross-sectional area); followed by monkeys and cats; and followed by rats. The obtained atlas establishes a neuroanatomical reference for the intact lumbosacral spinal cord in these species. It can also be used to guide the planning of surgical procedures of the spinal cord and technology design and development of spinal cord neuroprostheses, as well as precise delivery of cells/drugs into target regions within the spinal cord parenchyma.
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Affiliation(s)
- Amirali Toossi
- Krembil Research Institute, University Health Network, Toronto, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Canada
| | - Bradley Bergin
- Department of Medicine, University of Alberta, Edmonton, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Canada
| | - Maedeh Marefatallah
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Canada
| | - Behdad Parhizi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Canada
| | - Neil Tyreman
- Department of Medicine, University of Alberta, Edmonton, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Canada
| | - Dirk G Everaert
- Department of Medicine, University of Alberta, Edmonton, Canada
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Canada
| | - Sabereh Rezaei
- Department of Materials Science and Engineering, University of Toronto, Toronto, Canada
| | - Peter Seres
- Department of Biomedical Engineering, University of Alberta, Edmonton, Canada
| | | | - Steve I Perlmutter
- Department of Physiology and Biophysics, University of Washington, Seattle, USA
- Washington National Primate Research Centre, Seattle, USA
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Canada
| | - Vivian K Mushahwar
- Department of Medicine, University of Alberta, Edmonton, Canada.
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada.
- Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Canada.
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Fathi Y, Erfanian A. Decoding hindlimb kinematics from descending and ascending neural signals during cat locomotion. J Neural Eng 2021; 18. [PMID: 33395669 DOI: 10.1088/1741-2552/abd82a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 01/04/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The main objective of this research is to record both sensory and motor information from the ascending and descending tracts within the spinal cord for decoding the hindlimb kinematics during walking on the treadmill. APPROACH Two different experimental paradigms (i.e., active and passive) were used in the current study. During active experiments, five cats were trained to walk bipedally while their hands kept on the front frame of the treadmill for balance or to walk quadrupedally. During passive experiments, the limb was passively moved by the experimenter. Local field potential (LFP) activity was recorded using a microwire array implanted in the dorsal column (DC) and lateral column (LC) of the L3-L4 spinal segments. The amplitude and frequency components of the LFP formed the feature set and the elastic net regularization was used to decode the hindlimb joint angles. MAIN RESULTS The results show that there is no significant difference between the information content of the signals recorded from the DC and LC regions during walking on the treadmill, but the information content of the DC is significantly higher than that of the LC during passively applied movement of the hindlimb in the anesthetized cats. Moreover, the decoding performance obtained using the recorded signals from the DC is comparable with that from the LC during locomotion. But, the decoding performance obtained using the recording channels in the DC is significantly better than that obtained using the signals recorded from the LC. The long-term analysis shows that robust decoding performance can be achieved over 2-3 months without a significant decrease in performance. SIGNIFICANCE This work presents a promising approach to developing a natural and robust motor neuroprosthesis device using descending neural signals to execute the movement and ascending neural signals as the feedback information for control of the movement.
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Affiliation(s)
- Yaser Fathi
- Biomedical Engineering, Iran University of Science and Technology, Narmak, Resalat Square, Hengam Street, Iran University of Science and Technology, Tehran, Tehran, 16844, Iran (the Islamic Republic of)
| | - Abbas Erfanian
- Biomedical Engineering, Iran University of Science & Technology, Hengam Street, Narmak, Tehran 16844, Iran, Tehran, 16844, IRAN, ISLAMIC REPUBLIC OF
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10
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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: 4] [Impact Index Per Article: 0.8] [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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11
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Sunshine MD, Ganji CN, Fuller DD, Moritz CT. Respiratory resetting elicited by single pulse spinal stimulation. Respir Physiol Neurobiol 2019; 274:103339. [PMID: 31734416 DOI: 10.1016/j.resp.2019.103339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/04/2019] [Accepted: 11/12/2019] [Indexed: 01/21/2023]
Abstract
Intraspinal microstimulation (ISMS) can effectively activate spinal motor circuits, but the impact on the endogenous respiratory pattern has not been systematically evaluated. Here we delivered ISMS in spontaneously breathing adult rats while simultaneously recording diaphragm and external intercostal electromyography activity. ISMS pulses were delivered from C2-T1 along two rostrocaudal tracts located 0.5 or 1 mm lateral to midline. A tungsten electrode was incrementally advanced from the dorsal spinal surface and 300μs biphasic pulses (10-90 μA) were delivered at depth increments of 600 μm. Dorsal ISMS often produced fractionated inspiratory bursting or caused early termination of the inspiratory effort. Conversely, ventral stimulation had no discernable impact on respiratory resetting. We conclude that ISMS targeting the ventral spinal cord is unlikely to directly alter the respiratory rhythm. Dorsal ISMS, however, may terminate the inspiratory burst through activation of spinobulbar pathways. We suggest that respiratory patterns should be included as an outcome variable in preclinical studies of ISMS.
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Affiliation(s)
- Michael D Sunshine
- Department of Rehabilitation Medicine, University of Washington, United States; Center for Neurotechnology, an NSF ERC, United States; Department of Physical Therapy, University of Florida, United States; McKnight Brain Institute, University of Florida, United States; Rehabilitation Science PhD Program, University of Florida, United States; Center for Respiratory Research and Rehabilitation, University of Florida, United States.
| | - Comron N Ganji
- Department of Rehabilitation Medicine, University of Washington, United States
| | - David D Fuller
- Department of Physical Therapy, University of Florida, United States; McKnight Brain Institute, University of Florida, United States; Center for Respiratory Research and Rehabilitation, University of Florida, United States
| | - Chet T Moritz
- Department of Rehabilitation Medicine, University of Washington, United States; Center for Neurotechnology, an NSF ERC, United States; Center for Respiratory Research and Rehabilitation, University of Florida, United States; Department of Electrical and Computer Engineering, United States; University of Washington, Institute for Neuroengineering (UWIN), University of Washington, United States; Department of Physiology and Biophysics, University of Washington, United States
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12
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Spinal Cord Epidural Stimulation for Lower Limb Motor Function Recovery in Individuals with Motor Complete Spinal Cord Injury. Phys Med Rehabil Clin N Am 2019; 30:337-354. [DOI: 10.1016/j.pmr.2018.12.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Toossi A, Everaert DG, Uwiera RRE, Hu DS, Robinson K, Gragasin FS, Mushahwar VK. Effect of anesthesia on motor responses evoked by spinal neural prostheses during intraoperative procedures. J Neural Eng 2019; 16:036003. [PMID: 30790787 DOI: 10.1088/1741-2552/ab0938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The overall goal of this study was to investigate the effects of various anesthetic protocols on the intraoperative responses to intraspinal microstimulation (ISMS). ISMS is a neuroprosthetic approach that targets the motor networks in the ventral horns of the spinal cord to restore function after spinal cord injury. In preclinical studies, ISMS in the lumbosacral enlargement produced standing and walking by activating networks controlling the hindlimb muscles. ISMS implants are placed surgically under anesthesia, and refinements in placement are made based on the evoked responses. Anesthesia can have a significant effect on the responses evoked by spinal neuroprostheses; therefore, in preparation for clinical testing of ISMS, we compared the evoked responses under a common clinical neurosurgical anesthetic protocol with those evoked under protocols commonly used in preclinical studies. APPROACH Experiments were conducted in seven pigs. An ISMS microelectrode array was implanted in the lumbar enlargement and responses to ISMS were measured under three anesthetic protocols: (1) isoflurane, an agent used pre-clinically and clinically, (2) total intravenous anesthesia (TIVA) with propofol as the main agent commonly used in clinical neurosurgical procedures, (3) TIVA with sodium pentobarbital, an anesthetic agent used mostly preclinically. Responses to ISMS were evaluated based on stimulation thresholds, movement kinematics, and joint torques. Motor evoked potentials (MEP) and plasma concentrations of propofol were also measured. MAIN RESULTS ISMS under propofol anesthesia produced large and functional responses that were not statistically different from those produced under pentobarbital anesthesia. Isoflurane, however, significantly suppressed the ISMS-evoked responses. SIGNIFICANCE This study demonstrated that the choice of anesthesia is critical for intraoperative assessments of motor responses evoked by spinal neuroprostheses. Propofol and pentobarbital anesthesia did not overly suppress the effects of ISMS; therefore, propofol is expected to be a suitable anesthetic agent for clinical intraoperative testing of an intraspinal neuroprosthetic system.
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Affiliation(s)
- Amirali Toossi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada. Sensory Motor Adaptive Rehabilitative Technology (SMART) Network, University of Alberta, Edmonton, AB, Canada
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Guiho T, Azevedo-Coste C, Guiraud D, Delleci C, Capon G, Delgado-Piccoli N, Bauchet L, Vignes JR. Validation of a methodology for neuro-urological and lumbosacral stimulation studies in domestic pigs: a humanlike animal model. J Neurosurg Spine 2019; 30:644-654. [PMID: 30771756 DOI: 10.3171/2018.11.spine18676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 11/02/2018] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Spinal cord injuries (SCIs) result in loss of movement and sensory feedback, but also organ dysfunction. Nearly all patients with complete SCI lose bladder control and are prone to kidney failure if intermittent catheterization is not performed. Electrical stimulation of sacral spinal roots was initially considered to be a promising approach for restoring continence and micturition control, but many patients are discouraged by the need for surgical deafferentation as it could lead to a loss of sensory functions and reflexes. Nevertheless, recent research findings highlight the renewed interest in spinal cord stimulation (SCS). It is thought that synergic recruitment of spinal fibers could be achieved by stimulating the spinal neural networks involved in regulating physiological processes. Paradoxically, most of these recent studies focused on locomotor issues, while few addressed visceral dysfunction. This could at least partially be attributed to the lack of methodological tools. In this study, the authors aim to fill this gap by presenting a comprehensive method for investigating the potential of SCS to restore visceral functions in domestic pigs, a large-animal model considered to be a close approximation to humans. METHODS This methodology was tested in 7 female pigs (Landrace pig breed, 45-60 kg, 4 months old) during acute experiments. A combination of morphine and propofol was used for anesthesia when transurethral catheterization and lumbosacral laminectomy (L4-S4) were performed. At the end of the operation, spinal root stimulation (L6-S5) and urodynamic recordings were performed to compare the evoked responses with those observed intraoperatively in humans. RESULTS Nervous excitability was preserved despite long-term anesthesia (mean 8.43 ± 1.5 hours). Transurethral catheterization and conventional laminectomy were possible while motor responses (gluteus muscle monitoring) were unaffected throughout the procedure. Consistent detrusor (approximately 25 cm H2O) and sphincter responses were obtained, whereas spinal root stimulation elicited detrusor and external urethral sphincter co-contractions similar to those observed intraoperatively in humans. CONCLUSIONS Pigs represent an ideal model for SCS studies aimed at visceral function investigation and restoration because of the close similarities between female domestic pigs and humans, both in terms of anatomical structure and experimental techniques implemented. This article provides methodological keys for conducting experiments with equipment routinely used in clinical practice.
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Affiliation(s)
- Thomas Guiho
- 1University of Montpellier, INRIA, Montpellier, Occitanie, France
- 2University of Newcastle, Institute of Neuroscience, Newcastle upon Tyne, Tyne and Wear, United Kingdom
| | | | - David Guiraud
- 1University of Montpellier, INRIA, Montpellier, Occitanie, France
| | | | | | | | - Luc Bauchet
- 6Department of Neurosurgery, Montpellier University Medical Center, National Institute for Health and Medical Research (INSERM), U1051, Hôpital Gui de Chauliac, Centre Hospitalo-Universitaire, Montpellier, France
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15
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Toossi A, Everaert DG, Seres P, Jaremko JL, Robinson K, Kao CC, Konrad PE, Mushahwar VK. Ultrasound-guided spinal stereotactic system for intraspinal implants. J Neurosurg Spine 2018; 29:292-305. [DOI: 10.3171/2018.1.spine17903] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVEThe overall goal of this study was to develop an image-guided spinal stereotactic setup for intraoperative intraspinal microstimulation (ISMS). System requirements were as follows: 1) ability to place implants in various segments of the spinal cord, targeting the gray matter with a < 0.5-mm error; 2) modularity; and 3) compatibility with standard surgical tools.METHODSA spine-mounted stereotactic system was developed, optimized, and tested in pigs. The system consists of a platform supporting a micromanipulator with 6 degrees of freedom. It is modular and flexible in design and can be applied to various regions of the spine. An intraoperative ultrasound imaging technique was also developed and assessed for guidance of electrode alignment prior to and after electrode insertion into the spinal cord. Performance of the ultrasound-guided stereotactic system was assessed both in pigs (1 live and 6 fresh cadaveric pigs) and on the bench using four gelatin-based surrogate spinal cords. Pig experiments were conducted to evaluate the performance of ultrasound imaging in aligning the electrode trajectory using three techniques and under two conditions. Benchtop experiments were performed to assess the performance of ultrasound-guided targeting more directly. These experiments were used to quantify the accuracy of electrode alignment as well as assess the accuracy of the implantation depth and the error in spatial targeting within the gray matter of the spinal cord. As proof of concept, an intraoperative ISMS experiment was also conducted in an additional live pig using the stereotactic system, and the resulting movements and electromyographic responses were recorded.RESULTSThe stereotactic system was quick to set up (< 10 minutes) and provided sufficient stability and range of motion to reach the ISMS targets reliably in the pigs. Transverse ultrasound images with the probe angled at 25°–45° provided acceptable contrast between the gray and white matter of the spinal cord. In pigs, the largest electrode alignment error using ultrasound guidance, relative to the minor axis of the spinal cord, was ≤ 3.57° (upper bound of the 95% confidence interval). The targeting error with ultrasound guidance in bench testing for targets 4 mm deep into the surrogate spinal cords was 0.2 ± 0.02 mm (mean ± standard deviation).CONCLUSIONSThe authors developed and evaluated an ultrasound-guided spinal stereotactic system for precise insertion of intraspinal implants. The system is compatible with existing spinal instrumentation. Intraoperative ultrasound imaging of the spinal cord aids in alignment of the implants before insertion and provides feedback during and after implantation. The ability of ultrasound imaging to distinguish between spinal cord gray and white matter also improves confidence in the localization of targets within the gray matter. This system would be suitable for accurate guidance of intraspinal electrodes and drug or cell injections.
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Affiliation(s)
- Amirali Toossi
- 1Neuroscience and Mental Health Institute
- 7Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Alberta, Canada
| | - Dirk G. Everaert
- 2Division of Physical Medicine and Rehabilitation, Department of Medicine
- 7Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Alberta, Canada
| | | | - Jacob L. Jaremko
- 4Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | | | - C. Chris Kao
- 6Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | - Peter E. Konrad
- 6Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, Tennessee; and
- 7Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Alberta, Canada
| | - Vivian K. Mushahwar
- 1Neuroscience and Mental Health Institute
- 2Division of Physical Medicine and Rehabilitation, Department of Medicine
- 7Sensory Motor Adaptive Rehabilitation Technology (SMART) Network, University of Alberta, Edmonton, Alberta, Canada
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Shepherd RK, Villalobos J, Burns O, Nayagam DAX. The development of neural stimulators: a review of preclinical safety and efficacy studies. J Neural Eng 2018; 15:041004. [PMID: 29756600 PMCID: PMC6049833 DOI: 10.1088/1741-2552/aac43c] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Given the rapid expansion of the field of neural stimulation and the rigorous regulatory approval requirements required before these devices can be applied clinically, it is important that there is clarity around conducting preclinical safety and efficacy studies required for the development of this technology. APPROACH The present review examines basic design principles associated with the development of a safe neural stimulator and describes the suite of preclinical safety studies that need to be considered when taking a device to clinical trial. MAIN RESULTS Neural stimulators are active implantable devices that provide therapeutic intervention, sensory feedback or improved motor control via electrical stimulation of neural or neuro-muscular tissue in response to trauma or disease. Because of their complexity, regulatory bodies classify these devices in the highest risk category (Class III), and they are therefore required to go through a rigorous regulatory approval process before progressing to market. The successful development of these devices is achieved through close collaboration across disciplines including engineers, scientists and a surgical/clinical team, and the adherence to clear design principles. Preclinical studies form one of several key components in the development pathway from concept to product release of neural stimulators. Importantly, these studies provide iterative feedback in order to optimise the final design of the device. Key components of any preclinical evaluation include: in vitro studies that are focussed on device reliability and include accelerated testing under highly controlled environments; in vivo studies using animal models of the disease or injury in order to assess efficacy and, given an appropriate animal model, the safety of the technology under both passive and electrically active conditions; and human cadaver and ex vivo studies designed to ensure the device's form factor conforms to human anatomy, to optimise the surgical approach and to develop any specialist surgical tooling required. SIGNIFICANCE The pipeline from concept to commercialisation of these devices is long and expensive; careful attention to both device design and its preclinical evaluation will have significant impact on the duration and cost associated with taking a device through to commercialisation. Carefully controlled in vitro and in vivo studies together with ex vivo and human cadaver trials are key components of a thorough preclinical evaluation of any new neural stimulator.
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Affiliation(s)
- Robert K Shepherd
- Bionics Institute, East Melbourne, Australia. Medical Bionics Department, University of Melbourne, Melbourne, Australia
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Koss KM, Churchward MA, Jeffery AF, Mushahwar VK, Elias AL, Todd KG. Improved 3D Hydrogel Cultures of Primary Glial Cells for In Vitro Modelling of Neuroinflammation. J Vis Exp 2017. [PMID: 29286415 DOI: 10.3791/56615] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In the central nervous system, numerous acute injuries and neurodegenerative disorders, as well as implanted devices or biomaterials engineered to enhance function result in the same outcome: excess inflammation leads to gliosis, cytotoxicity, and/or formation of a glial scar that collectively exacerbate injury or prevent healthy recovery. With the intent of creating a system to model glial scar formation and study inflammatory processes, we have generated a 3D cell scaffold capable of housing primary cultured glial cells: microglia that regulate the foreign body response and initiate the inflammatory event, astrocytes that respond to form a fibrous scar, and oligodendrocytes that are typically vulnerable to inflammatory injury. The present work provides a detailed step-by-step method for the fabrication, culture, and microscopic characterization of a hyaluronic acid-based 3D hydrogel scaffold with encapsulated rat brain-derived glial cells. Further, protocols for characterization of cell encapsulation and the hydrogel scaffold by confocal immunofluorescence and scanning electron microscopy are demonstrated, as well as the capacity to modify the scaffold with bioactive substrates, with incorporation of a commercial basal lamina mixture to improved cell integration.
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Affiliation(s)
- Kyle M Koss
- Department of Psychiatry, University of Alberta; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta
| | - Matthew A Churchward
- Department of Psychiatry, University of Alberta; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta
| | - Andrea F Jeffery
- Department of Psychiatry, University of Alberta; Department of Chemical and Materials Engineering, University of Alberta
| | - Vivian K Mushahwar
- Department of Psychiatry, University of Alberta; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta; Division of Physical Medicine and Rehabilitation, University of Alberta
| | - Anastasia L Elias
- Department of Chemical and Materials Engineering, University of Alberta
| | - Kathryn G Todd
- Department of Psychiatry, University of Alberta; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta; Centre for Neuroscience, University of Alberta;
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Cuellar CA, Mendez AA, Islam R, Calvert JS, Grahn PJ, Knudsen B, Pham T, Lee KH, Lavrov IA. The Role of Functional Neuroanatomy of the Lumbar Spinal Cord in Effect of Epidural Stimulation. Front Neuroanat 2017; 11:82. [PMID: 29075183 PMCID: PMC5642185 DOI: 10.3389/fnana.2017.00082] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/07/2017] [Indexed: 01/07/2023] Open
Abstract
In this study, the neuroanatomy of the swine lumbar spinal cord, particularly the spatial orientation of dorsal roots was correlated to the anatomical landmarks of the lumbar spine and to the magnitude of motor evoked potentials during epidural electrical stimulation (EES). We found that the proximity of the stimulating electrode to the dorsal roots entry zone across spinal segments was a critical factor to evoke higher peak-to-peak motor responses. Positioning the electrode close to the dorsal roots produced a significantly higher impact on motor evoked responses than rostro-caudal shift of electrode from segment to segment. Based on anatomical measurements of the lumbar spine and spinal cord, significant differences were found between L1-L4 to L5-L6 segments in terms of spinal cord gross anatomy, dorsal roots and spine landmarks. Linear regression analysis between intersegmental landmarks was performed and L2 intervertebral spinous process length was selected as the anatomical reference in order to correlate vertebral landmarks and the spinal cord structures. These findings present for the first time, the influence of spinal cord anatomy on the effects of epidural stimulation and the role of specific orientation of electrodes on the dorsal surface of the dura mater in relation to the dorsal roots. These results are critical to consider as spinal cord neuromodulation strategies continue to evolve and novel spinal interfaces translate into clinical practice.
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Affiliation(s)
- Carlos A Cuellar
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Aldo A Mendez
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Riazul Islam
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Jonathan S Calvert
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo ClinicRochester, MN, United States
| | - Peter J Grahn
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Bruce Knudsen
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Tuan Pham
- Department of Biological Sciences, Lehigh UniversityBethlehem, PA, United States
| | - Kendall H Lee
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States.,Department of Physical Medicine and Rehabilitation, Mayo ClinicRochester, MN, United States.,Department of Physiology and Biomedical Engineering, Mayo ClinicRochester, MN, United States
| | - Igor A Lavrov
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States.,Department of Physiology and Biomedical Engineering, Mayo ClinicRochester, MN, United States.,Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
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