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Debenham MIB, Franz CK, Berger MJ. Neuromuscular consequences of spinal cord injury: New mechanistic insights and clinical considerations. Muscle Nerve 2024; 70:12-27. [PMID: 38477416 DOI: 10.1002/mus.28070] [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: 10/20/2023] [Revised: 02/13/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024]
Abstract
The spinal cord facilitates communication between the brain and the body, containing intrinsic systems that work with lower motor neurons (LMNs) to manage movement. Spinal cord injuries (SCIs) can lead to partial paralysis and dysfunctions in muscles below the injury. While traditionally this paralysis has been attributed to disruptions in the corticospinal tract, a growing body of work demonstrates LMN damage is a factor. Motor units, comprising the LMN and the muscle fibers with which they connect, are essential for voluntary movement. Our understanding of their changes post-SCI is still emerging, but the health of motor units is vital, especially when considering innovative SCI treatments like nerve transfer surgery. This review seeks to collate current literature on how SCI impact motor units and explore neuromuscular clinical implications and treatment avenues. SCI reduced motor unit number estimates, and surviving motor units had impaired signal transmission at the neuromuscular junction, force-generating capacity, and excitability, which have the potential to recover chronically, yet the underlaying mechanisms are unclear. Furthermore, electrodiagnostic evaluations can aid in assessing the health lower and upper motor neurons, identify suitable targets for nerve transfer surgeries, and detect patients with time sensitive injuries. Lastly, many electrodiagnostic abnormalities occur in both chronic and acute SCI, yet factors contributing to these abnormalities are unknown. Future studies are required to determine how motor units adapt following SCI and the clinical implications of these adaptations.
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Affiliation(s)
- Mathew I B Debenham
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin K Franz
- Biologics Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois, USA
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Jende JME, Heutehaus L, Preisner F, Verez Sola CM, Mooshage CM, Heiland S, Rupp R, Bendszus M, Weidner N, Kurz FT, Franz S. Magnetic resonance neurography in spinal cord injury: Imaging findings and clinical significance. Eur J Neurol 2024; 31:e16198. [PMID: 38235932 PMCID: PMC11235803 DOI: 10.1111/ene.16198] [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: 07/27/2023] [Revised: 12/10/2023] [Accepted: 12/21/2023] [Indexed: 01/19/2024]
Abstract
BACKGROUND AND PURPOSE It is unknown whether changes to the peripheral nervous system following spinal cord injury (SCI) are relevant for functional recovery or the development of neuropathic pain below the level of injury. Magnetic resonance neurography (MRN) at 3 T allows detection and localization of structural and functional nerve damage. This study aimed to combine MRN and clinical assessments in individuals with chronic SCI and nondisabled controls. METHODS Twenty participants with chronic SCI and 20 controls matched for gender, age, and body mass index underwent MRN of the L5 dorsal root ganglia (DRG) and the sciatic nerve. DRG volume, sciatic nerve mean cross-sectional area (CSA), fascicular lesion load, and fractional anisotropy (FA), a marker for functional nerve integrity, were calculated. Results were correlated with clinical assessments and nerve conduction studies. RESULTS Sciatic nerve CSA and lesion load were higher (21.29 ± 5.82 mm2 vs. 14.08 ± 4.62 mm2 , p < 0.001; and 8.70 ± 7.47% vs. 3.60 ± 2.45%, p < 0.001) in individuals with SCI compared to controls, whereas FA was lower (0.55 ± 0.11 vs. 0.63 ± 0.08, p = 0.022). DRG volumes were larger in individuals with SCI who suffered from neuropathic pain compared to those without neuropathic pain (223.7 ± 53.08 mm3 vs. 159.7 ± 55.66 mm3 , p = 0.043). Sciatic MRN parameters correlated with electrophysiological results but did not correlate with the extent of myelopathy or clinical severity of SCI. CONCLUSIONS Individuals with chronic SCI are subject to a decline of structural peripheral nerve integrity that may occur independently from the clinical severity of SCI. Larger volumes of DRG in SCI with neuropathic pain support existing evidence from animal studies on SCI-related neuropathic pain.
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Affiliation(s)
- Johann M. E. Jende
- Department of NeuroradiologyHeidelberg University HospitalHeidelbergGermany
| | - Laura Heutehaus
- Spinal Cord Injury CenterHeidelberg University HospitalHeidelbergGermany
| | - Fabian Preisner
- Department of NeuroradiologyHeidelberg University HospitalHeidelbergGermany
| | | | | | - Sabine Heiland
- Department of NeuroradiologyHeidelberg University HospitalHeidelbergGermany
- Division of Experimental Radiology, Department of NeuroradiologyHeidelberg University HospitalHeidelbergGermany
| | - Rüdiger Rupp
- Spinal Cord Injury CenterHeidelberg University HospitalHeidelbergGermany
| | - Martin Bendszus
- Department of NeuroradiologyHeidelberg University HospitalHeidelbergGermany
| | - Norbert Weidner
- Spinal Cord Injury CenterHeidelberg University HospitalHeidelbergGermany
| | - Felix T. Kurz
- Department of NeuroradiologyHeidelberg University HospitalHeidelbergGermany
- German Cancer Research CenterHeidelbergGermany
| | - Steffen Franz
- Spinal Cord Injury CenterHeidelberg University HospitalHeidelbergGermany
- Department for Spinal Cord InjuryAllgemeine Unfallversicherungsanstalt ‐ Austrain Workers' Compensation Board, Rehabilitation Center Weisser HofKlosterneuburgAustria
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Berger MJ, Adewuyi AA, Doherty C, Hanlan AK, Morin C, O'Connor R, Sharma R, Sproule S, Swong KN, Wu H, Franz CK, Brown E. Segmental infralesional pathological spontaneous activity in subacute traumatic spinal cord injury. Muscle Nerve 2024; 69:403-408. [PMID: 38294062 DOI: 10.1002/mus.28053] [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: 07/17/2023] [Revised: 01/13/2024] [Accepted: 01/21/2024] [Indexed: 02/01/2024]
Abstract
INTRODUCTION/AIMS There is a dearth of knowledge regarding the status of infralesional lower motor neurons (LMNs) in individuals with traumatic cervical spinal cord injury (SCI), yet there is a growing need to understand how the spinal lesion impacts LMNs caudal to the lesion epicenter, especially in the context of nerve transfer surgery to restore several key upper limb functions. Our objective was to determine the frequency of pathological spontaneous activity (PSA) at, and below, the level of spinal injury, to gain an understanding of LMN health below the spinal lesion. METHODS Ninety-one limbs in 57 individuals (53 males, mean age = 44.4 ± 16.9 years, mean duration from injury = 3.4 ± 1.4 months, 32 with motor complete injuries), were analyzed. Analysis was stratified by injury level as (1) C4 and above, (2) C5, and (3) C6-7. Needle electromyography was performed on representative muscles innervated by the C5-6, C6-7, C7-8, and C8-T1 nerve roots. PSA was dichotomized as present or absent. Data were pooled for the most caudal infralesional segment (C8-T1). RESULTS A high frequency of PSA was seen in all infralesional segments. The pooled frequency of PSA for all injury levels at C8-T1 was 68.7% of the limbs tested. There was also evidence of PSA at the rostral border of the neurological level of injury, with 58.3% of C5-6 muscles in those with C5-level injuries. DISCUSSION These data support a high prevalence of infralesional LMN abnormalities following SCI, which has implications to nerve transfer candidacy, timing of the intervention, and donor nerve options.
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Affiliation(s)
- Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Authority, Vancouver, British Columbia, Canada
| | - Adenike A Adewuyi
- Regenerative Neurorehabilitation Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois, USA
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Christopher Doherty
- Vancouver Coastal Health Authority, Vancouver, British Columbia, Canada
- Division of Plastic Surgery, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amy K Hanlan
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Authority, Vancouver, British Columbia, Canada
| | - Cynthia Morin
- Division of Plastic Surgery, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Russ O'Connor
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Coastal Health Authority, Vancouver, British Columbia, Canada
| | - Radhika Sharma
- Regenerative Neurorehabilitation Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois, USA
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Shannon Sproule
- Division of Plastic Surgery, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kevin N Swong
- Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Harvey Wu
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin K Franz
- Regenerative Neurorehabilitation Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois, USA
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Erin Brown
- Vancouver Coastal Health Authority, Vancouver, British Columbia, Canada
- Division of Plastic Surgery, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
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Berger MJ, Dengler J, Westman A, Curt A, Schubert M, Abel R, Weidner N, Röhrich F, Fox IK. Nerve Transfer After Cervical Spinal Cord Injury: Who Has a "Time Sensitive" Injury Based on Electrodiagnostic Findings? Arch Phys Med Rehabil 2024; 105:682-689. [PMID: 37979641 DOI: 10.1016/j.apmr.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/20/2023]
Abstract
OBJECTIVE To use the ulnar compound muscle action potential (CMAP) to abductor digiti minimi (ADM) to identify the proportion of individuals with cervical spinal cord injury (SCI) who have lower motor neuron (LMN) abnormalities involving the C8-T1 spinal nerve roots, within 3-6 months, and thus may influence the response to nerve transfer surgery. DESIGN Retrospective analysis of prospectively collected data. Data were analyzed from European Multicenter Study About SCI database. SETTING Multi-center, academic hospitals. PARTICIPANTS We included 79 subjects (age=41.4±17.7, range:16-75; 59 men; N=79), who were classified as cervical level injuries 2 weeks after injury and who had manual muscle strength examinations that would warrant consideration for nerve transfer (C5≥4, C8<3). INTERVENTIONS None. MAIN OUTCOME MEASURES The ulnar nerve CMAP amplitude to ADM was used as a proxy measure for C8-T1 spinal segment health. CMAP amplitude was stratified into very abnormal (<1.0 mV), sub-normal (1.0-5.9 mV), and normal (>6.0 mV). Analysis took place at 3 (n=148 limbs) and 6 months (n=145 limbs). RESULTS At 3- and 6-month post-injury, 33.1% and 28.3% of limbs had very abnormal CMAP amplitudes, respectively, while in 54.1% and 51.7%, CMAPs were sub-normal. Median change in amplitude from 3 to 6 months was 0.0 mV for very abnormal and 1.0 mV for subnormal groups. A 3-month ulnar CMAP <1 mV had a positive predictive value of 0.73 (95% CI 0.69-0.76) and 0.78 (95% CI 0.75-0.80) for C8 and T1 muscle strength of 0 vs 1 or 2. CONCLUSION A high proportion of individuals have ulnar CMAPs below the lower limit of normal 3- and 6-month post cervical SCI and may also have intercurrent LMN injury. Failure to identify individuals with LMN denervation could result in a lost opportunity to improve hand function through timely nerve transfer surgeries.
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Affiliation(s)
- Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Jana Dengler
- Division of Plastic Surgery, Tory Trauma Program, Sunnybrook Health Sciences Centre, Toronto, Ontario; Division of Plastic, Reconstructive and Aesthetic Surgery, Department of Surgery, University of Toronto, Toronto, Ontario
| | - Amanda Westman
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Schubert
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | | | - Norbert Weidner
- Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Frank Röhrich
- BG Klinikum Bergmannstrost, Zentrum für Rückenmarkverletzte und Klinik für Orthopädie, Halle, Germany
| | - Ida K Fox
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO
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Li G, Balbinot G, Furlan JC, Kalsi-Ryan S, Zariffa J. A computational model of surface electromyography signal alterations after spinal cord injury. J Neural Eng 2023; 20:066020. [PMID: 37948762 DOI: 10.1088/1741-2552/ad0b8e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/10/2023] [Indexed: 11/12/2023]
Abstract
Objective. Spinal cord injury (SCI) can cause significant impairment and disability with an impact on the quality of life for individuals with SCI and their caregivers. Surface electromyography (sEMG) is a sensitive and non-invasive technique to measure muscle activity and has demonstrated great potential in capturing neuromuscular changes resulting from SCI. The mechanisms of the sEMG signal characteristic changes due to SCI are multi-faceted and difficult to studyin vivo. In this study, we utilized well-established computational models to characterize changes in sEMG signal after SCI and identify sEMG features that are sensitive and specific to different aspects of the SCI.Approach. Starting from existing models for motor neuron pool organization and motor unit action potential generation for healthy neuromuscular systems, we implemented scenarios to model damages to upper motor neurons, lower motor neurons, and the number of muscle fibers within each motor unit. After simulating sEMG signals from each scenario, we extracted time and frequency domain features and investigated the impact of SCI disruptions on sEMG features using the Kendall Rank Correlation analysis.Main results. The commonly used amplitude-based sEMG features (such as mean absolute values and root mean square) cannot differentiate between injury scenarios, but a broader set of features (including autoregression and cepstrum coefficients) provides greater specificity to the type of damage present.Significance. We introduce a novel approach to mechanistically relate sEMG features (often underused in SCI research) to different types of neuromuscular alterations that may occur after SCI. This work contributes to the further understanding and utilization of sEMG in clinical applications, which will ultimately improve patient outcomes after SCI.
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Affiliation(s)
- Guijin Li
- KITE Research Institute, University Health Network, Toronto, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Gustavo Balbinot
- KITE Research Institute, University Health Network, Toronto, Canada
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Julio C Furlan
- KITE Research Institute, University Health Network, Toronto, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Canada
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of Toronto, Toronto, Canada
- Division of Physical Medicine and Rehabilitation, Toronto Rehabilitation Institute, University Health Network, Toronto, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Sukhvinder Kalsi-Ryan
- KITE Research Institute, University Health Network, Toronto, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Canada
- Department of Physical Therapy, University of Toronto, Toronto, Canada
| | - José Zariffa
- KITE Research Institute, University Health Network, Toronto, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Canada
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada
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Li L, Hu H, Yao B, Huang C, Lu Z, Klein CS, Zhou P. Electromyography-Force Relation and Muscle Fiber Conduction Velocity Affected by Spinal Cord Injury. Bioengineering (Basel) 2023; 10:217. [PMID: 36829711 PMCID: PMC9952596 DOI: 10.3390/bioengineering10020217] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
A surface electromyography (EMG) analysis was performed in this study to examine central neural and peripheral muscle changes after a spinal cord injury (SCI). A linear electrode array was used to record surface EMG signals from the biceps brachii (BB) in 15 SCI subjects and 14 matched healthy control subjects as they performed elbow flexor isometric contractions from 10% to 80% maximum voluntary contraction. Muscle fiber conduction velocity (MFCV) and BB EMG-force relation were examined. MFCV was found to be significantly slower in the SCI group than the control group, evident at all force levels. The BB EMG-force relation was well fit by quadratic functions in both groups. All healthy control EMG-force relations were best fit with positive quadratic coefficients. In contrast, the EMG-force relation in eight SCI subjects was best fit with negative quadratic coefficients, suggesting impaired EMG modulation at high forces. The alterations in MFCV and EMG-force relation after SCI suggest complex neuromuscular changes after SCI, including alterations in central neural drive and muscle properties.
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Affiliation(s)
- Le Li
- Institute of Medical Research, Northwestern Polytechnical University, Xi’an 710072, China
| | - Huijing Hu
- Institute of Medical Research, Northwestern Polytechnical University, Xi’an 710072, China
| | - Bo Yao
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Medical College, Beijing 100006, China
| | - Chengjun Huang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhiyuan Lu
- School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao 266072, China
| | - Cliff S. Klein
- Rehabilitation Research Institute, Guangdong Work Injury Rehabilitation Center, Guangzhou 510440, China
| | - Ping Zhou
- School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao 266072, China
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Berger MJ, Adewuyi AA, Fox IK, Franz CK. Clinical electrodiagnostic evaluation for nerve transfer surgery in spinal cord injury: a new indication and clinical pearls. J Neurophysiol 2022; 128:847-853. [PMID: 36043801 PMCID: PMC10190829 DOI: 10.1152/jn.00289.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/23/2022] [Accepted: 08/26/2022] [Indexed: 11/22/2022] Open
Abstract
In this review, we highlight the important role of the clinical electrodiagnostic (EDX) evaluation after cervical spinal cord injury (SCI). Our discussion focuses on the need for timely, frequent, and accurate EDX evaluations in the context of nerve transfer surgery to restore critical upper limb functions, including elbow extension, hand opening, and hand closing. The EDX evaluation is crucial to define the extent of lower motor neuron lesions and determine candidacy for surgery. We also discuss the important role of the postoperative EDX evaluation in determining prognosis and supporting rehabilitation. We propose a practical framework for EDX evaluation in this clinical setting.
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Affiliation(s)
- Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Adenike A Adewuyi
- Regenerative Neurorehabilitation Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois
- Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Ida K Fox
- Division of Plastic Surgery, Department of Surgery, Washington University School of Medicine, Saint Louis, Missouri
| | - Colin K Franz
- Regenerative Neurorehabilitation Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois
- Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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Silverman J, Dengler J, Song C, Robinson LR. Pre-operative electrodiagnostic planning for upper limb peripheral nerve transfers in cervical spinal cord injury: A Narrative Review. PM R 2022. [PMID: 35726540 DOI: 10.1002/pmrj.12868] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 02/13/2022] [Accepted: 05/31/2022] [Indexed: 11/08/2022]
Abstract
Peripheral nerve transfer (PNT) to improve upper limb function following cervical spinal cord injury (SCI) involves the transfer of supralesional donor nerves under voluntary control to intralesional or sublesional lower motor neurons not under voluntary control. Appropriate selection of donor and recipient nerves and surgical timing impact functional outcomes. While the gold standard of nerve selection is intra-operative nerve stimulation, preoperative electrodiagnostic (EDX) evaluation may help guide surgical planning. Currently there is no standardized preoperative EDX protocol. This study reviews the EDX workup preceding peripheral nerve transfer surgery in cervical SCI, and proposes an informed EDX protocol to assist with surgical planning. The PICO (Population, Intervention, Comparison, Outcome) framework was used to formulate relevant MeSH terms and identify published cases of PNT in cervical SCI in Medline, Embase, CINAHL, and Emcare databases in the last 10 years. The electrodiagnostic techniques evaluating putative donor nerves, recipient nerve branches, time-sensitivity of nerve transfer and other electrophysiological parameters were summarized to guide creation of a preoperative EDX protocol. Needle electromyography (EMG) was the most commonly used EDX technique to identify healthy donor nerves. Although needle EMG has also been used on recipient nerves, compound muscle action potential (CMAP) amplitudes may provide a more accurate determination of recipient nerve health and time-sensitivity for nerve transfer. While there has been progress in pre-surgical EDX evaluation, EMG and NCS approaches are quite variable, and each has limitations in their utility for pre-operative planning. There is need for standardization in the EDX evaluation preceding peripheral nerve transfer surgery to assist with donor and recipient nerve selection, surgical timing and to optimize outcomes. Based on results of this review, herein we propose the PreSCIse (PRotocol for Electrodiagnosis in SCI Surgery of the upper Extremity) pre-operative EDX panel to achieve said goals through an interdisciplinary and patient-centered approach. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jordan Silverman
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Jana Dengler
- Division of Plastic and Reconstructive Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Cimon Song
- Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Lawrence R Robinson
- Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada
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Mauti E, Robinson LR. Radial motor nerve conduction studies recorded from triceps brachii and extensor carpi radialis longus: Techniques and reference values. Muscle Nerve 2021; 65:337-340. [PMID: 34862799 DOI: 10.1002/mus.27470] [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: 06/21/2021] [Revised: 11/27/2021] [Accepted: 11/30/2021] [Indexed: 11/10/2022]
Abstract
INTRODUCTION/AIMS Optimal timing of nerve transfer surgery in cervical spinal cord injury (SCI) depends upon the integrity of lower motor neurons (LMNs) in recipient nerves, which is best predicted by compound muscle action potential (CMAP) amplitude. There are no established techniques for obtaining the CMAP in two recipient muscles: triceps brachii and extensor carpi radialis longus (ECRL). This study aimed to develop recording techniques for radial motor studies to triceps and ECRL, and to determine reference values for CMAP amplitudes in healthy volunteers. METHODS This was a prospective observational study of healthy adults aged 18 years and older. Motor nerve conduction studies were performed, stimulating the radial nerve in the axilla, over the axillary pulse at the pectoralis major insertion. Recording was from triceps (long head) and ECRL. CMAP amplitude, area, latency, and stimulus intensity were recorded. Reference values (RV) were calculated for CMAP amplitudes using a value 2 standard deviations below the mean. Cube root or logarithmic transformations were used to correct for non-normal distributions. RESULTS Twenty-five healthy subjects participated. Triceps mean CMAP amplitude was 15.5 mV (SD 4.19), with an RV of 8.1 mV. ECRL mean CMAP amplitude was 11.5 mV (SD 3.54), with an RV of 6.2 mV. CMAP amplitude at ECRL was 75% (95% confidence interval 50%-100%) of that at triceps. DISCUSSION We describe a technique for recording radial motor NCS from triceps and ECRL. Knowledge of normal CMAP amplitudes will help identify LMN injury in patients with cervical SCI being considered for nerve transfers.
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Affiliation(s)
- Emma Mauti
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Lawrence R Robinson
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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Zong Y, Lu Z, Chen M, Li X, Stampas A, Deng L, Zhou P. CMAP Scan Examination of the First Dorsal Interosseous Muscle After Spinal Cord Injury. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1199-1205. [PMID: 34106858 PMCID: PMC8780215 DOI: 10.1109/tnsre.2021.3088061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The study assessed motor unit loss in muscles paralyzed by spinal cord injury (SCI) using a novel compound muscle action potential (CMAP) scan examination. The CMAP scan of the first dorsal interosseous (FDI) muscle was applied in tetraplegia (n = 13) and neurologically intact (n = 13) subjects. MScanFit was used for estimating motor unit numbers in each subject. The D50 value of the CMAP scan was also calculated. We observed a significant decrease in both CMAP amplitude and motor unit number estimation (MUNE) in paralyzed FDI muscles, as compared with neurologically intact muscles. Across all subjects, the CMAP (negative peak) amplitude was 8.01 ± 3.97 mV for the paralyzed muscles and 16.75 ± 3.55 mV for the neurologically intact muscles (p < 0.001). The CMAP scan resulted in a MUNE of 59 ± 37 for the paralyzed muscles, much lower than 108 ± 21 for the neurologically intact muscles (p < 0.001). No significant difference in D50 was observed between the two groups (p = 0.2). For the SCI subjects, there was no significant correlation between MUNE and CMAP amplitude, or any of the clinical assessments including pinch force, grip force, the Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) score, and SCI duration (p > 0.05). The findings provide an evidence of motor unit loss in the FDI muscles of individuals with tetraplegia, which may contribute to weakness and other hand function deterioration. The CMAP scan offers several practical benefits compared with the traditional MUNE techniques because it is noninvasive, automated and can be performed within several minutes.
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Berger MJ, Robinson L, Krauss EM. Lower Motor Neuron Abnormality in Chronic Cervical Spinal Cord Injury: Implications for Nerve Transfer Surgery. J Neurotrauma 2021; 39:259-265. [PMID: 33626968 DOI: 10.1089/neu.2020.7579] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Nerve transfer surgery (NT) constitutes an exciting option to improve upper limb functions in chronic spinal cord injury (SCI), but requires intact sublesional lower motor neuron (LMN) health. The purpose of this study was to characterize patterns of LMN abnormality in nerve-muscle groups that are the potential recipients of NT, using a standardized electrodiagnostic examination, in individuals with chronic SCI (injury duration >2 years, injury levels C4-T1). The LMN abnormality was determined using a semihierarchical approach, combining the amplitude compound muscle action potential (CMAP) and abnormal spontaneous activity on needle electromyography (EMG). Ten participants (46 potential recipient muscles) were included (median age, 42.5 years; six males and four females; median duration from injury, 15.5 years). A high frequency of LMN abnormality was observed (87%), although there was substantial variation within and between individuals. No statistically significant discordance was observed between LMN abnormality on CMAP and EMG (p = 0.24), however, 50% of muscles with normal CMAP demonstrated abnormal spontaneous activity. The high frequency of LMN abnormality in recipient nerve-muscle groups has implications to candidate selection for NT surgery in chronic SCI and supports the important role of the pre-operative electrodiagnostic examination. Our results further support the inclusion of both CMAP and needle EMG parameters for characterization of LMN health. Although the number of nerve-muscle groups with normal LMN health was small (13%), this underscores the neurophysiological potential of some patients with chronic injuries to benefit from NT surgery.
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Affiliation(s)
- Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lawrence Robinson
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Emily M Krauss
- Division of Plastic Surgery, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
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12
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Mealy A, Tierney S, Sorensen J. Lower extremity amputations in Ireland: a registry-based study. Ir J Med Sci 2021; 191:839-844. [PMID: 33755918 DOI: 10.1007/s11845-021-02536-z] [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: 11/19/2020] [Accepted: 01/28/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE To analyse the current provision of lower extremity amputations (LEA) in Irish public hospitals by patient characteristics and assess the potential savings for reducing numbers if a national multi-disciplinary foot protection clinic (MDFPC) was established nation-wide. DESIGN AND DATA SOURCES Patient characteristics of LEA conducted during 2016-2019 were analysed based on discharge data from the national hospital inpatient enquiry system. Reported consequences from existing literature were used to extrapolate national consequences. RESULTS Public hospitals registered 3104 hospital admissions with LEA during 2016-2019. 68% (n = 2099) of these were minor amputations. About 76% (n = 1592) of minor amputations and 52% (n = 525) of major amputations were performed on patients with a diagnosis of diabetes. If the implementation of a national MDFPC programmed could reduce the number of diabetic amputations by 20%, 80 minor and 26 major amputations could be avoided annually. This would avoid nearly 3000 hospital bed days and correspond to a potential annual saving of €3 M. CONCLUSION LEA has severe impact on patients' lives and hospital resources. Potential savings from effective prevention strategies may offer both health improvements and cost-savings.
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Affiliation(s)
| | - Sean Tierney
- Tallaght University Hospital, Dublin, Republic of Ireland
| | - Jan Sorensen
- Healthcare Outcome Research Centre, RCSI, Dublin, Republic of Ireland
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13
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Soloukey S, Drenthen J, Osterthun R, de Vos CC, De Zeeuw CI, Huygen FJPM, Harhangi BS. How to Identify Responders and Nonresponders to Dorsal Root Ganglion-Stimulation Aimed at Eliciting Motor Responses in Chronic Spinal Cord Injury: Post Hoc Clinical and Neurophysiological Tests in a Case Series of Five Patients. Neuromodulation 2021; 24:719-728. [PMID: 33749941 PMCID: PMC8359838 DOI: 10.1111/ner.13379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 01/11/2021] [Accepted: 01/28/2021] [Indexed: 11/29/2022]
Abstract
Objective While integrity of spinal pathways below injury is generally thought to be an important factor in the success‐rate of neuromodulation strategies for spinal cord injury (SCI), it is still unclear how the integrity of these pathways conveying the effects of stimulation should be assessed. In one of our institutional case series of five patients receiving dorsal root ganglion (DRG)‐stimulation for elicitation of immediate motor response in motor complete SCI, only two out of five patients presented as responders, showing immediate muscle activation upon DRG‐stimulation. The current study focuses on post hoc clinical‐neurophysiological tests performed within this patient series to illustrate their use for prediction of spinal pathway integrity, and presumably, responder‐status. Materials and Methods In a series of three nonresponders and two responders (all male, American Spinal Injury Association [ASIA] impairment scale [AIS] A/B), a test‐battery consisting of questionnaires, clinical measurements, as well as a series of neurophysiological measurements was performed less than eight months after participation in the initial study. Results Nonresponders presented with a complete absence of spasticity and absence of leg reflexes. Additionally, nonresponders presented with close to no compound muscle action potentials (CMAPs) or Hofmann(H)‐reflexes. In contrast, both responders presented with clear spasticity, elicitable leg reflexes, CMAPs, H‐reflexes, and sensory nerve action potentials, although not always consistent for all tested muscles. Conclusions Post hoc neurophysiological measurements were limited in clearly separating responders from nonresponders. Clinically, complete absence of spasticity‐related complaints in the nonresponders was a distinguishing factor between responders and nonresponders in this case series, which mimics prior reports of epidural electrical stimulation, potentially illustrating similarities in mechanisms of action between the two techniques. However, the problem remains that explicit use and report of preinclusion clinical‐neurophysiological measurements is missing in SCI literature. Identifying proper ways to assess these criteria might therefore be unnecessarily difficult, especially for nonestablished neuromodulation techniques.
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Affiliation(s)
- Sadaf Soloukey
- Department of Neurosurgery, Erasmus MC, Rotterdam, The Netherlands.,Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Judith Drenthen
- Department of Clinical Neurophysiology, Erasmus MC, Rotterdam, The Netherlands
| | - Rutger Osterthun
- Department of Rehabilitation Medicine, Erasmus MC, Rotterdam, The Netherlands.,Spinal Cord Injury Department, Rijndam Rehabilitation Center, Rotterdam, The Netherlands
| | - Cecile C de Vos
- Center for Pain Medicine, Department of Anesthesiology, Erasmus MC, Rotterdam, The Netherlands
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands.,Netherlands Institute for Neuroscience, Royal Dutch Academy for Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Frank J P M Huygen
- Center for Pain Medicine, Department of Anesthesiology, Erasmus MC, Rotterdam, The Netherlands
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14
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Witt A, Fuglsang-Frederiksen A, Finnerup N, Kasch H, Tankisi H. Detecting peripheral motor nervous system involvement in chronic spinal cord injury using two novel methods: MScanFit MUNE and muscle velocity recovery cycles. Clin Neurophysiol 2020; 131:2383-2392. [DOI: 10.1016/j.clinph.2020.06.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 06/14/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022]
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15
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Dillingham TR, Annaswamy TM, Plastaras CT. Evaluation of persons with suspected lumbosacral and cervical radiculopathy: Electrodiagnostic assessment and implications for treatment and outcomes (Part I). Muscle Nerve 2020; 62:462-473. [PMID: 32557709 DOI: 10.1002/mus.26997] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 06/03/2020] [Indexed: 11/11/2022]
Abstract
Persons with back, neck, and limb symptoms constitute a major referral population to specialists in electrodiagnostic (EDX) medicine. The evaluation of these patients involves consideration of both the common and less common disorders. The EDX examination with needle electromyography (EMG) is the most important means of testing for radiculopathy. This test has modest sensitivity but high specificity and well complements imaging of the spine. Needle EMG in combination with nerve conduction testing is valuable in excluding entrapment neuropathies and polyneuropathy-conditions that frequently mimic radicular symptoms. In this first of a two-part review, the optimal EDX evaluation of persons with suspected radiculopathy is presented. In part two, the implications of EDX findings for diagnosis and clinical management of persons with radiculopathy are reviewed.
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Affiliation(s)
- Timothy R Dillingham
- Department of Physical Medicine and Rehabilitation, the Perelman School of Medicine, The University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Thiru M Annaswamy
- Department of Physical Medicine & Rehabilitation, Electrodiagnostic and Spine Sections, VA North Texas Health Care System, Dallas VA Medical Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Christopher T Plastaras
- Musculoskeletal Spine & Sports Rehabilitation Medicine, MossRehab, Einstein Spine Institute, Einstein Healthcare Network, Rehabilitation Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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16
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Liu J, Li R, Huang Z, Huang Z, Li Y, Wu X, Lin J, Jiang H, Cheng Y, Kong G, Wu X, Liu Q, Liu Y, Yang Z, Li R, Chen J, Fu J, Ramer MS, Kwon BK, Liu J, Kramer JLK, Tetzlaff W, Hu Y, Zhu Q. A Cervical Spinal Cord Hemi-Contusion Injury Model Based on Displacement Control in Non-Human Primates (Macaca fascicularis). J Neurotrauma 2020; 37:1669-1686. [PMID: 32174266 DOI: 10.1089/neu.2019.6822] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Non-human primate (NHP) spinal cord injury (SCI) models can be informative in the evaluation of treatments that show promise in rodent models prior to translation to humans. In the present study, we aimed to establish a cervical spinal hemi-contusion model with controlled displacement and evaluate the abnormalities in behavior, electrophysiology, histology, and magnetic resonance imaging. Twelve adult NHPs were divided into an SCI group (n = 8, 24 and 48 weeks) and a control group (n = 4). An impactor (Φ = 4 mm) was driven to compress the left C5 cord at 800 mm/sec. The contusion displacement and peak force was 4.08 ± 0.17 mm and 19.8 ± 4.6 N. The behavioral assessment showed a consistent dysfunction below the wrist and spontaneous recovery of limb function after injury. Lesion length and lesion area at the epicenter based on T2 hyperintensity were 5.68 ± 0.47 mm and 5.99 ± 0.24 mm2 at 24 weeks post-injury (wpi), and 5.29 ± 0.17 mm and 5.95 ± 0.24 mm2 at 48 wpi. The spared spinal cord area immuno-positive for glial fibrillary acidic protein was significantly reduced, while the staining intensity increased at 24 wpi and 48 wpi, compared with the sham group. Ipsilateral somatosensory and motor evoked potentials were dynamic, increasing in latency and decreasing in amplitude compared with pre-operative values or the contralateral values, and correlated to varying degrees with behavioral outcomes. A shift in size-frequency distribution of sensory neurons of the dorsal root ganglia (DRG) was consistent with a loss of large-diameter cells. The present study demonstrated that the NHP SCI model resulted in consistent unilateral limb dysfunction and potential plasticity in the face of loss of spinal cord and DRG tissue.
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Affiliation(s)
- Junhao Liu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Rong Li
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zucheng Huang
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhiping Huang
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuefeng Li
- Guangdong Landau Biotechnology Co. Ltd., Guangzhou, China
| | - Xiaoliang Wu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Junyu Lin
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Hui Jiang
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yongquan Cheng
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ganggang Kong
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiuhua Wu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qi Liu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yapu Liu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhou Yang
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ruoyao Li
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jianting Chen
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Joey Fu
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matt S Ramer
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian K Kwon
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - John L K Kramer
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), Blusson Spinal Cord Center, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yong Hu
- Department of Orthopedics and Traumatology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Qingan Zhu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
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17
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Galea M, Messina A, Hill B, Cooper C, Hahn J, van Zyl N. Reanimating hand function after spinal cord injury using nerve transfer surgery. ADVANCES IN CLINICAL NEUROSCIENCE & REHABILITATION 2020. [DOI: 10.47795/cqzf2655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Loss of arm and hand function is a devastating consequence of cervical spinal cord injury. Tendon transfer surgery has traditionally been used to restore key functions including elbow extension, wrist extension and grasp and pinch. The more recent development of nerve transfer surgery enables direct restoration of voluntary control of these functions. While both types of surgery are safe and effective, nerve transfer surgery results in a more open, flexible and natural hand, with more subtle control for a range of activities of daily living.
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18
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Moon CW, Jung IY, Cho KH. Electrophysiological Changes in the Peripheral Nervous System After Subacute Spinal Cord Injury. Arch Phys Med Rehabil 2020; 101:994-1000. [PMID: 32035142 DOI: 10.1016/j.apmr.2019.12.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/24/2019] [Accepted: 12/29/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To assess factors affecting electrophysiological changes in the peripheral nervous system below the neurologic level of injury (NLI) in patients with subacute spinal cord injury (SCI). DESIGN Retrospective observational study. SETTING An inpatient rehabilitation center of a university hospital. PARTICIPANTS Through reviewing the medical records of 151 subjects with SCI, 42 without any other disease inducing peripheral neurologic abnormalities were included. They were classified into 2 groups, with or without denervation potentials in electromyography (EMG) below NLI. INTERVENTION Not applicable. MAIN OUTCOME MEASURES Demographics and clinical characteristics including NLI, American Spinal Injury Association Impairment Scale (AIS), and Lower Extremity Motor Score were compared. Results of electrophysiological study including nerve conduction study, somatosensory-evoked potential (SSEP), and motor-evoked potential (MEP) were compared. RESULTS Denervation potentials in EMG below NLI were observed in 20 subjects, and 10 of them were AIS A or B, but there was none in subjects without denervation potentials (P<.001). The lower extremity motor score was 4.35±7.74 in the group with denervation potentials, lower than 33.64±13.60 of the opposite group (P<.001). In the analysis of electrophysiological study, patients with denervation potentials showed a higher proportion of no response than patients without denervation potentials (60.0% vs 11.4% in peroneal nerve conduction study, 35.0% vs 2.3% in tibial nerve conduction study, 80.0% vs 18.2% in SSEP, 87.5% vs 22.7% in MEP; P<.001, respectively). Additionally, greater axonal loss, based on decrease of amplitude without delayed latency on nerve conduction study, was observed in the group with denervation potentials than the opposite group (P<.001). CONCLUSION Among subjects with subacute SCI, cases of peripheral nervous dysfunction below the injury site occur, possibly associated with the severity of SCI.
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Affiliation(s)
- Chang-Won Moon
- Department of Rehabilitation Medicine, Chungnam National University College of Medicine, Daejeon, Korea
| | - Il-Young Jung
- Department of Rehabilitation Medicine, Chungnam National University College of Medicine, Daejeon, Korea
| | - Kang Hee Cho
- Department of Rehabilitation Medicine, Chungnam National University College of Medicine, Daejeon, Korea.
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19
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Zakrasek EC, Jaramillo JP, Lateva ZC, Punj V, Kiratli BJ, McGill KC. Quantitative electrodiagnostic patterns of damage and recovery after spinal cord injury: a pilot study. Spinal Cord Ser Cases 2019; 5:101. [PMID: 31871766 PMCID: PMC6908655 DOI: 10.1038/s41394-019-0246-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/16/2019] [Accepted: 11/18/2019] [Indexed: 01/09/2023] Open
Abstract
Study design Prospective observational pilot study. Objectives To compare quantitative electromyographic (EMG), imaging and strength data at two time points in individuals with cervical spinal cord injury (SCI). Setting SCI center, Veterans Affairs Health Care System, Palo Alto, California, USA. Methods Subjects without suspected peripheral nerve injury were recruited within 3 months of injury. Needle EMG examination was performed in myotomes above, at, and below the SCI level around 11- and 12-months post injury. EMG data were decomposed using custom software into constituent motor unit trains and each distinct motor unit was analyzed for firing rate and amplitude. Strength measurements were made with dynamometry and according to the International Standard of Neurologic Classification of SCI (ISNCSCI). Cervical magnetic resonance images (MRI) were evaluated by two neuroradiologists for gray and white matter damage around the SCI. Here, we compare the EMG, strength, and imaging findings of the one of the four participants who completed both 3- and 12-month EMG evaluations. Results There was an increase in force generation in all muscles tested at 1 year. Localized findings of very fast firing motor units helped localize spinal cord damage and revealed gray matter damage in spinal segments where MRI was normal. Meanwhile, improvement in strength over time corresponded with different electrophysiologic patterns. Conclusions Electromyographic decomposition at two time points provides valuable information about localization of spinal cord damage, integrity of motor neuron pools and may provide a unique understanding of neural recovery mechanisms.
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Affiliation(s)
- Elissa C. Zakrasek
- Spinal Cord Injury Center, VA Palo Alto Health Care System, Palo Alto, CA USA
| | | | - Zoia C. Lateva
- Spinal Cord Injury Center, VA Palo Alto Health Care System, Palo Alto, CA USA
| | - Vandana Punj
- Spinal Cord Injury Center, VA Palo Alto Health Care System, Palo Alto, CA USA
| | - B. Jenny Kiratli
- Spinal Cord Injury Center, VA Palo Alto Health Care System, Palo Alto, CA USA
| | - Kevin C. McGill
- Spinal Cord Injury Center, VA Palo Alto Health Care System, Palo Alto, CA USA
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20
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Li L, Stampas A, Shin H, Li X, Zhou P. Alterations in Localized Electrical Impedance Myography of Biceps Brachii Muscles Paralyzed by Spinal Cord Injury. Front Neurol 2017; 8:253. [PMID: 28676786 PMCID: PMC5476999 DOI: 10.3389/fneur.2017.00253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/22/2017] [Indexed: 12/13/2022] Open
Abstract
This study assessed electrical impedance myography (EIM) changes after spinal cord injury (SCI) with a localized multifrequency technology. The EIM measurement was performed on the biceps brachii muscle at rest condition of 17 cervical SCI subjects, and 23 neurologically intact subjects as control group. The results showed that there was a significant decrease in muscle reactance (X) and phase angle (θ) at selected frequencies (i.e., 50 and 100 kHz) in SCI compared to control. There was no significant difference in muscle resistance (R) between the two groups. The anisotropy examination revealed that SCI group had a decreased anisotropy ratio in resistance. In addition, the multifrequency spectrum analysis showed a decreased slope of the log(freq)-resistance regression in SCI group when compared to healthy control. Findings of the EIM changes are related to inherit muscle changes after the injury. Since EIM requires no patient effort and is quick and convenient to conduct, it may provide a useful tool for examination of paralyzed muscle changes after SCI.
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Affiliation(s)
- Le Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States.,Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Argyrios Stampas
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States
| | - Henry Shin
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States.,Guangdong Work Injury Rehabilitation Center, Guangzhou, China
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Thomas CK, Häger CK, Klein CS. Increases in human motoneuron excitability after cervical spinal cord injury depend on the level of injury. J Neurophysiol 2016; 117:684-691. [PMID: 27852734 DOI: 10.1152/jn.00676.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/11/2016] [Indexed: 11/22/2022] Open
Abstract
After human spinal cord injury (SCI), motoneuron recruitment and firing rate during voluntary and involuntary contractions may be altered by changes in motoneuron excitability. Our aim was to compare F waves in single thenar motor units paralyzed by cervical SCI to those in uninjured controls because at the single-unit level F waves primarily reflect the intrinsic properties of the motoneuron and its initial segment. With intraneural motor axon stimulation, F waves were evident in all 4 participants with C4-level SCI, absent in 8 with C5 or C6 injury, and present in 6 of 12 Uninjured participants (P < 0.001). The percentage of units that generated F waves differed across groups (C4: 30%, C5 or C6: 0%, Uninjured: 16%; P < 0.001). Mean (±SD) proximal axon conduction velocity was slower after C4 SCI [64 ± 4 m/s (n = 6 units), Uninjured: 73 ± 8 m/s (n = 7 units); P = 0.037]. Mean distal axon conduction velocity differed by group [C4: 40 ± 8 m/s (n = 20 units), C5 or C6: 49 ± 9 m/s (n = 28), Uninjured: 60 ± 7 m/s (n = 45); P < 0.001]. Motor unit properties (EMG amplitude, twitch force) only differed after SCI (P ≤ 0.004), not by injury level. Motor units with F waves had distal conduction velocities, M-wave amplitudes, and twitch forces that spanned the respective group range, indicating that units with heterogeneous properties produced F waves. Recording unitary F waves has shown that thenar motoneurons closer to the SCI (C5 or C6) have reduced excitability whereas those further away (C4) have increased excitability, which may exacerbate muscle spasms. This difference in motoneuron excitability may be related to the extent of membrane depolarization following SCI. NEW & NOTEWORTHY Unitary F waves were common in paralyzed thenar muscles of people who had a chronic spinal cord injury (SCI) at the C4 level compared with uninjured people, but F waves did not occur in people that had SCI at the C5 or C6 level. These results highlight that intrinsic motoneuron excitability depends, in part, on how close the motoneurons are to the site of the spinal injury, which could alter the generation and strength of voluntary and involuntary muscle contractions.
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Affiliation(s)
- Christine K Thomas
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida;
| | - Charlotte K Häger
- Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden; and
| | - Cliff S Klein
- Guangdong Work Injury Rehabilitation Center, Guangzhou, People's Republic of China
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22
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Morphology of Donor and Recipient Nerves Utilised in Nerve Transfers to Restore Upper Limb Function in Cervical Spinal Cord Injury. Brain Sci 2016; 6:brainsci6040042. [PMID: 27690115 PMCID: PMC5187556 DOI: 10.3390/brainsci6040042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 09/19/2016] [Accepted: 09/21/2016] [Indexed: 11/21/2022] Open
Abstract
Loss of hand function after cervical spinal cord injury (SCI) impacts heavily on independence. Multiple nerve transfer surgery has been applied successfully after cervical SCI to restore critical arm and hand functions, and the outcome depends on nerve integrity. Nerve integrity is assessed indirectly using muscle strength testing and intramuscular electromyography, but these measures cannot show the manifestation that SCI has on the peripheral nerves. We directly assessed the morphology of nerves biopsied at the time of surgery, from three patients within 18 months post injury. Our objective was to document their morphologic features. Donor nerves included teres minor, posterior axillary, brachialis, extensor carpi radialis brevis and supinator. Recipient nerves included triceps, posterior interosseus (PIN) and anterior interosseus nerves (AIN). They were fixed in glutaraldehyde, processed and embedded in Araldite Epon for light microscopy. Eighty percent of nerves showed abnormalities. Most common were myelin thickening and folding, demyelination, inflammation and a reduction of large myelinated axon density. Others were a thickened perineurium, oedematous endoneurium and Renaut bodies. Significantly, very thinly myelinated axons and groups of unmyelinated axons were observed indicating regenerative efforts. Abnormalities exist in both donor and recipient nerves and they differ in appearance and aetiology. The abnormalities observed may be preventable or reversible.
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23
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Tankisi H, Pugdahl K, Rasmussen MM, Clemmensen D, Rawashdeh YF, Christensen P, Krogh K, Fuglsang-Frederiksen A. Peripheral nervous system involvement in chronic spinal cord injury. Muscle Nerve 2015; 52:1016-22. [DOI: 10.1002/mus.24644] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 02/20/2015] [Accepted: 03/03/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Hatice Tankisi
- Department of Clinical Neurophysiology; Aarhus University Hospital; Nørrebrogade 44 DK-8000 Aarhus C Denmark
| | - Kirsten Pugdahl
- Department of Clinical Neurophysiology; Aarhus University Hospital; Nørrebrogade 44 DK-8000 Aarhus C Denmark
| | - Mikkel Mylius Rasmussen
- The Spinal Cord Research Centre; Department of Neurosurgery; Aarhus University Hospital; Aarhus Denmark
- Pelvic Floor Unit; Department of Surgery; Aarhus University Hospital; Aarhus Denmark
| | - Dorte Clemmensen
- The Spinal Cord Research Centre; Department of Neurosurgery; Aarhus University Hospital; Aarhus Denmark
| | - Yazan F. Rawashdeh
- Department of Urology; Aarhus University Hospital; Aarhus Aarhus Denmark
| | - Peter Christensen
- Pelvic Floor Unit; Department of Surgery; Aarhus University Hospital; Aarhus Denmark
| | - Klaus Krogh
- Neurogastroenterology Unit; Department of Hepatology and Gastroenterology; Aarhus University Hospital; Aarhus Denmark
| | - Anders Fuglsang-Frederiksen
- Department of Clinical Neurophysiology; Aarhus University Hospital; Nørrebrogade 44 DK-8000 Aarhus C Denmark
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Li L, Li X, Liu J, Zhou P. Alterations in multidimensional motor unit number index of hand muscles after incomplete cervical spinal cord injury. Front Hum Neurosci 2015; 9:238. [PMID: 26005410 PMCID: PMC4424856 DOI: 10.3389/fnhum.2015.00238] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 04/13/2015] [Indexed: 12/13/2022] Open
Abstract
The objective of this study was to apply a novel multidimensional motor unit number index (MD-MUNIX) technique to examine hand muscles in patients with incomplete cervical spinal cord injury (SCI). The MD-MUNIX was estimated from the compound muscle action potential (CMAP) and different levels of surface interference pattern electromyogram (EMG) at multiple directions of voluntary isometric muscle contraction. The MD-MUNIX was applied in the first dorsal interosseous (FDI), thenar and hypothenar muscles of SCI (n = 12) and healthy control (n = 12) subjects. The results showed that the SCI subjects had significantly smaller CMAP and MD-MUNIX in all the three examined muscles, compared to those derived from the healthy control subjects. The multidimensional motor unit size index (MD-MUSIX) demonstrated significantly larger values for the FDI and hypothenar muscles in SCI subjects than those from healthy control subjects, whereas the MD-MUSIX enlargement was marginally significant for the thenar muscles. The findings from the MD-MUNIX analyses provide an evidence of motor unit loss in hand muscles of cervical SCI patients, contributing to hand function deterioration.
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Affiliation(s)
- Le Li
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-Sen University Guangzhou, China ; Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA
| | - Jie Liu
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago Chicago, IL, USA
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA ; Biomedical Engineering Program, University of Science and Technology of China Hefei, China
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25
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Ruet A, Durand MC, Denys P, Lofaso F, Genet F, Schnitzler A. Single-fiber electromyography analysis of botulinum toxin diffusion in patients with fatigue and pseudobotulism. Arch Phys Med Rehabil 2015; 96:1103-9. [PMID: 25620718 DOI: 10.1016/j.apmr.2015.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 12/17/2014] [Accepted: 01/07/2015] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To characterize electromyographic abnormalities according to symptoms (asymptomatic, fatigue, pseudobotulism) reported 1 month after botulinum toxin injection. DESIGN Retrospective, single-center study comparing single-fiber electromyography (SFEMG) in the extensor digitorum communis (EDC) or orbicularis oculi (OO) muscles. SETTING Hospital. PARTICIPANTS Four groups of adults treated for spasticity or neurologic bladder hyperactivity (N=55): control group (asymptomatic patients: n=17), fatigue group (unusual fatigue with no weakness: n=15), pseudobotulism group (muscle weakness and/or visual disturbance: n=20), and botulism group (from intensive care unit of the same hospital: n=3). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Mean jitter, percentage of pathologic fibers, and percentage of blocked fibers were compared between groups. RESULTS SFEMG was abnormal for 17.6% of control patients and 75% of patients in the pseudobotulism group. There were no differences between the control and fatigue groups. Mean jitter, percentage of pathologic fibers, and percentage of blocked fibers of the EDC muscle were significantly higher in the pseudobotulism group than in the fatigue and control groups. There were no differences between groups for the OO muscle. The SFEMG results in the botulism group were qualitatively similar to those of the pseudobotulism group. CONCLUSIONS SFEMG of the EDC muscle confirmed diffusion of the toxin into muscles distant from the injection site in the pseudobotulism group. SFEMG in the OO muscle is not useful for the diagnosis of diffusion. No major signs of diffusion of botulinum toxin type A were found away from the injection site in patients with fatigue but no motor weakness. Such fatigue may be related to other mechanisms.
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Affiliation(s)
- Alexis Ruet
- Physical Medicine and Rehabilitation Department, Raymond Poincaré Hospital, Paris' Public Assistance Hospitals, University of Versailles Saint Quentin, Garches, France.
| | - Marie Christine Durand
- Department of Physiology, Raymond Poincaré Hospital, Paris' Public Assistance Hospitals, University of Versailles Saint Quentin (EA 4497), Garches, France
| | - Pierre Denys
- Physical Medicine and Rehabilitation Department, Raymond Poincaré Hospital, Paris' Public Assistance Hospitals, University of Versailles Saint Quentin, Garches, France
| | - Frederic Lofaso
- Department of Physiology, Raymond Poincaré Hospital, Paris' Public Assistance Hospitals, University of Versailles Saint Quentin (EA 4497), Garches, France
| | - François Genet
- Physical Medicine and Rehabilitation Department, Raymond Poincaré Hospital, Paris' Public Assistance Hospitals, University of Versailles Saint Quentin, Garches, France
| | - Alexis Schnitzler
- Physical Medicine and Rehabilitation Department, Raymond Poincaré Hospital, Paris' Public Assistance Hospitals, University of Versailles Saint Quentin, Garches, France
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26
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Pond A, Marcante A, Zanato R, Martino L, Stramare R, Vindigni V, Zampieri S, Hofer C, Kern H, Masiero S, Piccione F. History, Mechanisms and Clinical Value of Fibrillation Analyses in Muscle Denervation and Reinnervation by Single Fiber Electromyography and Dynamic Echomyography. Eur J Transl Myol 2014; 24:3297. [PMID: 26913128 PMCID: PMC4749004 DOI: 10.4081/ejtm.2014.3297] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This work reviews history, current clinical relevance and future of fibrillation, a functional marker of skeletal muscle denervated fibers. Fibrillations, i.e., spontaneous contraction, in denervated muscle were first described during the nineteenth century. It is known that alterations in membrane potential are responsible for the phenomenon and that they are related to changes in electrophysiological factors, cellular metabolism, cell turnover and gene expression. They are known to inhibit muscle atrophy to some degree and are used to diagnose neural injury and reinnervation that are occurring in patients. Electromyography (EMG) is useful in determining progress, prognosis and efficacy of therapeutic interventions and their eventual change. For patients with peripheral nerve injury, and thus without the option of volitional contractions, electrical muscle stimulation may be helpful in preserving the contractility and extensibility of denervated muscle tissue and in retarding/counteracting muscle atrophy. It is obvious from the paucity of recent literature that research in this area has declined over the years. This is likely a consequence of the decrease in funding available for research and the fact that the fibrillations do not appear to cause serious health issues. Nonetheless, further exploration of them as diagnostic tools in long-term denervation is merited, in particular if Single Fiber EMG (SFEMG) is combined with Dynamic Echomyography (DyEM), an Ultra Sound muscle approach we recently designed and developed to explore denervated and reinnervating muscles.
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Affiliation(s)
- Amber Pond
- Anatomy Department, Southern Illinois University School of Medicine, Carbondale, IL USA
| | - Andrea Marcante
- CIR-Myo, Rehabilitation and Physical Medicine Unit, Department of Neurosciences, University of Padova, Italy
| | - Riccardo Zanato
- CIR-Myo, Radiology, Department of Medicine, University of Padova, Italy
| | - Leonora Martino
- CIR-Myo, Radiology, Department of Medicine, University of Padova, Italy
| | - Roberto Stramare
- CIR-Myo, Radiology, Department of Medicine, University of Padova, Italy
| | - Vincenzo Vindigni
- CIR-Myo, Plastic Surgery, Department of Neuroscience, University of Padova, Italy
| | | | - Christian Hofer
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | | | - Stefano Masiero
- CIR-Myo, Rehabilitation and Physical Medicine Unit, Department of Neurosciences, University of Padova, Italy
| | - Francesco Piccione
- Clinical Neurophysiology, San Camillo Hospital I.R.C.C.S., Venezia-Lido, Italy
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27
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Akbal A, Kurtaran A, Gürcan A, Selçuk B, Batgi H, Akyüz M, Gökmen F, Coşar M, Güven M, Bozkurt Aras A. P-wave and QT dispersion in spinal cord injury. Intern Med 2014; 53:1607-11. [PMID: 25088871 DOI: 10.2169/internalmedicine.53.1406] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE Spinal cord injury (SCI) can lead to significant cardiac arrhythmia. However, P-wave, QT dispersion, and risk factors in these patients have not been widely investigated. In this study, we assessed whether there is a relationship between electrocardiogram (ECG) parameters and risk factors in SCI patients. METHODS The study population consisted of 85 SCI patients and 38 control subjects. P-wave durations were measured using 12 leads of the surface ECG. P-wave dispersion was defined as the difference between the P-wave maximum and P-wave minimum duration. QT dispersion was defined as the difference between the largest and smallest QT interval for any of the 12 leads (QTmax-QT-min). QT intervals were also corrected (QTc) in accordance with the heart rate using Bazett's formula (QT Interval/√[RR interval]). We also evaluated the independent risk factors for P-wave dispersion and QT dispersion in SCI patients. RESULTS The P-wave minimum, P-wave maximum, QT minimum, and dispersion were significantly different between the control and SCI groups. There was no significant difference in P-wave dispersion, QT maximum, or QTc. Multivariate regression analysis showed that disease duration, glucose and high-density lipoprotein cholesterol (HDL-C) levels, and systolic tension were independent risk factors for P-wave dispersion. CONCLUSION Our results demonstrate that QT dispersion is related to SCI and that P-wave dispersion was linked to the duration of SCI, HDL-C and glucose levels, and arterial tension in SCI patients.
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Affiliation(s)
- Ayla Akbal
- Çanakkale Onsekiz Mart University, Turkey
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28
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Thomas CK, Bakels R, Klein CS, Zijdewind I. Human spinal cord injury: motor unit properties and behaviour. Acta Physiol (Oxf) 2014; 210:5-19. [PMID: 23901835 DOI: 10.1111/apha.12153] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 05/31/2013] [Accepted: 07/29/2013] [Indexed: 01/03/2023]
Abstract
Spinal cord injury (SCI) results in widespread variation in muscle function. Review of motor unit data shows that changes in the amount and balance of excitatory and inhibitory inputs after SCI alter management of motoneurons. Not only are units recruited up to higher than usual relative forces when SCI leaves few units under voluntary control, the force contribution from recruitment increases due to elevation of twitch/tetanic force ratios. Force gradation and precision are also coarser with reduced unit numbers. Maximal unit firing rates are low in hand muscles, limiting voluntary strength, but are low, normal or high in limb muscles. Unit firing rates during spasms can exceed voluntary rates, emphasizing that deficits in descending drive limit force production. SCI also changes muscle properties. Motor unit weakness and fatigability seem universal across muscles and species, increasing the muscle weakness that arises from paralysis of units, motoneuron death and sensory impairment. Motor axon conduction velocity decreases after human SCI. Muscle contractile speed is also reduced, which lowers the stimulation frequencies needed to grade force when paralysed muscles are activated with patterned electrical stimulation. This slowing does not necessarily occur in hind limb muscles after cord transection in cats and rats. The nature, duration and level of SCI underlie some of these species differences, as do variations in muscle function, daily usage, tract control and fibre-type composition. Exploring this diversity is important to promote recovery of the hand, bowel, bladder and locomotor function most wanted by people with SCI.
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Affiliation(s)
- C. K. Thomas
- The Miami Project to Cure Paralysis, Departments of Neurological Surgery, and Physiology and Biophysics; University of Miami; Miami FL USA
| | - R. Bakels
- Department of Neuroscience; University Medical Center Groningen; University of Groningen; Groningen the Netherlands
| | - C. S. Klein
- Rehabilitation Institute of Chicago; Chicago IL USA
| | - I. Zijdewind
- Department of Neuroscience; University Medical Center Groningen; University of Groningen; Groningen the Netherlands
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Redondo-Castro E, Navarro X. Peripheral nerve alterations after spinal cord injury in the adult rat. Spinal Cord 2013; 51:630-3. [PMID: 23774128 DOI: 10.1038/sc.2013.57] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 04/29/2013] [Accepted: 05/14/2013] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To assess if spinal cord injury (SCI) can produce alterations in axons of peripheral nerves emerging caudal to the injury. METHODS Mild/severe contusion or complete transection was performed at T8 in adult rats. The function and morphology of the sciatic nerve were assessed 3 months after the lesion. RESULTS There was a decrease in the amplitudes of muscle responses in nerve conduction tests. The number of myelinated fibers was maintained, but some of them presented structural abnormalities. CONCLUSION SCIs cause alterations in peripheral axons not affected by the injury. Preservation of the peripheral components is essential for potential regenerative and rehabilitation therapies. Thus, special care has to be taken to avoid secondary complications, due to compressions or immobility, in SCI humans.
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Affiliation(s)
- E Redondo-Castro
- Department of Cell Biology, Physiology and Immunology, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Li X, Jahanmiri-Nezhad F, Rymer WZ, Zhou P. An Examination of the Motor Unit Number Index (MUNIX) in muscles paralyzed by spinal cord injury. ACTA ACUST UNITED AC 2012; 16:1143-9. [PMID: 22491097 DOI: 10.1109/titb.2012.2193410] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The objective of this study was to assess whether there is evidence of motor unit loss in muscles paralyzed by spinal cord injury (SCI), using a measurement called motor unit number index (MUNIX). The MUNIX technique was applied in SCI (n=12) and neurologically intact (n=12) subjects. The maximum M waves and voluntary surface electromyography (EMG) signals at different muscle contraction levels were recorded from the first dorsal interosseous (FDI) muscle in each subject. The MUNIX values were estimated using a mathematical model describing the relation between the surface EMG signal and the ideal motor unit number count derived from the M wave and surface EMG measurements. We recorded a significant decrease in both maximum M wave amplitude and in estimated MUNIX values in paralyzed FDI muscles, as compared with neurologically intact muscles. Across all subjects, the maximum M wave amplitude was 8.3 ± 4.4 mV for the paralyzed muscles and 14.4 ± 2.0 mV for the neurologically intact muscles (p<0.0001). These measurements, when combined with voluntary EMG recordings, resulted in a mean MUNIX value of 112 ± 71 for the paralyzed muscles, much lower than the mean MUNIX value of 228 ± 49 for the neurologically intact muscles (p<0.00001). A motor unit size index was also calculated, using the maximum M wave recording and the MUNIX values. We found that paralyzed muscles showed a mean motor unit size index value of 80.7 ± 17.7 ìV, significantly higher than the mean value of 64.9 ± 10.1 ìV obtained from neurologically intact muscles (p<0.001). The MUNIX method used in this study offers several practical benefits compared with the traditional motor unit number estimation technique because it is noninvasive, induces minimal discomfort due to electrical nerve stimulation, and can be performed quickly. The findings from this study help understand the complicated determinants of SCI induced muscle weakness and provide further evidence of motoneuron degeneration after a spinal injury.
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