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Towards functional restoration for persons with limb amputation: A dual-stage implementation of regenerative agonist-antagonist myoneural interfaces.

ABSTRACT: While amputation has traditionally been viewed as a failure of therapy, recent developments in amputation surgery and neural interfacing demonstrate improved functionality and bidirectional communication with prosthetic devices. The agonist antagonist myoneural interface (AMI) is one such bi-directional neural communication model comprised of two muscles, an agonist and an antagonist, surgically connected in series within the amputated residuum such that contraction of one muscle stretches the other. By preserving agonist-antagonist muscle dynamics, the AMI allows proprioceptive signals from mechanoreceptors within both muscles to be communicated to the central nervous system. Preliminary human evidence suggests that AMIs have the capacity to provide high fidelity control of a prosthetic device, force feedback, and natural proprioception. However, AMIs have been implemented only in planned amputations and require healthy distal tissues, whereas the majority of amputations occur in patients who do not have healthy distal tissues. Through the use of a dual-stage surgical procedure which leverages existent tissues, this study proposes a revision model for implementation of the AMI in patients who are undergoing traumatic amputation or have already undergone a standard amputation. This paper validates the resulting AMI's physiology, revealing robust viability and mechanical and electrophysiological function. We demonstrate the presence of H-waves in regenerative grafts, indicating the incorporation of the AMI into physiological reflexive loops.

SUBMITTER: Srinivasan SS

PROVIDER: S-EPMC6374452 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Towards functional restoration for persons with limb amputation: A dual-stage implementation of regenerative agonist-antagonist myoneural interfaces.

Srinivasan Shriya S SS Diaz Maurizio M Carty Matthew M Herr Hugh M HM

Scientific reports 20190213 1

While amputation has traditionally been viewed as a failure of therapy, recent developments in amputation surgery and neural interfacing demonstrate improved functionality and bidirectional communication with prosthetic devices. The agonist antagonist myoneural interface (AMI) is one such bi-directional neural communication model comprised of two muscles, an agonist and an antagonist, surgically connected in series within the amputated residuum such that contraction of one muscle stretches the o ...[more]

PMID: 30760764

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Project description:BackgroundNeuroprosthetic devices controlled by persons with standard limb amputation often lack the dexterity of the physiological limb due to limitations of both the user's ability to output accurate control signals and the control system's ability to formulate dynamic trajectories from those signals. To restore full limb functionality to persons with amputation, it is necessary to first deduce and quantify the motor performance of the missing limbs, then meet these performance requirements through direct, volitional control of neuroprosthetic devices.MethodsWe develop a neuromuscular modeling and optimization paradigm for the agonist-antagonist myoneural interface, a novel tissue architecture and neural interface for the control of myoelectric prostheses, that enables it to generate virtual joint trajectories coordinated with an intact biological joint at full physiologically-relevant movement bandwidth. In this investigation, a baseline of performance is first established in a population of non-amputee control subjects ([Formula: see text]). Then, a neuromuscular modeling and optimization technique is advanced that allows unilateral AMI amputation subjects ([Formula: see text]) and standard amputation subjects ([Formula: see text]) to generate virtual subtalar prosthetic joint kinematics using measured surface electromyography (sEMG) signals generated by musculature within the affected leg residuum.ResultsUsing their optimized neuromuscular subtalar models under blindfolded conditions with only proprioceptive feedback, AMI amputation subjects demonstrate bilateral subtalar coordination accuracy not significantly different from that of the non-amputee control group (Kolmogorov-Smirnov test, [Formula: see text]) while standard amputation subjects demonstrate significantly poorer performance (Kolmogorov-Smirnov test, [Formula: see text]).ConclusionsThese results suggest that the absence of an intact biological joint does not necessarily remove the ability to produce neurophysical signals with sufficient information to reconstruct physiological movements. Further, the seamless manner in which virtual and intact biological joints are shown to coordinate reinforces the theory that desired movement trajectories are mentally formulated in an abstract task space which does not depend on physical limb configurations.

Project description:Purpose: To gather ideas from lower-limb prosthesis users and certified prosthetists regarding possible residual limb monitoring system features and data presentation. We also gathered information on the type of residual limb problems typically encountered, how they currently manage those problems, and their ideas for methods to better manage them.Materials and methods: Two focus groups were held; one with certified prosthetists and another with lower-limb prosthesis users. Open-ended questions were used in a moderated discussion that was audio recorded, transcribed, and assessed using applied thematic analysis.Results and conclusions: Seven individuals participated in each focus group. Prosthetists came from a mix of practice settings, while prosthesis users were diverse in level of amputation, aetiology, and years of experience using lower-limb prostheses. Residual limb problems reported by participants were consistent with those in the literature. Participants suggested better managing residual limb problems through improved education, better detection of residual limb problems, and using sensor-based information to improve prosthetic technology. Participants favoured short-term use of a possible residual limb monitoring systems to troubleshoot residual limb problems, with temperature and pressure the most frequently mentioned measurements. Participants described that an ideal residual limb monitoring system would be lightweight, not interfere with prosthesis function, and result in benefits with regard to prosthetic care and socket function that outweighed inconveniences or concerns regarding system use. A potential positive of system use included having objective data for reimbursement justification, although it was pointed out that the residual limb monitoring system itself also needed to be reimbursable.Implications for RehabilitationStakeholders suggested better managing residual limb problems through improved education, better detection of residual limb problems, and using sensor-based information to improve prosthetic technology.Stakeholders favored short-term use of a possible system to troubleshoot residual limb problems, with temperature and pressure the most frequently mentioned measurements.Stakeholders described that an ideal residual limb monitoring system would be lightweight, not interfere with prosthesis function, and result in benefits with regard to prosthetic care and socket function that outweighs any inconveniences or concerns regarding system use.Stakeholders indicated that a potential positive of system use included having objective data for reimbursement justification, although it was pointed out that the residual limb monitoring system itself also needed to be reimbursable.

Project description:PurposeThis study sought to measure and identify factors associated with satisfaction with care among veterans. The metrics were colelcted for those receiving prosthetic limb care at the US Department of Veterans Affairs (VA) and US Department of Defense (DoD) care settings and at community-based care providers.MethodsA longitudinal cohort of veterans with major upper limb amputation receiving any VA care from 2010 to 2015 were interviewed by phone twice, 1 year apart. Care satisfaction was measured by the Orthotics and Prosthetics User's Survey (OPUS) client satisfaction survey (CSS), and prosthesis satisfaction was measured by the OPUS client satisfaction with device (CSD), and the Trinity Amputation and Prosthetic Experience Scale satisfaction scales. The Quality of Care index, developed for this study, assessed care quality. Bivariate analyses and multivariable linear regressions identified factors associated with CSS. Wilcoxon Mann-Whitney rank tests and Fisher exact tests compared CSS and Quality of Care items at follow-up for those with care within and outside of the VA and DoD.ResultsThe study included 808 baseline participants and 585 follow-up participants. Device satisfaction and receipt of amputation care in the prior year were associated with greater satisfaction with care quality. Persons with bilateral amputation were significantly less satisfied with wait times. Veterans who received amputation care in the VA or DoD had better, but not statistically different, mean (SD) CSS scores: 31.6 (22.6) vs 39.4 (16.9), when compared with those who received care outside the VA or DoD. Those with care inside the VA or DoD were also more likely to have a functional assessment in the prior year (33.7% vs 7.1%, P = .06), be contacted by providers (42.7% vs 18.8%, P = .07), and receive amputation care information (41.6% vs 0%, P =.002). No statistically significant differences in CSS, Quality of Care scores, or pain measures were observed between baseline and follow-up. In regression models, those with higher CSD scores and with prior year amputation care had higher satisfaction when compared to those who had not received care.ConclusionsSatisfaction with prosthetic limb care is associated with device satisfaction and receipt of care within the prior year. Veterans receiving amputation care within the VA or DoD received better care quality scores than those receiving prosthetic care outside of the VA or DoD. Satisfaction with care and quality of care were stable over the 12 months of this study. Findings from this study can serve as benchmarks for future work on care satisfaction and quality of amputation rehabilitative care.

Project description:ObjectiveTo systematically review the literature on the metabolic costs of activities of daily living (ADL) in persons with a lower limb amputation (LLA).Data sourcesA literature search was undertaken in the Pubmed, Embase, CINAHL, CENTRAL, and PsycINFO databases using keywords and synonyms for LLA, metabolic costs, and ADL. The last search was performed on November 29th, 2017.Study selectionStudies were included if they met the following 2 criteria: participants were adults with a (unilateral or bilateral) LLA and metabolic costs were measured while participants performed a physical activity or ADL.Data extraction and synthesisData of 1,912 participants from 61 studies were included in the systematic review and meta-analysis. The studies used different terms to describe metabolic costs. Participants were recruited in different settings, relatively healthy, with few comorbidities. Limited data were available on metabolic costs of other activities than walking with a prosthesis. A linear mixed model analysis was performed based on the means reported, with study as unit of analysis and test results of different groups and measurement conditions as repeated measures within the unit of analysis. Predictors entered in the analysis were e.g. level and reason of amputation, age, weight, and height. During walking, oxygen consumption (ml O2/kg/min) and heart rate (beats/min) increased with a higher walking speed and a more proximal amputation. Additionally, oxygen consumption was determined by the interaction terms walking speed x amputation level and walking speed squared. Heart rate was determined by the interaction term walking speed squared.ConclusionDuring walking, oxygen consumption (ml O2/kg/min) and heart rate (beats/min) increased with a higher walking speed and a more proximal amputation. Data on metabolic costs of other activities were limited. The poor quality of the studies and the relatively healthy participants limited generalizability of the results of the meta-analysis.

Dataset Information

Towards functional restoration for persons with limb amputation: A dual-stage implementation of regenerative agonist-antagonist myoneural interfaces.

Publications

Towards functional restoration for persons with limb amputation: A dual-stage implementation of regenerative agonist-antagonist myoneural interfaces.

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