Agonist-Antagonist Myoneural Interface for Functional Limb Restoration After Transtibial Amputation
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|ClinicalTrials.gov Identifier: NCT03913273|
Recruitment Status : Not yet recruiting
First Posted : April 12, 2019
Last Update Posted : April 12, 2019
This study involves the functional testing of a new lower extremity prosthesis by twenty-two healthy, active participants with fully healed transtibial (below knee) amputations. The study design calls for an experimental group of eleven participants who received two agonist-antagonist myoneural interfaces (AMIs) that were surgically constructed during a modified transtibial amputation procedure, and a control group of eleven matched participants who received standard transtibial amputations. The study protocol involves one or more of the following activities:
- Collection of electromyography (EMG) data from participants' lower limbs to characterize muscle activation and create maps specific to individual participants,
- Investigation of participants' capabilities to use a new lower extremity prosthesis that is designed to allow independent actuation of the ankle and subtalar joints, and offers EMG-modulated control over prosthetic joint position and stiffness, and
- Exploration of AMIs as a means of communicating information between the participant and the new prosthesis using an experimental system involving EMG, functional electrical stimulation, and ultrasound.
The hypothesis is that transtibial amputations involving AMIs can offer improved motor control of the new prosthesis while also enabling proprioceptive sensation (perception of the position, movement, and torque of the affected limb and prosthetic joint). The AMIs are expected to improve voluntary prosthetic control, improve prosthetic terrain adaptations, and offer new possibilities for bi-directional communication across the human-device interface.
|Condition or disease||Intervention/treatment||Phase|
|Amputation||Procedure: AMI transtibial amputation Procedure: Standard transtibial amputation||Not Applicable|
Show Detailed Description
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||22 participants|
|Intervention Model:||Parallel Assignment|
|Intervention Model Description:||The study calls for an experimental group of eleven participants who underwent AMI transtibial amputations incorporating surgically constructed Agonist-antagonist Myoneural Interfaces (AMIs), and a control group of eleven participants who underwent standard transtibial amputations. Each participant in the control group is prospectively matched to a participant in the experimental group to the degree possible based on time since amputation, body habitus, age, and biological sex. Matching is conducted by methods that estimate causal effects by reducing imbalance in the matching variables; any differences in outcomes in the two groups should therefore be attributable to the AMIs. The study protocol focuses on functional performance testing of a multi-degree of freedom prosthesis in fully healed participants.|
|Masking:||None (Open Label)|
|Primary Purpose:||Basic Science|
|Official Title:||Agonist-Antagonist Myoneural Interface for Functional Limb Restoration After Transtibial Amputation|
|Estimated Study Start Date :||April 2019|
|Estimated Primary Completion Date :||February 2025|
|Estimated Study Completion Date :||February 2025|
Experimental: Intervention group
Intervention: AMI transtibial amputation
Procedure: AMI transtibial amputation
Two Agonist-antagonist myoneural interfaces (AMIs) were surgically constructed during a modified transtibial amputation procedure. Each AMI was made of natively innervated and vascularized muscle segments - an agonist and antagonist - that were surgically connected in series within the amputated residuum. Tarsal tunnels, including segments of each tunnel's native tendon component, were procured from the amputated joint. The tunnels were affixed to the residual limb tibia and the AMIs were constructed by coaptation of an agonist and an antagonist muscle to either end of the tendon passing through the tunnel. Consequently, the force produced by one muscle stretches its partner such that the AMI can communicate signals from the mechanoreceptors in both muscles to the central nervous system.
Active Comparator: Control group
Intervention: Standard transtibial amputation
Procedure: Standard transtibial amputation
A standard transtibial amputation was performed according to traditional techniques. No surgical construction of agonist-antagonist myoneural interfaces (AMIs) was performed.
- Stability of Joint Position Control in Free Space [ Time Frame: 0 - 5 years ]A measure of the capability to maintain prosthetic joint position in free space. Determined as the amount of time the prosthesis can be maintained in a given position relative to the requested hold time.
- Economy of Motion during Joint Position and Impedance Control in Free Space [ Time Frame: 0 - 5 years ]A measure of the distance traversed by the prosthetic joint during a target tracking task involving position and impedance control in free space. Determined as the total travel distance, in angle space, normalized by the minimum travel distance from start to finish.
- Subtalar Eversion for an Obstacle [ Time Frame: 0 - 5 years ]A measure of the capability to navigate an obstacle presented in the participant's path. The task involves eversion of the prosthetic subtalar joint such that the lateral edge of the prosthetic foot contacts a vertically offset block while the medial edge of the prosthetic foot remains at the base height. Determined as the maximum late-swing subtalar joint eversion angle measured between 80 and 100 percent of the participant's gait cycle during task performance.
- Late Swing Ankle Plantar Flexion during Stair Descent [ Time Frame: 0 - 5 years ]A measure of the capability to exhibit prosthetic ankle joint plantar flexion that is characteristic of stair descent. Determined as the maximum late-swing ankle joint plantar flexion angle measured between 80 and 100 percent of the participant's gait cycle during task performance.
- Late Swing Ankle Dorsiflexion during Stair Ascent [ Time Frame: 0 - 5 years ]A measure of the capability to exhibit prosthetic ankle joint dorsiflexion that is characteristic of stair ascent. Determined as the maximum late-swing ankle joint dorsiflexion angle measured between 80 and 100 percent of the participant's gait cycle during task performance.
- Correlation and Repeatability of Ankle Joint Proprioception [ Time Frame: 0 - 5 years ]A measure of the correlation of force estimated within the agonist-antagonist muscle unit with the participant's reported perception of prosthetic joint torque.
- Controllability over Prosthetic Joint Plantar Flexion Torque [ Time Frame: 0 - 5 years ]A measure of the number of participant plantar flexion effort levels that resulted in torque production that differed significantly from the torques produced at all other effort levels.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03913273
|Contact: Hugh M Herr, PhD||617-253-6780||HHerr@media.mit.edu|
|Contact: Lisa E Freed, MD, PhD||617-452-5633||LFreed@media.mit.edu|
|United States, Massachusetts|
|Massachusetts Institute of Technology||Not yet recruiting|
|Cambridge, Massachusetts, United States, 02139|
|Contact: Committee on the Use of Humans as Experimental Subjects 617-253-6787 email@example.com|
|Principal Investigator: Hugh M Herr, PhD|
|Principal Investigator:||Hugh M Herr, PhD||Massachusetts Institute of Technology|