Agonist-Antagonist Myoneural Interface for Functional Limb Restoration After Transtibial Amputation

Summary

This study involves the functional testing of a new lower extremity prosthesis by 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:

1. Collection of electromyography (EMG) data from participants' lower limbs to characterize muscle activation and create maps specific to individual participants,
2. 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
3. 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.

Conditions

• Amputation

Interventions

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.

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.

Sponsors & Collaborators

• National Institutes of Health (NIH)

  collaborator NIH

• Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

  collaborator NIH

• Massachusetts Institute of Technology

  lead OTHER

Principal Investigators

• Hugh M Herr, PhD · Massachusetts Institute of Technology

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2019-06-12

Primary Completion

2025-06-01

Completion

2025-06-01

Countries

• United States

Study Locations