A Novel Approach to Upper Extremity Amputation to Augment Volitional Control and Restore Proprioception

Summary

The hypothesis of this research protocol is that the investigators will be able to redesign the manner in which upper limb amputations are performed so as to enable volitional control of next generation prosthetic devices and restore sensation and proprioception to the amputated limb. The investigators will test this hypothesis by performing modified above elbow or below elbow amputations in ten intervention patients, and compare their outcomes to ten control patients who have undergone tradition amputations at similar levels. The specific aims of the project are: 1. To define a standardized approach to the performance of a novel operative procedure for both below elbow (BEA) and above elbow amputations (AEA) 2. To measure the degree of volitional motor activation and excursion achievable in the residual limb constructs, and to determine the optimal configuration and design of such constructs 3. To describe the extent of proprioceptive feedback achievable through the employment of these modified surgical techniques 4. To validate the functional and somatosensory superiority of the proposed amputation technique over standard approaches to BEA and AEA 5. To develop a modified acute postoperative rehabilitation strategy suited to this new surgical approach This will be a phase I/pilot clinical trial to be performed over a three-year period as a collaborative initiative involving Brigham \& Women's Hospital/Brigham \& Women's Faulkner Hospital (BWH/BWFH), Walter Reed National Military Medical Center (WRNMMC), and the Massachusetts Institute of Technology (MIT). The investigators will plan to perform 6 of the 10 amputations at BWH/BWFH, and 4 of the amputations at WRNMMC.

Description

Eligibility

Age range

18–65 years

Sex

All

Healthy volunteers

Yes

Interventions

• Procedure
  Modified amputation procedure

  A fishmouth incision will be made. Radial and ulnar (BEA) or humoral (AEA) osteotomies will be performed. Segments of the flexor carpi radialis (FCR), extensor carpi radialis longus (ECRL), flexor digitorum profundi (FDP), extensor digitorum communis (EDC), flexor pollicis longus (FPL) and extensor pollicis longus (EPL) will be isolated, as well as the biceps (B) and triceps (T) groups in the AEA model; if it is not possible to preserve native innervation to these muscles, functional motor units will be constructed from muscle coapted to the appropriate motor nerve endings. Sensory nerve endings of the distal median, ulnar and radial nerves will then be isolated and redirected to discrete skin patches in the proximal residual forearm or proximal brachium. Coaptation of the FCR/ECRL, FDP/EDC, FPL/EPL and B/T muscles will then be performed to promote dynamic coupling of these agonist/antagonist pairs. The skin envelope will then be closed in layers over percutaneous drains.

• Procedure
  Standard amputation procedure

  Amputation is performed via standard techniques at either the BEA or AEA level. No construction of agonist-antagonist muscle pairs will be performed.

Locations (4)