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.
Males or females between the ages of 18 and 65
Candidates for elective unilateral or bilateral upper extremity amputation at either the above elbow or below elbow level due to traumatic injury, congenital limb deformities or progressive arthritis
Must demonstrate sufficiently sound health to undergo the operative procedure, including adequate cardiopulmonary stability to undergo general anesthesia (specifically, American Society of Anesthesiology Class I or II)
Must have intact inherent wound healing capacity
Patients beyond the stated age restrictions
Those with severe illness rendering them unable to undergo the operative procedure safely (e.g., unresolved sepsis or cardiopulmonary instability manifest as documented coronary artery disease and/or chronic obstructive pulmonary disease)
Patients with active infections, particularly deep infections in the arm to be amputated
Patients who are taking immunosuppressive agents
Parallel
Modified amputation procedure
Procedure/SurgeryA 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.
Standard amputation procedure
Procedure/SurgeryAmputation is performed via standard techniques at either the BEA or AEA level. No construction of agonist-antagonist muscle pairs will be performed.
Motor Unit Innervation
Intact volitional activation of motor constructs, as assessed by electromyographic evidence of activation (muscle potentials measured in mV)
Motor Unit Excursion
Intact volitional activation of motor constructs with measurable excursion, as assessed by ultrasound (excursion measured in mm)
Proprioception Recovery
Manifestation of functional proprioception with motor unit activation, as evidenced by spatial limb position testing using a modified upper limb prosthesis (accurate limb positioning relative to target measured in mm)
Infection Rate
Postoperative infection rate
Delayed Wound Healing Rate
Postoperative delayed wound healing rate
Operative Revision Rate
Subsequent rate of reoperation
Seroma Rate
Postoperative seroma rate
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Brigham and Women's Hospital
Lead sponsor
Massachusetts Institute of Technology
Collaborator
Walter Reed Army Institute of Research (WRAIR)
Collaborator
Massachusetts General Hospital
Collaborator
