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73 active trials for Amputation

Investigation of Embodiment for Upper Limb Amputees

Today, prosthetic hands are numb. They provide no tactile or proprioceptive sensory information back to the user. The lack of sensory feedback has been shown to reduce the utility of a prosthesis by half. The prosthesis is seen as a tool, not as an incorporated part of the body schema. Only now are there chronically-implantable technologies which can provide physiologically appropriate sensory feedback to upper limb amputees to recreate tactile and proprioceptive percepts. These sensations are the building blocks to enable the embodiment of the device. Furthermore, newly developed outcome measures are now available which can detail the improved embodiment such neural interfaces can create. The investigator's mission is to enable the embodiment of artificial devices using peripheral nerve stimulation and thereby close the gap between the experience of our intact physiological systems and those using prosthetic remedies. This investigation of embodiment for upper limb amputees is organized into three main areas of work including 1) normative data collection, 2) device development, and 3) characterization of embodiment using peripheral nerve stimulation. The normative data collection will quantify the embodiment of conventional cosmetic, body-powered, and myoelectric prosthetic hand options using a modified Rubber Hand Illusion protocol (Specific Aim 1). This thrust will ask how does the amount of embodiment vary among conventional prosthetic hands as well as probe the relationship between agency and embodiment. The device development project entails the design of multi-modal sensors in order to study full-hand embodiment (Specific Aim 2). The ability to measure and then elicit sensation on the passive surfaces of the hand (palm, ulnar border, and dorsal surface) has never been explored. Here, a multi-modal sensor which can detect proximity, contact, and force will be integrated into a commercially available prosthetic hand in order to provide detailed measurements across the palm, ulnar border, and dorsal surfaces in order to study embodiment in more depth. Finally, the characterization of embodiment using peripheral nerve stimulation will take place over a multiple subject factorial experiment which quantifies the effects of quantity and spatial parameters of the peripheral nerve stimulation on the embodiment of prosthetic hands (Specific Aim 3). This study asks what somatosensory percepts from the hand are most critical for embodiment by varying the parameters of the peripheral nerve stimulation (quantity and spatiality) and measuring the level of embodiment in each case.

Start: June 2022
A Test-Drive Strategy for the Prescription of Prosthetic Feet for People With Leg Amputations

Objective/Hypotheses and Specific Aims: The primary aim of this proposal is to determine whether a PFE can be used to predict foot preference and mobility outcomes with corresponding commercial prosthetic feet in people with a unilateral transtibial amputation (TTA). Secondarily, the investigators aim to determine whether a brief trial of commercial prosthetic feet would be able to similarly predict longer-term foot preference and mobility outcomes with those feet. Study Design: The investigators will use a participant blinded cross-over study with repeated measurements. Participants with TTA will be enrolled at each of the three study sites: two VA sites (Puget Sound and Minneapolis), and one Department of Defense site (Center for the Intrepid). Participants will complete up to 6 visits. After an initial assessment visit, participants will be assigned to the high or low mobility group, and then during visit 2 they will be randomized to use the PFE in three foot modes or the three corresponding actual (commercially available) feet during walking tests in the laboratory. During visit 3 participants will repeat the procedures in the other condition (e.g., PFE if Day 2 included actual feet testing). At the end of visit 3 participants will be fit with one of the actual feet and wear it at home and in the community for approximately two weeks. At visit 4 participants will be fit with the next actual foot and repeat the 2 week use window. The same process will be followed for the final foot at visit 5, and the study foot will be returned at visit 6. Participants' preference, satisfaction and perceived mobility, and functional mobility will be measured and compared across all foot conditions (emulated and actual). After participants complete the procedures detailed above, they may be eligible to be invited to participate in follow-up phone interviews. Additionally, a subset of participants may be invited to participate in follow-up biomechanical data collection comparing the PFE foot conditions to the respective actual prosthetic feet during walking.

Start: September 2018
An Osseoanchored Percutaneous Prosthesis Study Evaluating Stable Neural Signal Transmission in Subjects With Transhumeral Amputations

This early feasibility study proposes to evaluate use of the electronic-Osseoanchored Prostheses for the Rehabilitation of Amputees (e-OPRA) device, a transhumeral implant system for direct skeletal anchorage of amputation prostheses, with a test prosthesis. The e-OPRA System is being investigated to better understand the ability to improve the functionality of the prosthesis and enhance the sense of embodiment of the prosthesis itself. This will be a 10 subject Early Feasibility Study in which the primary objective is to capture preliminary safety and effectiveness information on the implanted e-OPRA system. With the addition of electrodes to the muscle segments, this biological interface allows for both the extraction of fine motor control signals from the nerve fascicles and the generation of sensory percepts via electrical stimulation of the muscles. In addition, electrodes placed on muscles within the residuum with native vascularization and innervation also allow the extraction of critical motor control signals and the generation of sensory feedback through muscle stimulation. The electrical activity recorded from these muscle segments (called electromyography or EMG) is specific to certain movements and can be used to determine precisely how a person wants to move their arm and hand. Use of the e-OPRA device with the well-documented neuro-electronic capabilities of EMG control systems provides an alternative to traditional socket prostheses by establishing a direct, loadbearing link between the patient's skeleton and prosthesis.

Start: January 2020
Human Penile Allotransplantation

Injuries to the external genitalia are of great concern to the military with emphasis being placed on the surgical reconstruction and psychological health of these Wounded Warriors. However, despite significant surgical advances in microvascular surgery and autologous free tissue transfer, conventional reconstructions cannot truly replace the complicated structures and functions of the penis including the urethra, erogenous sensation, and erectile corporal bodies. Conventional reconstruction poses several challenges: patients may not have sufficient donor tissue (i.e., the forearm or thigh) due to other injuries or previous surgery; multiple operations are often needed to restore the neophallus; the final reconstruction only approximates the penis' native form; recreating the urethra is challenging and the new urethra is prone to stricture and fistula formation; the erectile function necessary for sexual intercourse is often lacking; and insufficient protective sensation can lead to penile implant extrusion, infection, and subsequent explantation or loss of the reconstruction. For these reasons, the investigators propose the current clinical trial to determine functional outcomes and quality of life (QOL) for Wounded Warriors and civilians who choose to undergo penile allotransplantation. The investigators will combine extensive experience performing total penile reconstruction in a large population affected by congenital, traumatic, and therapeutically extirpated Genitourinary (GU) deformities and expertise in reconstructive transplantation using an immunomodulatory protocol to implement this study. The investigators anticipate that penile transplantation can potentially replace "like with like," restoring the appearance, anatomy, and function of the recipient in a manner far superior to autologous reconstruction. This project will establish the ability to perform penile allotransplantation using an immunomodulatory protocol and will compare outcomes with conventional phalloplasty patient results. Study Design: This is a non-randomized subject self-controlled clinical trial to implement a cell-based immunomodulatory protocol for penile allotransplantation. An intermediate deliverable is achieving allograft survival and functional return with reduced dosing/frequency of maintenance immunosuppression on steroid-free monotherapy (tacrolimus) immunosuppression. The long-term deliverable and goal is to demonstrate equivalent or superior outcomes when compared to satisfaction and QOL in conventional phalloplasty patients 12-60 months post-transplant.

Start: June 2014
A Novel Approach to Upper Extremity Amputation to Augment Volitional Control and Restore Proprioception

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: To define a standardized approach to the performance of a novel operative procedure for both below elbow (BEA) and above elbow amputations (AEA) 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 To describe the extent of proprioceptive feedback achievable through the employment of these modified surgical techniques To validate the functional and somatosensory superiority of the proposed amputation technique over standard approaches to BEA and AEA 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.

Start: May 2019