Objectives and Rationale: The proposed work will address the challenge of restoring upper-extremity motor function in patients with severe nerve damage that limits sensation and movement of the limb. Over the 3-year period, a device will be designed that supports movement and rehabilitation of the affected limb. Device function and patient satisfaction will be assessed.

Applicability and Impact of the Research: The proposal addresses the FY19 JPC-8/CRMRP Restoring Warfighters with Neuromusculoskeletal Injuries Research Award (RESTORE). At present, there is no powered orthosis designed specifically for patients with nerve damage affecting the upper extremity. These patients are frequently fitted with a powered orthosis designed for rehabilitation of stroke patients to aid in elbow bending. This device lacks a mechanism to help the patient hold their arm in a desired position, making it unsuitable because the patient’s limb fatigues early. A powered orthosis, specifically designed for patients with upper-extremity nerve damage and capable of helping patients hold their affected limb in a given position, has the potential to reduce the many lasting, life-altering outcomes that negatively affect quality of life in these patients.

Patients: Severe upper-extremity nerve injuries frequently affect young, otherwise healthy individuals, dramatically altering their physical function, mental well-being, financial situation, and self-image. Although surgical procedures such as nerve transfers and grafts and muscle transfers can restore some function, many patients do not receive reconstructive surgery, leaving them with a dysfunctional arm. Even those who do receive reconstructive surgery can remain dissatisfied with the functional results. Analyses of patient satisfaction and self-reported outcomes after severe nerve damage revealed low satisfaction with the function of the extremity following surgery. Quality of life assessments showed that the effects of these injuries are severe, lasting, and connected with reduced physical function. Depression is common in patients with poor elbow flexion, and financial concerns due to the cost of care and the inability to retain employment can compound functional and emotional issues. Upper-extremity peripheral nerve injuries accounted for approximately 6% of all combat injuries during Operation Iraqi Freedom, not including many nerve injures that were identified later in the course of care. Among civilians, approximately 3,000 severe upper-extremity peripheral nerve injuries occur annually as a result of traumatic events including motorcycle and automobile accidents.

Clinical Applications, Benefits, and Risks: The user will don the orthosis on their affected side and the electrical signals from the patient’s own muscle will control an electric motor, which will provide the user power assist to achieve their desired movements. A specially designed cable system will hold the arm in a given position, eliminating the need for the user to continually contract the affected muscle. This feature is essential for patients with nerve damage, as they frequently cannot produce the continual muscle contraction needed to hold the arm in position, rendering their arm and the orthosis useless. All tests used in this research protocol are noninvasive and pose low risk and high benefit to the patient. Commercialization risk has been mitigated by investigating and identifying interest from commercially entities well positioned to bring the product to market successfully.

Projected Timeline: We anticipate that the first year will be devoted to designing and producing a prototype powered exoskeleton. Algorithm development will begin in year 2 with user feedback being incorporated into the design. Patient function testing will occur in year 3.

Military Benefit: Quality of life analyses and patient interviews have revealed that, even with reconstructive surgery, upper-extremity nerve injuries alter individuals’ lives, physical abilities, emotional state, finances, and self-image, making this type of injury physically and emotionally debilitating. A powered exoskeleton capable of providing critical restoration of limb function has the potential to reduce the many lasting, life-altering outcomes of upper-extremity nerve injury that reduce ability and quality of life. Restoring arm function and psychological and social well-being also has the potential to reduce lost duty time and discharge rates across all branches of the military. Enabling Service members to remain in military service or transition more successfully to civilian employment have the potential to reduce the devastating psychosocial factors associated with upper-extremity injury and disability.