Rationale and Objectives: Limb loss is a significant problem for US military personnel. Optimizing service members' recovery after limb loss is an important goal, as military amputees tend to be otherwise young and healthy. Rehabilitation following amputation is critical, but severe post-amputation pain prevents individuals from performing rehabilitation exercises and regaining physical fitness. In addition, pain can lead to deteriorating quality of life, frustration, and depression. In fact, it is often the pain following amputation rather than the loss of a limb itself that interferes most with the simple activities of daily life.

More than 85 percent of US service members with combat-related amputations from Operation Enduring Freedom and Operation Iraqi Freedom suffer from moderate to severe post-amputation pain, and the majority do not obtain sufficient relief from available therapies, resulting in an inability of these individuals to fully recover from their injuries. Therefore, the development of an effective treatment for post-amputation pain is critically important.

The objective of the proposed research is to evaluate a new treatment for post-amputation pain in which small pulses of electrical stimulation are delivered to nerves in the portion of the limb that remains after amputation. This therapy is intended to produce a comfortable sensation where pain is felt and decrease or eliminate the perception of pain. This approach may be more effective and safer than present methods of delivering stimulation to the skin surface or the spinal cord. The ultimate goal of this research is to make available to the US military a safe and effective treatment for post-amputation pain that will optimize recovery and restoration of physical functioning after major limb amputation.

Applicability: The treatment to be studied in this research is intended to reduce pain and improve functional outcomes in US service members and veterans with combat-related injuries leading to one or more major limb amputations. This research may also benefit civilians with amputations following traumatic injuries such as gunshot and motor vehicle accidents.

Many therapies are used to treat post-amputation pain, but they are insufficient for the majority of amputees and often have risks of side effects such as impaired physical or cognitive performance or addiction. The non-narcotic, non-addictive therapy to be studied in this research has already been tested in a clinical feasibility study. In this preliminary study, study participants reported substantial pain relief and a substantial reduction in the amount in which pain interfered with their daily activities. None of the study participants experienced side effects, but it is expected that some individuals in the proposed study may experience minor and temporary side effects such as skin irritation, bruising, or tissue damage. Overall, the results of the preliminary study suggest that this innovative therapy may be safe and effective in relieving post-amputation pain, thereby improving physical functioning and quality of life.

If this treatment is found to be safe and effective, it could change the way in which pain is treated after limb amputation, giving wounded individuals significant pain relief and allowing them to regain their physical fitness. Future research could allow this therapy to be used to treat other types of pain following combat injuries and other orthopedic injuries.

Military Benefit: The US Military describes the "management of pain associated with traumatic or war-related injuries as a primary interest." Over the years, the US military has developed a rich tradition of addressing the special care needs of traumatic military amputees. However, there is a significant gap in care for post-amputation pain, preventing rapid recovery from these severe injuries. Preliminary data indicate the proposed treatment can provide almost immediate (within minutes) pain relief leading to improvement in activities such as work, sleep, walking ability, and recreation. If this treatment is found to be safe and effective, it will provide rapid and lasting improvement in the quality of life of individuals with severe combat-related amputations.