Peripheral nerve stimulation for amputee pain

DESCRIPTION (provided by applicant): Almost all amputees have pain related to their amputation and most of them have phantom pain and residual limb (stump) pain. These chronic conditions can lead to depression, disability, general suffering, and a reduced quality of life. Over 1.7 million Americans are living with an amputation and over 185,000 more Americans have an amputation each year. The present treatments for stump and phantom pain are unsatisfactory. In amputees with moderate to severe stump and phantom pain, it is typically the pain following amputation instead of the loss of a limb that most limits the activities of daily living, makes the completion of simple tasks difficult, and prevents the return to employment. The long-term goal of this project is to develop and commercialize an implantable neurostimulation product to reduce stump and phantom pain in amputees. We propose to relieve pain through electrical stimulation of the peripheral nerves (PN) innervating the painful stump and phantom regions. The proposed approach is supported by previous studies on electrical stimulation of the PN to reduce post-amputation pain, which demonstrated efficacy but identified the delivery method as the limiting factor in clinical success. If percutaneous stimulation can reduce stump and phantom pain in the present (phase I) in-office study then it will justify a future (phase II) 2-staged home trial in which the amputee patients are sent home with a percutaneous system for 1 week and patients who experience sustained pain relief over the 1-week period will receive a fully implanted system that will be evaluated over the following 12 months. The specific aims of this phase I project are to determine the feasibility of using a percutaneous lead in upper-extremity amputees to 1) generate comfortable stimulation-evoked sensations (paresthesias) in the painful region and reduce 2) stump pain and 3) phantom pain. The hypothesis is that percutaneous stimulation will 1) activate the PN and generate paresthesias in the regions of pain in the stump and the phantom limb and reduce 2) stump pain and 3) phantom pain. This hypothesis will be tested in humans with post-amputation pain by 1) asking the subjects to report if stimulation generates sensation in the regions of pain in the stump and phantom limb and by recording the subject's 2) stump pain and 3) phantom pain on the 0-10 point numerical rating scale of the brief pain inventory short form at baseline and during stimulation to determine if their stump and phantom pain are significantly reduced during stimulation. At the conclusion of this phase I project, we will have determined the feasibility of using percutaneous stimulation to stimulate the PN and reduce stump and phantom pain in amputee patients. If phase I demonstrates feasibility in the office setting, phase II will determine if application of this therapy can be extended to the home environment. PUBLIC HEALTH RELEVANCE: Approximately 1.7 million persons in the United States are living with amputations and the majority of them have stump pain and phantom pain, which are often severe and lead to disability, depression, and general suffering. Stump and phantom pain can greatly reduce quality of life and interfere with the simple activities of daily living, but none of the present treatment options are adequate in managing the pain. The goal of this study is to determine if stump pain and phantom pain can be reduced with percutaneous electrical stimulation of a peripheral nerve in upper-extremity amputees.