Clinical Research Directory

Improving Postamputation Functioning by Decreasing Phantom Pain With Perioperative Continuous Peripheral Nerve Blocks: A Department of Defense Funded Multicenter Study

When a limb is amputated, pain perceived in the part of the body that no longer exists often develops, called "phantom limb" pain. The exact reason that phantom limb pain occurs is unclear, but when a nerve is cut-as happens with an amputation-changes occur in the brain and spinal cord that are associated with persistent pain. The negative feedback-loop between the injured limb and the brain can be stopped by putting local anesthetic-called a "nerve block"-on the injured nerve, effectively keeping any "bad signals" from reaching the brain. A "continuous peripheral nerve block" (CPNB) is a technique providing pain relief that involves inserting a tiny tube-smaller than a piece of spaghetti-through the skin and next to the target nerve. Local anesthetic is then introduced through the tiny tube, which bathes the nerve in the numbing medicine. This provides a multiple-day block that provides opioid-free pain control with no systemic side effects, and may prevent the destructive feedback loop that results in phantom limb pain following an amputation. We propose a multicenter, randomized, triple-masked (investigators, subjects, statisticians), placebo-controlled, parallel arm, human-subjects clinical trial to determine if a prolonged, high-concentration (dense), perioperative CPNB improves post-amputation physical and emotional functioning while decreasing opioid consumption, primarily by preventing chronic phantom limb pain.