Unmasking Neuroma Pain in the Upper Extremity Amputee

BACKGROUND: Surgical management of a symptomatic neuroma can result in the development of pain in a previously asymptomatic amputated nerve. We report our institution's experience with diagnosing and managing this "unmasking" phenomenon in upper extremity amputees. METHODS: A single-center prospective registry was reviewed for patients who underwent surgery for a symptomatic neuroma in an upper limb over a 3-year period from 2017 to 2020. All patients presenting with a painful neuroma that was previously asymptomatic but became symptomatic after successful surgical management of a separate nerve in the same extremity were described. RESULTS: The incidence of unmasked neuroma pain in the upper extremity amputee database was 4 of 86 (4.7%) patients. Three of the 4 patients opted for surgical treatment of the unmasked neuroma, with 2 patients undergoing targeted muscle reinnervation (TMR) and 1 patient being treated with a regenerative peripheral nerve interface (RPNI). All patients reported a significant improvement in pain following their post-unmasking procedure. CONCLUSIONS: The rate of neuroma unmasking is low, and in this series, it occurred predominantly in the digits. Due to this low incidence in the upper extremity, it is reasonable to surgically address the symptomatic neuroma only, but the phenomenon of unmasking a neuroma in a previously asymptomatic peripheral nerve should be discussed when counseling upper extremity amputee patients undergoing surgical management of a symptomatic neuroma. While further study is required to determine the risk factors of this uncommon clinical diagnosis, surgical management of the unmasked neuroma with TMR or RPNI can be effective.