TMR/RPNI Awareness and Timing Outcomes: A Nationwide Survey of Amputees

Background: Amputation leads to a symptomatic neuroma in 5-25% of amputees, causing debilitating pain. Targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) are novel peripheral nerve interventions used to prevent/treat neuromas. Our objective was to assess whether amputees who underwent TMR or RPNI at primary amputation reported less pain and greater ability to use prosthetics than those receiving a delayed (secondary) TMR/RPNI or no TMR/RPNI. Methods: A REDCap survey was administered to 1,377 amputees and 294 responded. Participants were recruited via social media and the Amputee Coalition website. Amputees were queried on demographics, amputation, and quality-of-life characteristics. Knowledge of TMR/RPNI procedures was also assessed. Results: 13% and 7% of patients had a primary and secondary TMR/RPNI, respectively. Outcomes were adjusted for amputation physician and clinical setting. Patients receiving primary TMR/RPNI had significantly lower pain severity score (p=0.019), pain interference score (p=0.046) compared to no intervention. Pain with prosthetic use and proportion experiencing severe pain was not significantly lower amongst those receiving prophylactic TMR or RPNI. Conclusions: Compared to no or secondary peripheral nerve intervention, primary TMR/RPNI led to a significant reduction in pain interference and pain severity. Although not significant, preliminary trends also show reduction in pain with prosthetic use, proportion experiencing severe pain, and sustained opioid use with primary TMR/RPNI. As utilization of TMR/RPNI as a primary procedure yields better pain outcomes in a nation-wide cohort, we must identify and address barriers to performance.