843 - Investigating the Impact of Time Interval Between Lower Extremity Amputation and Delayed TMR on Outcomes in the Aging Population

Background:

Annually, nearly 200,000 individuals in the U.S. undergo a major lower extremity amputation (LEA), with over 2 million currently living with such amputations. Post-amputation, 85% experience phantom limb pain (PLP), and 80% develop symptomatic neuromas. TMR, initially designed for upper extremity prosthetics, reduces pain by redirecting sensory and mixed nerves into motor nerves, improving axonal connections. Acute TMR, performed within 2 weeks of amputation, prevents PLP, while delayed TMR, occurring ≥2 weeks, may benefit long-standing amputees by addressing both PLP and neuroma-related pain.

Purpose:


To analyze the impact of the time interval between major lower extremity amputation (LEA) and delayed (≥2 weeks) targeted muscle reinnervation (TMR) on prescription pain medication use and phantom limb pain (PLP) in patients age 60 or older, while considering factors such as amputation indication, level, age, sex, race, BMI, and diabetic status.

Design:

This retrospective chart review examines post-operative outcomes for patients aged 60 and older who underwent delayed TMR to treat PLP following major LEA between 1/1/2009 and 12/31/2022. Among 111 major LEA patients who underwent TMR, 30 were 60 years old or older. Of these, 7 patients had undergone delayed TMR and had follow-up data available. Self-reported use of prescription neuropathic pain medication and PLP presence were assessed during follow-up visits after the TMR procedure.

Results: Data from 7 patients revealed an average interval of 99.14 weeks between amputation and TMR. Preliminary findings show a decrease in neuropathic pain medication use from 86% to 50% and PLP from 43% to 29% across follow-up visits. Further statistical analysis is ongoing.

Conclusions: Delayed TMR may significantly reduce polypharmacy and PLP in older LEA patients, despite concerns about delayed axonal regeneration. Future research will involve a larger sample size to validate these findings and potentially refining guidelines for the timing of TMR interventions in the aging population.