An analysis of the role of targeted muscle reinnervation (TMR) in quality of life and pain outcomes: a case series

Abstract

Aim: Targeted muscle reinnervation (TMR) surgery has fundamentally changed the management of patients who have suffered or are about to undergo amputation. Providing nerve stumps with a muscle target has been shown to have profound effects on levels of post-amputation pain in relation to phantom limb pain (PLP) and neuroma pain (NP). The primary objective of this report was to quantify pain parameters for this population and to measure the impact on health-related quality of life (HRQol) before and after TMR surgery. In this case series, we evaluate the role of TMR in addressing both pain and the impact of the surgery on the patient’s quality of life. Methods: A retrospective analysis of 15 upper limb amputee patients who underwent TMR by the Relimb Unit in London, UK. Participants’ perceptions of pain were determined using the 11-point numerical (Pain) rating scale (NRS) and HRQoL was calculated using the Euroqol EQ-5D-5L questionnaire at two time points, comparing both pain and perceived quality of life pre and post surgery. The Wilcoxon Signed Rank Test was used for the NRS data and a paired sample t-test was used for the EQ-VAS data. Results: A total of 15 patients completed the evaluation. We observed statistically significant reductions in both PLP (pre-operative mean: 7.6, post-operative mean: 2.7, P < 0.05) and NP (pre-operative mean: 6.4, post-operative mean: 2.5, P < 0.05) in these patients. Similarly, HRQoL observed on the EQ-VAS scale demonstrated a significant improvement in quality of life, from 68 pre-operatively to 78 post-procedure (P < 0.05). Conclusion: This is the first quantified evaluation of changes in HRQoL after TMR surgery for upper limb amputation. There appears to be a significant improvement in both HRQoL and overall perception of pain. This finding may have important implications for funding and national resource allocation for TMR surgery.