Targeted muscle reinnervation in managing post-amputation related pain: A systematic review and meta-analysis

IntroductionLimb amputation can cause residual limb pain (RLP) and/or phantom limb pain (PLP). Although targeted muscle reinnervation (TMR) was initially introduced to facilitate the control of prosthetic limbs, it has been noted that these patients experience less pain and improved prosthetic functional outcomes. As a result, the use of TMR in managing neuroma-related RLP is increasing. The aim of this review is to assess the quality and strength of the evidence supporting the effectiveness of TMR in managing amputation-related pain. MethodsFive different databases, including MEDLINE (PubMed), Scopus, Web of Science, Cochrane Library, and Embase, were searched from inception to March 2022. The protocol for this systematic review has been registered in the PROSPERO database (CRD42020218242). To be included, studies needed to compare pre- and postoperative pain outcomes or different techniques for adult patients who underwent TMR following amputation. Eligible studies also needed to use patient-reported outcome measures (PROMS) and be clinical trials or observational studies published in English. Excluded studies were case reports, case series, reviews, proof of concept studies, and conference proceedings. A meta-analysis was performed on studies that had similar intervention and control groups to examine treatment effects using a random-effects model. Studies were weighted using the inverse variance method, and a statistically significant p-value was considered to be less than or equal to 0.05. ResultsThis review included five studies for qualitative analysis and four studies for quantitative analysis. Reviewed studies enrolled a total of 127 patients. The TMR group was compared with standard treatment at 12 months follow-up. The TMR group showed significantly better PLP as assessed by the numerical rating score RLP, and PLP assessed using Patient-Reported Outcomes Measurement Information System (PROMIS) also showed significantly lower pain intensity in the TMR group. ConclusionThere is limited evidence of good quality favoring TMR in reducing postamputation PLP and RLP pain compared with standard care. Randomized clinical trials are encouraged to compare the efficacy of different surgical techniques.