Targeted Muscle Reinnervation Treats Neuroma and Phantom Pain in Major Limb Amputees

Abstract

Objective: To compare targeted muscle reinnervation (TMR) to “standard treatment” of neuroma excision and burying into muscle for postamputation pain. Summary Background Data: To date, no intervention is consistently effective for neuroma-related residual limb or phantom limb pain (PLP). TMR is a nerve transfer procedure developed for prosthesis control, incidentally found to improve postamputation pain. Methods: A prospective, randomized clinical trial was conducted. 28 amputees with chronic pain were assigned to standard treatment or TMR. Primary outcome was change between pre- and postoperative numerical rating scale (NRS, 0–10) pain scores for residual limb pain and PLP at 1 year. Secondary outcomes included NRS for all patients at final follow-up, PROMIS pain scales, neuroma size, and patient function. Results: In intention-to-treat analysis, changes in PLP scores at 1 year were 3.2 versus −0.2 (difference 3.4, adjusted confidence interval (aCI) −0.1 to 6.9, adjusted P = 0.06) for TMR and standard treatment, respectively. Changes in residual limb pain scores were 2.9 versus 0.9 (difference 1.9, aCI −0.5 to 4.4, P = 0.15). In longitudinal mixed model analysis, difference in change scores for PLP was significantly greater in the TMR group compared with standard treatment [mean (aCI) = 3.5 (0.6, 6.3), P = 0.03]. Reduction in residual limb pain was favorable for TMR (P = 0.10). At longest follow-up, including 3 crossover patients, results favored TMR over standard treatment. Conclusions: In this first surgical RCT for the treatment of postamputation pain in major limb amputees, TMR improved PLP and trended toward improved residual limb pain compared with conventional neurectomy. Trial Registration: NCT 02205385 at ClinicalTrials.gov.

Targeted muscle reinnervation in oncologic amputees: Early experience of a novel institutional protocol

“…A recent randomized control trial for the treatment of established residual limb and neuroma pain in amputees with TMR versus neuroma excision and muscle burying showed improved PLP with TMR. 59 Furthermore, Serino et al 60 objectively demonstrated the beneficial effect of targeted muscle and sensory reinnervation on the normalization of motor and sensory cortical organization and the prevention of cortical reorganization that occurs after amputation, confirming similar findings by Chen et al 61 The potential for this strategy in the oncology population was recently highlighted. 62 With the recognition that chronic pain is difficult to treat, we have instituted TMR at the time of major limb amputation as routine practice at our institution, in particular for oncologic amputees, for the preemptive management of postamputation pain.…”

“…In a study focusing on the effect of TMR on postamputation neuroma pain, Souza et al demonstrated successful treatment of neuroma‐related symptoms in 93% of patients who had neuroma‐related pain before TMR. A recent randomized control trial for the treatment of established residual limb and neuroma pain in amputees with TMR versus neuroma excision and muscle burying showed improved PLP with TMR . Furthermore, Serino et al objectively demonstrated the beneficial effect of targeted muscle and sensory reinnervation on the normalization of motor and sensory cortical organization and the prevention of cortical reorganization that occurs after amputation, confirming similar findings by Chen et al The potential for this strategy in the oncology population was recently highlighted …”

“…Most patients experience mild symptoms in the long‐term, but approximately 25%‐33% continue to experience debilitating symptoms . In contrast, our experience with TMR has shown continued improvement after 1 year in NRS pain scores after the treatment of symptomatic neuromas and our unpublished experience has found continued improvement in postamputation pain 1 year after primary TMR. Due to these findings, we would expect the differences between the control and TMR group to be greater with more pain experienced by the control group with shorter follow‐up.…”

“…Furthermore, there is a significant difference in the follow‐up between the control and TMR cohorts. However, previous studies have shown that the prevalence of postamputation pain, in particular, phantom limb and residual limb pain, improves with time in the general population, but plateaus to slightly increases with greater than 1‐year follow‐up . Most patients experience mild symptoms in the long‐term, but approximately 25%‐33% continue to experience debilitating symptoms .…”

“…Following Institutional Review Board approval, patient-reported outcomes were collected using a previously developed amputee survey for patients who underwent improves with time in the general population, 17 but plateaus to slightly increases with greater than 1-year follow-up. 59 Most patients experience mild symptoms in the long-term, but approximately 25%-33% continue to experience debilitating symptoms. 4 In contrast, our experience with TMR has shown continued improvement after 1 year in NRS pain scores after the treatment of symptomatic neuromas 59 and our unpublished experience has found continued improvement in postamputation pain 1…”