Experience with ultrasound neurography for postoperative evaluation of targeted muscle reinnervation.

Targeted muscle reinnervation (TMR) was originally developed as a means for increasing intuitive prosthesis control, though later found to play a role in phantom limb pain and neuroma prevention. There is a paucity of literature describing the clinical course of patients with poor TMR surgical outcomes and the value of imaging in the postoperative recovery period. This report will illustrate the potential utility of ultrasound neurography to accurately differentiate TMR surgical outcomes in two patients that received upper extremity amputation and subsequent reconstruction with TMR. Ultrasound evaluation of TMR sites in patient 1 confirmed successful reinnervation, evident by nerve fascicle continuity and eventual integration of the transferred nerve into the target muscle. Conversely, the ultrasound of patient 2 showed discontinuity of the nerve fascicles, neuroma formation, and muscle atrophy in all three sites of nerve transfer, suggesting an unsuccessful procedure and poor functional recovery. Ultrasound neurography is uniquely able to capture the longitudinal trajectory of rerouted nerves to confirm continuity and eventual reinnervation into muscle. Therefore, the application of ultrasound in a postoperative setting can correctly identify instances of failed TMR before this information would become available through clinical evaluation. Early identification of poor TMR outcomes may benefit future patients by fostering the discovery of failure mechanisms and aiding in further surgical planning to improve functional outcomes.

Assessment of efficiency of mirror therapy in preventing phantom limb pain in patients undergoing below-knee amputation surgery-a randomized clinical trial.

PURPOSE AND OBJECTIVES: Phantom limb pain (PLP) is a major cause of physical limitation and disability accounting for about 85% of amputated patients. Mirror therapy is used as a therapeutic modality for patients with phantom limb pain. Primary objective was to study the incidence of PLP at 6 months following below-knee amputation between the mirror therapy group and control group. METHODS: Patients posted for below-knee amputation surgery were randomized into two groups. Patients allocated to group M received mirror therapy in post-operative period. Two sessions of therapy were given per day for 7 days and each session lasted for 20 min. Patients who developed pain from the missing portion of the amputated limb were considered to have PLP. All patients were followed up for six months and the time of occurrence of PLP and intensity of the pain were recorded among other demographic factors. RESULTS: A total of 120 patients completed the study after recruitment. The demographic parameters were comparable between the two groups. Overall incidence of phantom limb pain was significantly higher in the control group (Group C) when compared to the mirror therapy (Group M) group [Group M = 7 (11.7%) vs Group C = 17 (28.3%); p = 0.022]. Intensity of PLP measured on the Numerical Rating Scale (NRS) was significantly lower at 3 months in Group M compared to Group C among patients who developed PLP [NRS - median (Inter quartile range): Group M 5 (4,5) vs Group C 6 (5,6); p 0.001]. CONCLUSION: Mirror therapy reduced the incidence of phantom limb pain when administered pre-emptively in patients undergoing amputation surgeries. The severity of the pain was also found to be lower at 3 months in patients who received pre-emptive mirror therapy. TRIAL REGISTRATION: This prospective study was registered in the clinical trial registry of India. TRIAL REGISTRATION NUMBER: CTRI/2020/07/026488.

Chronic post amputation pain: pathophysiology and prevention options for a heterogenous phenomenon.

PURPOSE OF REVIEW: Chronic postamputation pain (cPAP) remains a clinical challenge, and current understanding places a high emphasis on prevention strategies. Unfortunately, there is still no evidence-based regimen to reliably prevent chronic pain after amputation. RECENT FINDINGS: Risk factors for the development of phantom limb pain have been proposed. Analgesic preventive interventions are numerous and no silver bullet has been found. Novel techniques such as neuromodulation and cryoablation have been proposed. Surgical techniques focusing on reimplantation of the injured nerve might reduce the incidence of phantom limb pain after surgery. SUMMARY: Phantom limb pain is a multifactorial process involving profound functional and structural changes in the peripheral and central nervous system. These changes interact with individual medical, psychosocial and genetic patient risk factors. The patient collective of amputees is very heterogeneous. Available evidence suggests that efforts should focus on prevention of phantom limb pain, since treatment is notoriously difficult. Questions as yet unanswered include the evidence-base of specific analgesic interventions, their optimal "window of opportunity" where they may be most effective, and whether patient stratification according to biopsychosocial risk factors can help guide preventive therapy.

[Treatment and prevention phantom pain syndrome in mine-explosive injuries]. / Analiz ispol'zovaniya sovremennykh metodov lecheniya i profilaktiki fantomnogo bolevogo sindroma pri minno-vzryvnykh travmakh.

Phantom pain syndrome significantly impairs the quality of life and effectiveness of surgical treatment after limb amputations. The authors consider possible strategies for treatment and prevention in elective surgical intervention and mine-explosive injuries.

Systematic Review and Meta-Analysis of the Effect of Perineural Catheters in Major Lower Limb Amputations.

OBJECTIVE: Controlling pain after major lower limb amputation (MLLA) is of critical importance to patients and clinicians. The aim of this systematic review and meta-analysis was to assess the effect of perineural catheters (PNCs) on post-operative pain, post-operative morphine requirement, in-hospital mortality, long term phantom limb pain, and chronic stump pain. METHODS: A systematic review using PubMed, EMBASE via OVID and the Cochrane library from database inception (1946) to 20 October 2020 was performed according to PRISMA guidelines. Studies involving patients undergoing MLLA which reported on post-operative morphine requirement, pain scores, in-hospital mortality, phantom limb pain (PLP), and chronic stump pain were included. Studies comparing PNC use with epidural or wound site local anaesthetic infusions were excluded. Outcome data were extracted from individual studies and meta-analysis was performed using a random effects (Mantel-Haenszel) model for dichotomous data using an odds ratio (OR) summary statistic with 95% confidence intervals (CI), and with an inverse variance random effects model for continuous data using a standardised mean difference (SMD) summary statistic with 95% CIs. Sensitivity analyses were performed for post-operative pain scores and post-operative morphine requirement. Study quality was assessed using the Downs and Black score, and outcomes were assessed using the GRADE tool. RESULTS: Ten studies reporting on 731 patients were included, with 350 patients receiving a PNC and 381 receiving standard care. PNC use is associated with a reduction in post-operative pain (SMD -0.30, 95% CI -0.58 - -0.01, p = .040, I2 = 54%, GRADE quality of evidence: low) and post-operative morphine requirements (SMD -0.63, 95% CI -1.03 - -0.23, p = .002, I2 = 75%, GRADE quality of evidence: moderate), although the effect of PNC on reduced post-operative morphine requirements is lost on sensitivity analysis of randomised trials only (p = .40). No demonstrable effect was found on in-hospital mortality, PLP, or chronic stump pain (GRADE quality of evidence: low). CONCLUSION: PNC use in amputees is associated with a significant reduction in post-operative pain scores and post-operative morphine requirements, although this latter finding is lost on sensitivity analysis of randomised trials only.

Targeted muscle reinnervation following external hemipelvectomy or hip disarticulation: An anatomic description of technique and clinical case correlates.

BACKGROUND: Targeted muscle reinnervation (TMR) has been shown to decrease or prevent neuropathic pain, including phantom and residual limb pain, after extremity amputation. Currently, a paucity of data and lack of anatomical description exists regarding TMR in the setting of hemipelvectomy and/or hip disarticulations. We elaborate on the technique of TMR, illustrated through cadaveric and clinical correlates. METHODS: Cadaveric dissections of multiple transpelvic exposures were performed. The major mixed motor and sensory nerve branches were identified, dissected, and tagged. Amputated peripheral nerves were transferred to identified, labeled target motor nerves via direct end-to-end nerve coaptations per traditional TMR technique. A retrospective review was completed by our multi-institutional teams to include examples of clinical correlates for TMR performed in the setting of hemipelvectomies and hip disarticulations. RESULTS: A total of 12 TMR hemipelvectomy/hip disarticulation cases were performed over a 2 to 3-year period (2018-2020). Of these 12 cases, 9 were oncologic in nature, 2 were secondary to traumatic injury, and 1 was a failed limb salvage in the setting of chronic refractory osteomyelitis of the femoral shaft. CONCLUSIONS: This manuscript outlines the technical considerations for TMR in the setting of hemipelvectomy and hip disarticulation with supporting clinical case correlates.

[Perioperative measures for prevention of phantom pain: an evidence-based approach to risk reduction]. / Perioperative Maßnahmen zur Prävention von Phantomschmerz: ein evidenzbasierter Ansatz zur Risikoreduktion.

Prevention of phantom limb pain is one of the biggest and still largely unsolved challenges in perioperative medicine. Despite many study efforts and optimization of postoperative pain treatment over the last 30 years, a significant reduction in the incidence of phantom limb pain has not been achieved. Current studies have also shown that at least 50% of patients develop phantom pain after 6 months. A possible approach could be to combine multiple synergistic interventions and implement them as a perioperative phantom pain management strategy bundle. In addition to regional anesthesia, NMDA antagonists, gabapentinoids, antidepressants and systemic lidocaine could play a relevant role. The aim of this pharmacological intervention was the modification of the pathophysiological changes in peripheral nerves and in the central nervous system after amputation.

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

BACKGROUND: We describe a multidisciplinary approach for comprehensive care of amputees with concurrent targeted muscle reinnervation (TMR) at the time of amputation. METHODS: Our TMR cohort was compared to a cross-sectional sample of unselected oncologic amputees not treated at our institution (N = 58). Patient-Reported Outcomes Measurement Information System (NRS, PROMIS) were used to assess postamputation pain. RESULTS: Thirty-one patients underwent amputation with concurrent TMR during the study; 27 patients completed pain surveys; 15 had greater than 1 year follow-up (mean follow-up 14.7 months). Neuroma symptoms occurred significantly less frequently and with less intensity among the TMR cohort. Mean differences for PROMIS pain intensity, behavior, and interference for phantom limb pain (PLP) were 5.855 (95%CI 1.159-10.55; P = .015), 5.896 (95%CI 0.492-11.30; P = .033), and 7.435 (95%CI 1.797-13.07; P = .011) respectively, with lower scores for TMR cohort. For residual limb pain, PROMIS pain intensity, behavior, and interference mean differences were 5.477 (95%CI 0.528-10.42; P = .031), 6.195 (95%CI 0.705-11.69; P = .028), and 6.816 (95%CI 1.438-12.2; P = .014), respectively. Fifty-six percent took opioids before amputation compared to 22% at 1 year postoperatively. CONCLUSIONS: Multidisciplinary care of amputees including concurrent amputation and TMR, multimodal postoperative pain management, amputee-centered rehabilitation, and peer support demonstrates reduced incidence and severity of neuroma and PLP.

Home-Based Tactile Discrimination Training Reduces Phantom Limb Pain.

BACKGROUND: Phantom limb pain (PLP) affects a high percentage of amputees. Since treatment options are limited, low quality of life and addiction to pain medication frequently occur. New treatments, such as mirror therapy or electrical sensory discrimination training, make use of the brain's plasticity to alleviate this centrally derived pain. AIM: This pilot study assessed the question of whether home-based tactile discrimination training (TDT) leads to a stronger decrease in PLP levels compared to standard massage treatment. DESIGN: Controlled study. SETTING: Outpatient. POPULATION: Amputees (upper/lower extremity) with a PLP score of 4 or higher out of a possible 10 points on the visual analog scale. METHODS: Eight patients participated in the study. The treatment phase comprised 2 weeks (15 minutes daily). Subjects were examined at baseline, after treatment, 2 weeks after completing treatment, and 4 weeks after completing treatment. Pain was assessed using the West Haven-Yale Multidimensional Pain Inventory. RESULTS: There was a significantly stronger reduction in PLP in the treatment group receiving TDT. PLP intensity ratings were significantly reduced at the end of therapy, and at 2 and 4 weeks after completing treatment compared to pretreatment. CONCLUSIONS: TDT seems to be an easy, cheap, time-effective, and safe method to achieve sustained alleviation of PLP and also brings about a positive change in body image. REHABILITATION IMPACT: Home-based TDT could achieve a sustained reduction in PLP and should be considered as a possible alternative to established treatment methods.

The Preventive Value of Epidural Calcitonin in Patients with Lower Limb Amputation.

BACKGROUND: Postamputation pain is highly prevalent after limb amputation with neuropathic nature; calcitonin may effectively relieve many neuropathic pain states. DESIGN: Double-blind randomized multicenter study. SETTING: Our study hypothesis is to evaluate the preventive value of epidural calcitonin on postoperative pain, grade of phantom pain, and the development of allodynia and hyperalgesia in patients undergoing lower limb amputation. PATIENTS: A cohort of 60 diabetic patients of both genders suffering from vascular insufficiency of one or both lower limbs underwent minor or major lower limb amputation. Patients were divided randomly into two equal groups: an epidural bupivacaine-calcitonin-fentanyl (BCF) group and a bupivacaine-fentanyl (BF) group. METHODS: Patients were instructed about the use of a 10 cm visual analog scale (VAS). Phantom limb pain was graded using a four-grade scale. Pin-prick hyperalgesia and allodynia were evaluated at one week, one month, three months, and six months after surgery. RESULTS: There were no significant differences between groups regarding patients' characteristics. There was no significant difference in the VAS scale between groups. There was statically significant improvement in the grade of phantom pain in the BCF group at six and 12 months after surgery ( P = 0.033 and 0.001, respectively). A significantly higher number of patients developed allodynia in the BF group at six ( P = 0.039) and 12 ( P = 0.013) months and hyperalgesia at 12 months ( P = 0.025). CONCLUSION: The preventive use of epidural calcitonin improved the grade of phantom pain and reduced the incidence of allodynia and hyperalgesia in patients undergoing lower limb amputation under combined spinal-epidural anesthesia during one year of follow-up.

Improving Functional Outcomes for Vascular Amputees Through Use of Mirror Therapy and Elimination of the Effects of Electromagnetic Fields.

The objective of this pilot study was to investigate the effectiveness of combining an amputee limb cover to eliminate the effects of electromagnetic fields (i.e., pain) and a Mirror Therapy exercise program to improve functional outcomes for vascular amputees. A cross-sectional repeated-measures design was used with 14 participants with either acute amputations or surgery at least 8 to 24 months previously. The 4-week intervention included the use of an amputee limb cover and mirror therapy exercises each day. The outcome measures were activities of daily living interference (e.g., self-care, walking, car transfer, low chair transfer, sleep), and well-being (e.g., satisfaction, mood, quality of life) at three times (pre- and posttreatment and maintenance). Participants with acute amputations made significant improvements in the areas of self-care, walking, car transfer, sleep, mood, and quality of life, while the subacute participants improved significantly in sleep and satisfaction. A reduction in the time required before prosthetic fitting decreased from 12 weeks to 8 weeks for acute amputees and an improvement in wearing tolerance from 0-2 to 8-12 hours for the subacute amputees were unexpected results suggesting the combined intervention may improves the extent to which amputees can increase participation in their activities of everyday living.

Systematic review and meta-analysis of the efficacy of perineural local anaesthetic catheters after major lower limb amputation.

OBJECTIVE: The aim of this systematic review and meta-analysis was to evaluate the effects of using an intraoperatively placed perineural catheter (PNC) with a postoperative local anaesthetic infusion on immediate and long-term outcomes after lower limb amputation. METHODS: A systematic review of key electronic journal databases was undertaken from inception to January 2015. Studies comparing PNC use with either a control, or no PNC, were included. Meta-analysis was performed for postoperative opioid use, pain scores, mortality, and long-term incidence of stump and phantom limb pain. Sensitivity analysis was performed for opioid use. Quality of evidence was assessed using the GRADE system. RESULTS: Seven studies reporting on 416 patients undergoing lower limb amputation with PNC usage (n = 199) or not (n = 217) were included. Approximately 60% were transtibial amputations PNC use reduced postoperative opioid consumption (standardised mean difference: -0.59, 95% CI -1.10 to -0.07, p = .03), maintained on sensitivity analysis for large (p = .03) and high-quality (p = .003) studies, but was marginally lost (p = .06) on studies enrolling patients with peripheral arterial disease only. PNC treatment did not affect postoperative pain scores (p = .48), in-hospital mortality (p = .77), phantom limb pain (p = .28) or stump pain (p = .37). GRADE quality of evidence for all outcomes was very low. CONCLUSION: There is poor-quality evidence that PNC usage significantly reduces opioid consumption following lower limb amputation, without affecting other short- or long-term outcomes. Well-performed randomised studies are required.

Targeted muscle reinnervation: a novel approach to postamputation neuroma pain.

BACKGROUND: Postamputation neuroma pain can prevent comfortable prosthesis wear in patients with limb amputations, and currently available treatments are not consistently effective. Targeted muscle reinnervation (TMR) is a decade-old technique that employs a series of novel nerve transfers to permit intuitive control of upper-limb prostheses. Clinical experience suggests that it may also serve as an effective therapy for postamputation neuroma pain; however, this has not been explicitly studied. QUESTIONS/PURPOSES: We evaluated the effect of TMR on residual limb neuroma pain in upper-extremity amputees. METHODS: We conducted a retrospective medical record review of all 28 patients treated with TMR from 2002 to 2012 at Northwestern Memorial Hospital/Rehabilitation Institute of Chicago (Chicago, IL, USA) and San Antonio Military Medical Center (San Antonio, TX, USA). Twenty-six of 28 patients had sufficient (> 6 months) followup for study inclusion. The amputation levels were shoulder disarticulation (10 patients) and transhumeral (16 patients). All patients underwent TMR for the primary purpose of improved myoelectric control. Of the 26 patients included in the study, 15 patients had evidence of postamputation neuroma pain before undergoing TMR. RESULTS: Of the 15 patients presenting with neuroma pain before TMR, 14 experienced complete resolution of pain in the transferred nerves, and the remaining patient's pain improved (though did not resolve). None of the patients who presented without evidence of postamputation neuroma pain developed neuroma pain after the TMR procedure. All 26 patients were fitted with a prosthesis, and 23 of the 26 patients were able to operate a TMR-controlled prosthesis. CONCLUSIONS: None of the 26 patients who underwent TMR demonstrated evidence of new neuroma pain after the procedure, and all but one of the 15 patients who presented with preoperative neuroma pain experienced complete relief of pain in the distribution of the transferred nerves. TMR offers a novel and potentially more effective therapy for the management of neuroma pain after limb amputation.

Does a torsion adapter improve functional mobility, pain, and fatigue in patients with transtibial amputation?

BACKGROUND: Turning gait is an integral part of daily ambulation and likely poses a greater challenge for patients with transtibial amputation compared with walking a straight pathway. A torsion adapter is a prosthetic component that can increase transverse plane compliance of the prosthesis and decrease the torque applied to the residual limb, but whether this will improve patients' mobility, pain, and fatigue remains unknown. QUESTIONS/PURPOSES: Does prescription of a torsion adapter translate to improvements in (1) functional mobility and (2) self-perceived pain and fatigue in moderately active patients with lower limb amputation? METHODS: Ten unilateral transtibial amputees wore a torsion or rigid adapter in random order. Functional mobility was assessed through a field measurement using an activity monitor and through a laboratory measurement using a 6-minute walk test that included turns. The residual limb pain grade assessed self-perceived pain and the Multidimensional Fatigue Inventory assessed fatigue. RESULTS: We found relatively small functional differences for amputees wearing a torsion adapter versus a rigid adapter. Amputees wearing a torsion adapter tended to take more low- and medium-intensity steps per day (331 ± 365 and 437 ± 511 difference in steps; effect size = 0.44 and 0.17; confidence interval [CI], 70-592 and 71-802; p = 0.019 and 0.024, respectively). They also experienced less pain interference with activities (1.9 ± 1.7 change in score; effect size = 0.83; CI, 0.3-3.4; p = 0.026) when wearing a torsion adapter. However, these patients took a similar number of total steps per day, walked a comparable distance in 6 minutes, and reported similar residual limb pain and fatigue. CONCLUSIONS: For a moderately active group of amputees, the torsion adapter did not translate to substantial improvements in functional mobility and self-perceived pain and fatigue. The small increases in low- and medium-intensity activities with less pain interference when wearing a torsion adapter provides evidence to support prescribing this device for amputees with difficulty navigating the household and community environments.

Does targeted nerve implantation reduce neuroma pain in amputees?

BACKGROUND: Symptomatic neuroma occurs in 13% to 32% of amputees, causing pain and limiting or preventing the use of prosthetic devices. Targeted nerve implantation (TNI) is a procedure that seeks to prevent or treat neuroma-related pain in amputees by implanting the proximal amputated nerve stump onto a surgically denervated portion of a nearby muscle at a secondary motor point so that regenerating axons might arborize into the intramuscular motor nerve branches rather than form a neuroma. However, the efficacy of this approach has not been demonstrated. QUESTIONS/PURPOSES: We asked: Does TNI (1) prevent primary neuroma-related pain in the setting of acute traumatic amputation and (2) reduce established neuroma pain in upper- and lower-extremity amputees? METHODS: We retrospectively reviewed two groups of patients treated by one surgeon: (1) 12 patients who underwent primary TNI for neuroma prevention at the time of acute amputation and (2) 23 patients with established neuromas who underwent neuroma excision with secondary TNI. The primary outcome was the presence or absence of palpation-induced neuroma pain at last followup, based on a review of medical records. The patients presented here represent 71% of those who underwent primary TNI (12 of 17) and 79% of those who underwent neuroma excision with secondary TNI (23 of 29 patients) during the period in question; the others were lost to followup. Minimum followup was 8 months (mean, 22 months; range, 8-60 months) for the primary TNI group and 4 months (mean, 22 months; range, 4-72 months) for the secondary TNI group. RESULTS: At last followup, 11 of 12 patients (92%) after primary TNI and 20 of 23 patients (87%) after secondary TNI were free of palpation-induced neuroma pain. CONCLUSIONS: TNI performed either primarily at the time of acute amputation or secondarily for the treatment of established symptomatic neuroma is associated with a low frequency of neuroma-related pain. By providing a distal target for regenerating axons, TNI may offer an effective strategy for the prevention and treatment of neuroma pain in amputees.

The effectiveness of targeted muscle reinnervation in reducing pain and improving quality of life for patients following lower limb amputation.

BACKGROUND: Globally, over 1 million lower limb amputations are performed annually, with approximately 75% of patients experiencing significant pain, profoundly impacting their quality of life and functional capabilities. Targeted muscle reinnervation (TMR) has emerged as a surgical solution involving the rerouting of amputated nerves to specific muscle targets. Originally introduced to enhance signal amplification for myoelectric prosthesis control, TMR has expanded its applications to include neuroma management and pain relief. However, the literature assessing patient outcomes is lacking, specifically for lower limb amputees. This systematic review aims to assess the effectiveness of TMR in reducing pain and enhancing functional outcomes for patients who have undergone lower limb amputation. METHODS: A systematic review was performed by examining relevant studies between 2010 and 2023, focusing on pain reduction, functional outcomes and patient-reported quality of life measures. RESULTS: In total, 20 studies were eligible encompassing a total of 778 extremities, of which 75.06% (n = 584) were lower limb amputees. Average age was 46.66 years and patients were predominantly male (n = 70.67%). Seven studies (35%) reported functional outcomes. Patients who underwent primary TMR exhibited lower average patient-reported outcome measurement information system (PROMIS) scores for phantom limb pain (PLP) and residual limb pain (RLP). Secondary TMR led to improvements in PLP, RLP and general limb pain as indicated by average numeric rating scale and PROMIS scores. CONCLUSION: The systematic review underscores TMR's potential benefits in alleviating pain, fostering post-amputation rehabilitation and enhancing overall well-being for lower limb amputees.

Targeted Muscle Reinnervation at the Time of Amputation Decreases Recurrent Symptomatic Neuroma Formation.

BACKGROUND: Targeted muscle reinnervation (TMR) is an effective technique for the prevention and management of phantom limb pain (PLP) and residual limb pain (RLP) among amputees. The purpose of this study was to evaluate symptomatic neuroma recurrence and neuropathic pain outcomes between cohorts undergoing TMR at the time of amputation (ie, acute) versus TMR following symptomatic neuroma formation (ie, delayed). METHODS: A cross-sectional, retrospective chart review was conducted using patients undergoing TMR between 2015 and 2020. Symptomatic neuroma recurrence and surgical complications were collected. A subanalysis was conducted for patients who completed Patient-Reported Outcome Measurement Information System (PROMIS) pain intensity, interference, and behavior scales and an 11-point numeric rating scale (NRS) form. RESULTS: A total of 105 limbs from 103 patients were identified, with 73 acute TMR limbs and 32 delayed TMR limbs. Nineteen percent of the delayed TMR group had symptomatic neuromas recur in the distribution of original TMR compared with 1% of the acute TMR group ( P < 0.05). Pain surveys were completed at final follow-up by 85% of patients in the acute TMR group and 69% of patients in the delayed TMR group. Of this subanalysis, acute TMR patients reported significantly lower PLP PROMIS pain interference ( P < 0.05), RLP PROMIS pain intensity ( P < 0.05), and RLP PROMIS pain interference ( P < 0.05) scores in comparison to the delayed group. CONCLUSIONS: Patients who underwent acute TMR reported improved pain scores and a decreased rate of neuroma formation compared with TMR performed in a delayed fashion. These results highlight the promising role of TMR in the prevention of neuropathic pain and neuroma formation at the time of amputation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Acute versus non-acute targeted muscle reinnervation for pain control following major limb amputation: A comparative study.

BACKGROUND: Targeted muscle reinnervation (TMR) has been shown to reduce phantom limb pain (PLP) and residual limb pain (RLP) after major limb amputation. However, the effect of the timing of surgery on pain control and quality of life outcomes is controversial. We conducted a retrospective study to compare the outcomes of acute TMR for pain prevention with non-acute TMR for the treatment of established pain. METHODS: All patients treated with TMR in our institution between January 2018 and December 2021 were evaluated at 6, 12, 18 and 24 months post-operatively. Pain intensity and quality of life outcomes were assessed using the Brief Pain Inventory (Pain Severity and Pain Interference scales) and Pain Catastrophizing Scale. Outcomes were compared between acute and non-acute TMR using the Wilcoxon ranked-sum test or Fisher's exact test as appropriate. Multilevel mixed-effects linear regression was used to account for repeat measures and potential pain confounders. RESULTS: Thirty-two patients with 38 major limb amputations were included. Acute TMR patients reported significantly lower RLP and PLP scores, pain interference and pain catastrophisation at all time points (p < 0.05). Acute TMR was significantly associated with lower pain severity and pain interference in a linear mixed-effects model accounting for patient age, gender, amputation indication, amputation site, time post-TMR and repeated surveys (p < 0.05). There was no significant difference in the complication rate (p = 0.51). CONCLUSION: Acute TMR was associated with clinically and statistically significant pain outcomes that were better than that in non-acute TMR. This suggests that TMR should be performed with preventative intent, when possible, as part of a multidisciplinary approach to pain management, rather than deferred until the development of chronic pain.