Targeted Muscle Reinnervation Technique in Below-Knee Amputation

Abstract

Summary: Approximately 25 percent of major limb amputees will develop chronic localized symptomatic neuromas and phantom limb pain in the residual limb. A method to treat and possibly prevent these pain symptoms is targeted reinnervation. Previous studies prove that targeted reinnervation successfully treats and, in some cases, resolves peripheral neuropathy and phantom limb pain in patients who have undergone previous amputation (i.e., secondary targeted reinnervation). This article seeks to share the authors’ clinical indications and surgical technique for targeted muscle reinnervation in below-knee amputation, a surgical description currently absent from our literature. Targeted reinnervation for the below-knee amputee has been performed on 22 patients at the authors’ institution. Each patient has been followed on an outpatient basis for 1 year to evaluate symptoms of neuroma or phantom limb pain, patient satisfaction, and functionality. All subjects have denied neuroma pain following amputation. The majority of subjects reported phantom pain at 1 month. However, at 3 months, all patients reported resolution of this pain. Dumanian et al. first noted the improvement of symptomatic neuroma and phantom limb pain in patients undergoing targeted reinnervation to provide intuitive control of upper limb prostheses. These findings have been substantiated by multiple previous studies at various amputation levels. This study extends the success of targeted muscle reinnervation to below-knee amputations and provides a description for this technique.

Targeted Muscle Reinnervation: Outcomes in Treating Chronic Pain Secondary to Extremity Amputation and Phantom Limb Syndrome

“…11,[15][16][17][18] Only one trial focused specifically on lower extremity. 18 Four of the articles were retrospective reviews, [15][16][17][18] and one was a randomized control trial. 11 A total of 149 patients were included, of whom 82 underwent lower extremity amputation.…”

“…Each article defined and addressed pain differently, with Dumanian et al 11 and Valerio et al 17 using the 0 to 10 numerical rating scale and the PROMIS (Patient-Reported Outcomes Measurement Information System) T-scale for both phantom and residual limb pain. Souza et al, 16 Bowen et al, 18 and Pet et al 15 simply described binary symptomatic or asymptomatic neuroma pain, though Souza et al did not evaluate for phantom pain.…”

“…For patients who underwent TMR at the time of amputation (prophylactic group), all articles reported minimal development of palpation-induced pain or symptomatic neuroma subsequent to the procedure, with an average follow-up time of 15.5 months (range: 8-18 months). In three of the four articles that addressed prophylactic TMR, 15,16,18 only 1 of the 45 patients treated went on to develop neuroma pain. In the fourth article, 17 49.2% of those followed were noted to be free of pain versus 19.5% of the control.…”

“…In cases in which TMR was performed following the amputation as a treatment for chronic pain, there was near-complete resolution of previously existing neuroma pain, with 34 of the 38 patients noting complete resolution of pain. 15,16,18 In the third article, the pain was rated on the numerical rating scale (Likert scale) as 3.6 out of 10 versus 5.7 out of 10 in controls. 11 Phantom pain in the prophylactic group was less studied.…”

Amputation demographic assessment at Saiful Anwar hospital: 5 years of study

“…5 About 25% of patients undergoing amputation developed neuromas which will cause phantom pain sensation. 6 Other morbidity such as affected social life of the patients, function to work, quality of life, and patients self-confidence. 7 The great impact of this trouble is expected to increase with increasing diabetes patients and increasing age in population.…”