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

Abstract

Background Secondary to vascular disease, oncological resection, or devastating trauma, lower extremity amputations are performed globally at a yearly rate exceeding 1 million patients. Three-quarters of these patients will develop chronic pain or phantom pain, which presents a functional limitation for prosthetic use and contributes to deconditioning and increased mortality. Targeted muscle reinnervation (TMR) presents a surgical solution to this problem as either a primary or secondary intervention. Methods A review of the existing literature was conducted using a combination of the terms “phantom pain” “chronic pain,” “neuroma,” and “targeted muscle reinnervation” in Medline and PubMed. Results Five articles were found which addressed TMR for pain syndromes, four of which involved lower extremity amputation. Four of the articles were retrospective reviews, and one was a randomized control trial. A total of 149 patients were included, of which 82 underwent lower extremity amputation. Ninety-two of the patients underwent prophylactic TMR, of which 57 were secondary procedures.In patients who underwent TMR at the time of amputation, all studies reported a minimal development of symptomatic neuromas (27%). For secondary TMR, near-complete resolution of previous pain was found (90%). Phantom pain was noted to be similar to other studies in the literature but noted to improve over time with both primary (average drop of 3.5 out of 10 points on the numerical rating scale) and secondary (diminishing from 72% of patients to 13% over 6 months) operations. Conclusion Although much of the current literature is limited to retrospective studies with few patients, these data point toward near-complete resolution of neuroma pain after treatment as well as complete prevention of chronic pain if TMR is used as a prophylactic measure during the index amputation. This study was a level of evidence IV.

Treatment of Neuroma of the Dorsal Branch of the Ulnar Nerve With Transfer to the Distal Anterior Interosseous Nerve

“…When a suitable distal segment of the severed nerve is unavailable or its use is not advisable, a recently described technique for painful neuromas is STM nerve transfer. 5 , 6 , 7 , 9 , 10 The proximal sensory nerve is coapted to a distal expendable motor nerve branch, giving the growing axons a distal nerve segment toward the motor end plates of the muscle cells. The midterm results have been encouraging.…”

“… 6 The observed associated improvement in chronic pain and phantom limb syndrome prompted its use to treat these painful conditions in amputees. 7 The regenerating sensory axons would enter the distal endoneural tubes of the distal motor nerve and reach the neuromuscular plates, where they are thought to stop and remain quiescent, thus avoiding neuroma formation.…”

Auricular Therapy for Treating Phantom Limb Pain Accompanied by Jumping Residual Limb: A Short Review and Case Study

“…Regarding surgical intervention, nerve resection, nerve root cutting, and anterior column cutting are gradually replaced by interventional surgery because of their large trauma and various complications. As a surgical technique, targeted muscle reinnervation (TMR) refers to transferring the residual peripheral nerve to the redundant motor nerve of target muscle, restoring physiological continuity, encouraging organized nerve regeneration, so as to reduce and potentially prevent nerve confusion and directional growth [16] and it presents a surgical solution to this problem as either a primary or secondary intervention [17]. Imageguided percutaneous nerve cryoablation is feasible and safe and may represent a new efficacious therapeutic option for patients with PLP [18].…”

Long-Term Opioid Use Following Surgery for Symptomatic Neuroma

“…There are myriad options for surgical intervention, and each surgical strategy may improve patient symptoms, but complete pain relief remains challenging. 3 4 5 However, poor coping strategies, negative mood, and prior history of depression are associated with inferior outcomes following neuroma surgery, thus elevating these patient groups' risk for prolonged opioid use. 6 7…”