Targeted Muscle Reinnervation and Nerve Transfers for Brachial Plexus Injuries: optimising upper limb functional recovery and minimising donor site morbidity

This comprehensive review examines targeted muscle reinnervation (TMR) and nerve transfer strategies in the management of brachial plexus injuries (BPI), aiming to restore upper limb function while minimizing donor site morbidity. A focused literature search was conducted on PubMed, restricted to the last 10 years. Commonly utilized transfers, such as the ulnar fascicle and double fascicular transfers for elbow flexion, and spinal accessory or intercostal nerve transfers for shoulder and hand reanimation were evaluated in terms of indications, outcomes, and donor site risks. Among these, the double fascicular transfer demonstrated superior recovery of elbow flexion, especially when performed early. Shoulder reanimation was most effective when both the suprascapular and axillary nerves were targeted, improving abduction and external rotation. Distal nerve transfers yielded better fine motor recovery and faster reinnervation than tendon transfers. Adjunctive strategies, including photobiomodulation and preoperative electrodiagnostic tools, were noted to enhance reinnervation outcomes. TMR, particularly in combination with free functional muscle transfer (FFMT), showed promise in delayed presentations by bringing the site of neurotization closer to the target muscle and reducing axonal regeneration distance. Success depended heavily on appropriate donor nerve selection, timing of intervention, and individualized surgical planning. However, the heterogeneity in reported outcomes and lack of standardized assessment tools remain significant barriers to optimal technique comparison. Future research should emphasize long-term, prospective studies using unified evaluation metrics to strengthen clinical decision-making and guide technique refinement.