Motor Nerve Transfers in Complete and Incomplete Brachial Plexus Injuries: A State-of-the-Art Review

Brachial plexus injuries are challenging conditions. Over the past decades, nerve transfer surgery has progressively evolved from proximal nerve reconstruction toward selective distal neurotization strategies, considerably expanding the possibilities for functional restoration. As the number of described donor-recipient combinations has increased, the literature has become increasingly fragmented, often focusing on isolated techniques or specific functional targets. The aim of the present study was to provide a comprehensive state-of-the-art overview of currently available motor nerve transfer strategies for upper-limb reinnervation in BPI. A literature review was conducted according to PRISMA guidelines using PubMed/MEDLINE, Embase, Cochrane Library, Scopus, and Web of Science databases. Studies concerning motor nerve transfers for upper-limb reconstruction were systematically reviewed and categorized according to recipient nerve and functional target, including shoulder function, scapular stabilization, elbow flexion and extension, wrist and finger extension, wrist and finger flexion, intrinsic hand function, and extraplexal donor nerve reconstruction. A total of 250 studies met the inclusion criteria. Both intraplexal and extraplexal donor strategies were identified for most reconstructive targets. Intraplexal distal nerve transfers currently represent the preferred approach whenever feasible because of shorter reinnervation distances and more predictable outcomes. Extraplexal donors, including the spinal accessory, intercostal, contralateral C7, and phrenic nerves, remain essential in complete BPIs and root avulsion injuries. Despite substantial advances, restoration of intrinsic hand function and reliable distal reinnervation remain major reconstructive challenges. Motor nerve transfers represent an increasingly versatile and function-oriented reconstructive strategy that should be tailored to the individual injury pattern, available donor nerves, and functional priorities.