Review of Outcomes After Peripheral Nerve Transfers for Motor Nerve Injury in the Upper Extremity

Background: Modern nerve-to-nerve transfers are a significant advancement in peripheral nerve surgery. Nerve transfers involve transferring donor nerves or branches to recipient nerves close to the motor end unit, leading to earlier reinnervation and preservation of the musculotendinous units in proximal nerve injuries. After nerve reinnervation, function may be superior to traditional tendon transfer techniques in terms of strength and independent motion. Nerve transfer surgery has emerged as a promising treatment option for many cases of nerve injury that were previously expected to result in poor outcomes, such as proximal injuries, long nerve gaps, or unavailability of the proximal injured segment. Methods: A review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Publications that focused on upper extremity nerve transfers were included, and functional motor and sensory recovery was analyzed. Technique reports, case reports, brachial plexus injuries, and reports on multiple nerve injuries were excluded. Results: A total of 48 relevant articles were identified with search criteria, and we discuss functional outcomes on nerve transfers for ulnar nerve injury, musculocutaneous nerve injury, median nerve injury, and radial nerve injury that met inclusion criteria. Conclusions: Nerve transfers are an option for restoring hand and forearm function in patients with peripheral nerve injuries adversely affecting their ability to function. The literature demonstrates positive functional outcomes after nerve transfer operations, and thus, the utility and variations have increased. We aim to provide an overview of the outcomes of current nerve transfer techniques for ulnar, radial, median, and musculocutaneous acquired/traumatic mononeuropathies in the hand and upper extremity.