Transfer of the Radial Nerve Branch to the Extensor Carpi Radialis Brevis to the Anterior Interosseous Nerve to Reconstruct Thumb and Finger Flexion

Delayed Transfer of the Extensor Carpi Radialis Brevis Branch of the Radial Nerve to the Anterior Interosseous Nerve for Restoration of Thumb and Index Finger Flexion: Case Report

“…2,4 In this way, distal nerve transfers have been used increasingly to improve outcomes. 2,[4][5][6][7][8] As of this writing, nerve transfers are the preferred strategy for obtaining these goals, especially in patients within 12 months of injury for motor recovery and 3 years for sensory recovery. 4 MN repair by grafting or end-toend repair is still recommended, particularly for those patients experiencing pain.…”

“…2,3 In this regard, selective distal nerve transfers were recently introduced to improve functional outcomes after HMNI. 2,[4][5][6][7][8] Influenced by the results of Sedain et al 9 in obtaining satisfactory outcomes after delayed Oberlin transfer, we report the surgical results of a patient affected by HMNI with a partial spontaneous recovery that occurred after a gunshot wound to the arm, who was treated in a delayed fashion by transferring the radial nerve branch to the extensor carpi radialis brevis (ECRB) to the AIN.…”

Tendon palpation during agonist contraction and antagonist co-contraction to assess wrist flexor and extensor muscle function

“…It is particularly relevant to determine which wrist muscles are functional in brachial plexus injuries and spinal cord lesion in the following situations: the need to correctly identify the roots involved in partial brachial plexus trauma; radial wrist extensors are paralyzed in extended upper-type lesions, whereas the ECU is consistently preserved; meanwhile, the FCR is consistently paralyzed in upper-type lesions affecting C5-C7, whereas the FCU is functional; and the PL is consistently innervated by the T1 root and preserved in C5-C8 root injuries; a few patients have wrist extension produced by finger extension; however, when grasping objects, their fingers do not extend further and their wrist drops, leading to decreased grip strength; such patients warrant a tendon or nerve transfer to strengthen their ECRB; when the FCU is being considered as an axon donor for reinnervation of the biceps [20], the anterior interosseous nerve [21], or the triceps [22]; when the FCU is being considered as a standard tendon transfer for thumb and finger extension [23]; before harvesting the FCU, PL integrity should be demonstrated, as the FCR is routinely paralyzed in extended upper-type lesions of the brachial plexus; in the absence of a strong FCU, wrist extension should be reconstructed by transferring the pronator quadratus motor branch to the ECRB motor branch [5], or to a free gracilis; we do not recommend transferring the flexor digitorum superficialis motor nerves to wrist extensors in extended brachial plexus palsy cases [24]; in lower-type injuries of the brachial plexus or in spinal cord injuries, the ECRL tendon is used to reconstruct finger flexion; before removing the ECRL, ECRB function must be demonstrated in order to preserve wrist extension [25]; also, a distal terminal branch of the nerve to the ECRB can be used to reinnervate the flexor pollicis longus or the anterior interosseous nerve [26,27]; in lower-type injuries of the brachial plexus and in midcervical spinal cord trauma, the nerve to the supinator muscle can be transferred to the posterior interosseous nerve to reconstruct thumb and finger extension; however, assessment of supinator muscle function is difficult. The nerve to the supinator shares the same spinal cord level innervation as the ECRB; consequently, if the ECRB is functional, the nerve to the supinator should also be preserved [28].…”

Novel Uses of Nerve Transfers

“…Restoring the function of these muscles can significantly improve pinch function, and thus, the anterior interosseous nerve serves as a good target for nerve transfer. Two potential options for the donor nerve have emerged, including the brachialis branch of the musculocutaneous nerve and the extensor carpi radialis brevis (ECRB) branch of the radial nerve [1,29,[38][39][40]. The largest series involved 8 nerve transfers using the brachialis branch as the donor and five nerve transfers using the branch to the ECRB as the donor.…”