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

Purpose To report our experiences reconstructing thumb and finger flexion in patients with extensive palsy of the upper limb by transferring the radial nerve branch to the extensor carpi radialis brevis (ECRB) to the anterior interosseous nerve (AIN). Methods Within 8 months after injury, 4 patients with either a combined high median/ulnar nerve palsy or C7-T1 brachial plexus root avulsion underwent surgical reconstruction for thumb and finger flexion. As part of the reconstructive procedure, the branch of the radial nerve to the ECRB was transferred to the AIN. Results At final evaluation, which averaged 13 months postoperatively, all patients had recovered full finger and thumb flexion, scoring M4 per Medical Research Council guidelines. Average grasp strength was 5 kg, and pinch strength was 2 kg. Even in anesthetic fingers and with their eyes closed, patients could correctly identify passive extension of their distal interphalangeal joints. Wrist extension was preserved in all patients. Conclusions In 4 patients, transfer of the branch of the radial nerve to the ECRB to the AIN predictably reconstructed thumb and finger flexion. Finger flexion also recovered in those fingers in which the flexor digitorum profundus was primarily innervated by the ulnar nerve. Despite extended sensory deficits, patients ultimately were able to use their hands regularly in daily life. Type of study/level of evidence Therapeutic III.