Double Fascicular Nerve Transfer for Elbow Flexion and Extension

Traumatic brachial plexus injuries are life changing, often leaving affected individuals with severe functional deficits. Recent advances in nerve transfers have allowed surgeons to improve elbow flexion, shoulder abduction, and prehension of the hand in some patients. We hypothesize that in a patient who lacks both biceps and triceps function, a double fascicular transfer may be the key to restore elbow flexion and extension. In three cadaver upper limbs, we transferred the expendable motor fascicle of the ulnar nerve to the biceps branch of the musculocutaneous nerve, and the expendable motor fascicle of the median nerve to the triceps (ulnar collateral) branch of the radial nerve. We evaluated the feasibility of this double nerve transfer via a medial approach, and elucidated the anatomy. The transfers were easily performed and were tension-free throughout full range of motion at the elbow. The triceps branch of the radial nerve that we utilized has a length of approximately 4.9 cm, and is best found between 3.5 and 6 cm from the anterior axillary line. We consistently identified a relatively avascular plane in the region between 7.5 and 11 cm from the anterior axillary line, which corresponds with the recipient sites of the medial head of the triceps. The distance between the triceps branch to the median nerve was an average of 2.5 cm. Transfer of expendable motor fascicles from the ulnar and median nerves to the biceps and triceps nerve branches can be successfully and consistently performed through a medial approach in a cadaver.