We conducted an anatomical study to determine
the best technique for transfer of the anterior interosseous nerve (AIN)
for the treatment of proximal ulnar nerve injuries. The AIN, ulnar
nerve, and associated branches were dissected in 24 cadaver arms.
The number of branches of the AIN and length available for transfer
were measured. The nerve was divided just proximal to its termination
in pronator quadratus and transferred to the ulnar nerve through
the shortest available route. Separation of the deep and superficial
branches of the ulnar nerve by blunt dissection alone, was also
assessed. The mean number of AIN branches was 4.8 (3 to 8) and the
mean length of the nerve available for transfer was 72 mm (41 to
106). The transferred nerve reached the ulnar nerve most distally
when placed dorsal to flexor digitorum profundus (FDP). We therefore
conclude that the AIN should be passed dorsal to FDP, and that the
deep and superficial branches of the ulnar nerve require approximately
30 mm of blunt dissection and 20 mm of sharp dissection from the
point of bifurcation to the site of the anastomosis. The use of this technique for transfer of the AIN should improve
the outcome for patients with proximal ulnar nerve injuries. Cite this article:
