Background:
Proximal ulnar-nerve lesions have an unfavorable prognosis. The
goal of the present study was to evaluate the feasibility of selective
restoration of motor function of the ulnar nerve by the transfer
of the anterior interosseous nerve or one of its branches to the
motor branch of the ulnar nerve.
Methods:
Ten cadaveric arms were used in the present study. The ulnar
nerve and its motor and sensory branches as well as the anterior
interosseous nerve and its branches were dissected. The widths of
the motor branch of the ulnar nerve and the anterior interosseous
nerve and its motor branches as well as the relevant distances from
the points of divergence were measured. The axons were counted,
and the distances from the end of the main anterior interosseous
nerve, its motor branches, and the motor branch of the ulnar nerve
to the level of the dorsal sensory branch of the ulnar nerve were
measured.
Results:
Our results indicate that the length, width, and number of axons
of the branch of the anterior interosseous nerve to the pronator
quadratus make it suitable for transfer to the motor branch of the ulnar
nerve. The use of the main anterior interosseous nerve or its motor
branches to the flexor pollicis longus and the flexor digitorum
profundus is less feasible because of the need to graft a long segment
and the longer distance from the level of transfer to the motor
end points.
Conclusions:
The findings of the present study confirm the feasibility of
motor-nerve transfer for reconstruction after an injury of the ulnar
nerve. Nerve-grafting would be needed for injuries distal to the
level of the dorsal sensory branch of the ulnar nerve.