Palliative surgery for thumb involvement in ulnar paralysis.

Ulnar paralysis has multiple clinical presentations, which are due to partial recovery or to anatomical variations between the ulnar and median nerves. The main sequelae of ulnar nerve paralysis are the loss of hand strength with impairment of all intrinsic functions of the fingers and some of the thumb's functions. Weakness of the adductor pollicis and flexor pollicis brevis muscles may manifest as weak key pinch with automatic flexion of the thumb interphalangeal joint when gripping. Indications for palliative surgery have decreased due to advances in peripheral nerve surgery. However, palliative surgery still has a significant role to play when nerve repair techniques are not indicated or do not provide satisfactory results. The principle is to reinforce metacarpophalangeal flexion while stabilizing the thumb's interphalangeal joint, thus supplementing the action of the flexor pollicis brevis. This is generally done by transferring the flexor digitorum superficialis tendon of the fourth finger to the distal insertion of the superficial thenar muscles and the extensor pollicis longus. Restoration of the first dorsal interosseous is more rarely indicated.