Brachialis muscle transfer to reconstruct finger flexion or wrist extension in brachial plexus palsy

PURPOSE: Tendon transfers are a routine procedure used to improve hand function in brachial plexus injuries; however, muscles from forearm donors are not always available for transfer. In this situation a distant muscle may be used. This study describes transfer of the brachialis muscle to the forearm muscles to reconstruct finger flexion or wrist extension in patients with brachial plexus injuries. METHODS: In 6 patients the brachialis muscle was transferred to the flexor digitorum profundus and the flexor pollicis longus to restore finger and thumb flexion with the goal of reconstructing a key pinch and hook grasp. In 3 patients the brachialis muscle was transferred to the extensor carpi radialis brevis to restore wrist extension. The patients were evaluated at regular intervals and had final assessments between 10 and 12 months after surgery. RESULTS: Brachialis transfer to the flexor digitorum profundus and the flexor pollicis longus resulted in active motion with full range of digital flexion in the 2 patients who had partial flexion before surgery, and for the 4 patients who had no finger flexion before surgery it resulted in a pulp-to-palm distance for the middle finger of 1 cm in 3 patients and of 2 cm in 1 patient. A lateral key pinch and hook grasp reconstruction was achieved in all patients. Grasping and lateral pinch strengths averaged 110 and 94 mm Hg, respectively. When the brachialis was transferred to the wrist extensors the patients recovered 20 degrees of active wrist extension against resistance. CONCLUSIONS: Brachialis muscle transfer to the forearm muscle constitutes a valid strategy in the reconstruction of finger and thumb flexion and wrist extension after brachial plexus injury when forearm donor muscles are not available. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.