Anatomical and clinical study of phrenic nerve transfer to the upper trunk of brachial plexus

Objective Based on the anatomical study of the muscle branch of the musculocutaneous nerve to the biceps brachii muscle, a new surgical procedure using phrenic nerve transfer to the upper trunk was designed for restoration of elbow flexion after brachial plexus injuries. Methods 20 upper extremities of 10 cadavers were used. The muscle branch of the musculocutaneous nerve to the biceps brachii muscle was dissected retrogradely. The location of the muscular branch in the anterior division of the upper trunk was observed. In 21 cases of brachial plexus injuries, the phrenic nerve was transferred to the appropriate part of the anterior division of the upper trunk. The treatment outcome was followed. Results The muscular branch to biceps muscle located at the antero lateral or antero middle portion of the anterior division of the upper trunk. The cross-sectional area of the muscle branch was 34 % of that of the anterior division of the upper trunk. The overall effective rate of elbow flexion was 80.95 %. The effective rate in the cases of upper middle trunk injury was 87.5 %, while that of total brachial plexus injury 76.92 %. Conclusions The surgical procedure can be advocated for clinical application in that it possesses such advantages as satisfactory outcome, simple manipulation, and minor trauma.