Restoration of winged scapula in upper arm type brachial plexus injury: anatomic feasibility

The patients who have C5-C6 root avulsion in brachial plexus injury, suffered from loss of elbow flexion, shoulder abduction and winged scapula. The purpose of study is to provide anatomic feasibility of thoracodorsal nerve (medial and lateral branches) and long thoracic nerve for restoration of the shoulder function caused by winged scapula. To study the length of thoracodorsal nerve and long thoracic nerve from the apex of the posterior axillary line to the insertion of the latissimus dorsi muscle and the serratus anterior muscle respectively, 10 fresh cadavers were dissected. The distance between the thoracodorsal nerve and long thoracic nerve, and the numbers of fascicles and axon were measured by histomorphometry. We transferred the lateral branch of the thoracodorsal nerve to the long thoracic nerve in order to restore the serratus anterior muscle function. The mean length of the thoracodorsal nerve from apex of posterior axillary line to bifurcation before separation to medial and lateral branches was 31.5 mm. The average length of the thoracodorsal nerve and long thoracic nerve from bifurcation to the insertion of the latissimus dorsi muscle and the serratus anterior muscle were 10.3, 82.2, and 99.5 mm, respectively. The distance between the lateral branch of the thoracodorsal nerve and long thoracic nerve was 33.4 mm. The mean number of myelinated nerve fiber of the thoracodorsal nerve medial and lateral branches and long thoracic nerve were 973.8, 1843.3 and 1135.3 axons, respectively. The anatomic study of the thoracodorsal nerve and long thoracic nerve showed that the lateral branch of the thoracodorsal nerve is proper in the length and numbers of axon to transfer to the long thoracic nerve for restoration of shoulder function caused by the winged scapula.