An improved technical trick for identification of the thoracodorsal nerve during axillary clearance surgery: a cadaveric dissection study.

Background: Accurate anatomical landmarks to locate the thoracodorsal nerve are important in axillary clearance surgery.

Methods: Twenty axillary dissections were carried out on ten preserved Sri Lankan cadavers. Cadavers were positioned dorsal decubitus with upper limbs abducted to 900 . An incision was made in the upper part of the anterior axillary line. The lateral thoracic vein was identified and traced bi-directionally. The anatomical location of the thoracodorsal nerve was studied in relation to the lateral border of pectoralis minor and from a point along the lateral thoracic vein, 2 cm inferior to its confluence with the axillary vein.

Results: The lateral thoracic vein was invariably present in all the specimens. All the lateral thoracic veins passed lateral to the lateral border of pectoralis minor except in one specimen, where the lateral thoracic vein passed along its lateral border. The thoracodorsal nerve was consistently present posterolateral to the lateral thoracic vein. The mean distance to the lateral thoracic vein from the lateral border of pectoralis minor was 28.7 ± 12.6 mm. The mean horizontal distance, depth, and displacement, from a point along the lateral thoracic vein, 2 cm inferior to its confluence with the axillary vein to the thoracodorsal nerve were 14.5 ± 8.9 mm, 19.7 ± 7.3 mm and 25 ± 5 mm respectively. The thoracodorsal nerve was found in a posterolateral direction, at a 540  ± 120 angle to the horizontal plane, 95% of the time.

Conclusions: The lateral thoracic vein is an accurate guide to the thoracodorsal nerve. We recommend exploring for the thoracodorsal nerve from a point 2 cm from the confluence of the lateral thoracic vein and the axillary vein for a distance of 25 ± 5 mm in a posterolateral direction, at a 540  ± 120 angle to the horizontal plane.