Lateral thoracic myocutaneous flap transfer for post-sternocleidomastoidectomy neck deformity: Anatomy study and case report.

Background: Complex defects after radical surgery for head and neck malignancies require comprehensive reconstruction strategies to restore both structure and function. Based on anatomical studies of the lateral thoracic artery (LTA) and its branches, we innovatively designed a lateral thoracic myocutaneous flap (LTMF) transfer for post-sternocleidomastoidectomy neck deformity. Methods: Regional dissection was performed bilaterally on five fresh adult cadavers to document the anatomy of the LTA and its branches. We also present a clinical case in which the LTMF was used to reconstruct the sternocleidomastoid muscle (SCM), and the medial pectoral nerve was used to reconstruct the accessory nerve. Results: The LTA was present in nine of 10 sides. It originated from the axillary artery on six sides and the subscapular artery on three sides. The LTA courses inferolaterally, nearly parallel to the midclavicular line (1.93 ± 0.79 cm ∼ 2.77± 0.68 cm lateral) and the midaxillary line (2.38 ± 0.85 cm ∼ 4.22 ± 1.65 cm anterior), extending 9.00 ± 2.25 cm and branching every 1.02 ± 0.95 cm ∼ 2.85 ± 1.52 cm. Twenty-four-month follow-up in one patient confirmed good flap integration, showing 80° cervical rotation, 90° shoulder abduction. The QuickDASH and MDADI scores demonstrated stability over follow-up period, reflecting persistent mild upper limb dysfunction and mild swallowing impairment. Conclusions: While the origin of the LTA is highly variable, its course and distribution remain consistent. The LTMF based on the LTA represents a valuable and promising novel option for functional and aesthetic restoration of SCM defects.