Abstract:

Objective　To provide the anatomical basis for the endoscope-assisted submandibular sialoadenectomy via retroauricular hairline approach （EASSRHA） and assess its feasibility and safety.  Methods　 The surgical anatomy of retroauricular hairline region and submandibular region was observed in 15 fresh human cadavers (30 halves). The submandibular gland resections were performed on 5 human cadavers（10 halves）. After the procedure, the related vascular and neural structures were evaluated.　Results　Dissection in the retroauricular hairline region should be performed between the superficial musculoaponeurotic system and the investing cervical fascia. On the superficial surface of the upper sternocleidomastoid lied the lesser occipital nerve, the great auricular nerve and the external jugular vein.  The submandibular region extended between the deep surface of the platysma and submandibular sheath. The marginal mandibular branch emerging from the inferior border of parotid gland was found（7.21±0.50）mm above the inferior border of the mandible in 66.7%, along the inferior border in 23.3% and （9.43±0.32）mm below the inferior border in 10% of the cases. Near the antero-inferior angle of the masseter muscle, the marginal mandibular branches of the facial nerve crossed over the facial artery and facial vein （29.86±2.77）mm and （25.71±3.32）mm from the mandibular angle , respectively. The hypoglossal nerve passed through the deep surface of the stylohyoid muscle and posterior belly of digastric muscle to enter the submandibular region. On the superficial surface of hyoglossus lied the lingual nerve, the Wharton's duct and the hypoglossal nerve. In all cases, the resection of the submandibular gland was successful without the need for an additional incision. No major neurovascular damage was reported.　Conclusions　A thorough knowledge of the surgical anatomy of the retroauricular hairline region and submandibular region is an essential requirement in performing the safe and feasible submandibular sialoadenectomy.

Key words: Retroauricular hairline approach (RHA), Endocope-assisted(EA), Submandibular gland(SMG), Anatomy, Surgery