[Endoscope-assisted superficial parotidectomy via retroauricular hairline approach: anatomical study]

To provide anantomical basis for the endoscope-assisted partial superficial parotidectomy via retroauricular hairline approach (EASPRHA) and assess its feasibility and safety.

The surgical anatomy of retroauricular hairline region and parotid gland region were observed in 15 fresh human cadavers (30 halves). The EASPRHA was performed on 5 human cadavers (10 halves). After the procedure, the related vascular and neural structures were evaluated.

The retroauricular hairline region extends between superficial musculoaponeurotic system and superficial cervical fascia. On the superficial surface of the upper sternocleidomastoid lie the lesser occipital nerve, the great auricular nerve and the external jugular vein. The bifurcation of great auricular nerve is(22.85 ± 2.01) mm from the bottom of earlobe. The parotid gland region extends between parotidomassteric fascia and parotid gland parenchyma. The facial nerve emerging from the stylomastoid foramen runs across the superficial surface of base of styloid process, passes through the interspace between cartilage of external acoustic meatus and posterior belly of digastric muscle, and enters the parotid gland. The bifurcation of facial nerve trunk is (19.10 ± 3.10)mm from the mastoidale and (39.49 ± 5.78) mm from the mandibular angle. Above the posterior belly of digastric muscle, the posterior auricular artery arises from the posterior wall of the external carotid artery with its main stem running over the superficial surface of facial nerve trunk. In all endoscope-assisted operations, the partial superficial parotidectomy was successful without the need for an additional incision. No major neurovascular damage wasobserved.

A thorough knowledge of the surgical anatomy of retroauricular hairline region and parotid gland region is an essential requirement in performing the safe and feasible EASPRHA.