Retromandibular Vein, Digastric Muscle, and Greater Auricular Nerve in Superficial Parotidectomies for Patients with Pleomorphic Adenoma-A Surgical Experience.

Abstract

Retromandibular vein (RMV) and posterior belly of digastric muscle are among the landmarks used to identify facial nerve in parotid surgery. This observational cross-sectional study was done in the Department of ENT &HNS at a tertiary care teaching hospital for a period of 8 years with the aim to aware young otorhinolaryngologist about the relationship of posterior belly of digastric muscle & retromandibular vein with facial nerve and share our experience about preservation of posterior branch of greater auricular nerve. A total of 34 cases of superficial parotidectomies done for pleomorphic adenoma were included in this study. Relationship of facial nerve with retromandibular vein and posterior belly of digastric muscle was noted. Greater auricular nerve was identified, and every attempt was made to preserve its posterior branch. Retromandibular vein was medial to the trunks of facial nerve in 33 (97%) patients. It was lateral to lower division and medial to upper division in one case. Greater auricular nerve was seen to bifurcate into two branches (Anterior and posterior) in 21 (62%) cases while in one case(3%) three branches were seen emerging from main trunk and in another case(3%) first two branches were seen emerging and then anterior branch was further dividing into two. Preservation of posterior branch of greater auricular nerve was possible in 23 (68%) of patients. Posterior belly of digastric muscle was seen as a reliable and constant landmark. Facial nerve was seen superior to upper border of posterior belly of digastric muscle in all cases (100%). No anatomical variation of posterior belly was seen. Retromandibular vein is invariably seen medial to the trunks of facial nerve. Facial nerve is always seen superior to upper border of posterior belly of digastric muscle in almost all cases. Preservation of posterior branch of greater auricular nerve is possible in majority of the cases.