Branching Pattern of the Facial Nerve in the Parotid Gland

Kim, Young Soon; Suh, Young Jin; Kim, Wook; Chun, Chung Soo

Abstract

Iatrogenic injury of the facial nerve branch is the main complication during a parotidectomy, leading to functional damage in the patient. An exact and thorough understanding of the anatomy of the branching pattern of the facial nerve in the parotid gland is prerequisite for surgeons performing a parotidectomy. The aim of this study was to elucidate the branching pattern of the facial nerve inside the parotid gland. The relationships between the branches of the facial nerve were investigated in 23 adult faces during parotidectomies for various etiologies. The branches of the facial nerve were divided into six types according to their branching patterns and their communication. Straight branching with two subtrunks was seen in 12 (52%) out of the 23 cases (Type I), two buccal branches from the lower and upper subtrunks was seen in 4 (17%) cases (Type II), and anastomosis between the buccal and zygomatic branches in 4 (17%) cases (Type III). There were multiple anastomoses among the temporal, zygomatic and buccal branches in 2 (9%) cases (Type IV). Only one (4%) case had buccal branch stemming from the marginal mandibular branch (Type VI). In most cases, the buccal branch was the thinnest. We think that many of the patients having a parotid tumor would possibly show a Type I branching pattern during a parotidectomy. Although the marginal mandibular branch was known to have a long course, almost no anastomosis with other branches, and the most devastating functional damage after iatrogenic injury. Surgeons should be especially careful during the dissection along the course of buccal branch, which may be the thinnest, and prone to damage, transiently or permanently, following the procedure.