Distribution of Facial Nerve in Parotid Gland: Analysis of 50 Cases

抄録

Summary: The purpose of the present study is to reduce the postoperative morbidity related to facial paralysis during parotid surgery and to layout the different characteristics related to intraparotideal distribution and anatomoses of the facial nerve in our community. We also report new variations in the facial nerve branchings that have not been previously published.
In this paper, facial nerves from 48 cadavers and 2 patients of which 45(90%) were males and 5(10%) were females; 26(52%) being right and 24(48%) being left facial nerves were put forward. Their photographs were taken and the diagrams of intraparotideal distributions of each facial nerve were drawn. The intraparotideal configuration of the facial nerve was evaluated in 5 types. Twenty-four% of the facial nerves had no anastomoses (Type I); 12% had a ring-like shape anastomosis between the buccal and the zygomatic branches (Type II); 14% anastomoses were between the buccal and the other branches in a ring-like shape (Type III); 38% of the facial nerves had multiple complex anastomoses and were named as multiple loops (Type IV); 12% had two main trunks (Type V).
Of the bilateral cadaver dissections, the facial nerve distribution in 9(47.3%) were bilaterally the same and in 10(52.7%) main trunks were different. A facial nerve trifurcation composed of two main trunks were also established. There were no statistical differences between branching of the facial nerves in the right and left side of the faces. It was shown that there were primary nerve anastomoses between the main trunk and the lower trunk in 4 cadavers (8%); also in 1(2%) cadaver they were between the main and lower trunk and between the upper and lower trunk.
This study shows that there are racial differences in the branching of the facial nerve, and it is important to remind the surgeon of the surprises related to the topographic anatomy during the facial surgery.