New classification of branching pattern of facial nerve during parotidectomy: A cross sectional study

Parotidectomy is one of the most frequent modes to treate tumors of parotid gland. Previous studies documented a variation in the facial nerve branching which might risk facial nerve injury during Parotidectomy.

To make a new classification system that includes a new branching pattern of facial nerve trunk that has not been described before, also to mention a simple method of how to identify the facial nerve trunk, all that will help the new surgeon in performing parotidectomy with less complications and unpredictable outcome.

A prospective cross sectional study on 460 patients underwent partial or total parotidectomy for different pathologies were enrolled during the period January 2004 till September 2020. Three investigations were considered; the anatomy of the facial nerve trunk (FNT), exact site of facial nerve trunk in relation to fixed landmarks, finally we observed any communications between the branches. We made a new classification based mainly on the anatomical variations in the branching pattern of the FNT; namely, types (I, II and III). Each type subdivided according to the length of facial nerve trunk and also according to the communication between the branches.

Type I reported in majority of cases; 78.26%. type II (15.2%) which is the newly discovered branching pattern, and type III (6.6%). Total FNT length was 1-10 mm in more than half (54.35%) of cases. In 64.35% of cases FNT was in the midpoint between the tragal pointer (TP) and tip of mastoid's process (TMP). In 50 (10.87%) of the cases there was anastomotic connection between the buccal and mandibular branches, and in 20(4.34%) the communication was always a loop between the upper and lower divisions of FNT.

There is a profound variation in the facial nerve branching pattern that has not been previously reported. Awareness about differences in the anatomy of the facial nerve assisted useful information to surgeon to preserve FN during parotidectomies.