Anatomic Variability and Distribution of Facial Nerve Posing Surgical Challenge in Parotidectomy: Lesson Learnt from 106 Cases
DOI:
https://doi.org/10.48111/2021.04.05Keywords:
Facial nerve, Parotidectomy, Variations, Anatomy of Parotid RegionAbstract
IMPORTANCE Functional and anatomic preservation of facial nerve and its terminal branches is a major challenge faced by surgeons during parotid gland surgery. Extra-temporal segment of facial nerve can be injured due to trauma, laceration or iatrogenic causes. Surgical procedures of parotid gland, submandibular gland, temporomandibular joint and face lift are commonly associated with complication of facial nerve palsy. Since iatrogenic injury is quite common, knowledge about relation of facial nerve with parotid gland and facial muscles is essential for competent surgical approach. The rationale for conducting this retrospective study was to identify variations in the course of facial nerve which may lead to better understanding of the surgeon while dissecting it.
PATIENTS AND METHODS We have analyzed records of 106 patients undergoing parotid surgery. In this retrospective study special attention is paid to operative trunk distance, type of peripheral branching pattern and interconnections of facial nerve branches.
RESULTS Greatest variation is observed in upper division of the five-level branching pattern. The frequency of peripheral pattern of facial nerve was type I (31.1%), type II (17.9%), type III (21.6%), type IV (24.52%), type V (2.8%), and type VI (1.88%). This study shows that type I is the most common branching pattern, followed by type IV, type III and type II, respectively. Marginal mandibular branch was found below the mandibular border on live cervicofacial dissections in half of the included cases.
CONCLUSIONS The conclusions are confirmative that extra-temporal course of facial nerve is extremely variable. Distinct knowledge of anatomic variation and distribution of facial nerve is essential for surgeons to enable safe dissection particularly during parotid surgery.
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