Short summary

Parotid surgery is the treatment for benign parotid gland tumors. Parotid surgery carries a risk of facial nerve injury. Information on the frequency of facial nerve palsy is valuable when explaining the surgical procedure to patients. Therefore, this retrospective quality project aims to determine the incidence of facial palsy after parotid gland surgery for benign tumors at OUH between January 2018 and December 2020, this will be of benefit to both the patient and their surgeon.

Rationale

The parotid gland is the largest salivary gland produces about 25 % of all salvia in the mouth. Parotid gland tumors represent less than 3 percent of all head and neck tumors and around 70 % of salivary gland tumors. Most of the parotid gland tumors are benign, of which pleomorphic adenomas (71 %) and Warthin's tumors (22 %) are the most frequent subtypes. Parotid surgery is the recommended treatment for benign parotid gland tumors because of the risk of malignancy or malignant transformation. Parotid surgery carries a risk of facial nerve injury due to the proximity of the facial nerve to the tumor. This risk is the most severe complication and a source of anxiety for both the patient and their surgeon.

The incidence of facial palsy after parotid surgery for benign diseases varies in the literature. Recent studies have reported that temporary and permanent facial nerve dysfunction occurs in 18-27 % and 0-6 % of the patients, respectively.

Information on the frequency of facial nerve palsy is valuable when explaining the surgical procedure to patients before surgery. Therefore, this retrospective quality project aims to determine the incidence of facial palsy in total and divided by the House-Brackmann grading system after parotid gland surgery for benign tumors at Odense University Hospital (OUH) in the period between January 2018 and December 2020.

Description of the cohort

This project will include all patients who had undergone parotid surgery because of benign disease. The participants will be chosen based on diagnostic codes, including KELB40 and KELB50, in the electronic medical record system. Patients with preoperative facial weakness or malignant parotid tumors will be excluded.

Data and biological material

We will obtain data on initial postoperative facial nerve function graded using the House-Brackmann scale and facial function described in the routine follow-up program. In addition, we will obtain data on the surgeon, surgical technique, operative time, facial nerve monitor use, and tumor characterization such as histopathology, location, and size. Lastly, we will collect covariate data, including patient sex and age.