METHODS
Our study ruled the Declaration of Helsinki regarding ethics guidelines. The study protocol was approved by the ’[removed for blind peer review]’. The latter waived written informed consent because of the retrospective nature of our study. Our ethics committee (’[removed for blind peer review]’) approved the waiver of informed consent for this study.
All consecutive patients undergoing partial superficial or superficial or subtotal or total parotidectomy between January 2015 and December 2019 were included in this study. All patients underwent preoperative diagnosis by ultrasound or computed tomography (CT) scan. Patients were excluded from the study for the following reasons: (1) postoperative pathology suggests malignancy tumor; (2) previous history of radiation therapy or operated to the head and neck region; (3) incomplete medical records or follow-up. We collected all kinds of data including sex, age, type of tumor, type of parotidectomy, and tumor size, specimen volume, diabetes mellitus, hypertension, etc. The postoperative complication, drainage, aesthetic score outcome were analyzed. All patients were followed up for at least 6 months.
Parotidectomy was performed in the standard manner (Fig 1A, 1B). All parotid operations were performed by 1 of 2 experienced chief physician. The marginal mandibular of the facial nerve was first identified, and then a retrograde dissection of the nerve was performed. The acellular dermal matrix (ADM) used in our study was J1-ADM (Beijing Jayyalife Biological Technology Co. Ltd., Beijing, China). The ADM size was selected by the actual needs of operation. All patients were placed on prophylactic antibiotics for the duration their drain was in place.
Frey’s syndrome (FS) and aesthetic score was evaluated by subjective methods. For the subjective FS evaluation, patients were queried about warming, flushing, or sweating over the preauricular regions during the follow-up period. For the subjective aesthetic score was achieved by asking patients to complete a questionnaire designed to assess their satisfaction with the resulting scar and upper cervical and retromandibular contour. Subjective aesthetic score was scaled from 1 to 10 (1 representing very dissatisfied; 10 representing very satisfied).(20)
The mean and variance were used as continuous variables and n (%) were used as categorical variables. T test was used for continuous variables and Pearson Chi-square test or Fisher’s exact test were used for categorical variables. P < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS 22.0 for Windows.