Factors associated with facial weakness following surgery for benign parotid disease: a retrospective multicenter study

BACKGROUND: Facial nerve weakness is the most common and most concerning complication after parotidectomy. Risk factors for this complication following surgery for benign diseases remain controversial. OBJECTIVE: Review the frequency and prognosis of facial nerve weakness after parotidectomy and analyze potential risk factors. DESIGN: Retrospective review of medical records. SETTINGS: Two tertiary care centers. PATIENTS AND METHODS: We included all parotidectomies performed for benign diseases from January 2006 to December 2018. Details about the development and recovery of postoperative facial weakness were recorded. Patient, disease and surgery-related variables were analyzed using bivariate and multivariate analyses to identify risk factors. MAIN OUTCOME MEASURES: Frequency, recovery rates and risk factors for facial nerve weakness SAMPLE SIZE: 191 parotidectomies, 183 patients, 61 patients with facial weakness. RESULTS: The frequency of postoperative facial weakness was 31.9% (61/191 parotidectomies). Among patients with temporary weakness, 90% regained normal facial movement within 6 months. Steroid therapy was not associated with a faster recovery. Postoperative weakness was not associated with age, diabetes, smoking, disease location, use of an intraoperative facial nerve monitor or direction of facial nerve dissection. Risk factors for temporary weakness were total parotidectomy and surgical specimens larger than 60 cubic centimeters. Revision surgery was the only identified risk factor for permanent weakness. CONCLUSION: Larger parotid resections increase the risk of temporary facial nerve weakness while permanent weakness is mainly influenced by previous surgeries. LIMITATIONS: Retrospective nature, underpowered sample size, selection bias associated with tertiary care cases. CONFLICT OF INTEREST: None.