Facial nerve palsy in parotid gland surgery: A comprehensive analysis of incidence, severity, duration, and risk factors; insights from the Polish Salivary Network Database

BACKGROUND: Facial nerve (FN) palsy is the most serious complication of parotid gland surgery, with risk influenced by tumor size, location and pathology. OBJECTIVE: To assess the incidence, severity, duration, and risk factors of FN palsy following parotidectomy, based on the Polish Salivary Network Database. METHODS: This multicenter study included 2650 patients treated surgically between 2018 and 2022. FN function was evaluated using the House-Brackmann scale, consider-ing extent, severity and duration of FN dysfunction. Multiple potential risk factors were examined. RESULTS: FN palsy occurred in 20% of patients: 17.2% transient and 4.5% permanent. The marginal mandibular branch was most frequently affected. Multivariate analysis showed that parapharyngeal space involvement, presence of malignant neoplasm and preoperative FN dysfunction independently predicted complete paralysis. Additional risk factors for more extensive, severe, and prolonged FN impairment included clinical signs of malignancy, prior radiation, non-radical margins, larger tumor size (>4 cm), and advanced stage of malignancy. A greater number of affected regions (defined by the European Salivary Gland Society (ESGS) classification) was identified as the most significant adverse risk factor for both the degree and persistence of postoperative facial nerve palsy. CONCLUSION: FN palsy remains a relevant risk in parotid surgery, particularly with large or malignant tumors. Early diagnosis and radical excision of smaller lesions are key to preserving nerve function.