Assessment of Postoperative Facial Nerve Outcomes Following Parotidectomy for Benign and Malignant Parotid Gland Lesions: A Prospective Observational Study.

Background Postoperative facial nerve dysfunction is the most feared complication of parotidectomy. This study determined its incidence, severity, branch-wise distribution, recovery pattern, and determinants, and compared the outcomes between benign and malignant parotid lesions. Methods In this prospective observational study, 120 consecutive adults underwent superficial, total conservative, or radical parotidectomy at a tertiary care hospital. Facial nerve function was graded using the House-Brackmann (HB) scale preoperatively and at defined postoperative intervals (postoperative day 1, one month, three months, and six months). Facial weakness persisting at six months was considered permanent for the purpose of this study. Outcomes were compared according to histopathology, extent of surgery, and tumor size using the chi-square test, Fisher's exact test, and the Cochran-Armitage trend test. Results The study included 120 patients with a mean age of 47.8±14.2 years; 66 were men and 54 were women. Of them, 82 (68.3%) had benign lesions, while 38 (31.7%) had malignant lesions. Facial nerve function remained normal in 72 (60.0%); 38 (31.7%) had temporary dysfunction, all recovering to HB grade I by six months, and 10 (8.3%) had permanent paralysis. The overall incidence of postoperative facial nerve dysfunction, including both temporary and permanent dysfunction, was higher in patients with malignant tumors than in those with benign tumors. Dysfunction occurred in 28 of 38 patients (73.7%) with malignant tumors and in 20 of 82 patients (24.3%) with benign tumors (relative risk, 3.02; 95% confidence interval, 1.97-4.62; p<0.001). The incidence of dysfunction also increased with the extent of surgery, from 20.3% after superficial parotidectomy to 58.1% after total conservative parotidectomy and 100% after radical parotidectomy (p for trend <0.001). Similarly, dysfunction increased with tumor size, from 8.6% for tumors <2 cm to 36.7% for tumors 2-4 cm and 92.0% for tumors >4 cm (p for trend <0.001). The marginal mandibular branch accounted for half of all deficits (24/48). Conclusions Facial nerve dysfunction after parotidectomy is common but predominantly transient. Malignant histology, greater resection extent, and larger tumor size were each strongly associated with postoperative facial nerve dysfunction. Risk-specific counseling, judicious selection of surgical extent, and early rehabilitation remain central to minimizing morbidity.