Predictors of facial palsy after surgery for benign parotid disease: multivariate analysis of 626 operations.

BACKGROUND The objective was to identify the risk factors for, and incidence of, facial palsy following conservative parotidectomy. METHODS Conservative parotidectomies for benign diseases (N = 626) were studied retrospectively. The risk factors for postoperative facial palsy were determined by univariate and multivariate analyses of variables related to patient demographics, comorbid illnesses, and characteristics of the operation. RESULTS The rate of transient facial palsies was 23.16% following parotidectomy. Significant risk factors for transient facial palsy were diabetic mellitus (odds ratio [OR] 1.727 [95% CI: 1.062-2.810]) and extended surgery (OR 3.049 [95% CI: 2.058-4.515]). Only the type of surgery was found to have a statistically significant causal relation with permanent facial palsy (p = .017). CONCLUSIONS Comorbid diabetes, and more extensive as opposed to partial superficial parotidectomy, may be associated with transient facial palsy following operation for benign parotid disease. The incidence of permanent facial palsy may be higher when a more extensive parotidectomy is performed.