Prevalence and prediction of trismus in patients with head and neck cancer: A cross-sectional study

Background Trismus occurs frequently in patients with head and neck cancer. Determining the prevalence and associated factors of trismus would enable prediction of the risk of trismus for future patients. Methods Based on maximal mouth opening measurements, we determined the prevalence of trismus in 730 patients with head and neck cancer. Associated factors for trismus were analyzed using univariate analyses and multivariate logistic regression analyses. Based on the regression model, a calculation tool to predict trismus was made. Results Prevalence of trismus was 23.6%. Factors associated with trismus were: advanced age; partial or full dentition; tumors located at the maxilla; mandible; cheek; major salivary glands; oropharynx; an unknown primary; a free soft tissue transfer after surgery; reirradiation; and chemotherapy. Conclusion About one-fourth of patients with head and neck cancer develop trismus. Based on prevalence and associated factors of trismus, a simple calculation tool predicts the risk of trismus in these patients.