Prognostic factors associated with a restricted mouth opening (trismus) in patients with head and neck cancer: Systematic review.

BACKGROUND: To prescribe early trismus therapy, prognostic factors influencing the restricted mouth opening should be identified first. Our aim is to present an overview of these factors in patients with head and neck cancer. METHODS: PubMed, Cochrane, EMBASE, and CINAHL were searched using terms related to head and neck cancer and mouth opening. Risk of bias was assessed using the "Quality in Prognosis Studies" tool. A best evidence synthesis was performed. RESULTS: Of the identified 1418 studies, 53 were included. Three studies contained a prognostic multivariate model for a restricted mouth opening. CONCLUSIONS: Patients with head and neck cancer will most likely develop a restricted mouth opening when they have a large tumor near the masticatory muscles that requires extensive cancer treatment. A restricted mouth opening most likely occurs within 6 months after cancer treatment. Further research is necessary on factors related to healing tendency or pain intensity.

Criterion for trismus in head and neck cancer patients: a verification study.

PURPOSE: Several cut-off points for trismus in head and neck cancer patients have been used. A mouth opening of 35 mm or less is most frequently used as cut-off point. Due to the variation in cut-off points, prevalence, risk factors and treatment outcomes of trismus cannot be studied in a uniform manner. To provide uniformity, we aimed to verify the cut-off point of 35 mm or less. Additionally, we aimed to determine associated covariates with reported difficulties when opening the mouth. METHODS: In a cross-sectional design, we measured the mouth opening in 671 head and neck cancer patients at the Department of Oral and Maxillofacial Surgery, at the University Medical Center Groningen. The cut-off point was determined using the receiver operating characteristic curve and Youden index, with reported difficulties when opening the mouth as criterion for trismus. Cut-off points for significant covariates were also determined. RESULTS: The Youden index was highest at 35 mm, with a sensitivity of 0.71 and a specificity of 0.86. Of the covariates analysed, type of treatment modality was significantly associated with reported difficulties when opening the mouth. The highest Youden index for patients treated with surgery alone was 37 mm and for patients treated with radiotherapy alone 33 mm. CONCLUSIONS: The cut-off point of 35 mm or less for trismus was confirmed in a head and neck cancer population and is recommended to be used in future studies. Patients receiving different treatment modalities experience difficulty when opening the mouth differently.

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.