Longitudinal evaluation of restricted mouth opening (trismus) in patients following primary surgery for oral and oropharyngeal squamous cell carcinoma.

Trismus is a serious problem for some patients after oral and oropharyngeal cancer, and it has a detrimental impact on quality of life and function. We know of few published papers that include preoperative assessment in reports on the longitudinal outcomes of mouth opening after oral and oropharyngeal surgery. We prospectively measured mouth opening in patients who had primary surgery for oral and oropharyngeal cancer from baseline to six months to find out the characteristics at baseline and at discharge of those who develop trismus at six months. Ninety-eight patients were eligible between February 2007 and March 2008, and 64 (65%) were recruited into the study. The range of mouth opening was measured on three occasions: before operation, on the ward before discharge from hospital, and at follow-up six months after operation. Using a criterion of 35 mm or less as an indication of trismus, 30% (19/63) had trismus before operation, 65% (37/57) at hospital discharge, and 54% (26/48) at six month follow-up. Patients at high risk of trismus were those with T stage 3 or 4 cancers who required free flap reconstruction and adjuvant radiotherapy; radiotherapy was the most significant factor at six months. Trismus at discharge was a prediction of trismus at six months. Interventions such as spatulas or a passive jaw mobiliser should be targeted at patients at high risk early in the postoperative phase. The efficacy of such interventions needs further research.