The impact of different timing of mouth opening exercises on trismus in postoperative radiotherapy patients with oral cancer.

Objective: To compare the effects of starting mouth opening exercises at two different times on trismus in postoperative radiotherapy patients with oral cancer.

Methods: Through a prospective randomized controlled trial, purposive sampling was used to select 76 patients undergoing postoperative radiotherapy for oral cancer from March 2023 to January 2024 at the Department of Oral and Maxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. Patients were randomly divided into an experimental group (n = 38) and a control group (n = 38) using a random number table at a ratio of 1:1. The experimental group began mouth opening exercises in the second week after surgery (before radiotherapy), while the control group began in the fourth week after surgery (at the start of radiotherapy). The primary outcome measure was maximum interincisal opening (MIO). Secondary outcome measures included pain visual analog scale (VAS) scores and quality of life scores (UW-QOL), assessed at baseline, the second week post-surgery (before radiotherapy), the fourth week post-surgery (at the start of radiotherapy), the ninth week post-surgery (end of radiotherapy), and the twelfth week post-surgery (three weeks after the end of radiotherapy).

Results: A total of 72 patients completed all assessments, with 36 in each group, resulting in an overall sample attrition rate of 5.26 % (less than 15 %). There were no statistically significant differences in general demographic and clinical characteristics between the two groups. Repeated measures ANOVA showed significant differences in MIO, VAS, and UW-QOL scores between groups, over time, and in group-time interactions (P < 0.001). From the fourth week post-surgery (at the start of radiotherapy), the experimental group had significantly higher MIO (P < 0.001), significantly lower VAS scores (P < 0.001), and significantly higher UW-QOL scores (P < 0.001) compared to the control group. These differences persisted at subsequent assessment points.

Conclusion: Initiating mouth opening exercises in the second week post-surgery (before radiotherapy) can significantly improve mouth opening, reduce pain, and enhance the quality of life in postoperative radiotherapy patients with oral cancer. This provides important evidence for clinical practice, although further research is needed to verify the long-term effects.