The role of exercise therapy in managing post-radiotherapy trismus in head and neck cancer

Trismus is a post-radiotherapy complication that affects survivors of head and neck cancers. It is described as the reduction of mouth opening to less than 35 mm. The condition is a progressive process; hence early intervention is crucial to prevent further damage and weakness to the elevator muscles of the mandible. Here, we report a 40-year-old woman with known squamous cell carcinoma of the maxillary sinus in stage T3N0M0 who had undergone upper right partial maxillectomy with subsequent 33 fractions of radiotherapy (66 Gy; intensity modulating radiotherapy). Five months post radiotherapy, the patient showed interest in replacing her missing teeth to restore her oral functions and facial appearance. At her post-radiotherapy visit in the dental assessment clinic, she showed a mouth opening of 12 mm. The TheraBite (R) Jaw Motion Rehabilitation SystemTM and wooden tongue depressors were alternatively used for 6 weeks (4-5 stretches/day; each stretch held for 15 s). Mouth opening gradually increased to 20 mm. Consequently, a definitive obturator prosthesis was fabricated using computer-aided design and computer-aided manufacturing technologies with the 3Shape D900 model scanner. These were challenging and time-consuming steps, but acceptable facial appearance and mouth opening were restored for the patient. This case suggests that Therabite (R) Jaw Motion Rehabilitation SystemTM and wooden tongue depressors help to increase mouth opening significantly if used together and alternatively.