Trismus secondary to head and neck cancer
After treatment of head and neck cancer many patients suffer from side-effects, including trismus: a limited ability to open the mouth. A mouth opening of 35 mm or less is a commonly used cut-off point for trismus. Trismus can be caused by the tumor itself (invasion in the masticatory muscles and temporomandibular joint, or their surrounded tissues) or by the treatment (scar formation and fibrosis as a result of surgery and radiotherapy).
The risk factors for trismus identified in this thesis are: higher age, female sex, several locations of the tumor (oral cavity, oropharynx, nasopharynx, nasal cavity, maxillary sinus, salivary glands, and ear), T4 tumors, higher irradiation dose, smaller mouth opening prior or during radiotherapy, and more time since radiotherapy. Of patients treated with radiotherapy, the mouth opening can be predicted with models. Additionally, trismus can be predicted for different time points post-radiotherapy.
In this thesis, no exercise technique was found clearly superior and the results varied considerably. As a result of exercise therapy, less decrease (in case of preventive exercises) or a larger increase in mouth opening (in case of therapeutic exercises) can be expected in compliant patients and when exercise therapy starts early. Despite positive results of exercise therapy in general, trismus secondary to head neck cancer cannot always be prevented or treated.