Effectiveness of Manual Therapy in Combination With a Dynamic Splint (Dynasplint) in the Treatment of Trismus in Patients With Head and Neck Cancer: A Pilot Study

Trismus is a common impairment following treatment for head and neck cancer. The prevalence of trismus ranges from 25% to 46%, and may be the result of a tumour growth, infection, surgery or radiation. Trismus can dramatically affect the quality of life of subjects with cancer in a variety of ways, and may contribute to post treatment depression. Early intervention is key to reduce the chances of complications. Multiple modalities have been used in the treatment of trismus: Physical therapy, hyperbaric oxygen and pentoxifylline, forced mouth opening under general anesthesia, surgical coronoidectomy, botulinum toxin injection and jaw opening devices such as the TheraBite Jaw Motion Rehabilitation and the Dynasplint® Trismus System. Manual therapy (MT) constitutes a wide variety of different techniques which may be categorized into four major groups: manipulation, mobilization, and muscle energy techniques. MT in the form of mobilization associated with exercises has been frequently used to treat temporomandibular disorders (TMD) with promising results. The Dynasplint® Trismus System (DTS) is a jaw opening device used as a self-management strategy for trismus. The DTS provides low-torque, prolonged-duration stretching with the aim of lengthening the affected connective tissue permanently.Positive effects of the use of DTS in patients with trismus to increase mouth opening have been reported. To date, however, the evidence is limited regarding the effectiveness of manual therapy alone or in combination with exercises to treat specifically trismus in patients with head and neck cancer.

The main objectives of this project are: 1) To determine the feasibility and preliminary efficacy of a manual therapy protocol plus the use of a dynamic jaw opening device (DTS) on the maximal interincisor distance (MID) in subjects with trismus.

2. To determine the preliminary efficacy the manual therapy protocol plus the use of a dynamic jaw opening device (DTS) on the Gothenburg Trismus Questionnaire (GTQ). 3) To determine the preliminary efficacy of a manual therapy protocol plus the use of a dynamic jaw opening device (DTS) on pain-disability outcomes in subjects with trismus.

3. To determine the preliminary efficacy of a manual therapy protocol plus the use of a dynamic jaw opening device (DTS) on the quality of life, anxiety, and depression in subjects with trismus.

This study will be a pilot study and will follow the methodology of a single subject design with multiple baseline measures and during treatment phases to determine the effectiveness of the treatment protocol. The single subject design was chosen because in addition to provide sound research results, clinical significance of the results for a specific group of patients can be derived. Thus, variables that are functionally important for treatment can become evident. The multiple baseline measures will be used because it increases the potential number of comparisons that can be made between and within data series, ultimately strengthening the confidence with which conclusions are made from the data. A minimum sample of 10 subjects who attend the Cross Cancer Institute (CCI) in Edmonton will be recruited for this project. Subjects will be screened for eligibility and if they meet all eligibility criteria, an information letter of the study will be provided and they will be asked to sign a consent form according to the Health Research Ethics Board (HREB) - University of Alberta.