A pilot study of intensive intervention using a novel trismus device

Exercise adherence for patients with trismus after head and neck cancer treatment

BACKGROUND

Head and neck cancer treatment often leads to trismus, a condition characterized by limited mouth opening. Exercise-based therapy is the most common intervention but there are no clear guidelines as to the optimal exercise regimen. Restorabite™ is a portable and force-regulated trismus device designed to enhance exercise adherence. This study explores the adherence to exercises using Restorabite™ in head and neck cancer patients with trismus and identifies facilitators and barriers to exercise therapy.

MATERIALS AND METHODS

Mixed-methods, prospective cohort study undertaken at a quaternary oncology hospital, in Sydney Australia involving participants diagnosed with head and neck cancer diagnosed with trismus (maximal incisal opening under 35 mm). Patients underwent a 10-week individualized trismus program using Restorabite™ with weekly speech pathology reviews. Exercise adherence was tracked through categorized descriptors. Data were collected prospectively at baseline, during 10 weeks of therapy with Restorabite™, and at 6- and 12-month post-trismus exercise. Participants described facilitators of trismus therapy, and barriers to completing the prescribed exercises. Clinical documentation of these responses was then analyzed using content analysis.

RESULTS

One-hundred and thirty-five participants were recruited. During the intervention 69% (n = 93) exercised as recommended, 24% (n = 32) exercised less, and 7% (n = 10) exercised more than recommended. At 6 months post-intervention, 55.5% (n = 75) exercised as recommended, 38.5% (n = 52) exercised less, and 4% (n = 6) exercised more. At 12 months, 36% (n = 49) exercised as recommended, 48% (n = 62) exercised less, and 11% (n = 15) exercised more. MIO increased from a mean of 18.6 mm at baseline, to 30.1 mm at the end of the 10-week intervention. This was maintained at 6 and 12 months (31.7 and 32.1 mm, respectively). Adherence to the exercise program was associated with greater improvement in maximum interincisal opening (p < 0.001). Facilitators of adherence included intrinsic motivation, device portability, perceived functional change, and external support tools. Barriers included cancer treatment toxicities, competing priorities, and health challenges. Positive outcomes included functional improvements, while negative outcomes included increased pain.

CONCLUSIONS

Seventy-six percent of patients prescribed Restorabite™ performed trismus exercises at or more than the recommended frequency. Facilitators and barriers identified provide insights into factors influencing adherence. Future research should involve comparative studies that compare the adherence and effectiveness of different exercise programs.

Minimum detectable change in occlusal load - normative data for healthy and head and neck cancer populations

Traditionally, pain has been a signal to de-intensify jaw exercises for trismus to prevent tissue damage. It is unknown whether patients who have undergone surgery or radiotherapy for head and neck cancer have sufficient sensation to detect changes in occlusal load. This study sought to compare the minimum detectable occlusal load in a cohort of patients with head and neck cancer (HNC) and compare this with healthy controls. Twenty patients who were treated for HNC and 20 healthy controls were recruited from a single institution. A purpose-built pressure transducer was used to measure the minimum detectable force (measured in Newtons) applied to the jaw and the interincisal distance. Analysis was conducted using a mixed effects linear regression. The mean minimum detectable occlusal load in patients with HNC was 18.7N compared to 4.5N in healthy controls (mean difference 14.3N, 95% CI 12.2N to 16.4N, p < 0.001). Adjusted IID predicted force (0.15N per-mm IID, 95% CI 0.09 to 0.2, p < 0.001) with a weak interaction between treatment with radiotherapy and IID in HNC patients (p = 0.85). Patients who have been treated for HNC are less sensitive to changes in force applied to the jaw. This is concerning given that most jaw stretching devices use an unregulated and unknown amount of force to achieve greater mouth opening.