M. Aspin Nivya, K.L.  Jayakumar, 
    Objective Evaluation of Trismus in Patients Receiving Intensity‐Modulated Radiation Therapy (IMRT) for Oral Cavity and Oropharyngeal Carcinoma,
    Research Journal of Medical Sciences,
    Volume 18,Issue 10,
    2024,
    Pages 633-637,
    ISSN 1815-9346,
    makrjms.2024.10.633.637,
    (https://makhillpublications.co/view-article.php?doi=makrjms.2024.10.633.637)
    Abstract: <p style="text-align:justify">The aim of this study was to determine the role of risk factors in the development of trismus in patients with oral and oropharyngeal cancer (OOPC) receiving intensity‐modulated radiation therapy (IMRT) and to estimate the incidence of trismus in this population. A retrospective cohort study was conducted at our institution involving patients treated for Oral Cavity and Oropharyngeal Carcinoma with IMRT. Inclusion criteria consisted of patients with pre‐RT maximal inter‐incisor opening (MIO) $36 mm, who received high‐dose radiation therapy ($60 Gy) and had MIO measurements before and 6‐48 months post‐RT. Trismus was defined as MIO #35 mm. The study used Fisher&rsquo;s exact test to assess the association of risk factors (age, gender, tumor site, tumor size, tumor stage, pre‐RT MIO and radiation dose to the masticatory muscles) with trismus development. Wilcoxon Signed Rank test was applied to compare radiation doses to the ipsilateral muscles of mastication between patients with and without trismus. The cohort comprised 30 patients with a median age of 58 years, 60% of whom were male. The median follow‐up period was 10 months. The trismus incidence rate was 26.6%. Pre‐RT MIO measurements were significantly associated with the development of trismus (P&lt;0.001). While the mean radiation doses to the masseter and medial pterygoid muscles were numerically higher in patients who developed trismus, no statistically significant differences were observed (P=0.06, P=0.21, respectively). Other factors such as age, sex, tumor site, tumor size (T) and tumor stage were not significantly associated with trismus. Pre‐RT MIO measurement emerged as a significant risk factor for the development of trismus, though it is an unchangeable factor. To mitigate this complication, limiting radiation exposure to the masticator muscles may be a key preventive strategy.</p>

    Keywords: Trismus; oral and oropharyngeal cancer; intensity‐modulated radiation therapy