Longitudinal outcomes of trismus release with free-flap reconstruction in primary and secondary oral submucous fibrosis-related trismus

Abstract

Oral submucous fibrosis is a global health concern associated with betel quid use and results in trismus, which can be either primary or secondary in origin. Severe cases often require trismus release with free-flap reconstruction. This study examined longitudinal outcome trends following trismus release and compared the outcomes of patients with primary and secondary oral submucous fibrosis-related trismus. We conducted a retrospective cohort study by including patients who underwent trismus release between 2013 and 2022. All procedures were performed by a single surgical team to ensure technique standardisation. We measured the maximum mouth opening, the interincisal distance, perioperatively and 1, 2, 3, 4, 6 and 12 monthspost-operatively. Data were analysed using generalised estimating equations. A total of 35 patients were included in the study, 17 with primary and 18 with secondary oral submucous fibrosis-related trismus. Initially, patients with primary oral submucous fibrosis-related trismus had greater interincisal distance gains than those with secondary oral submucous fibrosis-related trismus (p=0.015 and p=0.025 at 3 and 4months post-operatively, respectively). However, after 12months, this initial advantage faded, with comparable interincisal distance improvements in patients with primary and secondary disease, despite the more complex surgical procedures required in secondary cases. Surgeons should carefully consider the benefits of trismus release procedures for patients with secondary oral submucous fibrosis-related trismus by recognising the changes in post-operative outcomes.