The impact of tongue size on submental negative pressure treatment of airway obstruction revealed by fluid-structure interaction simulations

The continuous negative external pressure (cNEP) applied on the submental surface is a method of non-surgical treatment for obstructive sleep apnea (OSA), which can effectively widen the airway in some OSA patients. However, it cannot effectively improve airway collapse in obese patients and its mechanism remains unclear. In this study, we aim to analyze the reasons for the ineffectiveness of cNEP treatment in OSA patients with obesity. Based on magnetic resonance imaging (MRI), three-dimensional models of the head and neck were constructed for a healthy subject, an OSA patient with enlarged tongue, and an OSA patient with the tongue adjusted to normal size. By performing the one step staggered fluid–structure interaction numerical simulations, we analyzed the collapse of the airway in these three models under the influence of cNEP. Restoring the tongue to normal size in the OSA patient significantly improves the airway critical closing pressure under cNEP treatment compared to the patient with enlarged tongue. The enlargement of the tongue in the OSA patient hindered the widening of the velopharyngeal airway under the action of cNEP. The numerical results reveal that cNEP treatment can effectively widen the laryngopharyngeal airway, thus providing a potential therapeutic option for OSA patients with laryngopharyngeal obstruction. Tongue enlargement in OSA patients is a critical factor influencing the efficacy of cNEP treatment. This study reveals the reasons for cNEP treatment failure in obese patients and the potential value of cNEP targeted therapy.