Abstract:Objective To analyze the effect of adenoid size on the upper airway flow by constructing 8 different upper airway finite element numerical models with the adenoid size decreasing successively in the same airway, so as to help clinicians to further understand the pathogenesis of adenoid in children with snoring disease and to regulate the indications for adenoid surgery. Methods Based on the computed tomography (CT) of the upper airway, 8 different upper airway three-dimensional (3D) models with decreasing adenoid size in the same airway were constructed by 3D reconstruction software Amira. Computational fluid dynamics (CFD) was used to simulate the inspiratory airflow in each upper airway. The influences of the size of adenoids on the flow field characteristics of the upper airway were analyzed from the aspects of flow velocity, flow pattern, flow pressure and ventilation volume. Results When the adenoid was enlarged and blocked nostril within 55%, the flow velocity and pressure during quiet inspiratory period were basically consistent with the normal airway, the flow line was regular, and the ventilation volume was between 77.812 to 74.854 mL/s. When the degree of obstruction reached more than 64%, the nasopharyngeal airflow velocity and pressure drop sharply increased, with disrupted streamline and significant reduction of upper airway ventilation volume during quiet inspiratory period. Conclusions Adenoid hypertrophy can affect the normal inspiration of children seriously when obstruction of nostril up to 2/3. The larger the adenoids, the more obvious the symptoms of suffocation, snoring, and apnea at night sleep. Adenoid hypertrophy is an important factor that causes obstructive sleep apnea-hypopnea syndrome in children.
