Application of numerical simulation of upper airway flow field in pediatric obstructive sleep apnea with adenoid hypertrophy.

BACKGROUND: At present, there is a lack of tools in clinical practice to evaluate the impact of obstructive sleep apnea (OSA) with adenoid hypertrophy (AH) on the upper airway (UA) flow field. This study was designed to analyze the UA aerodynamic parameters in pediatric OSA with AH, and explore its utility in diagnosing, and evaluating prognosis after adenoidectomy (AT). METHODS: Based on high-resolution computed tomography (CT) image data from normal children, pre- and post-surgical AH children, we constructed three-dimensional (3D) numerical models of the UA incorporating anatomical features. Computational fluid dynamics (CFD) was employed to simulate and analyze the dynamic characteristics of the UA flow field. RESULTS: AH led to a significant 68.3% reduction in nasopharyngeal airway cross-sectional area (CSA, normal: 302.3 mm2, AH: 95.8 mm2), which in turn resulted in an 81.1% maximum pressure (Pmax) increase within the stenotic region, a marked elevation in flow velocity (with a near 210% maximum increase), a 22.2% maximum rise in wall shear stress (WSS), and a 69.5% maximum decrease in volumetric flow rate. CFD analysis following AT demonstrated that nasopharyngeal stenosis had been alleviated, with airway pressure, flow velocity, and WSS all returning to near-normal physiological levels. CONCLUSIONS: Numerical simulation of the UA flow field provided a new perspective to unravel the mechanism by which AH affects inspiratory airflow. Additionally, it holds broad clinical application prospects in aided disease diagnosis, treatment regimen optimization, and therapeutic efficacy evaluation.