Computational aerodynamics of long segment congenital tracheal stenosis with bridging bronchus

Long segment congenital tracheal stenosis (LSCTS) is one of most severe malformation with high mortality rate and dismal prospective. Hypoventilation is the main issue for the death of children with LSCTS after surgical correction. However, currently, little information is available on local aerodynamics to disclose the reasons for the improvement of such therapies, especially LSCTS with distal bronchus stenoses. Here, we investigated a patient-specific model of LSCTS with complete tracheal rings and bridging bronchus (BB). Computational fluid dynamics (CFD) was applied to analyze the local aerodynamics around BB before and after tracheal surgery in inspiratory phase and expiratory phase. Average pressure drop, wall shear stress, streamlines and energy loss were calculated to evaluate the surgical outcomes. The results indicate the airflow at the trachea and BB become more turbulent in expiration phase than that in inspiration phase. The turbulence increases the workloads of respiration in expiration phase. It should be the cause for postoperative hypoventilation. To study the local aerodynamics is helpful for the improvement of surgical therapies of the LSCTS.