A preliminary study of computer assisted evaluation of congenital tracheal stenosis: a new tool for surgical decision-making.

OBJECTIVE: Congenital tracheal stenosis is a rare but severe condition with tracheal narrowing. There is no absolute correlation between luminal diameter and prognosis, and therapeutic decisions are difficult for intermediate cases. The aim of this study was to develop a dynamic model of the ventilatory consequences of congenital tracheal stenosis using computational fluid dynamics.
METHODS: In 8 children with congenital tracheal stenosis and 1 healthy child, 3-dimensional geometries of the trachea were constructed with computed tomography images and specialized software (ITK-SNAP). Airflow simulations were performed for each geometry using 2 physiologic inhalation flow rates under steady and laminar flow conditions. Flow velocity, static and total airway pressure, and pressure drop across the entire trachea were determined.
RESULTS: In the patients with congenital tracheal stenosis, the pressure drop from the tracheal inlet to outlet, at flow rate 3L/min, ranged from 14 to 430Pa; the pressure drop at flow rate 7.3L/min ranged from 60 to 1825Pa. The pressure drop enabled a classification based on the severity of stenosis. The classification based on pressure drop was retrospectively consistent with the classification based on clinical data from the patients.
CONCLUSIONS: Simulations with computational fluid dynamics may provide an objective method to evaluate the severity of the symptoms in patients with congenital tracheal stenosis and may help guide treatment.