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Case Reports
. 2018 Jun:109:180-184.
doi: 10.1016/j.ijporl.2018.04.002. Epub 2018 Apr 5.

Modeling congenital nasal pyriform aperture stenosis using computational fluid dynamics

Tirth R Patel  1 , Chengyu Li  2 , Jillian Krebs  3 , Kai Zhao  4 , Prashant Malhotra  5
Affiliations
Case Reports

Modeling congenital nasal pyriform aperture stenosis using computational fluid dynamics

Tirth R Patel et al. Int J Pediatr Otorhinolaryngol. 2018 Jun.

Abstract

Objectives: Congenital nasal pyriform aperture stenosis (CNPAS) is a rare cause of airway obstruction in the neonate. Computational airway modeling has not been done in neonates and young infants to understand the impact of stenosis on functional nasal airflow. In this study, we 1) applied computational fluid dynamics (CFD) model to the airway of a neonate with CNPAS and 2) compare airflow dynamics of a normal and CNPAS airway.

Methods: Three-dimensional models of the nasal airway of a normal neonate and a neonate with CNPAS were created using computed tomography scans of the facial bones. Measured anatomic parameters included volume, surface area, and cross-sectional area. CFD simulation was then performed. Simulated flow parameters included pressure, average velocity, and resistance.

Results: The neonate with CNPAS had a lesser volume (2.74 cm3 vs. 4.50 cm3) and surface area (18.8 cm2 vs. 45.5 cm2) than the normal airway. The CNPAS airway had a lesser bilateral cross-sectional area and average cross-sectional velocity throughout the length of the model. While there is a large pressure drop in the normal airway immediately after the entry point, the pressure drop in the CNPAS airway occurs more posteriorly. The total nasal resistance was approximately eight-fold greater in the CNPAS airway than the normal.

Conclusions: CFD analysis can be performed on airways of neonates with nasal obstruction, such as in CNPAS. A CFD model may help characterize severity of airway obstruction as it can predict the three-dimensional pattern of airflow. Determining the role of CFD in clinical management of CNPAS requires further investigation.

Keywords: Airway modeling; Congenital pyriform aperture stenosis; Fluid dynamics; Pediatric airway.

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Conflict of interest statement

Conflict of Interest: The authors report no conflicts of interest.

Figures

Figure 1
Figure 1
Axial and coronal CT images from the two patients studied: (a) CNPAS (b) normal airway control.
Figure 2
Figure 2
Schematic depicting the computational mesh of a nasal coronal section (left) and its corresponding CT scan image (right bottom). In a close-up view (right top), layers of small and fine elements along the wall can capture the rapid near wall changes of air velocity.
Figure 3
Figure 3
Sagittal view of the 3D geometry overlaying with the CT scans for CNPAS patient (a) and normal control (b).
Figure 4
Figure 4
Bilateral cross-sectional area (a), average cross-sectional velocity (b), and pressure (c) as a function of normalized distance to the nostril for CNPAS patient and healthy control.
Figure 5
Figure 5
Nasal airway of CNPAS patient (a) and normal control (b). 2D slide cuts are taken along the airway and color coded according to velocity magnitude.
See this image and copyright information in PMC

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