Investigation on the nasal airflow characteristics of anterior nasal cavity stenosis

Abstract

We used a computational fluid dynamics (CFD) model to study the inspiratory airflow profiles of patients with anterior nasal cavity stenosis who underwent curative surgery, by comparing pre- and postoperative airflow characteristics. Twenty patients with severe anterior nasal cavity stenosis, including one case of bilateral stenosis, underwent computed tomography (CT) scans for CFD modelling. The pre- and postoperative airflow characteristics of the nasal cavity were simulated and analyzed. The narrowest area of the nasal cavity in all 20 patients was located within the nasal valve area, and the mean cross-sectional area increased from 0.39 cm2 preoperative to 0.78 cm2 postoperative (P<0.01). Meanwhile, the mean airflow velocity in the nasal valve area decreased from 6.19 m/s to 2.88 m/s (P<0.01). Surgical restoration of the nasal symmetry in the bilateral nasal cavity reduced nasal resistance in the narrow sides from 0.24 Pa.s/mL to 0.11 Pa.s/mL (P<0.01). Numerical simulation of the nasal cavity in patients with anterior nasal cavity stenosis revealed structural changes and the resultant patterns of nasal airflow. Surgery achieved balanced bilateral nasal ventilation and decreased nasal resistance in the narrow region of the nasal cavity. The correction of nasal valve stenosis is not only indispensable for reducing nasal resistance, but also the key to obtain satisfactory curative effect.

Reconstruction of Alar Lining and Nostril Base by Oral Mucosal Flap on Muscular Pedicle

“…This surgical technique achieved nasal ventilation in a balanced pattern and has decreased nasal resistance for the airflow through the treated nasal opening, then increased the capacity of upper airway passage. In this study correction of external nasal valve stenosis is curative and this comes with the findings of Wang et al 13 Souter et al described the buccal mucosal flaps and their descriptions are designed on the labial mucosa of the upper buccal sulcus, based medially near the frenulum of the upper lip and extending laterally onto the mucosa of the cheek 14 Plastic Surgery pedicle allows the flap mobility and versatility and no need to be limited to the upper sulcus and could be harvested more far in the upper lip. This proposed flap technique doesn't has a risk of burying of the mucosa in deeper tissues like in Souter technique.…”

Computational modeling and validation of human nasal airflow under various breathing conditions

“…However, accurate predictions of such internal flow and turbulence features rely on the selection of appropriate CFD models. The laminar model has been commonly adopted for simulating nasal airflow at relatively low flow rates when the turbulence kinetic energy is negligible (Croce et al, 2006; Keyhani et al, 1995; Wang et al, 2016), but this approach has been questioned (Doorly et al, 2008a; Doorly et al, 2008b). To better evaluate the flow transition to turbulence, Reynolds-averaged Navier-Stokes (RANS) with two-equation turbulence models have been normally applied, such as k- model (Tan et al, 2012; Zhao et al, 2006), standard k- model (Zhang and Kleinstreuer, 2011), Shear Stress Transport (SST) k- model (Mylavarapu et al, 2009), and Reynolds Stress Model (RSM) (Ball et al, 2008).…”

Application of the Load Balancing Method on High Parallel Computing Cluster Systems

“…Эта процедура может быть понята как инкрементный, диффузионный метод DLB [17], основанный на разделении CFD, который может лучше подходить для крупномасштабного моделирования [18]. С вычислительной нагрузкой l i каждого параллельного поддомена, совокупные дисбалансы s j вычисляются в соответствии с формулой (5). Таким образом, расхождение нагрузки между всеми процессами слева и справа от каждой позиции разделения определяется количественно.…”

“…С развитием высокопроизводительных вычислений в последние годы многие исследователи рассматривали моделирование с помощью вычислительной гидродинамики (CFD) в качестве альтернативного подхода для изучения воздушного потока в дыхательных системах человека. В работах [3][4][5][6] для моделирования воздушного потока в носовой полости используют ламинарную модель при относительно низких скоростях. Так для получения более точного численного результата для моделирования воздушного потока в носовой полости используется высокопроизводительные вычисления.…”