Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
Department of Biomedical Engineering, Marquette University & The Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
Int J Comput Assist Radiol Surg. 2020 Jan;15(1):87-98. doi: 10.1007/s11548-019-02023-y. Epub 2019 Jul 2.
Virtual surgery planning based on computational fluid dynamics (CFD) simulations of nasal airflow has the potential to improve surgical outcomes for patients with nasal airway obstruction (NAO). Virtual surgery planning requires normative ranges of airflow variables, but few studies to date have quantified inter-individual variability of nasal airflow among healthy subjects. This study reports CFD simulations of nasal airflow in 47 healthy adults.
Anatomically accurate three-dimensional nasal models were reconstructed from cone beam computed tomography scans and used for steady-state inspiratory airflow simulations with a bilateral flowrate of 250 ml/s. Normal subjective sensation of nasal patency was confirmed using the nasal obstruction symptom evaluation and visual analog scale. Healthy ranges for several CFD variables known to correlate with subjective nasal patency were computed, including unilateral airflow, nasal resistance, airspace minimal cross-sectional area (mCSA), heat flux (HF), and surface area stimulated by mucosal cooling (defined as the area where HF > 50 W/m). The normative ranges were targeted to contain 95% of the healthy population and computed using a nonparametric method based on order statistics.
A wide range of inter-individual variability in nasal airflow was observed among healthy subjects. Unilateral airflow varied from 60 to 191 ml/s, airflow partitioning ranged from 23.8 to 76.2%, and unilateral mCSA varied from 0.24 to 1.21 cm. These ranges are in good agreement with rhinomanometry and acoustic rhinometry data from the literature. A key innovation of this study are the normative ranges of flow variables associated with mucosal cooling, which recent research suggests is the primary physiological mechanism of nasal airflow sensation. Unilateral HF ranged from 94 to 281 W/m, while the surface area stimulated by cooling ranged from 27.4 to 64.3 cm.
These normative ranges may serve as targets in future virtual surgery planning for patients with NAO.
基于计算流体动力学（CFD）模拟的鼻气流虚拟手术规划有可能改善鼻气道阻塞（NAO）患者的手术效果。虚拟手术规划需要气流变量的规范范围，但迄今为止，很少有研究量化健康受试者之间鼻气流的个体间变异性。本研究报告了 47 名健康成年人的鼻气流 CFD 模拟。
使用锥形束计算机断层扫描重建解剖精确的三维鼻模型，并使用双侧流量为 250 ml/s 的稳态吸气气流模拟。通过鼻阻塞症状评估和视觉模拟量表确认正常的鼻腔通畅感。计算了几个与主观鼻腔通畅感相关的 CFD 变量的健康范围，包括单侧气流、鼻腔阻力、空气空间最小横截面积（mCSA）、热通量（HF）和粘膜冷却刺激的表面积（定义为 HF>50 W/m 的区域）。使用基于有序统计的非参数方法计算包含 95%健康人群的规范范围。
在健康受试者中观察到鼻气流的个体间变异性很大。单侧气流从 60 到 191 ml/s 不等，气流分配范围从 23.8 到 76.2%，单侧 mCSA 从 0.24 到 1.21 cm 不等。这些范围与文献中的鼻测压法和声学鼻测法数据吻合良好。本研究的一个关键创新是与粘膜冷却相关的流动变量的规范范围，最近的研究表明，这是鼻气流感觉的主要生理机制。单侧 HF 从 94 到 281 W/m 不等，而冷却刺激的表面积从 27.4 到 64.3 cm 不等。
这些规范范围可作为未来 NAO 患者虚拟手术规划的目标。
