不同部位和大小的鼻中隔穿孔对鼻腔气流影响的数值模拟分析

目的运用数值模拟的方法探讨不同部位和大小的鼻中隔穿孔对鼻腔气流的影响。方法选取2名健康成年人的鼻腔CT数据,例1为45岁男性,例2为36岁女性,分别构建出不同部位(前端低位、中部低位、后端低位和前端高位)和尺寸(直径分别为10 mm和5 mm)的鼻中隔穿孔的鼻腔气流模型,数值模拟分析不同部位和大小的鼻中隔穿孔鼻腔数值模型的鼻腔容积、鼻腔壁面积、压强、鼻阻力、温度、气流速度、壁面剪切力、双侧鼻腔气流分配比、涡流等情况。分别将鼻阻力和气流温度差与鼻腔壁面积作Pearson相关性分析。结果在压强和鼻阻力方面,位于前端低位且较大尺寸的鼻中隔穿孔对局部的压强梯度影响更明显;前中部低位的鼻中隔穿孔可导致鼻腔阻力增加。在温度方面,前端低位和高位较大尺寸以及前端高位较小尺寸的鼻中隔穿孔对局部温度影响更明显;位于前端且具有较大尺寸的鼻中隔穿孔模型的鼻加热效率低于正常模型;前鼻孔至鼻中隔后缘的温度差与鼻腔壁面积之间存在正相关关系(例1和例2的R2值分别为0.69、0.41,P值均<0.01)。在气流平均速度方面,位于鼻腔前端低位和高位的不同尺寸穿孔相对于其他部位穿孔,对鼻腔局部的气流平均速度影响更明显。在气流的分配和涡流方面,前中部低位的鼻中隔穿孔可使原本气流分布不对称的双侧鼻腔内的气流分布更加趋于不均衡;位于鼻腔前端和中部的穿孔较鼻腔后端的穿孔会导致更加明显的涡流分布。结论鼻中隔穿孔所造成的影响与其发生的部位和大小有关,偏前端和较大的鼻中隔穿孔相对于偏后端和较小的穿孔对鼻腔内压强、鼻阻力、温度调节、气流分配等方面表现出更多的负面影响。

Numerical simulation of intranasal airflow in nasal numerical models with nasal septum perforations of different locations and sizes

Objective To investigate the effect of nasal septum perforation(SP)with different locations and sizes on nasal airflow by means of numerical simulation.Methods Two healthy persons with normal nasal anatomy were enrolled in this study,including a 45 years old male(case 1)and a 36 years old female(case 2).Nasal CT data was used as the basis to create nasal airway numerical models of nasal SP with different locations(anterior caudal,central caudal,posterior caudal and anterior cranial)and sizes(diameter of 10 mm and 5 mm respectively).The inspiratory airflow characteristics(nasal cavity volume,nasal cavity wall area,pressure,nasal resistance,temperature,airflow velocity,wall shear stress,airflow-rate partitioning and vortex)of these nasal airway numerical models were simulated and analyzed.Pearson correlation analysis was performed between nasal resistances,airflow temperature and nasal cavity wall area.Results In terms of pressure and nose resistance,the anterior caudal and larger size SP lead to more obvious variation of pressure distribution,and increased nasal resistance was especially found in the nasal cavity with anterior and medium caudal SP.In terms of temperature,the anterior(caudal and cranial)and larger size SP had significant effect on local temperature gradient as same as the anterior cranial and smaller size SP.Nasal heating efficiency was lower in nasal model with the anterior and larger size SP than that in the normal model.The temperature difference from the nostril to the end of nasal septum had positive correlation with nasal cavity wall area(R2 value of case 1 and case 2 was 0.69,0.41,respectively,all P<0.01).In terms of airflow velocity,the anterior caudal and cranial SP had more significant effect on the average airflow velocity in the nasal cavity.The anterior and medium caudal SP could make the airflow distribution in the asymmetric bilateral nasal cavity more unbalanced compared to the bilateral symmetrical nasal models.The anterior and medium SP resulted in a more pronounced vortex distribution than the posterior SP.Conclusions The effect of SP on nasal cavity is related to its location and size.The anterior and larger size SP shows more negative influence on intranasal pressure,nasal resistance,heat transmission efficiency,airflow-rate partitioning than the posterior and smaller size SP.