口腔矫治器对OSAHS患者咽腔气流及上气道壁形变影响的研究

Effects of oral cavity appliance on pharyngeal cavity airflow dynamics and deformations of upper airway wall in patients with OSAHS

目的通过建立OSAHS患者戴用口腔矫治器前后咽腔的三维有限元生物力学模型,利用流固耦合方法数值分析咽腔气流及上气道壁的变化,探讨OSAHS的口腔矫治器治疗机制。方法对1例确诊为中度OSAHS的成人患者戴矫治器前和戴矫治器3个月后分别行上气道及周围组织MRI检查。将以DICOM格式存储的扫描数据导入三维重建软件Mimics 17.0、NX 8.5,Geomagic Studio12.0对上气道及软腭进行三维重建,应用ANSYS Workbench13.0软件进行网格划分,赋予各部分材料属性,最终建立上气道的流固耦合有限元模型。将所得的模型导入CFXANSYS软件中进行FSI数值计算。结果患者戴OA后,在最大吸气时刻,腭咽处的气流速度由9.677 m/s降低到7.020 m/s,最大负压由-64.18 Pa降低到-37.88 Pa,气道壁的最大形变量由0.629 mm减小到0.244 mm。在最大呼气时刻,腭咽处的气流速度由10.44 m/s降低到7.441 m/s,最大负压由-36.25 Pa降低到-23.79 Pa,气道壁的最大形变量由0.648 mm减小到0.310 mm。结论 OSAHS患者戴OA后,在最大吸气和最大呼气时刻,腭咽气道的负压和气道壁的形变均降低,使咽腔不易出现塌陷,从而减轻了患者的打鼾和呼吸暂停症状。

Objective To establish pharyngeal cavity fluid-structure interaction finite element models with or without oral appliance （OA） by means of three-dimensional reconstruction software to analyze the changes of pharyngeal cavity airflow dynamics and upper airway wall by using fluid structure interaction method in patients with obstructive sleep apnea hypopnea syndrome （OSAHS） ,and to explore the action mechanism of OA in treatment of OSAHS. Methods The changes of upper airway and surrounding tissues in an adult patient with moderate OSAHS before wearing OA and on 3 months after wearing OA were examined by MRI. The DICOM format images were imported into 3D reconstruction software-Mimics 15. 0,NX 8. 5, Geomagic Studio 10.0. Mimics 15. 0 software to reconstruct the model of upper airway and soft palate, then to establish the pharyngeal cavity and upper airway wall fluid-structure interaction （FSI） finite element models by using ANSYS Workbench 13.0 software, finally the FSI finite element model was imported into the software ANSYS-CFD to carry out FSI numerical calculation. Results After wearing OA, FSI numerical calculation results showed that at the peak of inspiration, the maximum airflow velocity in the area of palate and pharynx was decreased from 9. 677m/s to 7. 020m/s,and the maximum negative pressure was reduced from - 64. 18Pa to -37. 88Pa, moreover, the maximum deformation degree in upper airway wall was decreased from 0. 629mm to 0. 244mm. At the peak of expiration, the maximum airflow velocity in the area of palate and pharynx was decreased from 10.44m/s to 7.441m/s,the maximum negative pressure was reduced from -36.25Pa to -23.79Pa,and the maximum deformation degree in upper airway wall was decreased from 0. 648mm to 0. 310mm. Conclusion After wearing OA in patients with OSAHS, at the peak of inspiration and expiration, the negative pressure and deformation degree in upper airway are decreased, so that the pharyngeal cavity is less prone to collapse, there by, which can relieve the symptoms of snoring and apnea of patients.