小下颌畸形患者上气道流体力学模型的构建及初步分析

摘要

目的：建立小下颌畸形患者上气道流体力学模型，探讨小下颌畸形患者正颌术前后上气道气流的动力学变化。方法：选取1例符合纳入标准的小下颌畸形患者正颌术前后上气道 CT 片，导入三维重建软件 Mimics10．01中，建立上呼吸道三维模型，通过 ANSYS ICEMCFD14．0对三维模型进行网格划分后，用 ANSYS 14．0-Fluid Dynamics 对上呼吸道内部流场进行数值模拟，采用 Tecplot 对模拟结果进行后处理，计算分析后获得上气道气流场相关信息。结果：成功构建出小下颌畸形患者正颌术前后上气道流体力学模型，患者手术后气道体积由37．284 cm3增大到44．498 cm3；上呼吸道最狭窄区域位于腭咽下界，手术后此区面积由1．135 cm2增大到2．297 cm2；最小压力由101308 Pa 降至101272 Pa；最大流速从3．476 m／s 增大到4．978 m／s。结论：小下颌畸形患者经过正颌手术后，不仅能有效矫治牙颌面畸形，同时可扩张上气道，降低上气道气流阻力，从而保持上气道气流通畅。%Objective:To establish a fluid dynamics model of upper airway before and after surgery and explore the changes of three-dimensional fluid dynamics in patients with micrognathia.Methods:A patient with micrognathia and severe obstructive sleep apnea-hypopnea syndrome(OSAHS)accepted CT scan before and six months after mandibular advancement operation.Computation-al fluid dynamics model was built on the base of CT scan by Mimics 1 0.01 and ANSYS ICEMCFD1 4.0.The internal flow of upper respiratory tract was simulated by ANSYS-FLUENT 1 4.0 and the results were analyzed by Tecplot.Results:Fluid dynamics model of upper airway was constructed before and after the surgery respectively.The volume of the upper airway of the patient increased from 37.284 cm3 to 44.498 cm3;the most narrow area of upper airway was located in the lower bound of pharyngopalatiae,and it was augmented from 1 .1 35 cm2 to 2.297 cm2;the minimum pressure was decreased from1 01 308 Pa to 1 01 272 Pa;the maximum air velocity increased from 3.476 m/s to 4.978 m/s.Conclusion:Mandibular advancement may correct the occlusal deformity,ex-panse the upper respiratory tract,decrease the negative pressure and maintain the patency of the airflow in the treatment of patients with micrognathia and OSAHS.