不完全腭裂咽腔三维有限元模型的建立

Establishment of pharyngeal 3-dimensional finite element model of patients with isolated cleft palate

目的:通过建立适合生物力学分析的不完全腭裂患者咽腔有限元模型,用于腭裂术前评估,为后续腭裂术式的设计和选择提供理论依据。方法:对1例不完全腭裂患儿和1例正常儿童进行头颅多层螺旋CT扫描,将所得的腭平面咽腔结构的图像扫描数据导入Mimics软件中,进行三维几何模型重建,并进行网格划分。采用有限元方法对咽腔结构在正常生理载荷,即分别在2个模型的软腭后缘施加5 cm水柱的压强载荷0.0005 MPa,比较常态与病态结构中力学性质的差异。结果:非正常的鼻咽腔模型在受力过程中的最大应力约为0.025 MPa,大于正常模型的应力数值(0.017 MPa)。分别提取、比较2个模型的软腭后缘、腭中部和硬腭前端的应力数值,发现软腭后缘及腭中部的应力变化区域相同,硬腭前缘应力较小。结论:具有良好几何相似性及生物力学特性的有限元模型,可用于不完全腭裂患儿术前生物力学分析,为手术修复及功能重建提供较理想的生物力学模型预测。

PURPOSE:The aim of this study was to provide basis for future design and selection of cleft palate surgery through establishing finite element model of pharyngeal cavity which was suitable for biomechanical analysis.METHODS:One patient with isolated cleft palate and 1 normal child underwent multilayer head CT examination.The scanned data of pharyngeal cavity were imported into Mimics software for a 3-D geometric model reconstruction.The model was divided into a grid,so it can be further processed for subsequent finite element analysis.RESULTS:After applying 5cm water column pressure load of 0.0005 MPa at the back edge of the soft palate in the two models respectively,the results showed that the maximum stress of the abnormal nasopharyngeal cavity model was 0.025 MPa,greater than the normal model (0.017 MPa).The same pressure loading was applied to different parts of the two models,the stress change area in the posterior margin of the soft palate and the middle of the palate was the same,and the stress in the front of the hard palate was smaller.CONCLUSIONS:Finite element model has good biomechanical characteristics and geometric similarity.It can be used in isolated cleft palate with preoperative biomechanical analysis,for repairing and functional reconstructive surgery to provide ideal biomechanical model predicts.