阻塞性睡眠呼吸暂停低通气综合征患者上气道及比邻结构三维有限元模型的构建
【摘要】
阻塞性睡眠呼吸暂停低通气综合征（obstructive sleep apnea hypopnea syndrome，OSAHS）是一种以睡眠中反复出现呼吸暂停、血氧饱和度下降、上气道阻塞为特征的复杂综合征[1]。长此以往，会导致心、脑、肾等并发症，甚至猝死。因此，OSAHS是一种有潜在致死性的睡眠呼吸紊乱性疾病。OSAHS的发病机制尚不十分清楚，一般认为上气道形态及其周围组织结构异常是阻塞性呼吸睡眠暂停综合征重要的发病机制[2-8]。因此，对上气道的研究成为探究OSAHS发生机制的重要方面。目前学者们主要采用X线头影测量法、计算机体层扫描技术（CT）和磁共振技术（MRI）来探讨OSAHS患者上气道的形态解剖特点及局部阻塞部位[9-14]，为临床诊断和治疗方案的选择提供客观依据，但将三维有限元分析方法用于OSAHS的研究，至今鲜见报道。
三维有限元法是目前医学生物力学研究中最先进有效的一种生物力学分析方法。本研究通过螺旋CT扫描获得精确的OSAHS患者上气道DICOM格式的图像信息，采用Mimics三维建模软件和Ansys有限元分析软件建立准确、可灵活模拟操作的OSAHS患者上气道及其毗邻结构的三维有限元模型，为患者上气道生物力学分析打下基础，以期深入了解OSAHS的发生机制以及为口腔矫治器治疗OSAHS的优化设计等提供理论依据，同时探索一种新的研究OSAHS的方法，为以后的研究提供一种新的思路。
目的：建立OSAHS患者上气道及比邻结构的三维有限元模型，为OSAHS患者上气道生物力学分析打下基础。
方法：对OSAHS患者上气道行薄层CT扫描，获得患者上气道DICOM格式的图像信息，采用Mimics三维建模软件和Ansys有限元分析软件建立上气道及毗邻结构的三维有限元模型。
结果：建立了OSAHS患者上气道及其毗邻结构的三维有限元模型，规定采用10节点的Solid 92四面体单元划分网格。计算机按要求划分网格后，骨、肌肉、气道得到的单元数和节点数分别为：24860、131530、15672个单元，4788、24992、3178个节点。
结论：应用螺旋CT技术和联合使用Mimics三维建模软件、Ansys有限元分析软件建立OSAHS患者上气道及其毗邻结构的三维有限元模型，是一种快速有效、准确、可灵活模拟操作的建立OSAHS患者上气道及其毗邻结构三维有限元模型的方法，建模效率高、速度快，模型的几何相似性较好，使用灵活，此模型可以作为今后深入研究OSAHS的原始模型，为研究OSAHS患者上气道生物力学分析打下良好的基础。
【关键词】阻塞性睡眠呼吸暂停低通气综合征；三维有限元法；Mimics软件；Ansys软件
Construction of the three-dimensional finite element model of the Upper airway and vicinity structure of an obstructive sleep apnea hypopnea syndrome patient(https://www.daowen.com)
ABSTRACT
Obstructive sleep apnea hypopnea syndrome（OSAHS），is a kind of recurring sleep apnea，oxygen saturation decreased，the upperairway obstructed complex syndrome[1].In the long run，the disease will lead to heart，brain，kidney and other complications，even sudden death.Therefore，OSAHS is a potentially fatal sleep breathing disorder disease.The pathogenesis of OSAHS is not yet very clear，generally considered the upper airway morphology and surrounding tissue abnormalities is important in the pathogen esis[2-8].Therefore，to study the upper airway of an OSAHS patient become an important aspect of the pathogenesis of OSAHS.Currently scholars often use imaging methods to study the upper airway of OSAHS patient including X cephalometric method，computer tomography technology（CT）and magnetic resonance imaging（MRI）to investigate the upper airway of OSAHS patients morphological and anatomical characteristics and position of local obstruction[9-14]，to provide an objective basis for the clinical diagnosis and treatment options，but it is so far rare reported that the method of three-dimensional finite element analysis is used for OSAHS study.
Three-dimensional finite element method is the most advanced and effective method of biomechanical analysis in medicine.This study obtained the accurate DICOM format of the image information of OSAHS patient’s upper airway by using spiral CT scan and establish an accurate，flexible simulation OSAHS patient’s upper airway model by using Mimics and Ansys software.This model lay the foundation for the OSAHS patient’s upper airway biomechanical analysis，in order to understand the pathogenesis of OSAHS，as well as provide a theoretical basis for Oral appliance optimal design for OSAHS therapy，while exploring a new method of OSAHS research in order to provide a new way of thinking for future research of OSAHS.
Objective：To construct a three-dimensional finite element model of the Upper airway and adjacent structure of an Obstructive sleep apnea hypopnea syndrome patient for OSAHS biomechanical analysis.
Methods：DICOM format image information of an OSAHS patient’s upper airway obtained by thin-section CT scanning and digital image processing were utilized to construct a three-dimensional finite element model by Mimics and Ansys software.
Results：A case of OSAHS and the adjacent upper airway structure of three-dimensional finite element model is constructed which is formed by solid 92 tetrahedral unit of a 10-node mesh.The model has bone：24860 elements，4788 nodes；muscle：131530 elements，24992 nodes；upper airway：15672 elements，3178 nodes.
Conclusion：The joint use of spiral CT technology and Mimics software，Ansys software on the establishment of upper airway and vicinity structure of OSAHS patient is a fast and efficient method to establish an accurate，flexible three-dimensional finite element model of the upper airway and vicinity structure of an OSAHS patient.The model can be used for simulation operation of OSAHS patient’s upper airway and vicinity structure.The model has good geometric similarity and good flexibility.this model can be used as the original model of OSAHS in future study of OSAHS and a good foundation of biomechanical analysis of OSAHS patients upper airway.
Key words：three-dimensional finite element method；Obstructive sleep apnea hypopnea syndrome；Mimics software；Ansys software