摘要
背景:目前对骨盆的力学分析还处于极其粗糙阶段,而有限元法因其具有不受样本量限制,实验误差小,重复性好等优点,正日益成为骨盆生物力学研究的重要手段。目的:建立正常骨盆的三维有限元模型,分析骨盆在垂直载荷作用下的应力/应变和位移分布。设计、时间及地点:三维有限元分析,单一样本观察。于2007-03/09在南方医科大学生物力学实验室完成。材料:健康成年男性志愿者1例进行PET-CT扫描,层厚1mm,得到二维原始图像以DICOM格式输出。方法:应用Mimics、Freeform、ANSYS等软件进行三维重建,并建立正常骨盆的有限元模型。模拟人体双腿直立位的生理姿势,对模型施加500N轴向载荷。具体方式为约束双侧髋臼,向骶骨椎体上表面垂直加压,压力均匀分布于各个结点。主要观察指标:计算该加载方式下骨盆的应力、应变及位移的分布情况。结果:垂直加载500N载荷于骶骨上表面时,应力经两侧骶骨翼、骶髂关节,斜向下方经过坐骨大切迹附近,髂骨中央弓状线,传导至两侧髋臼。骨盆前环即耻骨支和耻骨联合受力较小。应变集中在两侧骶髂关节,绝对值很小,前方的耻骨联合处应变极小,可忽略不计。位移以骶骨背侧的骶正中嵴处最大。结论:正常骨盆是一个非常稳定的力学结构。过大的垂直应力容易引起骶骨或骶髂关节受损导致骨盆的垂直稳定性下降;恢复骶骨至髋臼的连续性对应力传导非常重要。
BACKGROUND： Mechanical analysis of pelvis is under exploration. Finite element analysis is accepted gradually due to its advantages such as little limitation of samples, few errors, and good repeatability.
OBJECTIVE： To build a three-dimensional finite element model of normal pelvis, and to analyze stress/strain and displacement distribution under vertical load.
DESIGN, TIME AND SETTING： Three-dimensional finite element analysis and single sample observation. The experiment was performed at the Laboratory of Biomechanics, Southern Medical University from March to September 2007.
MATERIALS： A normal adult male volunteer was chosen and underwent CT scanning （1-mm slice thickness）. The initial two dimensional images of pelvis were output in DICOM format to PC.
METHODS： A three-dimensional reconstruction and a finite element model were made using software of Mimics, Freeform and ANSYS. An axial loading of 500 N was put to the model under bilateral acetabulum constraint.
MAIN OUTCOME MEASURES： The stress, strain and displacement nephograms were obtained under axial load.
RESULTS： The distribution of stress in bilateral iliac bones was equal. The stress passed through the ala of sacrum and the sacroiliac joint to the regions near the greater sciatic notch, and the arcuate line to the acetabulum. The stress at the anterior ring of pelvis was small. The strain concentrated at two sides of the sacroiliac joints, and it was very small. The peak value of displacement appeared at the median sacral crest.
CONCLUSION： The normal pelvis is a very steady structure. The huge vertical loading could easily damage the sacrum or sacroiliac joint, resulting in reduction of the stability of pelvis. The continuity from sacrum to acetabulum is very important to maintain the stress conduction.
出处
《中国组织工程研究与临床康复》
CAS
CSCD
北大核心
2008年第39期7615-7619,共5页
Journal of Clinical Rehabilitative Tissue Engineering Research
