平面力推拿揉法与腰椎间盘生物力学关系的有限元分析

A finite element analysis of the biomechanics of the lumbar spine under plane force kneading

目的 通过腰椎三维有限元建模方法,研究平面力推拿揉法对腰椎间盘生物力学的影响.方法 选取1例女性健康受试者,采用Somatom Sensation16型螺旋CT扫描机采集数据,进行精确三维分割与模型重建,生成正常人体L3～S1节段独立的三维实体模型,结合解剖知识构建肌肉实体模型后,采用专用生物力学软件建立L3～ S1节段腰椎三维有限元,根据推拿揉法的作用规律,按循环旋转方向在L4和L5棘突的外部肌肉处施加平面作用力50 N,观察腰椎间盘纤维环和髓核的变化.结果 在推拿揉法的左右摆动作用下,纤维环和髓核在水平方向上产生一定的循环旋转运动,运动的主要趋势是向椎间盘的中部及周边集中,髓核水分也向中部及周边聚集,椎间盘内密度发生变化,中部及周边密度增高.整个模型中骨皮质的应力分布较为均匀,说明推拿揉法的力传递过程在很大程度上依靠腰椎实体肌肉的协同和拮抗作用,L4-5椎间盘的纤维环和髓核应力分布显示椎间盘中部及周边的两侧应力较大.结论 在平面力推拿揉法作用下,腰椎纤维环和髓核向椎间盘中部及周边集中,椎间盘中部及两侧的应力较大.

Objective To analyze the impact of plane force kneading on the biomechanics of the lumbar intervertebral discs.Methods A 3D solid model was prepared of the L3 to S1 segments of the spine of a healthy woman volunteer.Data collected using a Somatom Sensation 16 CT scanner and biomechanics software were used to define a 3D finite element model.Based on the regular pattern of kneading in Chinese manipulation,a planar rotatory force of 50 N was applied to the external muscles of the L4 and L5 spinal processes and any changes in the nucleus pulposus and the fibrillar annulus of the lumbar intervertebral discs of the finite element model was observed.Results The planar rotary kneading focused on the center and periphery of the discs.The fluid in the central nucleus pulposus also gathered in the center and periphery,and the disc density increased in the center and periphery.The stress distribution of the cortical bones over the entire model was very uniform,indicating that force transmission during kneading relies on synergistic and antagonistic action of the lumbar muscles.The L4-L5 intervertebral disc nucleus stress distribution showed high stress at the center and both sides of the intervertebral discs.Conclusion Under the action of planar kneading,the nucleus pulposus and the annulus of the lumbar spine gather at the center and periphery of the intervertebral disks,and the center and both sides experience high stress.