腰椎退变影响拔伸按压手法生物力学作用的有限元研究

目的:研究腰椎退变对拔伸按压手法治疗腰椎间盘突出症的生物力学影响。方法:应用L_(3～5)运动节段轻度退变与中度退变模型进行研究。假定腰椎间盘突出发生于L_4椎间盘左侧,为模拟拔伸按压手法,L_3椎体上终板固定,L_5椎体下终板施以500 N拉力;在L_(4～5)运动节段左侧椎板分别施以50 N与80 N按压力,比较两模型在不同按压力作用下L_4椎间盘左后方位移与L_(4～5)运动节段左侧小关节接触力。结果:手法按压力分别为50 N与80 N时,与轻度退变模型相比,中度退变模型L_4椎间盘左后方位移分别下降18.1%与34.5%,小关节接触力分别下降17.6%与43.4%;当按压力由50 N增至80 N,轻度退变与中度退变模型L_4椎间盘左后方位移分别增加146.3%与96.8%,小关节接触力分别增加195.9%与103.3%。结论:腰椎退变影响拔伸按压手法生物力学效应,但并不增加腰椎小关节接触力。

Finite Element Study on Lumbar Degeneration Influencing Biomechanical Action of Pulling and Pressing Manipulation

Objective:To investigate the lumbar degeneration influencing the biomechanical action of pulling and pressing manipulation in treating the protrusion of lumbar intervertebral disc. Methods:The mild L_(3～5) motor segment degeneration and moderate degeneration model were studied. It was assumed that the protrusion of lumbar intervertebral disc occurred on the left side of the L_4 intervertebral disc. To simulate lumbar pulling-pressing manipulation,the superior endplate surface of L_3 was fixed in all directions,a 500 N tensile force was imposed on L_5 inferior endplate,and a 50 N and 80 N pressing force was imposed on the left vertebral laminae of L_(4 ～5) segment,respectively. The left and posterior displacement of L_4 intervertebral disc and the contact force of facet joint in L_(4 ～5) segment were investigated. Results:When pressing was 50 N and 80 N respectively,compared with the mild degeneration model,the left posterior displacement of the L_4 disc in the moderate degeneration decreased by 18.1% and 34.5% respectively,and the contact force of the facet joint decreased by 17.6% and 43.4% respectively. When pressing pressure increased from 50 N to 80 N,the left posterior displacement of the L_4 intervertebral disc of the mild and moderate degeneration increased by 146.3% and 96.8% respectively,and the contact strength of the small joints increased by 195.9% and 103.3% respectively. Conclusion:Lumbar degeneration affects the biomechanical action of the pulling and pressing manipulation,but does not increase the contact force of the lumbar facet joint.