椎弓根骨水泥锚定对椎体成形术治疗Kummell's病骨水泥团块稳定作用的有限元分析

The stabilization effect on bone cement aggregates of pedicle bone cement anchoring technology in the treatment of Kimmell's disease:a finite element analysis

目的:采用有限元分析评估椎弓根骨水泥锚定对椎体成形术治疗Kümmell's病骨水泥团块稳定作用,为Kümmell's病治疗提供理论依据.方法:提取1名志愿者胸腰段CT薄层扫描数据,应用三维有限元方法建立胸腰段(T12~L2)脊柱Kümmell's病模型,构建L1前皮质破裂组(A组)、前皮质破裂行骨水泥椎弓根锚定组(B组)、前皮质完整组(C组)、前皮质完整行椎弓根骨水泥锚定组(D组).对所有模型L2椎体下终板进行完全固定,同时对T12上终板施加500N的轴向、前屈、后伸、左侧屈、右侧屈方向载荷以及10N·m的左旋转、右旋转扭矩载荷,统计分析在不同运动方向上四组模型中心骨水泥团块以及B组、D组的椎弓根骨水泥锚定棒的最大位移值和最大应力值,并且对椎弓根骨水泥锚定棒变形程度进行观察.结果:在前屈、后伸、左侧屈、右侧屈载荷方向上,B组骨水泥块最大位移值均小于A组,在轴向、左旋转、右旋转载荷方向上,B组均大于A组;除轴向载荷以外,D组骨水泥块最大位移值均大于C组;在轴向、前屈、后伸、左侧屈、右侧屈、左旋转、右旋转载荷方向上,D组骨水泥椎弓根锚定棒最大应力值均大于B组;在前屈、后伸方向载荷下,D组椎弓根锚定棒最大位移值均小于B组,其他载荷方向D组均大于B组.B组、D组中骨水泥椎弓根锚定棒在轴向、前屈、后伸、左侧屈、右侧屈方向载荷下均无较大的变形,在左旋转、右旋转载荷下均出现较大变形.结论:椎体成形术治疗病椎前皮质破裂Kümmell's病时,椎弓根骨水泥锚定可对椎内中心骨水泥团块起到稳定作用,但椎弓根骨水泥锚定棒在人体脊柱左右旋转运动时存在断裂可能;对于椎体前皮质完整的Kümmell's病,椎弓根骨水泥锚定在力学上并不能增加中心骨水泥团块的稳定性.

Objectives:To use finite element analysis to evaluate the stability of bone cement clumps in the treatment of Kummell's disease using pedicle bone cement anchoring technology,and to provide a theoretical basis for the treatment of Kuimmell's disease.Methods:A three-dimensional finite element method was used to establish a Kimmell's disease model of the thoracolumbar spine(T12-L2)by extracting CT thin layer scanning data from one volunteer.The anterior cortex rupture group(group A,)a,nterior cortex rupture with pedicle bone cement anchoring group(group B),anterior cortex intact group(group C),and anterior cortex intact with pedicle bone cement anchoring group(group D)were constructed.The L2 vertebral lower endplate was fully fixed in all models,and 500N loads axial,forward,backward,and left and right bending,as well as 10N·m left and right rotation torque loads were applied to the T12 upper endplate.Statistical analysis was conducted on the maximum displacement values of the central bone cement block in the four groups of models in different motion directions,as well as the maximum displacement and stress values of the pedicle bone cement anchor rods in groups B and D.And the degree of deformation of the pedicle bone cement anchor rods was observed.Results:Comparing the maximum displacement values of bone cement blocks,group B was smaller in the load directions of flexion,extension,and left and right bending,and greater in the axial,left and right rotation than group A;Except for axial load,group D was greater than group C.Comparing the maximum stress values of bone cement pedicle anchor rods,group D was greater than group B in axial,flexion,extension,left and right bending,left and right rotation load directions;Comparing the maximum displacement values of bone anchor rods,group D was smaller than group B in flexion and extension directions,while greater in other load directions than group B.There was no significant deformation of the pedicle bone cement anchor rod in groups B and D under axial,flexion,extension,left and right bending loads,while there was significant deformation under both left and right rotation loads.Conclusions:The use of pedicle bone cement anchoring technology in the treatment of Kimmell's disease can stabilize the central bone cement mass in the vertebral body in the event of anterior cortical bone rupture,but there is a possibility of fracture of the bone anchoring rod during left and right rotation of the human spine.However,for Kimmell's disease with intact anterior cortex of the vertebral body,anchoring the pedicle bone cement does not increase the stability of the central bone cement mass mechanically.