腰椎不同融合方式对邻近节段影响的三维有限元分析

The effects of different fusion techniques on adjacent segments of lumbar spine: a three dimensional finite element analysis

目的建立腰椎不同方式腰椎融合手术的三维有限元模型,探究在采取不同融合手术方式后对相邻节段的影响,从而优化手术方式。方法利用三维有限元法建立了三种腰椎模型:(1)退变腰椎模型;(2)螺钉固定融合术后腰椎模型;(3)椎间融合器及螺钉固定腰椎模型;其中腰椎术后模型的手术节段均为L4~L5。分别比较上述三种模型在前屈、后伸、左右侧屈状态下,手术节段对上下相邻节段的影响,并量化为运动范围(ROM)、间隙压力、最大应力的参数百分比。结果在屈伸和侧向弯曲载荷下,退变腰椎模型相邻节段的运动范围(ROM)、间隙压力、最大应力明显小于两种融合手术模型。结论螺钉固定融合术及椎间融合器加螺钉固定融合术均可致相邻节段退变及失稳。

Objective To establish a three-dimensional finite element model of lumbar fusion for lumbar fusion and to explore the effect on the adjacent segments after adopting different fusion methods to optimize the operation method. Methods Three kinds of lumbar models were established by three-dimensional finite element method：（ 1） degenerative lumbar model;（ 2） screw fixation and fusion lumbar model;（ 3） intervertebral cage and screw fixation lumbar model. The lumbar spine surgery model of the surgical segments is L4~ L5. The effects of the surgical segments on the upper and lower adjacent segments under flexion,extension,left and right flexion were compared between the above three models,respectively,and quantified as percentages of parameters of motion range（ ROM）,gap pressure,and maximum stress. Result Under flexion and lateral bending loads,ROM,gap pressure and maximum stress of adjacent segments of degenerative lumbar model were significantly less than those of two fusion models. Conclusion Screw fixation fusion and interbody fusion plus screw fixation fusion can cause degeneration and instability of adjacent segments.