一种新型压配式腰椎椎间融合器的机械性能

Mechanical performance of a novel press-fit lumbar intervertebral fusion device

背景:行经皮微创椎间孔腰椎椎间融合置入椎间融合器时,由于入路操作范围狭窄,有牵拉神经根损伤或置入融合器位置不良等风险,为了解决以上问题作者课题组发明了一种新型机械结构可变形压配式cage(Press-fit cage,YP-cage)。目的:对新型腰椎融合器YP-cage的机械强度特性进行初步评估。方法:对不同尺寸9,11,13 mm高度的新型YP-cage(n=9)和聚醚醚酮-cage(n=9)进行了静态轴向压缩实验和静态轴向扭转实验,分别采集力-位移曲线计算屈服位移及载荷、极限载荷位移及刚度,屈服角位移及扭矩、极限载荷角位移扭矩及刚度,并进行对比分析。结果与结论:(1)在静态轴向压缩测试中,YP-cage在3组测试中(9,11,13 mm),其刚度、屈服载荷、极限位移和载荷极限方面均优于聚醚醚酮-cage(P <0.01),但YP-cage的屈服位移小于聚醚醚酮-cage(P <0.05);(2)在静态扭转测试中,除了9 mm组的YP-cage和聚醚醚酮-cage在极限扭转角度上差异无显著性意义,YP-cage在屈服扭矩、屈服扭转角度及极限扭矩均小于聚醚醚酮-cage(P <0.01),而YP-cage扭转刚度在9 mm组和11 mm组大于聚醚醚酮-ccage(P <0.01);(3)结果表明新型压配式机械结构椎间融合器相较于聚醚醚酮材质cage具有更高的抗压强度,但抗扭强度不如聚醚醚酮-cage。

BACKGROUND:When performing percutaneous minimally invasive transforaminal lumbar interbody fusion to implant an intervertebral cage,due to the narrow operating range of the approach,there is a risk of nerve root injury or poor position of cage.To solve the above problems,a novel mechanical deformable press-fit cage(YP-cage)was invented.OBJECTIVE:To preliminarily evaluate the mechanical strength characteristics of this new lumbar fusion device YP-cage.METHODS:Static axial compression and torsion tests were conducted on 9,11,and 13 mm YP-cages(n=9)and poly(ether ether ketone)(PEEK)-cages(n=9).The force-displacement curves were collected to calculate yield displacement and load,ultimate load displacement and stiffness,yield angular displacement and torque,ultimate load and angle displacement torque and stiffness for comparative analysis.RESULTS AND CONCLUSION:(1)In the static axial compression test,YP-cage was superior to PEEK-cage in terms of stiffness,yield load,ultimate displacement,and load limit in three groups of tests(9,11,13 mm)(P<0.01),but the yield displacement of YP-cage was smaller than that of PEEK-cage(P<0.05).(2)In the static torsion test,there was no significant difference in the ultimate torsion angle between YP-cage and PEEK-cage in 9 mm group.YP-cage was lower than PEEK-cage in yield torque,yield torsion angle,and ultimate torque(P<0.01),while YP-cage torsional stiffness was greater than PEEK-cage in 9 mm group and 11 mm group(P<0.01).(3)The results show that the novel press-fit mechanical lumbar cage has higher compressive strength than PEEK cage,but the torsional strength is not as good as PEEK-cage.