腰骶椎单向带刺轴向融合内固定系统的生物力学特征

Biomechanical characteristics of lumbosacral vertebra with unidirectional axial fusion fixation system

背景:探寻一种微创操作、固定牢靠、具有良好抗旋转能力的新技术对于治疗腰骶椎退行性疾病具有十分重要的临床意义。目的:观察腰骶椎单向带刺轴向融合内固定系统治疗腰骶椎失稳的生物力学特征,为其临床应用提供理论依据。方法:选取6具新鲜成人腰骶椎尸体标本,截取腰骶椎运动节段(L3-S5),分为以下5组:结构完整的正常组、双侧峡部裂组、双侧峡部裂+带刺轴向融合内固定组(A组)、双侧峡部裂+单纯中轴螺钉固定组(B组)、双侧峡部裂+单纯中轴螺钉固定+双侧椎弓根螺钉固定组(C组)。比较不同内固定方式中L5/S1节段屈伸、侧弯、旋转的三维运动范围及轴向抗压能力。结果与结论:①在不同方向的运动下,A、B、C组固定方式的稳定性均优于正常组与双侧峡部裂组,差异有显著性意义(P<0.05);②在前屈、后伸、左右侧屈方向,A、B、C组3种内固定方式组间差异无显著性意义(P>0.05);③而在左右旋转方向上,A组旋转运动的三维运动范围显著小于B组,且A组与C组比较差异无显著性意义(P>0.05);④结果表明,腰骶椎单向带刺轴向融合内固定系统具有良好的生物力学稳定性,抗旋转能力强,有望应用于临床。

BACKGROUND:It is very important to apply a new technique of minimally invasive,firm fixation and antirotation in the treatment of lumbosacral degenerative diseases.OBJECTIVE:To provide theoretical basis for clinical application by biomechanical study on the treatment of lumbosacral vertebra instability with unidirectional axial fusion internal fixation system.METHODS:Six fresh adult lumbosacral specimens were selected,and the lumbosacral motion segments(L3-S5)were intercepted and divided into the following five groups:The intact normal control group(N group),bilateral isthmus fissure group(UN group),bilateral isthmus fissure+spur axial fusion internal fixation group(A group),bilateral isthmus fissure+axial screw fixation group(B group),bilateral spondylolysis+axial screw fixation alone+pedicle screw fixation on both sides group(C group).The three-dimensional motion range of flexion,lateral bending and rotation of segment L5/S1 in each group of internal fixation was compared with the axial compression resistance.RESULTS AND CONCLUSION:(1)The stability of fixed mode in A,B and C groups was better than that in the N group and the UN group under different directions of motion,and there were statistically significant differences between the groups(P<0.05).(2)There was no significant difference in the anterior flexion,posterior flexion and lateral flexion between A,B and C groups(P>0.05).(3)In the left and right direction of rotation,the three-dimensional motion range of rotation in the A group was significantly reduced compared with that in the B group,and there was no significant difference between A group and C group(P>0.05).(4)The lumbosacral vertebra unidirectional axial fusion internal fixation system has good biomechanical stability and strong anti-rotation ability,and is expected to be used in clinic.