双侧钉棒及同侧单钉棒置入内固定的生物力学比较

Biomechanical comparison of bilateral pedicle screw and unilateral pedicle screw fixation

背景:腰椎失稳、腰椎滑脱等腰椎退行性疾病常常需要实施腰椎融合,其目标是稳定脊柱,但究竟采取何种内固定方式仍存在争论。目的:比较单侧与双侧经椎间孔减压椎体间融合治疗腰椎退行性病变的生物力学差异。方法:人新鲜尸体腰椎标本6具,L4～5模拟微创经椎间孔减压椎体间融合,根据不同的内固定组合方式分为2组,即双侧钉棒组及同侧单钉棒组。在生物力学试验机上测量各种固定方式不同工况下的运动范围(ROM值),并进行比较。结果与结论:以完整的腰椎运动单元为参照,两固定组的ROM值均低于对照组(P<0.05)。其中双侧钉棒组在各工况下ROM值均显著低于同侧单钉棒组(P<0.05)。提示在生物力学实验中,单侧椎弓根螺钉固定椎间融合生物力学性能优良,刚度适中,腰椎可获得可靠的稳定性。但与双侧钉棒固定比较,单钉棒方式仍然存在差距。

BACKGROUND：Most of lumbar degenerative diseases,such as lumbar instability and lumbar spondylolisthesis,need lumbar spinal fusion for the spine stability,but the choice of internal fixation approaches is an argument.OBJECTIVE：To investigate the biomechanical difference of unilateral and bilateral minimally invasive transforaminal lumbar interbody fusion（TLIF） for the treatment of lumbar degenerative diseases.METHODS：Minimally invasive TLIF with different internal fixations were performed on L4-5 segments from six fresh frozen human lumbar cadaveric specimens.Then,the specimens were divided into two groups according to different internal fixation methods：bilateral pedicle screw group and unilateral pedicle screw group.Range of motion（ROM） for the lumbar function unit was measured on the biomechanical machine and compared between the two groups.RESULTS AND CONCLUSION：Compared with the compact lumbar function unit,the ROM of the two fixation groups were significantly lower（P 0.05）.The ROM value of the bilateral pedicle screw group was significantly lower than that of the unilateral pedicle screw group in all working states（P 0.05）.Biomechanical experiments show that unilateral TLIF provides favorable biomechanical effect and stiffness,which offers the dependable stability of the lumbar vertebrae.However,compared with the bilateral pedicle screw fixation,there are still gaps in the unilateral pedicle screw fixation.