经椎间孔椎间融合后腰椎即刻稳定性的生物力学实验(英文)

Initial lumbar stability following transforaminal interbody fusion:Biomechanical test

背景:经椎间孔椎间融合适用于腰椎任何节段,并且保留了侧椎板和关节突关节的完整,较传统的椎间融合具有一定的优势,但有关其生物力学性能的研究很少。目的:应用生物力学应力方法观察经椎间孔椎间融合术后及附加单侧和双侧椎弓根螺钉后腰椎即刻稳定性的变化。设计、时间及地点:生物力学测试,于2005-08/2006-04在南通大学和上海大学生物力学研究所完成。材料:新鲜1月龄小牛腰椎标本20具。方法:20具小牛标本模拟临床手术,分别依次建立经椎间孔椎间融合单纯椎间融合模型、经椎间孔椎间融合附加单侧椎弓根螺钉模型、经椎间孔椎间融合附加双侧椎弓根螺钉模型,每组5个标本,在脊柱三维运动测试机上进行生物力学测试。主要观察指标:记录应变、位移、应力、扭角等力学量。结果:行单纯经椎间孔椎间融合后,虽然在平均应变和应力上变化不大,但刚度和扭转强度明显减小了,说明虽然椎间融合器的植入能提供即刻的稳定性。分别附加单侧椎弓根螺钉和双侧椎弓根螺钉固定后,其稳定性明显比单纯融合组加强了,甚至超过正常组,附加双侧内固定组的稳定性明显优于单侧内固定组。虽然附加单侧椎弓根螺钉固定后的腰椎稳定性逊于附加双侧椎弓根螺钉固定组,但是其即刻稳定性也大大地加强了,甚至超过了正常标本,说明附加单侧内固定同样也能提供腰椎术后足够的初始稳定性。结论:单纯经椎间孔椎间融合后,腰椎的初始稳定性是不够的,附加单侧和双侧椎弓根螺钉固定都能明显的增加腰椎的初始稳定性。

BACKGROUND： Transforaminal lumbar interbody fusion （TLIF） can be applied in any lumbar segment, and retain integrity of lateral vertebral plate and zygapophysial joints. However, few studies have been conducted about the biomechanical performance. OBJECTIVE： To explore the stability of lumbar intervertebral segment following TLIF applied bilateral and unilateral transpedicular screws fixation. DESIGN, TIME AND SETTING： Biomechanical test was performed at the Institute of Biomechanics, Shanghai University and Nantong University between August 2005 and April 2006. MATERIALS： Twenty samples of fresh one-month-old calf lumbar vertebra. METHODS： Twenty samples of calf lumbar vertebra underwent TLIF alone, TLIF in combination with bilateral or unilateral transpedicular screws fixation. Biomechanical test was performed on spinal three dimensional motion testing machine. MAIN OUTCOME MEASURES： Stress, displacement, strain and torsion angle were recorded. RESULTS： After TLIF without fixation, no obvious changes were found in mean stress and strain, but the axes stiffness and rotational stiffness were significantly decreased, indicating TLIF could produce immediate lumbar stability. After TLIF with unilateral or bilateral transpedicular screws fixation, the lumbar stability was significantly enhanced compared with TLIF alone, especially bilateral transpedicular screws fixation. Although the lumbar stability following unilateral transpedicular screws fixation was inferior to bilateral fixation, it was still greatly enhanced, even exceeded normal sample, indicating TLIF with unilateral transpedicular screws fixation could produce enough initial lumbar stability. CONCLUSION： TLIF alone cannot support sufficient initial stability, but TLIF with bilateral and unilateral transpedicular screws fixation can enhance lumbar initial stability.