TFC对腰椎水平稳定性影响的生物力学实验研究

A Biomechanical Experiment Study of TFC Affecting Sagittal Horizontal Stability in the Lumbar Spine.

目的 :通过离体腰椎的抗剪切应力研究 ,探讨峡部裂、RF- 型椎弓根螺钉内固定及带螺纹的钛合金椎间融合器 (Ray- TFC)椎间融合对腰椎水平稳定性的影响。方法 :将取自五具新鲜尸体标本的十个脊柱功能单位(FSU)分别在完整状态、峡部裂状态、失稳状态、RF- 固定状态、TFC植入状态和 TFC加 RF- 固定状态下进行剪切应力加载实验。结果 :峡部裂较完整 FSU水平稳定性显著下降 ,P<0 .0 5。RF- 固定的水平稳定性与完整 FSU相近 ,较峡部裂有显著性提高 ,P<0 .0 5。 TFC植入后较峡部裂稳定 ,但两者间无显著性差异。单、双 TFC植入间无显著性差异。TFC加 RF- 固定较峡部裂有极显著性提高 ,P<0 .0 1。完整 FSU、RF- 固定和 TFC加 RF- 固定的稳定性较失稳 FSU均有显著性提高 ,其中 RF- 固定的 P<0 .0 5 ,余二者 P<0 .0 1。结论 :峡部裂使腰椎失稳 ,抗剪切力能力下降 ,造成滑脱倾向。 RF- 复位内固定治疗腰椎滑脱具有可靠的生物力学性能。

Objective:Human cadaveric spines were used to determine sagittal horizontal stability of spondylolysis、RF-Ⅱ fixation and TFC insertion.Methods:Ten FSU got from five fresh cadaveric human spines were tested for intact FSU、spondylolysis、unstable FSU、RF-Ⅱ fixation and TFC insertion by using shear force.Results:Spondylolysis is significantly unstable than the intact spine P<0.05.The stability of RF-Ⅱfixation is almost same with intact spine,and significantly higher than spondylolysis,P<0.05.That TFC inserts spine is stiffer than spondylolysis,but there is no significant effect between them.There is also no significant effect between single TFC and double TFC insertion.TFC insertion with RF-Ⅱ fixation is significantly stable than spondylolysis,P<0.01.Intact FSU、RF-Ⅱ fixation and TFC insertion with RF-Ⅱ fixation are all significantly stable than unstable FSU,RF-Ⅱ fixation’s P<0.05,other two,P<0.01.Conclusions:Spondylolysis made lumbar spine unstable,reduce its ability to withstand the shear force,and made it prone to slipper.Biomechanic properties of RF-Ⅱ made it credible to treat spondylolisthesis.The application of TFC to treat spondylolisthesis needs more evaluation.