基于瞬时旋转轴（IAR）理论的腰椎节段稳定性精确评估及腰椎不稳动力学机制研究

Segmental motion of lumbar spine is a complicated coupled 3-dimensional motion. The kinematic mechanism of lumbar instability remains unclear. It’s difficult to assess a lumbar segmental movement accurately based on the current regular methods. The instantaneous axis of rotation (IAR) can precisely indicate the motion between two concrete bodies in a 3-dimentional space. Our previous study revealed that IAR could be utilized to describe the translation and rotation accurately between the two vertebral bodies in a lumbar segment, and show the real characteristic of lumbar segmental motion. It has incomparable sensibility and reliability to be used to investigate kinematic mechanism of lumbar instability. The purposes of the current study are to establish an advanced procedure combining the in vivo kinematic methods and three-dimensional reconstructive technique. This procedure will be used to reveal the feature of the lumbar segmental IAR , and to explore the kinematic mechanism of lumbar instability. The IAR features in a group with low back pain will be also analyzed to assess the effect of segmental instability on occurrence of low back pain. Based on the analysis on the relativity between the IAR and degeneration of discs and facet joints, the influence of degeneration of discs and facet joints on lumbar segmental motion will be determined. Then a novel criteria based on 3-D computed biomechanical measures are expected to build to obtain a precise and digitalized assessment in vivo on the spinal kinematics.The kinematic feature of lumbar segments and its changing pattern during the process of lumbar instability are expected to be further revealed. The findings will be ultimately used to guide the clinical diagnosis and treatment of lumbar instability and low back pain.

腰椎节段运动是一种三维、复杂的三关节耦联运动，腰椎失稳的动力学机制尚不明确，现有方法难以准确评估腰椎节段稳定性。瞬时旋转轴（IAR）可客观实时地反映三维空间中两个刚性物体间的相对运动，课题组前期研究证实IAR可准确评估腰椎节段运动中两椎体间的位移和旋转角度，真实展现腰椎节段运动特点，将其用于腰椎失稳的动力学机制研究，具有其他方法无可比拟的敏感性和可靠性。本项目拟将在体运动力学方法与计算机三维重建技术相结合，揭示腰椎节段运动的IAR特征，深入探讨腰椎失稳的动力学机制；进而根据顽固性腰背痛群体IAR指标的特征性变化，探讨节段不稳在顽固性腰背痛发病机制中的作用；根据不同程度的椎间盘及关节突退变与IAR特征的相关性，探讨腰椎退变对节段稳定性的影响。由此创建精确评估腰椎节段稳定性的在体计算机重建生物力学研究方法，并深入揭示腰椎节段运动的动力学特点，及其在腰椎不稳发展中的变化规律，用以指导临床诊疗。

腰椎节段运动是一种三维、复杂的三关节耦联运动，腰椎失稳的动力学机制尚不明确，现有方法难以准确评估腰椎节段稳定性。瞬时旋转轴（IAR）可客观实时地反映三维空间中两个刚性物体间的相对运动，课题组将计算机三维重建技术与在体运动力学方法相结合，创建了一套精确评估腰椎节段稳定性的在体计算机重建生物力学研究方法，发现了腰椎节段基于IAR的8种运动模式，以及每个腰椎节段的IAR参数特点。通过测算L4-5单节段不稳的下腰痛患者、L4-5单节段融合患者及L4-5单节段Wallis棘突间动态固定患者的IAR参数特点，发现了不同腰椎病理状态下的 IAR 特征及腰椎节段不稳的发生机制，即当腰椎节段失稳时，IAR到坐标原点最短距离及IAR到坐标原点最近的点P弥散程度增大，并在山羊腰椎不稳动物模型实验中做了进一步验证。本研究证实计算机三维重建技术相结合IAR可准确评估腰椎节段运动中两椎体间的位移和旋转角度，真实展现腰椎节段运动特点，将其用于腰椎失稳的动力学机制研究，具有较高的敏感性和可靠性。