退变性腰椎侧弯融合固定术后相邻节段的三维运动研究

Recently, posterior lumbar intervertebral fusion and pedicle screw fixation is a commonly used procedure for the treatment of degenerative lumbar scoliosis. Adjacent segment degeneration occurs in nearly 29.6% of the patients after operation, resulting in the recurrence of symptoms and even secondary surgery. The reconstruction angle of lumbar lordosis is an important iatrogenic factor that affects the adjacent segment degeneration. However, the choice of reconstruction angle is controversial. Previous studies on the adjacent segment degeneration are mostly in vitro experiments or finite element analysis.This project is the first noninvasive method in vivo to accurately measure the three-dimensional movement of degenerative lumbar scoliosis patients under weight bearing load before and after operation. This project intends to use combined dual fluoroscopic and MRI imaging system to obtain The orthodontic bi-plane X-ray two-dimensional images of the lower lumbar vertebrae in seven functional positions and the three-dimensional anatomy model of the vertebral body. The three-dimensional motion parameters of adjacent segments under weight bearing load are obtained by two-dimensional and three-dimensional image registration.Comparing the three-dimensional motion of the adjacent segments before and after the operation, we accurately evaluate the influence of the reconstruction range of lumbar lordosis on the three-dimensional movement of the adjacent segments. We strive to provide practical solutions to reduce the adjacent segment degeneration after lumbar fusion and a scientific basis to guide the choice of individualized lumbar lordosis reconstruction range.

腰椎融合固定术是治疗退变性腰椎侧弯的常用术式，术后近29.6%的患者发生相邻节段退变，从而导致症状的复发，甚至二次手术。腰椎前凸的重建角度是影响术后相邻节段退变的重要医源性因素，而重建角度的选择存在争议。既往关于相邻节段退变的研究多为体外实验或有限元分析。本项目首次采用体内无创方法，准确测量生理载荷条件下退变性腰椎侧弯患者术前术后相邻节段的三维运动，测量椎体解剖结构的运动学参数，并描绘其在运动过程中的运动轨迹。本项目拟采用双平面荧光透视系统与磁共振相结合的技术，获取7个功能性体位下腰椎的正交双平面X线二维图像及椎体的三维解剖模型，并通过二维-三维图像配准获得生理载荷下相邻节段的三维运动参数。对比患者术前术后相邻节段的三维运动，精确评价不同腰椎前凸角重建范围对其相邻节段的三维运动影响。力争为减少腰椎融合术后相邻节段退变提供切实可行的方案，指导选择国人个体化腰椎前凸角的重建范围提供科学依据。

随着人口老龄化的不断加剧，腰椎退行性疾病的发病率逐年增多。手术治疗往往是腰椎融合固定术。有许多患者却因为远期相邻节段的病变而导致症状复发，甚至需要翻修手术。本项目采用双平面荧光透视系统在体内采用无创方法通过二维-三维图像配准获得生理载荷下脊柱的三维运动参数。（1）正常国人的椎体及关节突关节活动度：①L5-S1节段发生的耦合运动明显高于其他节段；②随着年龄的增长，主旋转轴的运动减少，耦合运动代偿增加；③L4-5节段的主运动旋转随着年龄增加减少明显，L4-5和L5-S1节段的耦合运动增加也较明显。（2）退变性侧弯患者的椎体活动度：①DLS患者中L5-S1节段的耦合位移明显高于正常人；③对于南京鼓楼医院分型A型和B型的DLS患者在侧弯顶点的相邻节段主要通过主运动轴运动代偿，对于C型DLS患者在侧弯顶点以及相邻节段的耦合运动的活动度都要明显增加。（3）DLS患者的椎板活动度：①Cobb角越大的DLS患者在顶椎区域耦合运动越大；②Cobb角较小的DLS患者，椎间盘退变越重的节段耦合运动越大。（4）术后DLS患者的椎体活动度变化：①相邻节段的主运动增加，没有明显变化甚至减少，耦合运动明显减少。②L5-S1节段作为相邻节段整体耦合运动减少，主运动增加③PI-LL 在15°~28°的范围可能对于国人来说更合适。建立国人不同年龄的L1-S1椎体以及关节突关节三维运动的基准线，对于DLS患者本身L5-S1节段退变比较重耦合运动较大的可以考虑做L5-S1的融合。南京鼓楼C型的DLS患者在手术时应充分考虑退侧节段及相邻节段的耦合代偿作用。Cobb角较小的DLS患者尤其术前已经存在严重椎间盘退变的节段是否融合应谨慎。术后固定节段与相邻节段主运动轴以及耦合运动的明显差异可能是造成相邻节段退变的因素之一，对于固定到L5的患者，PI-LL<9°的患者L5-S1耦合运动增加，PI-LL=15°~28°的患者L5-S1耦合运动减少，主运动活动增加，PI-LL 在15°~28°的范围可能对于国人来说更合适