应用MRI对腰椎峡部断裂后相关解剖位置改变的基础研究

The shift of relative anatomy structures in lumbar spondylolysis:a foundation research using MRI

目的 :对L5峡部裂病例的MRI正中矢状面图像进行形态学测量 ,探讨L5峡部裂患者腰椎各部的移位情况。方法 :在腰椎正中矢状面T1WI上建立以S1后上缘为原点 ,通过S1前上缘和后上缘的直线为X轴的平面直角坐标系 ,对4 5例L5峡部裂患者 (无滑脱组 15例 ,滑脱组 30例 )及 10 0例健康成人腰椎各点的坐标进行测量 ,并对所得数据进行统计分析。结果 :与正常组比较 ,无滑脱组及滑脱组L5棘突基底部的横坐标显著增大、纵坐标显著减小。无滑脱组L4水平各测量点及L5椎体各测量点 (L5椎体前下缘除外 )的横坐标与正常组比较均无显著差异 ,L5水平硬膜囊前、后缘的横坐标较正常组显著增大。滑脱组L4、L5水平各测量点 (L5棘突基底部除外 )的横坐标显著小于正常组。峡部裂组上述各点的横坐标与L5椎体后下缘的横坐标呈线形相关。无滑脱组及滑脱组的L5椎体下缘水平椎管前后径、硬膜囊前间隙及硬膜囊后间隙显著增宽。结论 :L5峡部裂患者滑脱前期L5椎弓断端后部向后下移位 ,L5椎体层面硬膜囊轻度后移。滑脱期除L5椎弓断端后部向后下移位以外 ,L4椎体及附件、硬膜囊均随L5椎体向前移位。上述空间位置的变化是造成峡部裂患者形态学改变的基础。

Objective:To determine the displacement of the vertebral body and arc in L 5 spondylolysis by measuring the lumbar structures on mid sagittal MR T 1 weighted images.Methods:The reference frame was established on mid sagittal MR T 1 weighted images (Origin point:superior posterior margin of S 1) vertebral body, x axis: the line joining the superior anterior and superior posterior margin of S 1 vertebral body).The coordinates were measured in 45 cases of lumbar spondylosis and 100 healthy adults. The data thus obtained were statistically processed.Results:The x coordinate of L 5 spinous process basement was significantly increased, and the y coordinate was significantly decreased both in pre spondylolisthesis group (n=15) and spondylolisthesis group (n=30). There was no significantly difference between pre spondylolisthesis group and control group for the x coordinate of each point at L 4 level and L 5 vertebral body (except the anterior inferior margin).In pre spondylolisthesis stage, the x coordinate of anterior and posterior margin of dural sac at L 5 level was both significantly increased.In spondylolisthesis stage,the x coordinate was significantly decreased for each point at L 4 and L 5 level (except the basement of L 5 spinous process).The x coordinate for each point above mentioned had goodlinear relation to the x coordinate of inferior posterior margin of L 5 vertebral body in spondylosis group (n=45).At the lower margin of L 5 level,the anterior posterior diameter of the canal,the fat spaces anterior to dural sac and posterior to dural sac was significantly widened both in pre spondylolisthesis group and spondylolisthesis group.Conclusion:In pre spondylolisthesis stage, the L 5 posterior spinal element was displaced backwards and downwards,the dural sac was displaced backwards slightly at L 5 level.In spondylolisthesis stage, besides the backwards and downwards slippage of L 5 posterior spinal element, the L 5 vertebral body was displaced forwards along the upper margin of S 1 associating forwards slippage of L 5 vertebral and dural sac. The morphometric findings were based on the displacement of lumbar structure.