腰椎“人”字嵴顶点定位的三维CT影像研究

Imaging anatomy of location of top point of '∧' shape crest by using three-dimensional CT

目的基于CT断层图像重建腰椎模型及三维可视化的方法研究如何确定腰椎"人"字嵴顶点,指导临床应用。方法将30例腰椎CT导入Mimics 10.01获得骨骼三维几何模型。在三维重建模型上应用"人"字嵴顶点法、"人"字嵴顶点上法及"人"字嵴顶点下法模拟置钉,测量进钉点至椎弓根轴线的距离及其与上下缘、内外缘的位置关系.比较3种方法在腰椎各节段的差异及优缺点。结果在L1-5",人"字嵴顶点法的进钉点到椎弓根轴线距离小于它其两种方法。说明该确定方法较为理想。同时随着椎体序列的增加逐渐低于椎弓根轴线。结论在此基础上模拟的3种确定"人"字嵴顶点的方法与椎弓根轴线的解剖关系存在较大差异;"人"字嵴顶点定位法的钉道与椎弓根纵行中心线最近。

Objective to study three methods of lumbar pedicle placement in different level based on CT tomographic image reconstruction model in order to determine the location of ＂∧＂ shape crest of the Lumbar vertebra and provide objective basis. Mothods In 30 cases of lumbar CT three-dimensional reconstruction model, the placement of the screw was simulated, using the method of the ＂∧＂shape crest, the method of above the ＂∧＂shape crest and the method of below the ＂∧＂shape crest, the distance between screw entry point and the pedicle axis was measured, and the anatomic relationship between the upper and lower edges, the internal and the external edges was studied. Differences, advantages and disadvantages of three methods at each segment of lumbar were analysed. Results The anatomic relationship between ＂∧ ＂shape crest and lumbar pedicle was different in the three methods. The distance between ＂∧ ＂shape crest and the pedicle axis was shortest in the median sagittal plane, but was slightly higher than pedicle axis in the L1, and was slightly lower than the horizontal axis in L5 . The Upper ＂∧ ＂ shape crest was located above the pedicle axis. Only in 2 cases Upper ＂∧ ＂ shape crest was lower than the pedicle axis in the L5. Conclusion in the lumbar pedicle screw fixation, ＂∧ ＂shape crest method is safe and reliable, applicable to L1- L5. But in L1 the screw in the median sagittal plane is slightly higher than the pedicle axis, and was slightly lower the axis of the pedicle in L5.