枢椎椎弓根螺旋CT多平面重建及其临床意义

APPLICATION OF MULTI-PLANAR RECONSTRUCTION TECHNIQUE OF SPIRAL CT AND ITS CLINICAL SIGNIFICANCE IN AXIS PEDICLES

目的 :探讨后路枢椎螺钉固定术患者术前个体化CT评估的螺旋CT技术及其临床价值。方法 :寰枢椎正常解剖关系下 ,5具成人干骨标本薄层 (1mm)螺旋CT扫描 ,并收集 10例上颈椎正常成人螺旋CT资料 ,均 1mm层厚多平面重建 (MPR)C2 椎弓根部图像 ,分析不同重建方式显示解剖结构的状况 ,及术前个体化CT评估可行性和安全性中的价值 ,并拟行钉道设计。 5具已CT评估的干骨标本示范后路行寰枢经关节螺钉固定及一侧钻孔设置经枢椎椎弓根钉道 ,同前方法CT扫描并重建图像 ,分析钉道。结果 :C2 椎弓根轴的垂直断面 (称斜冠状面 )相、经C2椎弓根轴的斜矢状面相及斜横断面相、枢椎标准横断面相共同构成后路枢椎螺钉固定术术前个体化CT评估的理想三维断面影像 ,可观察C2 椎弓根形态、骨质状态及与邻近结构的关系 ,准确测量枢椎椎弓根的大小、走行方向。根据这些三维影像可进行后路枢椎螺钉固定手术可行性及安全性分析。结论 :枢椎CT常规冠状、矢状面重建不能满足后路枢椎螺钉固定术前CT评估的需要 ,需多平面重建方可更准确术前CT评估 ,进行术前三维钉道设计。

Objective:To study the application of spiral-CT multi-planar reconstruction technique on the preoperative and personalized CT evaluation of the posterior axis screw fixation and to evaluate its clinical value. Method: Spiral-CT thin(1mm) axial slices scanning with multi-plannar reconstruction (MPR) through the C 2 pedicles was performed of 5 dry axis bones and the bones of to adults, including the routine sagittal and coronal planes, and additional oblique-sagittal, oblique-coronal and oblique-axial planes. Then, images of the C 2 pedicles were analyzed to find the value of MPR for the CT evaluation. The design of an ideal and safc screw trajectory was also carried out. 5 dry axis bones were operated on with bilateral atlantoaxial transarticular screw fixation and left C 2 transpedicular screw fixation. Then, spiral-CT scanned them, and the images were reconstructed in the multi-planes. The screw trajectories in the C 2 pedicles and lateral masses were surveyed. Result: The CT images of C 2 pedicles reconstructed through axial plane, oblique-axial plane, oblique-sagittal and oblique-coronal planes were valuable for the preoperative and personalized CT evaluation of posterior axis screw fixation technique. The C 2 pedicles could be accurately measured from these images. An ideal and safe screw trajectory could be designed with the three-dimensional images. Conclusion: The multi-planar reconstruction technique is required before a preoperative and personalized CT evaluation of posterior axis screw fixation. It can be used to design an ideal and safe screw trajectory before operation.