Tian Wei, Lang Zhao, Liu Ya-Jun, Liu Bo, Li Qin, Hu Lin, Li Zhi-Yu, Yuan Qiang, He Da, Cheng Xiao-Guang, Sun Yu-Zhen
Department of Spine Surgery, Beijing Jishuitan Hospital, Beijing 100035, China.
Zhonghua Wai Ke Za Zhi. 2010 Jun 1;48(11):838-41.
To evaluate the effect of axial rotation of lumbar vertebrae on the accuracy of pedicle screw placement using the traditional method, as well as to assess the value of intraoperative three-dimensional (3D) navigation in improving the accuracy.
Sixteen lumbar simulation models at different degrees of axial rotation (0°, 5°, 10° and 20°), with every four assigned with the same degree, were equally divided into two groups (traditional method group and intraoperative 3D navigation group). Random placement of pedicle screws was carried out, followed by CT scan postoperatively. Then the outer pedicle cortex contours were depicted from reconstructed sectional pedicle images using Photoshop. The accuracy of pedicle screw placement was evaluated by determining the interrelationship between screw trajectory and pedicle cortex (qualitative) and measuring the shortest distance from pedicle screw axis to outer cortex of the pedicle (quantitative).
Eighty pedicle screws were implanted respectively in each group. In traditional method group, statistical difference existed in the accuracy of pedicle screw placement at different axial rotational degrees (P < 0.05). With degrees increasing, the accuracy declined. The accuracy of intraoperative 3D navigation group was higher than traditional method group in vertebrae with axial rotation (P < 0.01). In qualitative evaluation, the accuracy of the two methods had statistical difference when the degree was 20°, and in quantitative evaluation, statistical difference existed in 5°, 10° and 20° of vertebral axial rotation.
Screw malposition can be caused by vertebral axial rotation in lumbar spine using traditional method. Accuracy of pedicle screw placement declines with the increase of axial rotational degrees. However, the accuracy can be improved by using intraoperative 3D navigation.
评估腰椎轴向旋转对采用传统方法置入椎弓根螺钉准确性的影响，以及评估术中三维（3D）导航在提高准确性方面的价值。
制作16个不同程度轴向旋转（0°、5°、10°和20°）的腰椎模拟模型，每种程度4个，将其平均分为两组（传统方法组和术中3D导航组）。随机置入椎弓根螺钉，术后进行CT扫描。然后使用Photoshop从重建的椎弓根断层图像描绘椎弓根外侧皮质轮廓。通过确定螺钉轨迹与椎弓根皮质之间的相互关系（定性）以及测量椎弓根螺钉轴线到椎弓根外侧皮质的最短距离（定量）来评估椎弓根螺钉置入的准确性。
每组分别植入80枚椎弓根螺钉。在传统方法组中，不同轴向旋转程度下椎弓根螺钉置入的准确性存在统计学差异（P<0.05）。随着旋转程度增加，准确性下降。在有轴向旋转的椎体中，术中3D导航组的准确性高于传统方法组（P<0.01）。在定性评估中，当旋转程度为20°时，两种方法的准确性存在统计学差异；在定量评估中，则在椎体轴向旋转5°、10°和20°时存在统计学差异。
使用传统方法时，腰椎椎体轴向旋转可导致螺钉位置不当。椎弓根螺钉置入的准确性随轴向旋转程度的增加而降低。然而，术中使用3D导航可提高准确性。
