[寰枢椎椎弓根螺钉内固定个体化钻孔模板的设计与实验研究]

[Design and experimental study of individual drill templates for atlantoaxial pedicle screw fixation].

作者信息

Qin Wei, Quan Zhengxue, Liu Yang, Ou Yunsheng

机构信息

Department of Orthopedics, First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, PR China.

出版信息

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Oct;24(10):1168-73.

PMID:21046800

Abstract

OBJECTIVE

To explore and evaluate the accuracy and feasibility of individual rapid prototype (RP) drill templates for atlantoaxial pedicle screw implantation.

METHODS

Volumetric CT scanning was performed in 8 adult cadaveric atlas and axis to collect Dicom format datas. Then three-dimensional (3D) images of atlas and axis were reconstructed and the parameters of pedicles of 3D model were measured by using software Mimics 10.01. The 3D model was saved by STL format in Mimics. The scattered point cloud data of 3D model were processed and the 3D coordinate system was located in software Imageware 12.1. The curves and surfaces of 3D model were processed in software Geomagic Studio 10. The optimal trajectory of pedicle screw was designed and a template was constructed which accorded with the anatomical morphology of posterior arch of atlas and lamina of axis by using software Pro/Engineer 4.0. The optimal trajectory of pedicle screw and the template were integrated into a drill template finally. The drill template and physical models of atlas and axis were manufactured by RP (3D print technology). The accuracy of pilot holes of drill templates was assessed by visually inspecting and CT scanning.

RESULTS

The individual drill template was used conveniently and each template could closely fit the anatomical morphology of posterior arch of atlas and lamina of axis. Template loosening and shifting were not found in the process of screw implantation. Thirty-two pedicle screws were inserted. Imaging and visual inspection revealed that the majority of trajectories did not penetrate the pedicle cortex, only 1 cortical penetration was judged as noncritical and did not injury the adjacent spinal cord, nerve roots, and vertebral arteries. The accuracy of atlas pedicle screw was grade 0 in 15 screws and grade I in 1 screw, and the accuracy of axis pedicle screw was grade 0 in 16 screws.

CONCLUSION

The potential of individual drill templates to aid implantation of atlantoaxial pedicle screw is promising because of its high accuracy.

摘要

目的

探讨并评估个体化快速成型（RP）钻孔模板在寰枢椎椎弓根螺钉植入术中的准确性和可行性。

方法

对8具成人尸体的寰椎和枢椎进行容积CT扫描，收集Dicom格式数据。然后重建寰椎和枢椎的三维（3D）图像，并使用Mimics 10.01软件测量3D模型椎弓根的参数。在Mimics中以STL格式保存3D模型。在Imageware 12.1软件中处理3D模型的散点云数据并定位3D坐标系。在Geomagic Studio 10软件中处理3D模型的曲线和曲面。使用Pro/Engineer 4.0软件设计椎弓根螺钉的最佳轨迹，并构建符合寰椎后弓和枢椎椎板解剖形态的模板。最终将椎弓根螺钉的最佳轨迹和模板整合到一个钻孔模板中。通过RP（3D打印技术）制造钻孔模板以及寰椎和枢椎的物理模型。通过目视检查和CT扫描评估钻孔模板导向孔的准确性。

结果

个体化钻孔模板使用方便，每个模板都能紧密贴合寰椎后弓和枢椎椎板的解剖形态。在螺钉植入过程中未发现模板松动和移位。共植入32枚椎弓根螺钉。影像学和目视检查显示，大多数轨迹未穿透椎弓根皮质，仅1例皮质穿透被判定为非关键性且未损伤相邻脊髓、神经根和椎动脉。15枚寰椎椎弓根螺钉的准确性为0级，1枚为I级，16枚枢椎椎弓根螺钉的准确性为0级。