快速成型个体化导航模板辅助颈椎椎弓根螺钉的置入

摘要

BACKGROUND:The cervical pedicle screws provide ideal three-column stability for cervical vertebra, but there is stil no a standard with the choice of pedicle screw place methods in cervical vertebra. Here, we try to seek a simpler, safer and accurate pedicle screw place method.OBJECTIVE:To evaluate the accuracy and security of transpedicular screw placement assisted by rapid prototyping individual navigation template. METHODS:Eight cadaver cervical specimens (C3-6) were selected to take CT-scan and data were saved in DICOM format. Three-dimensional (3D) software MIMICS was used to establish the C3~6 3D model, and designed the best pedicle screw channel. According to the morphological feature of the posterior cervical spine elements, the reverse template was designed. Then, the best pedicle screw channels were fused into bilateral navigation template. The navigation template was manufactured by rapid prototyping, and saved in STL format. Rapid prototyping technology was used to print out the navigation template. Cervical pedicle screws were inserted with the assistance of navigation templates fitted with the posterior structure of the vertebral body. Postoperative X-ray and CT scan were used to evaluate the accuracy of screw placement. RESULTS AND CONCLUSION:(1) Total y 64 screws were inserted with the assistance of individual navigation templates. Of them, 62 screws were completely in the pedicle;1 screw perforated the medial cortex of pedicle;1 screw perforated the lateral cortex of pedicle. Accuracy of screw placement was 97%. (2) The individual navigation template with a high accuracy rate is a feasible and safe method for cervical pedicle screw placement, which has great prospects for clinical application.%背景：颈椎椎弓根螺钉内固定系统治疗颈椎疾病可获得坚强的三柱稳定，但目前关于颈椎椎弓根置钉方法选择尚未达成一致，力求寻找一种更加简单、安全、准确的置钉方法。　　目的：综合利用逆向工程原理和快速成型技术设计出一种新型个体化颈椎椎弓根置钉导航模板，观察并评估其辅助颈椎椎弓根螺钉置入的安全性和准确性。　　方法：对8具成人尸体标本颈椎(C3-6)进行CT扫描获取DICOM数据，MIMICS软件重建颈椎三维模型，寻找颈椎椎弓根的最佳进钉通道。根据颈椎椎板的表面解剖学形态，设计与颈椎椎板相吻合的反向模板。最后将设计的椎弓根螺钉进钉通道和反向模板合成在一起，建立个体化导向模板的数据模型并以STL格式保存。利用快速成型技术打印出导航模板实物。将导航模板与椎体的后部结构贴合，辅助置入颈椎椎弓根螺钉，根据术后X射线片及CT扫描评价椎弓根螺钉位置的准确性。　　结果与结论：①利用导航模板辅助置入颈椎椎弓根螺钉共64枚，62枚螺钉完全在椎弓根内，其中1枚螺钉穿破椎弓根内侧壁，1枚螺钉穿破椎弓根外侧壁，置钉准确性为97%左右；②快速成型个体化导航模板辅助颈椎椎弓根螺钉置入准确率高，增加了颈椎手术的安全性，具有较大的临床应用前景。