3D打印技术辅助中上胸椎椎弓根置钉的准确性分析

目的评价3D打印技术在中上胸椎"分水岭"区域损伤(T3~7)椎弓根置钉时的应用价值。方法回顾性分析自2013-03—2016-02手术治疗的7例T3~7骨折或脱位。对患者进行薄层CT扫描,采用3D打印技术打印出中上胸椎实体模型,在模型上标定需固定节段的椎弓根钉进钉点(Magerl法),测量每一个节段螺钉的直径、长度、内倾角、头倾(尾倾)角,然后选择合适的椎弓根钉模拟置钉。结果本组共置入56枚椎弓根钉,按目前通行的评估椎弓根钉准确性的方法,在CT平扫的影像上对椎弓根穿透的程度进行分级:0级33枚,1级18枚,2级4枚(穿破外侧壁),3级1枚(穿破外侧壁,未造成不良后果),准确率91.1%。结论对于中上胸椎椎弓根置钉困难的患者,尤其是需要长节段置钉时,可以在3D打印的实体模型上模拟置钉,选择安全、有效的椎弓根钉,提高徒手置钉准确率,缩短了年轻医师的学习曲线。

Application of 3D printing in upper thoracic trauma of watershed area

Objective To evaluate the application value of pedicle screw placement in the upper thoracic trauma(watershed area),by using 3D printing technology.Methods From Mar.2013 to Feb.2016,7 patients with T3-T7 fracture or dislocation were collected in accordance with the inclusive criteria.All the cases were studied through thinner CT scanning,and conducted with preoperative design and simulation operation by using 3D printing models.The entry point of the pedicle screw was marked in the model (Magerl methods),the diameter and length of the screw were chosen,and the intersection angle,cranial angle or caudal angle were measured.Results Total 56 pedicle screws were evaluated by CT scanning,grade 0 in 33,grade 1 in 18,grade 2 in 4 (perforating the lateral wall of pedicle),grade 3 in 1 (perforating the lateral wall of pedicle without adverse consequences),the excellent and good rates were 91.1％.Conclusion In pedicle screw fixation for treatment of middle-upper thoracic vertebra,3D printing technique is an effective assistive technology,which can improve the accuracy of bare-handed screw placement and reduce empirical errors.