UNASSIGNED: Novel patient-specific single- and multi-level non-covering templates for cervical pedicle screw insertions were designed, 3D-printed, and evaluated.
UNASSIGNED: CT scans of two patients were acquired to reconstruct their 3D spine model. Two sets of single-level (C3-C7) and multi-level (C4-C6) templates were designed and 3D-printed. Pedicle screws were inserted into the 3D-printed vertebrae by free-hand and guided techniques. For single-level templates, a total of 40 screws (2 patients × 5 vertebrae × 2 methods × 2 screws) and for multi-level templates 24 screws (2 patients × 3 vertebrae × 2 methods × 2 screws) were inserted by an experienced surgeon. Postoperative CT images were acquired to measure the errors of the entry point, 3D angle, as well as axial and sagittal plane angles of the inserted screws as compared to the initial pre-surgery designs. Accuracy of free-hand and guided screw insertions, as well as those of the single- and multi-level guides, were also compared using paired t-tests.
UNASSIGNED: Despite the minimal removal of soft tissues, the 3D-printed templates had acceptable stability on the vertebrae during drillings and their utilization led to statistically significant reductions in all error variables. The mean error of entry point decreased from 3.02 mm (free-hand) to 0.29 mm (guided) using the single-level templates and from 5.7 mm to 0.76 mm using the multi-level templates. The percentage reduction in mean of other error variables for, respectively, single- and multi-level templates were as follows: axial plane angle: 72% and 87%, sagittal plane angle: 56% and 78%, and 3D angle: 67% and 83%. The error variables for the multi-level templates generally exceeded those of the single-level templates. The use of single- and multi-level templates also considerably reduced the duration of pedicle screw placements.
UNASSIGNED: The novel single- and multi-level non-covering templates are valuable tools for the accurate placement of cervical pedicle screws.
■设计了用于颈椎椎弓根螺钉插入的新型患者特异性单层和多层非覆盖模板,3D打印,并进行了评估。
■对两名患者进行CT扫描以重建其3D脊柱模型。设计并3D打印了两组单层(C3-C7)和多层(C4-C6)模板。通过徒手和引导技术将椎弓根螺钉插入3D打印的椎骨中。对于单层模板,一位经验丰富的外科医生总共插入了40枚螺钉(2例×5个椎骨×2个方法×2个螺钉)和24枚螺钉(2例×3个椎骨×2个方法×2个螺钉)。术后获取CT图像以测量进入点的误差,3D角度,与最初的手术前设计相比,插入的螺钉的轴向和矢状平面角度。徒手和导向螺钉插入的准确性,以及单层和多层指南,还使用配对t检验进行了比较。
■尽管软组织的去除很少,3D打印的模板在钻孔过程中在椎骨上具有可接受的稳定性,并且它们的使用导致所有错误变量的统计学显着减少。使用单层模板,进入点的平均误差从3.02mm(徒手)降低到0.29mm(引导),使用多层模板从5.7mm降低到0.76mm。其他误差变量的平均值减少百分比,分别,单层和多层模板如下:轴平面角:72%和87%,矢状平面角度:56%和78%,和3D角度:67%和83%。多级模板的误差变量通常超过单级模板的误差变量。单层和多层模板的使用也大大减少了椎弓根螺钉放置的持续时间。
■新颖的单层和多层非覆盖模板是准确放置颈椎椎弓根螺钉的宝贵工具。