Transpedicular screw placement in the cervical vertebrae assisted by rapid prototyping individual navigation template

Zhang Zhen-hui; Wang Qing-de; Mei Wei; Mao Ke-zheng; Zhu Yao-hui; Guo Run-dong; Jiang Wen-tao; Liu Pei-lin; Wang Zhong-wei

doi:10.3969/j.issn.2095-4344.2017.03.003

Abstract：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.