The applied value of 3D printed navigational guiding template in pedicle screw placement

English Keywords:Atlantoaxial vertebrae  Pedicle screw  3 dimensional printing model  Computer-assisted  Rapid prototyping technology

English Abstract:

  【Abstract】 Objectives: To investigate the applied value of 3D printed navigational guiding template in pedicle screw placement. Methods: From June 2013 to October 2015, data from 43 cases who had undergone opening reduction and internal fixation of atlantoaxial vertebra with pedicle screw placement were retrospectively analyzed. All the patients were divided into 3D printed navigational guiding template assisting pedicle screw placement group and traditional pedicle screw placement group. The accuracy of screw channel was evaluated by comparing differences of preoperative and postoperative indexes in 2 groups. The comparisons of operation time, intraoperative blood loss, the number of intraoperative fluoroscopy, the accuracy and the time of screw placement were performed. Besides, cervical spine visual analogue score(VAS) and spinal function score of Japanese Orthopedic Association(JOA) were also compared between the two groups. In addition, postoperative trajactories of pedicle screws were measured after the positions of preoperative and postoperative 3D atlantoaxial models in a redefining coordinate. Briefly, all the 19 patients in 3D printed navigational guiding template group had preoperatively performed CT scanning and the data were imported into Mimics 17.0 software. Afterward, the 3D models of cervical vertebrae were reconstructed and the optimal trajectory of virtual navigational template with guiding hole was established. After navigational template was manufactured by 3D printing and sterilizing, it was used to assist with the placement of pedicel screw intraoperatively. Results: There were no significant differences in general data of the two groups which included age, sex, clinical diagnosis, lesion segment, complication and proportion of preoperative traction and reduction(P＞0.05). All the 19 patients in 3D printed navigational guiding template group were totally placed 68 pedicle screws, with the accuracy of 94.1%, pedicle screw placement time was 2.2±0.4min, operation time was 197±41min, intraoperative blood loss was 395±64ml and intraoperative fluoroscopy number was 4.6±1.1 times. All the 24 cases in traditional pedicle screw placement group were placed 76 pedicle screws, with the accuracy of 76.3%, pedicle screw placement time was 3.4±0.7min, operation time was 245±67min, intraoperative blood loss was 552±79ml and intraoperative fluoroscopy number was 9.4±2.7 times. The differences between parameters mentioned above were all significant(P<0.05). The trajactories of pedicle screws in 3D printed navigational guiding template group had significant better results than those in traditional pedicle screw placement group(P<0.05). VAS and JOA scores of 3 days, 6 months and 12 months postoperatively were significantly improved compared with preoperative data(P<0.05), while VAS and JOA scores of postoperative 6 months and 12 months were of no significant differences between the two groups(P>0.05). Conclusions: The assistance of 3D printed navigational guiding template in guiding atlantoaxial pedicle screw placement can significantly increase the accuracy of atlantoaxial pedicle screw placement and reduce the time of screw placement, operation time, intraoperative blood loss and the number of intraoperative fluoroscopy.