Clinical study of C2 pedicle screw placement in patients with high-riding vertebral artery assisted by 3D-printed navigation template

English Keywords:High-riding vertebral artery  3D-printed navigation template  Freehand technology  C2 pedicle screw  Accuracy

English Abstract:

  【Abstract】 Objectives: To investigate the accuracy and safety of 3D-printed navigation template-assisted C2 pedicle screw(C2PS) placement in patients with high-riding vertebral artery. Methods: A retrospective study was performed on 72 patients with high-riding vertebral artery who underwent posterior internal fixation of upper cervical spine in our hospital from January 2018 to December 2018. According to the different placement methods of C2PS, they were divided into two groups: navigation template group(n=36), and freehand group(n=36). There were no significant difference in age, gender, body mass index(BMI) and disease type between the two groups(P>0.05). The single C2PS placement time, operation time, fluoroscopy time, intraoperative blood loss, operation-related complications, operation cost, hospitalization time, VAS scores and cervical JOA scores preoperatively and at 3 and 6 months postoperatively in the two groups were recorded and compared. The accuracy of C2PS placement was evaluated according to the screw classification standard proposed by Kawaguchi et al. And the deviation angles of C2PS in sagittal plane and cross section were recorded. Results: The C2PS placement time, operation time and fluoroscopy time in navigation template group were significantly better than those in freehand group(P<0.05), and the technical cost in freehand group was significantly lower than that in navigation template group(P<0.05). There were no significant difference in intraoperative blood loss and hospitalization time between the two groups(P>0.05), the VAS and JOA scores at 3 days and 6 months postoperatively were significantly improved compared with the preoperative scores(P<0.05) but did not differ significantly between the 2 groups(P>0.05). 42 and 43 C2 pedicle screws were placed in navigation template group and freehand group, respectively, The accuracy(grade 0+grade 1) was 95.2% and 72.1%, respectively. Deviation sagittal in the two groups were 0.52°±0.42°, 2.21°±0.69°, respectively. And deviation transversal were 0.51°±0.36°, 2.16°±0.77°, respectively. The accuracy, screw deviation angle of navigation template group were better than those of freehand group(P<0.05). Complications: four vertebral artery injuries(0 in navigation template group, 4 in freehand group). There were no screw loosening, broken screw or broken rod in all patients after surgery. Conclusions: In patients with HRVA, 3D-printed navigation template and freehand technology-assisted C2PS placement can provide similar clinical efficacy, but in terms of the accuracy of screw placement, navigation template technology is more dominant, and it can significantly shorten the time of screw placement, fluoroscopy time and reduce the complications of operation.