A Comparative Study of C2 Pedicle or Pars Screw Placement with Assistance from a 3-Dimensional (3D)-Printed Navigation Template versus C-Arm Based Navigation.

BACKGROUND Since C2 is adjacent to important nerves and blood vessels, the implantation risk of C2 internal fixation in this area is high and requires high accuracy. This study mainly discussed the application value of 3-dimensional (3D)-printed navigation template in C2 screw placement. MATERIAL AND METHODS A retrospective study compared 3D-printed navigation template-assisted screw placement (group A, n=32) and the C-arm based navigation-assisted screw placement group (group B, n=32). Group A was divided into 2 subgroups: A1 (C2 pedicle screw placement) and A2 (C2 pars screw placement); group B was divided into B1 (C2 pedicle screw placement) and B2 (C2 pars screw placement). The accuracy and safety of screw placement and clinical outcomes were evaluated. RESULTS There were 64 C2 screws placed in group A, and 95.31% achieved a grade A accuracy rating, including 52 screws in group A1 (96.15% grade A) and 12 screws in group A2 (91.67% grade A). A total of 64 C2 screws were placed in group B, and 84.38% achieved a grade A accuracy rating, including 50 screws in group B1 (84.00% grade A) and 14 screws in group B2 (85.71% grade A). The accuracy of screw placement differed significantly between groups A and B (=0.041) and between groups A1 and B1 (=0.039) but not between groups A2 and B2 (=0.636). The postoperative efficacy of the 2 groups was satisfactory. And there were no complications of blood vessels or nerves related to screw placement in either group. CONCLUSIONS Although 3D-printed navigation template-assisted and C-arm based navigation-assisted C2 pedicle and pars screw placement provided similar safety and clinical efficacy, 3D-printed navigation template technology achieved more accurate C2 pedicle screw placement.