Abstract: Objective    To measure the imaging indexes of C_2/3 transarticular transpedicular screw, and analyze the feasibility of this screw placement technique.    Methods   The CT data of 120 thin slice CT scan were collected, including 75 males and 45 females. The entry point of the C2/3 transarticular transpedicular screw was set, that is, the entry point was at the intersection of the horizontal midline and the mid-lateral 1/3 vertical line of the lateral mass of the axis. The screw passed through the facet joint of C_2/3 and the C3 lateral mass, from the lateral mass of the axis, and ended at the inferior edge of the pedicle of C3. The imaging data of C_2/3 transarticular transpedicular screw were measured, including C3 pedicle width and height, screw channel length, introversion angle, head tilt angle and the narrowest width. The relationship between the measurement results was analyzed.    Results    The average width of C₃ pedicle was 5.48mm, the average height was 6.82 mm, the average screw channel length was 18.68mm, the average introversion angle of screw channel was 20.46 °, the average head tilt angle was 50.1°, and the average width of the narrowest part was 2.80 mm. There was a positive correlation between C3 pedicle width and height (P=0.000). The length of screw channel was positively correlated with C₃ pedicle width and height (P=0.000; P=0.000 ). The width of the narrowest part of screw channel was positively correlated with C₃ pedicle width and height (P=0.000；P=0.000). In the measurement data of 240 cases, the screw placement could be completed if 3.5 mm diameter screws were used, and the screw was suitable for all patients.  Conclusions   C_2/3 transarticular transpedicular screw is anatomically feasible and can be used as a supplementary technique for posterior screw rod internal fixation of upper cervical spine.

Key words:  Axis； ,  , Imaging measurement； ,  , C_2/3 transarticular transpedicular screw