| Objective To observe the advantages of computer-assisted anterior axis pedicle screw (AAPS) placement, and to measure the maximum pullout force of AAPS, pedicle screw and vertebral body screw (VBS), and to provide biomechanical theoretical basis for selecting appropriate internal fixation type during clinical operations. Methods From October 2019 to January 2021, 16 antiseptic specimens of human cervical vertebrae were collected. There was 1 abnormal specimen. The remaining 15 specimens were from 10 males and 5 females. After CT scanning, the data were imported into Mimics software to form a three-dimensional reconstruction image and observed. Refer to Kolle method, anterior pedicle screw, posterior pedicle screw and anterior vertebral body screw were used to fix each axis. The maximum pullout force of each fixation method was tested on a biomechanical testing machine. Results The three-dimensional reconstruction image in Mimics software could directly observe and understand the structure from any perspective. The maximum axial pullout force of AAPS group was (635.95±220.35) N, the maximum axial pullout force of the posterior pedicle screw group was (772.95±230.55) N, and the maximum axial pullout force of the VBS group was (451.45±181.13) N. Using paired sample t test, the maximum axial pullout force of the AAPS group and the posterior pedicle screw group, as well as the AAPS group and the VBS group, were statistically different (P<0.05). It was shown that under monocortical fixation, the pullout force of posterior pedicle screw was larger than that of AAPS, and that of AAPS was larger than that of VBS. Conclusion It is helpful to understand the structural characteristics of the axis and to individualize the operation of AAPS. AAPS has good fixation performance and obvious biomechanical advantages. It can be used as an ideal method for surgical internal fixation. |
