Spiral CT measurement for atlantoaxial pedicle screw trajectory and its clinical application

This study aimed to focus on the atlantoaxial pedicle screw placement and evaluate the effects of anatomical data and degree of surgical exposure of the atlantoaxial pedicle screw trajectory determined using spiral CT on the reference sites for pedicle screw insertion and various parameters in clinical application.

The data of CT scan of cervical spine from individuals treated in our hospital were selected. Various anatomical parameters of the atlantoaxial pedicle screw trajectory were measured through multiplanar reconstruction (MPR) technology. Anatomical data and degree of surgical exposure of the atlantoaxial pedicle screw trajectory were obtained through spiral CT. Vernier calipers with least count of 0.01 mm was selected and the least count of the protractor was 0.2°. Prism 8.0 was adopted for graphical data analysis. The anatomical data of atlas of the local population were established. The measurement technique for pedicle screw trajectory and the method for pedicle screw insertion were mastered.

The results indicated that the intraoperative blood loss was between 30-280 ml with no case of excessive blood loss. Follow-up studies 10-18 months after the operations indicated stability of upper cervical spine without adverse conditions. The width of the pedicle screw was 13-24 mm, and the maximal inclination angle of the horizontal for the insertion was 17-21°.

The atlantoaxial pedicle screw placement was an effective surgical treatment for stabilizing the upper cervical spine. The measurement data of the atlantoaxial pedicle screw path was obtained through spiral CT and the surgical placement of pedicle screw was guided through individual data. Postoperative CT scan was adopted to evaluate the accuracy of pedicle screw placement, record the occurrence of secondary injuries, improve the stability of clinical applications, and reduce the risks for patients.