The impact of transverse angle on the shape of ideal cervical pedicle screw

Objective To explore the effects of transverse angle on the shape of ideal cervical pedicle screw by computed tomography (CT) three-dimensional reconstruction technology. Methods A total of 60 cases were performed CT scan,the ideal lengths and widths of cervical pedicle screw at transverse angle from 10° to 60° were measured by three-dimensional reconstruction technology. Results The ideal lengths and widths of the cervical pedicle screw from C3 to C7 increased to the peak and then diminished gradually at transverse angle from 10° to 60°. In C3～C6,the peak values of the widths of cervical pedicle screw were (4.3± 0.7),(4.4±0.7),(4.8±0.8) and (5.3±0.9)mm at the transverse angle of 50° respectively,and (6.3±0.9)mm in C7 at the transverse angle of 30°. In C3～C7,the peak values of the lengths of cervical pedicle screw were (30.2±2.1),(29.6±2.0),(30.6±2.5),(31.7±2.5) and (31.7±2.0)mm at the transverse angle of 40° respectively. Conclusions Measuring the ideal widths and lengths of cervical pedicle screw at different transverse angles by CT three-dimensional reconstruction technology is helpful to understand the changes of ideal cervical pedicle screw shape,having an important impact on selection of the angles and the shapes of cervical pedicle screw.