Fig. 3

The preoperative pedicle transverse angle (PTA) and pedicle-lateral mass angle (PLMA) were measured on the transverse and sagittal CT images, respectively (a, b), and other parameters, including the pedicle height (A), pedicle width (B) and pedicle axis length (C), were also measured (b, c). The PTA referred to the included angle between the pedicle trajectory and the vertical line of the posterior edge of the vertebral body on the transverse CT images, and the PLMA was defined as the included angle between the pedicle trajectory and the posterior edge of lateral mass on the sagittal CT images