Abstract: Objective    To  investigate the feasibility of cortical bone trajectory for cervical anterior transpedicular screw fixation (ATPS) by measuring the anatomical characteristics of lower cervical pedicle. Methods    Eighty sets adult healthy cervical specimens were randomly selected, and the scanned date were imported to the MIMICS 19.0 software. The following parameters in C3~C7 vertebrae: outer pedicle width (OPW) of vertebral body, outer pedicle height (OPH) of vertebral body, medial cortical shell thickness (MCT) of the pedicle, and the cortical bone screw parameters of ATPS were measured and analyzed statistically. Results    There were significant differences in OPH and MCT between two sides of each segment (P<0.05). The OPH and OPW of each segment in males were greater than those of in females, with statistical differences (P<0.05). The entry point for C3 and C4 was 1.0-3.0 mm contralateral to the pedicle in the midsagittal plane of vertebra body, 1.0-3.5 mm from the upper end plate of vertebra body. The C5 entry point was 1.0-2.0 mm ipsilateral or contralateral to the pedicle in the midsagittal plane of vertebra body, 3.0-4.0 mm from the upper end plate of vertebra body. The entry point for C6 and C7 was 2.0-4.5 mm ipsilateral to the pedicle in the midsagittal plane of vertebra body, 4.5-7.0 mm from the upper end plate of vertebra body. At the cortical bone trajectory, the mean values of overall leaning angles from C3 to C7 were 39.13°, 41.00°, 40.91°, 37.28°,and 31.84° respectively, the mean values of overall sagittal angles from C3 to C7 were 90.85°, 97.23°, 108.97°, 111.60°, and 104.83° respectively. For ATPS, the diameters of cortical bone screw was 3.5 mm and the inserted length was 30 mm or 32 mm.    Conclusions   The cortical bone trajectory is a theoretically feasible option for ATPS, and the parameters inserting screw are established, which provides theoretical basis for its further clinical application.

Key words: Cortical bone screw,  ,  , Lower cervical spine,  ,  , Anatomy,  ,  , Pedicle