Abstract: BACKGROUND: The anterior transpedicular screw fixation system can achieve adequate decompression and strong fixation in a single anterior surgery. However, due to its unique anatomical structure, the risk of screw placement is relatively high. Previous domestic and international scholars have confirmed the feasibility of this approach through anatomical measurements, but there are some drawbacks such as relatively small sample sizes, difficulties in locating the pedicle axis, and limitations in measurement methods.
OBJECTIVE: To perform morphological measurements of the adult cervical spine based on imaging to provide anatomical guidance for anterior transpedicular pedicle screw fixation.
METHODS: 3D CT scan data of 50 adult cervical vertebrae were imported into the Mimics system for 3D reconstruction. Morphological data were measured, including pedicle axis distance, pedicle width, pedicle height, pedicle horizontal axial angle, pedicle sagittal angle, distance from the entry point in the transverse plane, distance to the entry point in the sagittal plane, axial vertebral length and axial pedicle length. 
RESULTS AND CONCLUSION: (1) Positioning of nail entry points: C3 and C4 were located on the opposite side of the median sagittal plane of the vertebral body, with distances from the median sagittal line of approximately 2.060 mm and 2.310 mm. C5 could be located on the same side of the median sagittal line as or opposite to the median sagittal line, with an average value of approximately 1.224 mm. C6-C7 were located on the same side of the body, with distances from the center of the vertebral body of 1.132 mm and 2.538 mm; the distances of C3-C7 from the vertebral body of the upper endplates increasd gradually, with average values ranging from 2.362-7.350 mm. (2) In the direction of the entry point, the cross-sectional pinch angles: C3-4 gradually increased to 46.32°-47.36°, and C5-7 gradually decreased from 44.03° to 37.80°; the sagittal pinch angles: C3-C4 needed to be shifted caudally, with the angles of 95.75° and 100.93°; C5-C7 angles needed to be shifted toward the cephalad, with angles of 104.38°, 110.34°, and 104.86°, respectively. (3) There was no statistical significance in the positioning and orientation of the entry point between genders and sides 
(P > 0.05). For screw selection, except for individual patients with abnormal cervical vertebral development, the vast majority of the lower cervical pedicle screws were selected to be at least 30-mm-long, 4.0-mm-diameter screws for males, and at least 28-mm-long, 3.5-mm-diameter screws for females for anterior transpedicular pedicle screw fixation, which could ensure their safety and reliability while to achieve bicortical screws. (4) Morphological measurements confirm that anterior transpedicular screw fixation of the lower cervical spine is feasible, but a personalized fixation plan should be developed based on individual needs.

Key words: ">anterior cervical spine, transpedicular screw fixation, Mimics, three-dimensional reconstruction, cervical spine, internal fixation, morphological measurement