Objective To measure posterior cervical structures adopting the picture archiving and communication system (PACS) combined with CT, and provide anatomic data for the cervical pedicle screws placement. Methods Adopting PACS combined with CT skill, the sagittal and transverse slices through the neck of cervical vertebral arch from 2000 cases of the normal adults were measured precisely by 5 spinal surgeons separately. The mean values and standard deviations of the pedicle length, width, height, introversion angle, anteversion angle, and retroversion angle, at the different levels, were collected and statistically analyzed. Results The screw entry-point of atlas was at the midpoint of posterior arch about 17～20 mm laterally. The marrow cavities appeared from C2 to C7 pedicles, and the pedicle heights were more extensive than the pedicle widths from C2 to C7. 3.5 mm screws can be placed into pedicle arches of C3 and C4, despite of their smallest diameters. On the sagittal plane, the superior cervical screw should be tilted cranially, however, inferior cervical screws tilted caudally, with the C4 angle of horizontal direction, C5~7 angles of increasing, and C7 of about -19°. On the transverse planes, screw entry angle of C2 was the smallest, however, inferior entry screw angles were more variable. Conclusions Application of PACS system combined with CT images, the cervical pedicle screws can be inserted more safely, with no complications happened.
Just Accepted