Digital screw path analog measurement of C4-6 posterior fixation parameters in adolescents aged 12-14 years and its clinical significance / 中国组织工程研究

ABSTRACT

BACKGROUND: For recent decades, there has been a younger tendency in age of occurrence of the cervical spondylosis, and posterior fusion is the main method for cervical degeneration and injury, but no relevant fixation parameters are available in clinical practice for adolescents. OBJECTIVE: To measure the anatomical parameters of C4-6posterior fixation in the adolescents aged 12-14 years after three-dimensional reconstruction. METHODS: Twenty-one adolescents aged 12-14 years, who underwent cervical examination at the Affiliated Hospital of Inner Mongolia Medical University and Department of Orthopedics of the Second Hospital of Ulanqab between January 2014 and December 2016 were randomly selected, and the CT data of the C4-6were collected, and then imported into Mimics16.01 software for three-dimensional reconstruction. We measured the anteroposterior and transverse diameters and the heights of the vertebral body, anteroposterior and transverse diameters of the transverse foramina, angles of the left and right pedicle axes to sagittal and horizontal axes, and left and right pedicle axis lengths. RESULTS AND CONCLUSION: (1) Both anteroposterior and transverse diameters of the transverse foramina were increased with vertebral level incveasing. Both angles of pedicle axis to sagittal and horizontal axes, and pedicle axis lengths were increased with vertebral level. The anteroposterior diameter of the vertebral body at C4-6was in the range of 6.0-8.0 mm, the transversal diameter was in 25.0°-30.0°, the angle between the posterior screw and the horizontal axis was 29.0°-35.0°; in the sagittal plane, the angle to the sagittal axis was no more than 5°; and the pedicle screw path length was in 6-7 mm. (2) These results show the anatomical parameters of C4-6posterior fixation in the adolescents aged 12-14 years are successfully obtained by three-dimensional reconstruction.