Three-dimensional analysis of pedicle screw entry point and lateral concave between articular process in lower cervical vertebrae / 中国组织工程研究

ABSTRACT

BACKGROUND: The existing technique takes articular process and lateral mass as a reference mark. Due to differences of subjective judgment in operation and the impact of articular hyperplasia, some errors of screw entry point selection and serious complications such as vertebral artery or cervical spinal cord injury easily occurred, which limit the clinical application of the technique. At present, it is very important to select a constant reference mark of cervical pedicle screw entry point.OBJECTIVE: Three-dimensional reconstruction CT images were made to measure the relationship between the lower cervical pedicle screw entry point and the lateral concave between articular process.METHODS: Three-dimensional reconstruction of CT scan was performed in 30 patients with cervical deformity, and the occurrence rate and morphological characteristics of the lateral concave between articular process were observed. The following parameters were determined on specific reconstructed CT image of C3-C7 (1) the distance between pedicle axis projection point in the posterior surface and the outer edge of lateral mass in transversal section through bilateral pedicle axis and (2) the distance between the point and the lateral concave between articular process in oblique sagittal section through homolateral pedicle axis. Mean value and standard deviation were counted and statistics difference was compared.RESULTS AND CONCLUSION: (1) The lateral concave between articular process in lower cervical vertebrae was a obvious and less constant proliferative anatomical landmark and its occurrence rate was 100%. (2) Using CT technology of 3D reconstruction, C3-C7 lower cervical transversal section through bilateral pedicle axis and oblique sagittal section through homolateral pedicle axis were successfully obtained. (3) In transversal section, the left and right distances between C3-C7 pedicle axis projection point in the posterior surface and the outer edge of lateral mass were (4.1±0.9)mm and (4.3±0.9) mm, and the difference was not statistically significant (P=0.609). Except for C3 and C7, C4 and C7,there was no significant difference in the measured values of the same side (P > 0.05). (4) In oblique sagittal section, the left and right distances between C3-C7 point and the lateral concave between articular process were (-0.3±1.7) mm and (-0.3±1.6) mm, and the difference was not statistically significant (P=0.916). Except for C3 and C4, there was significant difference in the measured values of the same side (P < 0.05). (5) The above results suggest that the lower cervical pedicle entry point and the lateral concave between articular process have a relatively constant orientation relationship in transversal section and a large variation in the sagittal section.