ABSTRACT
BACKGROUND:In recent years,cervical facet joints have been paid more and more attention to the pathogenesis and surgical treatment of cervical spondylosis,but there are few anatomical studies on adult lower cervical facet joints. OBJECTIVE:To measure three-dimensional parameters of the lower cervical facet to provide a basis for the design of the lower cervical transarticular facet screw guide. METHODS:From June 2021 to June 2022,100 cases receiving cervical spine CT examination in the Affiliated Hospital of Xuzhou Medical University were selected,with 50 males and 50 females,aged 20-50 years.After screening,each image showed no cervical spinal stenosis,cervical disc herniation,obvious bone hyperplasia,infection or tumor.The sagittal inclination angle of each segment of the cervical spine facet joint and the angle between the lower cervical spine facet joint surface and the transarticular facet joint screw at the C3-7 levels were measured after 3D reconstruction.According to the measurement results of statistical analysis,a lower cervical transarticular facet screw guide was designed using CAD software. RESULTS AND CONCLUSION:The inclination angle of the cervical facet joint surface on the sagittal plane was distributed in a U-shaped shape centered on C5,and the magnitude relationship was C7>C6>C3>C4>C5.The relationship between transarticular facet screw angles on the sagittal plane was:C6/7>C5/6>C4/5>C3/4,where the angle of C3/4,C4/5 and C5/6 was close to 90°,and the angle of C6/7 exceeded 100°.By measuring the sagittal inclination angle of the cervical facet joint and the angle of the transarticular facet screw,this study designed a guide that was perpendicular to the lower cervical facet joint surface in the sagittal plane.
ABSTRACT
OBJECTIVE: Transarticular facet screws restore biomechanical stability to the cervical spine when posterior cervical anatomy has been compromised. This study compares the more recent, less invasive, and briefer transarticular facet screw system without rods with the lateral mass screw system with rods. METHODS: For this study, 6 human cervical spines were obtained from cadavers. Transarticular facet screws without rods were inserted bilaterally into the inferior articular facets at the C5-C6 and C5-C6-C7 levels. Lateral mass screws with rods were inserted bilaterally at the same levels using Magerl's technique. All specimens underwent range of motion (ROM) testing by a material testing machine for flexion, extension, lateral bending, and axial rotation. RESULTS: Both fixation methods, transarticular facet screws without rods and lateral mass screws with rods, reduced all ROM measurements and increased spinal stiffness. No statistically significant differences between the 2 stabilization methods were found in ROM measurements for 1-level insertions. However, in 2-level insertions, ROM for the nonrod transarticular facet screw group was significantly increased for flexion-extension and lateral bending. CONCLUSIONS: Transarticular facet screws without rods and lateral mass screws with rods had similar biomechanical stability in single-level insertions. For 2-level insertions, transarticular facet screws without rods are a valid option in cervical spine repair.