Lin Weipeng, Zheng Jianying, Zhang Meichao, Xu Panjie, Xiao Hang, Ji Wei
Department of Orthopaedics, Yunfu People's Hospital, Yunfu, China.
Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Orthop Surg. 2025 Feb;17(2):583-592. doi: 10.1111/os.14314. Epub 2024 Dec 19.
The clivus is trapezoidal in shape with uneven bone structure, the optimal number and position of screws for clival fixation are not clear. Therefore, this study aims to explore the optimization clival screw fixation method for occipitocervical instability using finite element analysis.
Seven finite element models were developed to evaluate biomechanical properties of clival screw fixation for treating occipitocervical stability, including (i) one clival screw fixation A1 and A2 models; (ii) two clival screws fixation B1 and B2 models; (iii) three clival screws fixation C1 and C2 models; (iv) four clival screws fixation D1 model. Loads of 1.5 Nm were applied to the model fRoM different directions to induce flexion, extension, lateral bending, and axial rotation movements.
The regular triangle C1 type three clival screws fixation exhibited great stability, with RoM of 4.20° in flexion, 5.80° in extension, 0.85° in lateral bending, and 1.60° in axial rotation. The peak stress on the internal fixation devices were relatively low, with maximum screw stress of 194 MPa in flexion, 276 MPa in extension, 180 MPa in lateral bending, and 213 MPa in axial rotation; the maximum plate stress were 126, 554, 426, and 378 MPa, respectively. The areas with higher stress were mainly concentrated at the robust neck section of the plate.
The triangular configuration of three clival screws fixation represented the optimized anterior occipitocervical fixation method through the clivus, offering superior biomechanical stability, lower stress on the devices and dispersed stress distribution in the occipitocervical region.
斜坡呈梯形，骨结构不均匀，用于斜坡固定的螺钉的最佳数量和位置尚不清楚。因此，本研究旨在通过有限元分析探索枕颈不稳的斜坡螺钉优化固定方法。
建立七个有限元模型来评估斜坡螺钉固定治疗枕颈稳定性的生物力学特性，包括：（i）一个斜坡单螺钉固定A1和A2模型；（ii）两个斜坡双螺钉固定B1和B2模型；（iii）三个斜坡三螺钉固定C1和C2模型；（iv）四个斜坡四螺钉固定D1模型。从不同方向对模型施加1.5 Nm的载荷，以诱导屈伸、侧弯和轴向旋转运动。
规则三角形C1型三螺钉斜坡固定表现出良好的稳定性，屈伸运动的活动度为4.20°，伸展运动为5.80°，侧弯运动为0.85°，轴向旋转运动为1.60°。内固定装置上的峰值应力相对较低，屈伸时螺钉最大应力为194 MPa，伸展时为276 MPa，侧弯时为180 MPa，轴向旋转时为213 MPa；钢板最大应力分别为126、554、426和378 MPa。应力较高的区域主要集中在钢板的坚固颈部。
三螺钉斜坡固定的三角形构型代表了经斜坡的优化枕颈前路固定方法，具有卓越的生物力学稳定性，装置上的应力较低，且枕颈区域的应力分布分散。
