Postgraduate School, Dalian Medical University, Dalian, 116000, Liaoning, China.
Department of Orthopedics, Hospital Affiliated 5 to Nantong University (Taizhou People's Hospital), Taizhou, 225300, Jiangsu, China.
BMC Surg. 2022 Mar 14;22(1):96. doi: 10.1186/s12893-022-01548-5.
From a biomechanical point of view, pedicle screws (PS) are better than other kinds of screws for implantation in the seventh cervical vertebra (C7). However, the application of PS is limited because of the high risk of severe complications. It is essential to define the optimal entry point and trajectory. The aim of this study was to comprehensively analyze the starting point and trajectory for C7 PS insertion using three dimensional (3D) models.
Overall, 60 subjects aged 18 to 67 years old were included. All CT images were used to construct 3D computer models of the C7 vertebrae. A new coordinate system was established for the next evaluation. The pedicle axis was calculated with respect to the entire pedicle; then, the ideal entry point, screw diameter and length, sagittal angle and lateral angle were assessed.
All the ideal entry points were located at the medial superior to lateral notch (LN), and the mean distance between the entry point and LN was 5.86 ± 1.67 mm in the horizontal direction and 3.47 ± 1.57 mm in the vertical direction. The mean distance between the entry point and the middle point of the inferior edge of the C6 articular process (MP) was 0.74 ± 1.83 mm in the horizontal direction. The mean sagittal angle of the pedicle axis was 90.42°, and the mean pedicle transverse angle was 30.70°. The average diameter and length of the PS were 6.51 ± 0.76 mm and 31.58 ± 4.40 mm, respectively.
This study provided a novel method to calculate the ideal starting point and trajectory for C7 PS insertion. These measurements may be helpful for preoperative planning. It is recommended that 3D CT imaging is used preoperatively to carefully evaluate the anatomy of each individual.
从生物力学的角度来看，椎弓根螺钉（PS）在第七颈椎（C7）植入物中比其他类型的螺钉更好。然而，由于严重并发症的风险较高，PS 的应用受到限制。确定最佳的进钉点和进钉轨迹至关重要。本研究旨在通过三维（3D）模型全面分析 C7 PS 插入的起点和轨迹。
总共纳入了 60 名 18 至 67 岁的受试者。所有 CT 图像均用于构建 C7 椎体的 3D 计算机模型。为下一步评估建立了新的坐标系。根据整个椎弓根计算椎弓根轴，然后评估理想的进钉点、螺钉直径和长度、矢状角和侧方角。
所有理想的进钉点均位于内上至外下切迹（LN），进钉点与 LN 的水平距离为 5.86±1.67mm，垂直距离为 3.47±1.57mm。进钉点与 C6 关节突下缘中点（MP）的水平距离为 0.74±1.83mm。椎弓根轴的平均矢状角为 90.42°，横突角为 30.70°。PS 的平均直径和长度分别为 6.51±0.76mm 和 31.58±4.40mm。
本研究提供了一种计算 C7 PS 插入理想进钉点和进钉轨迹的新方法。这些测量值可能有助于术前规划。建议术前使用 3D CT 成像仔细评估每个个体的解剖结构。
