Zhang Ren-Jie, Wang Jiaqi, Zhou Lu-Ping, Jia Chongyu, Zhang Huaqing, Kang Liang, Shen Cailiang
Department of Orthopedics and Spine Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
Laboratory of Spinal and Spinal Cord Injury Regeneration and Repair, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
Eur Spine J. 2025 Jun 7. doi: 10.1007/s00586-025-09025-2.
This study aims to design novel cortical bone trajectories for the lower thoracic vertebrae that traverse the anterior, middle, and posterior columns. We seek to establish novel theoretical guidelines and placement strategies to optimize the trajectory of CBT screws in osteoporotic patients.
Five different diameters of CBT screws, ranging from 3.5 mm to 5.5 mm, were designed. The tip of the simulated screw was aimed at the anterior half of the vertebral body, with appropriate cephalad and lateral angles. Screw placement was simulated using Mimics software, and key parameters-maximum screw length, cephalad angle, lateral angle, and bone density along the screw path-were measured. We then compared screw placement parameters across different spinal segments and screw specifications, analyzing factors influencing the success of three-column CBT screw placement.
Successful simulation of three-column CBT screw placement in the lower thoracic spine (T9-12) was achieved with a high success rate. As screw diameter increased, the maximum screw length decreased, while cephalad and lateral angles increased. The HU values along the trajectories of the three-column CBT screws were significantly higher than those of traditional thoracic pedicle screw trajectories (p < 0.05). Key factors affecting the success of three-column CBT screw placement were pedicle width and screw diameter.
By adjusting the entry point and modifying the cephalad and lateral angles, the concept of three-column CBT screw fixation can be effectively applied to the lower thoracic vertebrae.
本研究旨在设计用于下胸椎的新型皮质骨轨迹，使其贯穿前柱、中柱和后柱。我们试图建立新的理论指导方针和置入策略，以优化骨质疏松患者的CBT螺钉轨迹。
设计了五种不同直径的CBT螺钉，范围从3.5毫米到5.5毫米。模拟螺钉的尖端瞄准椎体的前半部分，并具有适当的头侧和外侧角度。使用Mimics软件模拟螺钉置入，并测量关键参数——最大螺钉长度、头侧角度、外侧角度以及沿螺钉路径的骨密度。然后我们比较了不同脊柱节段和螺钉规格的螺钉置入参数，分析影响三柱CBT螺钉置入成功的因素。
成功模拟了下胸椎（T9 - 12）的三柱CBT螺钉置入，成功率较高。随着螺钉直径增加，最大螺钉长度减小，而头侧和外侧角度增加。三柱CBT螺钉轨迹沿线的HU值显著高于传统胸椎椎弓根螺钉轨迹（p < 0.05）。影响三柱CBT螺钉置入成功的关键因素是椎弓根宽度和螺钉直径。
通过调整进针点并修改头侧和外侧角度，三柱CBT螺钉固定的概念可有效应用于下胸椎。
