为了对比腰椎改良皮质骨轨迹（modified cortical bone trajectory, MCBT）置钉技术中应用骨水泥增强新型变径皮质骨螺纹螺钉与椎弓根螺钉技术采用传统骨水泥强化螺钉（cement augmented pedicle screw instrumentation, CAPS）两者之间的力学性能差异。通过获取骨质疏松症病人的电子计算机断层扫描（computed tomography, CT）扫描数据建立L4椎体有限元模型，分别在L4椎体模型中完成骨水泥强化椎弓根螺钉的置钉以及改良皮质骨轨迹置钉。运用有限元方法比较采用不同螺钉技术的上、下、左、右4种工况的稳定性、螺钉轴向抗拔出力以及腰椎活动度。结果表明：轻、中、重度3种骨质疏松条件下，骨水泥MCBT在轴向抗拔出力、螺钉的上、下、左、右工况、椎体前屈、后屈的稳定性略优于CAPS，在左侧弯、右侧弯、轴向旋转工况稳定性弱于CAPS。此次研究结果论证了骨水泥MCBT相比CAPS有一定的优势，为骨水泥MCBT在骨质疏松症临床应用提供了前期基础。

In order to compare the difference in mechanical properties between the application of cementenhanced new variable-diameter cortical bone screws in the lumbar modified cortical bone trajectory nailing technique and the use of conventionalcement-enhanced screws in the pedicle screw technique. A finite element model of the L4 vertebral body was established by obtaining the CT(computed tomography) scan data of osteoporosis patients, and the cement-reinforced pedicle screws and the modified cortical bone trajectory nailing were accomplished in the L4 vertebral body model, respectively. The finite element method was used to compare the stability, screw axial pullout force, and lumbar spine mobility in the upper, lower, left, and rightworking conditions using different screw techniques. The results showed that under mild, moderate, and severe osteoporosis, the stability of cemented MCBT was slightly better than that of CAPS in terms of axial pullout force, screws in the upper, lower, left, and right working conditions, and vertebral anterior flexion and posterior flexion, and weaker than that of CAPS in terms of left lateral curvature, right lateralcurvature, and axial rotation working conditions. The results show that the cemented MCBT has some advantages over CAPS, and it provides a good basis for the clinical application of cemented MCBT in the osteoporosis clinic