不同直径椎弓根螺钉的应力分布研究：三维有限元分析。
Study of stress distribution in pedicle screws along a continuum of diameters: a three-dimensional finite element analysis.
机构信息
Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
出版信息
Orthop Surg. 2011 Feb;3(1):57-63. doi: 10.1111/j.1757-7861.2010.00112.x.
OBJECTIVE
To create a three-dimensional finite element model to identify the biomechanically optimal diameter of pedicle screws for placement in L1 vertebral bone.
METHODS
The effects of pedicle screws with different diameters on the maximum Von Mises stress in L1 vertebra bone were evaluated by a finite element method. Pedicle screw diameters ranging from 4.0 to 6.5 mm were assessed.
RESULTS
The simulation showed that, under axially oriented pullout forces, stress was decreased in all models when the diameter of screws was in the range of 4.0 mm to 6.5 mm. With a standard external load and a 6.5 mm diameter screw, load transferred to cortical and cancellous bone was reduced by 47.24% and 34.28%, respectively, and displacement of the screw was reduced by 21.35%. When the diameter was ≥5.0 mm, the variable of stress was stable in all models.
CONCLUSION
When the diameter of the screws is in the range of 4.0 mm to 6.5 mm, increasing the diameter of pedicle screw can improve the distribution of axial pullout stress on the screws, cortical bone and cancellous bone. Provided the bone mass permits it, pedicle screws with a diameter of not less than 5.0 mm should be chosen.
目的
建立三维有限元模型，以确定置入 L1 椎体的椎弓根螺钉的生物力学最佳直径。
方法
通过有限元法评估不同直径的椎弓根螺钉对 L1 椎体骨最大 Von Mises 应力的影响。评估了直径为 4.0 至 6.5 毫米的椎弓根螺钉。
结果
模拟结果表明，在轴向拔出力作用下，当螺钉直径在 4.0 至 6.5 毫米范围内时，所有模型中的应力均降低。在标准外部载荷和 6.5 毫米直径螺钉的情况下，皮质骨和松质骨的负荷分别减少了 47.24%和 34.28%，螺钉的位移减少了 21.35%。当直径≥5.0 毫米时，所有模型中的应力变量均稳定。
结论
当螺钉直径在 4.0 至 6.5 毫米范围内时，增加椎弓根螺钉的直径可以改善螺钉、皮质骨和松质骨上轴向拔出应力的分布。在骨质允许的情况下，应选择直径不小于 5.0 毫米的椎弓根螺钉。
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