骨质疏松性椎体中骨水泥强化实心椎弓根螺钉与开窗椎弓根螺钉的拔出强度
Pull-out strength of cemented solid versus fenestrated pedicle screws in osteoporotic vertebrae.
作者信息
Leichtle C I, Lorenz A, Rothstock S, Happel J, Walter F, Shiozawa T, Leichtle U G
机构信息
Department of Orthopaedic Surgery, University Hospital Tübingen, Tübingen, Germany.
Department of Orthopaedic Surgery, University Hospital Tübingen, Tübingen, Germany
出版信息
Bone Joint Res. 2016 Sep;5(9):419-26. doi: 10.1302/2046-3758.59.2000580.
OBJECTIVES
Cement augmentation of pedicle screws could be used to improve screw stability, especially in osteoporotic vertebrae. However, little is known concerning the influence of different screw types and amount of cement applied. Therefore, the aim of this biomechanical in vitro study was to evaluate the effect of cement augmentation on the screw pull-out force in osteoporotic vertebrae, comparing different pedicle screws (solid and fenestrated) and cement volumes (0 mL, 1 mL or 3 mL).
MATERIALS AND METHODS
A total of 54 osteoporotic human cadaver thoracic and lumbar vertebrae were instrumented with pedicle screws (uncemented, solid cemented or fenestrated cemented) and augmented with high-viscosity PMMA cement (0 mL, 1 mL or 3 mL). The insertion torque and bone mineral density were determined. Radiographs and CT scans were undertaken to evaluate cement distribution and cement leakage. Pull-out testing was performed with a material testing machine to measure failure load and stiffness. The paired t-test was used to compare the two screws within each vertebra.
RESULTS
Mean failure load was significantly greater for fenestrated cemented screws (+622 N; p ⩽ 0.001) and solid cemented screws (+460 N; p ⩽ 0.001) than for uncemented screws. There was no significant difference between the solid and fenestrated cemented screws (p = 0.5). In the lower thoracic vertebrae, 1 mL cement was enough to significantly increase failure load, while 3 mL led to further significant improvement in the upper thoracic, lower thoracic and lumbar regions.
CONCLUSION
Conventional, solid pedicle screws augmented with high-viscosity cement provided comparable screw stability in pull-out testing to that of sophisticated and more expensive fenestrated screws. In terms of cement volume, we recommend the use of at least 1 mL in the thoracic and 3 mL in the lumbar spine.Cite this article: C. I. Leichtle, A. Lorenz, S. Rothstock, J. Happel, F. Walter, T. Shiozawa, U. G. Leichtle. Pull-out strength of cemented solid versus fenestrated pedicle screws in osteoporotic vertebrae. Bone Joint Res 2016;5:419-426.
目的
椎弓根螺钉骨水泥强化可用于提高螺钉稳定性，尤其是在骨质疏松性椎体中。然而，关于不同螺钉类型和骨水泥用量的影响，人们了解甚少。因此，本生物力学体外研究的目的是评估骨水泥强化对骨质疏松性椎体中螺钉拔出力的影响，比较不同的椎弓根螺钉（实心和开孔）和骨水泥体积（0 mL、1 mL或3 mL）。
材料与方法
总共54个骨质疏松的人尸体胸腰椎椎体植入椎弓根螺钉（未强化、实心强化或开孔强化），并用高粘度聚甲基丙烯酸甲酯骨水泥（0 mL、1 mL或3 mL）进行强化。测定插入扭矩和骨密度。进行X线片和CT扫描以评估骨水泥分布和骨水泥渗漏情况。使用材料试验机进行拔出试验以测量破坏载荷和刚度。采用配对t检验比较每个椎体内的两种螺钉。
结果
开孔强化螺钉（+622 N；p⩽0.001）和实心强化螺钉（+460 N；p⩽0.001）的平均破坏载荷显著高于未强化螺钉。实心强化螺钉和开孔强化螺钉之间无显著差异（p = 0.5）。在下胸椎，1 mL骨水泥足以显著增加破坏载荷，而3 mL骨水泥在上胸椎、下胸椎和腰椎区域导致进一步显著改善。
结论
在拔出试验中，用高粘度骨水泥强化的传统实心椎弓根螺钉提供的螺钉稳定性与复杂且更昂贵的开孔螺钉相当。就骨水泥体积而言，我们建议胸椎至少使用1 mL，腰椎使用3 mL。引用本文：C. I. Leichtle，A. Lorenz，S. Rothstock，J. Happel，F. Walter，T. Shiozawa，U. G. Leichtle。骨质疏松性椎体中实心与开孔强化椎弓根螺钉的拔出强度。骨关节研究2016；5：419 - 426。
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