AO Research Institute, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland.
J Mech Behav Biomed Mater. 2011 Nov;4(8):2081-9. doi: 10.1016/j.jmbbm.2011.07.007. Epub 2011 Jul 22.
The use of polymethylmethacrylate (PMMA) cement to reinforce fragile or broken vertebral bodies (vertebroplasty) leads to extensive bone stiffening. This might be one reason for fractures at the adjacent vertebrae following this procedure. PMMA with a reduced Young's modulus may be more suitable. The goal of this study was to produce and characterize PMMA bone cements with a reduced Young's modulus by adding bone marrow. Bone cements were produced by combining PMMA with various volume fractions of freshly harvested bone marrow from sheep. Porosity, Young's modulus, yield strength, polymerization temperature, setting time and cement viscosity of different cement modifications were investigated. The samples generated comprised pores with diameters in the range of 30-250 μm leading to porosity up to 51%. Compared to the control cement, Young's modulus and yield strength decreased from 1830 to 740 MPa and from 58 to 23 MPa respectively by adding 7.5 ml bone marrow to 23 ml premixed cement. The polymerization temperature decreased from 61 to 38 ∘C for cement modification with 7.5 ml of bone marrow. Setting times of the modified cements were lower in comparison to the regular cement (28 min). Setting times increased with higher amounts of added bone marrow from around 16-25 min. The initial viscosities of the modified cements were higher in comparison to the control cement leading to a lower risk of extravasation. The hardening times followed the same trend as the setting times. In conclusion, blending bone marrow with acrylic bone cement seems to be a promising method to increase the compliance of PMMA cement for use in cancellous bone augmentation in osteoporotic patients due to its modified mechanical properties, lower polymerization temperature and elevated initial viscosity.
使用聚甲基丙烯酸甲酯（PMMA）水泥来增强脆弱或破裂的椎体（椎体成形术）会导致广泛的骨硬化。这可能是该手术后相邻椎体骨折的原因之一。具有较低杨氏模量的 PMMA 可能更为合适。本研究的目的是通过添加骨髓来生产和表征具有较低杨氏模量的 PMMA 骨水泥。通过将 PMMA 与绵羊新鲜收获的骨髓以不同体积分数混合来制备骨水泥。研究了不同水泥改性物的孔隙率、杨氏模量、屈服强度、聚合温度、凝固时间和水泥粘度。生成的样品具有 30-250μm 直径的孔，导致孔隙率高达 51%。与对照水泥相比，通过向 23ml 预混合水泥中添加 7.5ml 骨髓，杨氏模量和屈服强度分别从 1830MPa 降低到 740MPa，从 58MPa 降低到 23MPa。聚合温度从添加 7.5ml 骨髓的水泥改性物的 61℃降低到 38℃。与常规水泥相比，改性水泥的凝固时间更短（28 分钟）。随着添加骨髓量的增加，凝固时间从大约 16-25 分钟增加。与对照水泥相比，改性水泥的初始粘度较高，因此发生外渗的风险较低。固化时间遵循与凝固时间相同的趋势。总之，将骨髓与丙烯酸骨水泥混合似乎是一种很有前途的方法，可以通过改变其机械性能、降低聚合温度和提高初始粘度来提高 PMMA 水泥在骨质疏松患者松质骨增强中的顺应性。
