The use of polymethylmethacrylate (PMMA) cement to reinforce fragile or broken vertebral bodies (vertebroplasty) leads to extensive bone stiffening. Fractures in the adjacent vertebrae may be the consequence of this procedure. PMMA with a reduced Young's modulus may be more suitable. The goal of this study was to produce and characterize stiffness adapted PMMA bone cements. Porous PMMA bone cements were produced by combining PMMA with various volume fractions of an aqueous sodium hyaluronate solution. Porosity, Young's modulus, yield strength, polymerization temperature, setting time, viscosity, injectability, and monomer release of those porous cements were investigated. Samples presented pores with diameters in the range of 25-260 microm and porosity up to 56%. Young's modulus and yield strength decreased from 930 to 50 MPa and from 39 to 1.3 MPa between 0 and 56% porosity, respectively. The polymerization temperature decreased from 68 degrees C (0%, regular cement) to 41 degrees C for cement having 30% aqueous fraction. Setting time decreased from 1020 s (0%, regular cement) to 720 s for the 30% composition. Viscosity of the 30% composition (145 Pa s) was higher than the ones received from regular cement and the 45% composition (100-125 Pa s). The monomer release was in the range of 4-10 mg/mL for all porosities; showing no higher release for the porous materials. The generation of pores using an aqueous gel seems to be a promising method to make the PMMA cement more compliant and lower its mechanical properties to values close to those of cancellous bone.
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机译：使用聚甲基丙烯酸甲酯（PMMA）水泥来增强脆弱的或破裂的椎体（椎体成形术）会导致广泛的骨骼僵硬。邻近椎骨骨折可能是该手术的结果。降低杨氏模量的PMMA可能更合适。这项研究的目的是生产和表征适应刚度的PMMA骨水泥。多孔PMMA骨水泥是通过将PMMA与各种体积分数的透明质酸钠水溶液混合而制成的。研究了这些多孔水泥的孔隙率，杨氏模量，屈服强度，聚合温度，凝固时间，粘度，可注射性和单体释放。样品呈现出直径在25-260微米范围内的孔隙，孔隙率高达56％。在0至56％的孔隙率下，杨氏模量和屈服强度分别从930MPa降低至50MPa和从39MPa降低至1.3MPa。对于具有30％含水分数的水泥，聚合温度从68℃（0％，普通水泥）降至41℃。对于30％的成分，凝固时间从1020 s（0％，普通水泥）减少到720 s。 30％组成（145 Pa s）的粘度高于普通水泥和45％组成（100-125 Pa s）的粘度。对于所有孔隙率，单体释放量在4-10 mg / mL的范围内;对多孔材料没有更高的释放。使用水性凝胶生成孔似乎是使PMMA水泥更柔顺并将其机械性能降低到接近松质骨的值的有前途的方法。
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