椎体后凸成形术中不同骨水泥注入量的生物力学及临床疗效的相关性研究

目的：回顾分析经皮椎体成形术治疗胸腰段骨质疏松性椎体压缩骨折中不同骨水泥注射量与临床疗效的关系。同时采用三维有限元方法分析生理载荷作用下不同骨水泥量对伤椎段生物力学影响的差异。方法：选择本科2010年6月-2011年6月采用经皮椎体成形术治疗骨质疏松性椎体压缩骨折患者36例，共36个椎体。将其按注入的骨水泥量分为三组。所有患者均行椎体后凸成形术，比较术前及术后的VAS评分，ODI指数。同时利用MIMICS软件对36例骨质疏松性椎体压缩骨折椎体后凸成形术前后的CT数据进行预处理，后导入ABAQUS软件中建立三维有限元模型，设置O．3MPa轴向载荷进行生物力学分析，观察生理载荷下不同骨水泥量伤椎增强模型整体及各部分的Von Mises应力。结果：36例患者手术均获得成功，无原有症状加重或神经症状出现，5ml组2例，7ml中4例出现骨水泥渗漏。所有患者均获得随访，平均8．9月。三组术后VAS评分和ODI和术前相比均有统计学意义（P〈0．05），但组间相比无统计学意义（P〉0．05）。不同骨水泥注入量与疼痛缓解程度无相关性。成功建立了不同骨水泥量伤椎增强椎体后凸成形术前后的三维有限元模型，当轴向压力以生理载荷0．3MPa时，骨水泥量的注入量和伤椎的刚度呈正相关。结论：椎体后凸成形术能有效缓解疼痛，和骨水泥的的注入量无明显相关性。伤椎的刚度和强度恢复和骨水泥注入量呈正相关，随着骨水泥注入量的增加，相关并发症发牛率增大。

Biomechanical and clinical efficacy evaluation of different bone cement volumes in Kyphoplasty

Objective： To investigate the relationship between different bone cement volumes and clinical efficacy of percutaneous kyphoplasty for osteoporotic vertebral compression fracture retrospectively, and to analyze biomechanical differences of different amount of bone cement for injured vertebra by the way of finite element analysis. Methods： From June 2010 to June 2011, 36 patients with osteoporotic vertebral compres- sion fracture were underwent percutaneous kyphoplasty. According to the different volumes of bone cement, all cases were divided into 3 groups： 3ml （group A）, 5ml （group B）, 7ml （group C）. Visual Analog Scale and ODI index were accessed to estimate the clinical efficacy. All cases underwent CT scans. Three-dimensional finite element models of 36 patients were built in the MIMICS and the ABAQUS software. The stress on the vertebrae under axial pressure （0.3MPa） was analyzed to evaluate the influence of PKP on injured vertebrae. Results： The operation was performed successfully, there was no neurological symptoms occurred after operation. But bone cement leakage was noted in 2 cases of group B and 4 cases of group C. All cases were followed up for an average time of 8.9 months. There was a significant difference in VAS and ODI score between pre- and post-operation （P〈0.05）, but no difference in the groups （P〉0.05）. There was no correlation between bone cement volumes and clinical efficacy. The three-dimensional finite element models of PKP were successfully established before and after operation. Under axial pressure （0.3MPa）, the strength of the injured vertebrae was increased with increasing amount of bone cement. Conclusion： Percutaneous kyphoplasty can effectively relief the pain caused by osteoporosis. There was no correlation between bone cement volumes and clinical efficacy. The strength of the injured vertebrae was increased with increasing amount of bone cement, but the complication increased too.