Loeffel Mario, Ferguson Stephen J, Nolte Lutz-P, Kowal Jens H
MEM Research Center, University of Bern, Switzerland.
Spine (Phila Pa 1976). 2008 May 20;33(12):1352-9. doi: 10.1097/BRS.0b013e3181732aa9.
This is an experimental study on an artificial vertebra model and human cadaveric spine.
Characterization of polymethylmethacrylate (PMMA) bone cement distribution in the vertebral body as a function of cement viscosity, bone porosity, and injection speed. Identification of relevant parameters for improved cement flow predictability and leak prevention in vertebroplasty.
Vertebroplasty is an efficient procedure to treat vertebral fractures and stabilize osteoporotic bone in the spine. Severe complications result from bone cement leakage into the spinal canal or the vascular system. Cement viscosity has been identified as an important parameter for leak prevention but the influence of bone structure and injection speed remain obscure.
An artificial vertebra model based on open porous aluminum foam was used to simulate bone of known porosity. Fifty-six vertebroplasties with 4 different starting viscosity levels and 2 different injection speeds were performed on artificial vertebrae of 3 different porosities. A validation on a human cadaveric spine was executed. The experiments were radiographically monitored and the shape of the cement clouds quantitatively described with the 2 indicators circularity and mean cement spreading distance.
An increase in circularity and a decrease in mean cement spreading distance was observed with increasing viscosity, with the most striking change occurring between 50 and 100 Pas. Larger pores resulted in significantly reduced circularity and increased mean cement spreading distance whereas the effect of injection speed on the 2 indicators was not significant.
Viscosity is the key factor for reducing the risk of PMMA cement leakage and it should be adapted to the degree of osteoporosis encountered in each patient. It may be advisable to opt for a higher starting viscosity but to inject the material at a faster rate.
这是一项针对人工椎体模型和人体尸体脊柱的实验性研究。
表征聚甲基丙烯酸甲酯（PMMA）骨水泥在椎体内的分布情况，作为骨水泥粘度、骨孔隙率和注射速度的函数。确定在椎体成形术中提高骨水泥流动可预测性和预防渗漏的相关参数。
椎体成形术是治疗椎体骨折和稳定脊柱骨质疏松性骨的有效方法。骨水泥渗漏至椎管或血管系统会导致严重并发症。骨水泥粘度已被确定为预防渗漏的重要参数，但骨结构和注射速度的影响仍不明确。
使用基于开孔泡沫铝的人工椎体模型来模拟已知孔隙率的骨。在3种不同孔隙率的人工椎体上进行了56次椎体成形术，采用4种不同的起始粘度水平和2种不同的注射速度。在人体尸体脊柱上进行了验证。实验通过放射学监测，并使用圆度和平均骨水泥扩散距离这2个指标对骨水泥云的形状进行定量描述。
随着粘度增加，观察到圆度增加，平均骨水泥扩散距离减小，最显著的变化发生在50至100帕斯卡秒之间。较大的孔隙导致圆度显著降低，平均骨水泥扩散距离增加，而注射速度对这2个指标的影响不显著。
粘度是降低PMMA骨水泥渗漏风险的关键因素，应根据每位患者骨质疏松的程度进行调整。选择较高的起始粘度但以较快的速度注射材料可能是明智的。
