Mechanisms underlying the limited injectability of hydraulic calcium phosphate paste. Part II: Particle separation study
Mechanisms underlying the limited injectability of hydraulic calcium phosphate paste. Part II: Particle separation study
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DOI：
10.1016/j.actbio.2009.06.012
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发表时间：
2010-01-01
影响因子：
9.7
通讯作者：
Bohner, M.
中科院分区：
文献类型：
--
作者：
Habib, M.;Baroud, G.;Bohner, M.
磷酸钙骨水泥（CPC）在骨增量手术中具有重要意义。在这些手术中，通过小孔针将水硬性磷酸钙糊剂注入骨中。这些糊剂的可注射性相对较差，导致仅部分注射。在早期的研究中，我们已经表明相分离使注射过程停止。相分离的特征是在糊状物挤出过程中液体的流动速度比固体的流动速度更快。到目前为止，尚不清楚颗粒分离是否有助于这种水硬性糊剂的差的可注射性。据推测，细颗粒表现得像液体，因此在注射压力下分离，留下较大的颗粒。采用析因实验设计来检验这一假设。在每个注射实验的过程中使用激光衍射测量挤出物的粒度分布（PSD）。使用扫描电子显微镜进一步检查糊剂的固体含量。共进行了48个实验，每个实验涉及两个水平的四个因素。一个因素是超声暴露持续时间，以确保PSD测量期间颗粒的分散质量。另一个因素是注射过程中样品的位置，以便将挤出物与注射器中剩余的PSD进行比较。注射糊剂中的液体：粉末比（LPR）是研究的另一个因素。具体地，检查了具有40%和50%LPR的两种不同的糊剂。分散介质是研究的第四个因素，以确保在PSD测量期间颗粒的充分分散。方差分析表明，样本位置并没有显着影响PSD。通过扫描电子显微镜，未检测到挤出糊剂和注射器中剩余糊剂的明显PSD变化。总之，本研究没有显示出任何证据表明在注射过程中发生了颗粒分离，因此相分离仍然是导致CPC可注射性差的主要现象。(C)2009 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Calcium phosphate cements (CPCs) are of great interest for bone augmentation procedures. In these a hydraulic calcium phosphate paste is injected through a small bore needle into the bone. The injectability of these pastes is relatively poor, resulting into partial injection only. In earlier studies we have shown that phase separation brings the injection process to a halt. Phase separation is characterized by a faster flow of the liquid than of the solid during paste extrusion. So far it is unclear whether or not particle separation contributes to the poor injectability of such hydraulic pastes. It is hypothesized that fine particles behave like a liquid and thus separate under the injection pressure, leaving larger particles behind. A factorial experimental design was used to examine this hypothesis. The particle size distribution (PSD) of the extrudate was measured over the course of each injection experiment using laser diffraction. The solid content of the paste was further inspected using scanning electron microscopy. A total of 48 experiments covering four factors at two levels each were performed. One factor was the ultrasound exposure duration, to ensure the dispersion quality of the particles during the PSD measurements. Another factor was the location of the samples over the course of the injection, so as to compare the extrudate with the PSDs remaining in the syringe. The liquid:powder ratio (LPR) in the injected paste was another factor investigated. Specifically, two different pastes with 40% and 50% LPR were examined. The dispersal medium was a fourth factor investigated, to ensure adequate dispersion of the particles during the PSD measurements. Analysis of variance showed that sample location did not significantly affect PSD. No apparent PSD change for the extruded paste and the paste remaining in the syringe could be detected by scanning electron microscopy. In conclusion, the present study did not show any evidence suggesting that particle separation occurred over the course of injection and thus that phase separation remains the main phenomenon leading to the poor injectability of CPCs. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.