Heimbach D, Kourambas J, Zhong P, Jacobs J, Hesse A, Mueller S C, Delvecchio F C, Cocks F H, Preminger G M
Department of Urology, Section of Experimental Urology, University of Bonn, Bonn, Germany.
J Urol. 2004 May;171(5):1797-801. doi: 10.1097/01.ju.0000118962.31123.fd.
The acoustic and mechanical properties of various stone compositions are significantly different and thus result in varying degrees of fragility. Consequently, results to shock wave lithotripsy (SWL) are influenced accordingly. We report the results of a study of fragility of various stone compositions, and the influence on each stone's baseline physical properties and fragility when exposed to various chemolytic solutions.
Before SWL artificial stones of differing compositions were irrigated with various chemolytic solutions. Calcium oxalate monohydrate (COM) stones were treated with ethylenediaminetetraacetic acid (EDTA), stones composed of magnesium ammonium phosphate hydrogen were treated with hemiacidrin, and stones made of uric acid (UA) were treated with tromethamine. Synthetic urine served as a control for all stone groups. Using an ultrasound transmission technique, longitudinal wave propagation speed was measured in all groups of artificial stones. Stone density was also measured by using a pycnometer (based on Archimedes' principle). Based on these measurements transverse (shear) wave speed (assuming a constant Poisson's ratio), wave impedance and dynamic mechanical properties of the artificial stones were calculated. Moreover, the microhardness of these artificial stones was measured, and fragility testing using SWL with and without pretreatment with the previously mentioned chemolytic solutions, was performed.
Wave speed, wave impedance, dynamic mechanical properties and microhardness of EDTA treated COM stones and tromethamine treated UA stones were found to decrease compared to untreated (synthetic urine) control groups. The suggestion that chemolytic pretreatment increases stone fragility was verified by the finding of increased stone comminution after SWL testing. Combining this medical pretreatment and SWL, the findings demonstrate a significant impact of various solvents on stone comminution, in particular EDTA treated COM stones, tromethamine treated UA stones and hemiacidrin treated magnesium ammonium phosphate hydrogen stones. These data suggest that by altering the chemical environment of the fluid surrounding the stones it is possible to increase the fragility of renal calculi in vitro.
These results indicate that appropriate chemical treatments may provide a useful adjunctive modality for improving the efficacy of stone comminution during shock wave lithotripsy.
各种结石成分的声学和力学特性存在显著差异，进而导致不同程度的易碎性。因此，冲击波碎石术（SWL）的效果也会受到相应影响。我们报告了一项关于各种结石成分易碎性的研究结果，以及在暴露于各种化学溶解溶液时，对每种结石的基线物理特性和易碎性的影响。
在进行SWL之前，用各种化学溶解溶液冲洗不同成分的人工结石。用乙二胺四乙酸（EDTA）处理一水合草酸钙（COM）结石，用半胱氨酸处理磷酸氢镁铵结石，用氨丁三醇处理尿酸（UA）结石。合成尿液作为所有结石组的对照。使用超声传输技术，测量所有组人工结石中的纵波传播速度。还使用比重瓶（基于阿基米德原理）测量结石密度。基于这些测量结果，计算人工结石的横波（剪切波）速度（假设泊松比恒定）、波阻抗和动态力学性能。此外，测量这些人工结石的显微硬度，并进行使用SWL且有或没有用上述化学溶解溶液预处理的易碎性测试。
与未处理（合成尿液）对照组相比，发现经EDTA处理的COM结石和经氨丁三醇处理的UA结石的波速、波阻抗、动态力学性能和显微硬度降低。SWL测试后结石粉碎增加的发现证实了化学溶解预处理会增加结石易碎性的观点。结合这种医学预处理和SWL，研究结果表明各种溶剂对结石粉碎有显著影响，特别是经EDTA处理的COM结石、经氨丁三醇处理的UA结石和经半胱氨酸处理的磷酸氢镁铵结石。这些数据表明，通过改变结石周围液体的化学环境，有可能在体外增加肾结石的易碎性。
这些结果表明，适当的化学处理可能为提高冲击波碎石术中结石粉碎的疗效提供一种有用的辅助方式。
