Zisman A, Lindner A, Siegel Y I, Addadi L
Urology Department, Assaf Harofeh' Medical Center, Zerifin, Israel.
J Urol. 1999 Feb;161(2):399-402.
We define energy requirements for stone micro indentation as a quantifiable event equivalent to in vivo energy delivery and investigate the change in indentation characteristics with time.
The 7 stones extracted from 7 patients were cut, embedded in resin and polished. Multiple micro indentations were performed on each stone section using a diamond Vickers micro indentor with a 500x light microscope and video system. The resulting indentations were observed by optical and scanning electron microscopy as a function of time. Organic matrix content was determined by dissolving stones in ethylenediaminetetraacetic acid solution.
The energy requirement for stone indentation varies among stones (median range 43.6 to 109.9 kg/mm2) and at different locations in the same stone. Indentations relaxed by 10 to 70% during the first 2 weeks after indentation. Stones with a high organic matrix content were ductile and the phenomenon of indentation relaxation was pronounced. Brittle, low matrix stones relaxed to a lesser extent.
The relaxation phenomena may have a practical implementation when considering repeat shock wave lithotripsy. A significant fraction of the energy invested in a stone which did not cause fracture or critical cracks is lost within 1 to 2 weeks after the procedure, particularly in elastic stones with a high organic matrix content. We suggest that the preferred interval for repeat shock wave lithotripsy be less than 2 weeks.
我们将结石微压痕的能量需求定义为一种可量化的事件，等同于体内能量传递，并研究压痕特征随时间的变化。
从7例患者中取出的7块结石被切割、嵌入树脂并抛光。使用配备500倍光学显微镜和视频系统的金刚石维氏微压头对每个结石切片进行多次微压痕操作。通过光学显微镜和扫描电子显微镜观察所得压痕随时间的变化。通过将结石溶解在乙二胺四乙酸溶液中来测定有机基质含量。
结石压痕的能量需求在不同结石之间（中位数范围为43.6至109.9 kg/mm²）以及同一结石的不同位置有所不同。压痕在压痕后的前2周内松弛了10%至70%。有机基质含量高的结石具有韧性，压痕松弛现象明显。脆性、低基质的结石松弛程度较小。
在考虑重复冲击波碎石术时，松弛现象可能具有实际应用价值。在结石上投入的未导致骨折或临界裂纹的能量的很大一部分在手术后1至2周内损失，特别是在有机基质含量高的弹性结石中。我们建议重复冲击波碎石术的首选间隔时间应小于2周。
