Department of Mechanical Engineering and Materials Sciences, Pratt School of Engineering, Duke University, Durham, NC 27708, USA.
J Biomech. 2012 Oct 11;45(15):2520-5. doi: 10.1016/j.jbiomech.2012.07.025. Epub 2012 Aug 27.
To investigate the roles of lithotripter shock wave (LSW) parameters and cavitation in stone comminution, a series of in vitro fragmentation experiments have been conducted in water and 1,3-butanediol (a cavitation-suppressive fluid) at a variety of acoustic field positions of an electromagnetic shock wave lithotripter. Using field mapping data and integrated parameters averaged over a circular stone holder area (R(h)=7 mm), close logarithmic correlations between the average peak pressure (P(+(avg))) incident on the stone (D=10 mm BegoStone) and comminution efficiency after 500 and 1000 shocks have been identified. Moreover, the correlations have demonstrated distinctive thresholds in P(+(avg)) (5.3 MPa and 7.6 MPa for soft and hard stones, respectively), that are required to initiate stone fragmentation independent of surrounding fluid medium and LSW dose. These observations, should they be confirmed using other shock wave lithotripters, may provide an important field parameter (i.e., P(+(avg))) to guide appropriate application of SWL in clinics, and facilitate device comparison and design improvements in future lithotripters.
为了探究碎石机冲击波参数和空化在结石粉碎中的作用，我们在水和 1,3-丁二醇（一种空化抑制性液体）中进行了一系列体外破碎实验，实验使用了电磁冲击波碎石机的各种声场位置。通过场映射数据和圆形结石固定器区域（R(h)=7mm）的综合参数平均值，我们发现结石（D=10mm 的 BegoStone）上的平均峰值压力（P(+(avg)))与 500 和 1000 次冲击后的粉碎效率之间存在密切的对数相关性。此外，这些相关性表明，存在明显的 P(+(avg))阈值（分别为软石和硬石的 5.3MPa 和 7.6MPa），这一阈值是独立于周围流体介质和 LSW 剂量来启动结石破碎所必需的。这些观察结果（如果使用其他冲击波碎石机得到证实）可能为 SWL 在临床中的应用提供一个重要的场参数（即 P(+(avg)))，并有助于未来碎石机的设备比较和设计改进。
