Neucks Joshua S, Pishchalnikov Yuri A, Zancanaro Anthony J, VonDerHaar Jonathan N, Williams James C, McAteer James A
Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Dr. MS-5055, Indianapolis, IN 46202-5120, USA.
Urol Res. 2008 Feb;36(1):61-6. doi: 10.1007/s00240-007-0128-y. Epub 2008 Jan 3.
Previous in vitro studies of acoustic coupling in shock wave lithotripsy (SWL) have shown that air pockets trapped at the surface of the treatment head significantly reduce transmission of shock wave (SW) energy to the focal zone of the lithotripter, reducing the effectiveness of stone breakage. Since there are no reliable means to monitor the quality of coupling during SWL, we looked for a practical protocol to improve how coupling is achieved. In vitro studies were performed using a Dornier DoLi-50 lithotripter. LithoClear gel was used to couple the treatment head to the acoustic window of a clear acrylic test tank. Numerous methods of applying gel were tested including common sense variations of routine protocols typically used with patients. For each method the coverage of air pockets (% defects) was determined using digital imaging. Different coupling regimes were tested for effect on the breakage of gypsum model stones. The quality of acoustic coupling was affected by how the gel was handled--how it was dispensed and applied, and whether the gel was applied only to the treatment head or to both the lithotripter water cushion and the test tank (surrogate patient). Dispensing gel from a squeeze bottle for application by hand created significantly more defects than when a large volume (approximately 250 ml) of gel from the stock jug was applied as a mound to just the treatment head (26.5+/-2.7 vs. 1.2+/-0.5% defects, P<0.001). The efficiency of stone breakage was better when gel was applied from the stock jug compared to application by hand (P<0.006). Poor coupling was substantially improved by using the inflation feature of the water cushion to collapse air pockets, but this strategy was not a substitute for establishing good coupling at the outset. The quality of coupling in shock wave lithotripsy can be improved by minimizing the handling of the coupling medium. Hand application of coupling gel is clearly not the best way to prepare for lithotripsy. Better results can be obtained by delivering lithotripsy gel as a bolus to the treatment head alone, and allowing it to spread upon contact between the treatment head and the skin. These in vitro tests also suggest that the inflation feature of the lithotripter may be useful in reducing defects in coupling.
先前关于冲击波碎石术（SWL）中声学耦合的体外研究表明，被困在治疗头表面的气穴会显著降低冲击波（SW）能量向碎石机聚焦区的传输，从而降低结石破碎的效果。由于在SWL过程中没有可靠的方法来监测耦合质量，我们寻求一种实用的方案来改进耦合的实现方式。使用多尼尔DoLi - 50碎石机进行了体外研究。LithoClear凝胶用于将治疗头与透明丙烯酸测试水箱的声学窗口耦合。测试了多种涂抹凝胶的方法，包括对通常用于患者的常规方案进行常识性变通。对于每种方法，使用数字成像确定气穴的覆盖范围（%缺陷）。测试了不同的耦合方式对石膏模型结石破碎的影响。声学耦合的质量受凝胶处理方式的影响——凝胶的分配和涂抹方式，以及凝胶是仅涂抹在治疗头上还是同时涂抹在碎石机水垫和测试水箱（替代患者）上。用挤压瓶手动分配凝胶涂抹产生的缺陷明显多于将大量（约250毫升）库存罐中的凝胶作为一堆仅涂抹在治疗头上（缺陷率分别为26.5±2.7%和1.2±0.5%，P<0.001）。与手动涂抹相比，从库存罐中涂抹凝胶时结石破碎效率更高（P<0.006）。利用水垫的充气功能使气穴塌陷可显著改善耦合不佳的情况，但该策略不能替代从一开始就建立良好的耦合。通过尽量减少耦合介质的处理，可以提高冲击波碎石术中的耦合质量。手动涂抹耦合凝胶显然不是准备碎石术的最佳方法。将碎石术凝胶作为一团单独输送到治疗头，并使其在治疗头与皮肤接触时扩散，可获得更好的结果。这些体外测试还表明，碎石机的充气功能可能有助于减少耦合缺陷。
