Jain Arun, Shah Tariq K
Department of Urology, Bradford Teaching Hospitals NHS Foundation Trust, Bradford Royal Infirmary, Bradford, United Kingdom.
Eur Urol. 2007 Jun;51(6):1680-6; discussion 1686-7. doi: 10.1016/j.eururo.2006.10.049. Epub 2006 Nov 10.
Replacement of the water bath by a water cushion in newer lithotriptors introduces an acoustic interface and an ideal coupling agent is required to prevent energy loss at this interface. We aim to study the effect of bubbles in the coupling media on efficacy of extracorporeal shock wave lithotripsy (ESWL) by an in vitro experiment.
Using a standardised in vitro model 40 artificial stones were randomly treated on Modulith SLK lithotriptor using either conventional ultrasound gel (high bubble content) before and after displacing visible bubbles, a thin ultrasound gel (Therasonic) or silicon oil (both with negligible bubbles). Percentage area covered by bubbles in each case and the diameters and depth of crater created in each stone were measured by two blinded observers to determine the correlation between the bubble contents and disintegration efficacy. In vivo effect of two ultrasound gels was compared in terms of pain scores and stone fragmentation rates in ten patients treated with both gels.
Volume of the craters was significantly greater with the Therasonic gel (102.4+/-33.4 mm3) or silicon oil (98.8+/-9.8 mm3) than the conventional ultrasound gel (49.2+/-32.6 mm3). But it was greatest (p<0.001) with ultrasound gel without bubbles (163.5+/-22.6 mm3). Depth and volume of the stone crater increased significantly with decreasing bubble contents of gel (p<0.001). Compared to standard ultrasound gel, patients treated with Therasonic gel reported significantly higher pain scores (median 3.5 vs. 8.0; p<0.001).
Efficacy of ESWL is significantly correlated to air bubbles within the coupling gel and can be improved significantly by eliminating the bubbles from the coupling medium.
在新型碎石机中用水垫取代水浴会引入一个声学界面，因此需要一种理想的耦合剂来防止该界面处的能量损失。我们旨在通过体外实验研究耦合介质中的气泡对体外冲击波碎石术（ESWL）疗效的影响。
使用标准化的体外模型，在Modulith SLK碎石机上对40颗人工结石进行随机处理，分别使用常规超声凝胶（气泡含量高），在去除可见气泡前后、一种稀超声凝胶（Therasonic）或硅油（两者气泡含量可忽略不计）。由两名不知情的观察者测量每种情况下气泡覆盖的面积百分比以及每颗结石中形成的凹坑直径和深度，以确定气泡含量与碎石效果之间的相关性。在10名接受两种凝胶治疗的患者中，比较了两种超声凝胶在疼痛评分和结石破碎率方面的体内效果。
使用Therasonic凝胶（102.4±33.4立方毫米）或硅油（98.8±9.8立方毫米）形成的凹坑体积明显大于常规超声凝胶（49.2±32.6立方毫米）。但无气泡的超声凝胶形成的凹坑体积最大（p<0.001）（163.5±22.6立方毫米）。随着凝胶气泡含量的减少，结石凹坑的深度和体积显著增加（p<0.001）。与标准超声凝胶相比，使用Therasonic凝胶治疗的患者报告的疼痛评分明显更高（中位数3.5对8.0；p<0.001）。
ESWL的疗效与耦合凝胶中的气泡显著相关，通过去除耦合介质中的气泡可显著提高疗效。
