Extracorporeal shock wave lithotripsy is often 60 to 120 waves / min

Abstract

  

Introduction: The extracorporeal shock-wave lithotripsy (ESWL) is the only non invasive method to remove the stones from the urinary tract. Objectives: To caracterizer the results with the implementation of ESWL at a slow frequency (SF) of 60 waves/min compared to the fast frequency (FF) of 120 waves/min. Methods: Authors studied patients presenting with single and radiopaques stones of 0.5 mm2 or greater in renal pelvis treated by means of ESWL, using the lithotripter MODULITH SLX-MX (STORZ). Two groups were created: Group I (SF) of 60 waves/min and Group II (FF) of 120 waves/min. The stone, therapeutics and the success rate were analyzed at three months of completing treatment, comparing both groups. Results: 234 patients were evaluated, 117 in each group. There was not difference regarding sex, age, body mass index (BMI), number of sessions and applied energy. The difference was significant in the lithiasis surface greater for the FF (1,9 versus 1,3 cm2, p <0,001). It was necessary less shock waves in those patients treated with FF (mean 1 707, 0 versus 3 099,5 p <0,001). The mean time of treatment was larger in FF (28,5 versus 25,8/min, p 0,001).The success rate shows a trend to be higher for FF (98,9 % versus 92,3%, p <0.064). Conclusions: Monotherapy of renal pelvis stones to 60 waves/min allows to obtain better results than 120 waves/min, although with an acceptable increase in treatment time, a significant lower number of shock waves and a minor morbidity, lead to a decrease in costs.

Key words: Extracorporeal lithotripsy, frequency, shock wave.