Slower delivery of shock waves to kidney stones results in better treatment success than faster delivery, investigators reported online in the Journal of Urology.
In a study of 206 patients undergoing shock wave lithotripsy (SWL) for unilateral kidney stones, Chinese researchers found that the treatment success rate was 50.5% among patients receiving 60 shocks per minute versus 35.9% for those receiving 120 shocks per minute.
The two groups had similar success rates when stones were 10 mm or less, but the patients receiving 60 shocks per minute had a significantly better success rate when stones were larger than 10 mm.
Immediately following SWL, patients treated with 60 shocks per minute had significantly greater increases in renal injury markers, but the investigators said the clinical implication of this was uncertain.
The new study confirms the findings of a previous study of 220 kidney stone patients by Canadian investigators. That study, which was published in the Journal of Urology (2005;174:595-599), showed that the treatment success rate was 71% for patients treated with 60 shocks per minute versus 32% for those receiving 120 shocks per minute.