Two common methods for removing kidney stones - surgery and shock wave treatments - are effective and safe, and neither is clearly superior to the other, researchers report in a new systematic review of studies. But these conclusions aren't based on particularly strong data, the researchers say.
"The most important finding from our review is that current practice of managing urerteric stones is based on poor-quality evidence, mostly from small trials with a lot of heterogeneity," said lead investigator Ghulam Nabi, a lecturer in the Health Services Research Unit of the University of Aberdeen in Scotland.
The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The reviewers found six trials, involving 833 adults, that compared two minimally invasive kidney stone therapies: uretoscopy and extracorporeal shock wave lithotripsy.
In ureteroscopy, a surgeon passes a thin viewing instrument into the ducts that carry urine from the kidney. Once a kidney stone is located the urologist typically removes the crystalline mass with forceps or a "basket" instrument.
The other treatment, extracorporeal shock wave lithotripsy, uses sound waves to break each kidney stone into small pieces. The pieces later travel through the urinary tract and pass painlessly from the body.
The reviewed trials compared several different health outcomes: whether or not the patient was free of kidney stones, the need for additional treatment, therapy complications and length of hospitalization.
Results gathered three or four months after treatment suggest that surgery outperformed sound wave therapy to completely clear kidney stones. But, the authors said that the success of the sound wave treatment varied depending on the kind of lithotripter, or shock wave machine that was used.
Overall the review concludes that people treated with ureteroscopy achieve a higher stone-free rate, but have a longer hospital stay and more complications, although most problems were minor.
"At this point it is important to say that both methods work and both have their advantages for different patients. Choice of intervention really depends on the size and location of the stone," said Glenn Preminger, M.D., director of the Comprehensive Kidney Stone Center at Duke University Medical Center.
Preminger did not participate in the Cochrane review, but serves on an international panel of experts "reviewing all research in the field to create new guidelines." Those new recommendations are expected this summer.
By Bruce Sylvester, Contributing Writer
Health Behavior News Service