NEW ORLEANS — Extracorporeal shockwave lithotripsy, once the gold standard for removing smaller kidney stones, has fallen out of favor, in part because it might be less effective than ureteroscopy, but does that mean it should be taken out of commission altogether?
That question was debated by four experts — two pro and two con — during a special session here at the American Urological Association 2015 Annual Meeting.
Moderator Ralph Clayman, MD, from the University of California, Irvine, opened the debate by reporting that fewer graduating urologists are doing lithotripsy, and that more urologists recertifying for the first time than for the second time are choosing the procedure for stones (29% vs 50%).
Arguing for the retention of extracorporeal shockwave lithotripsy as an option was John Denstedt, MD, from the University of Western Ontario in London, Ontario, Canada.
It has been increasingly argued that lithotripsy does not break up stones reliably, retreatment rates are higher with lithotripsy than with endoscopic procedures, and lithotripsy costs too much.
"My argument is that patient selection is the key," Dr Denstedt explained. There are strategies to enhance the efficacy of lithotripsy and it is still the least invasive therapy. "If you look closely at the literature, patient preference, cost, and morbidity all favor extracorporeal shockwave lithotripsy," he pointed out.
Patients who are obese or who have large stones are better treated with ureteroscopy, he said. In fact, with ureteroscopy, stone-free rates in the distal ureter are greater. However, with lithotripsy, stone-free rates in the proximal ureter are 80%, which is as good as or better than with ureteroscopy, he argued.
A Cochrane review revealed higher complication rates for ureteroscopy, even though it produced higher stone-free rates (Cochrane Database Syst Rev. 2012;5:CD006029). Dr Denstedt said that 2% to 6% of patients will experience perforation, evulsion, or mucosal entry, and that other studies have pointed to problems with the introduction of the urethral access sheath and the placing of stents. "We all know this is a huge problem for the patients," he said.
Low Complication Rate
The lower complication rate makes lithotripsy the preferred choice of many patients. Adding to this is the fact that clinicians skilled in ureteroscopy might be harder to find, Dr Denstedt explained.
Lithotripsy still has a place, said founding director of the International Kidney Stone Institute, James Lingeman, MD, from Indiana University in Indianapolis, who joined Dr Denstedt on the pro side of the debate.
"We don't break up stones with shockwave as we did 25 years ago," he said. "But we can maximize the effectiveness of extracorporeal shockwave lithotripsy by focusing on proper patient selection and the technique of shockwave."
To ensure effectiveness, Dr Lingeman uses what he calls a "triple D score," which takes into consideration skin-to-stone distance, stone density, and stone volume and size. "By choosing wisely, you can get very good stone clearance with shockwave lithotripsy," he explained.
Clinicians should take their time with the procedure, he said, noting that with the dry lithotripters, breaking a stone causes a cloud. If you don't wait for that cloud to dissipate, it can block the succeeding wave, he added.
New types of lithotripters — like the burst wave machine — might improve results, but in the meantime, although lithotripters are less efficient, they still work for the majority of stones, he said. "The type of lithotripter might not be as important as the shockwave technique you use," he added.
Arguing against the retention of extracorporeal shockwave lithotripsy was Olivier Traxer, MD, from University Pierre et Marie Curie in Paris.
Time to Move On
Even though lithotripters have been evolving since they were introduced in the early 1980s, "the stone-free rate in 2015 is the same" as it was 30 years ago, he said.
Over the same period of time, there have been dramatic advances in endourology, including in visualization, laser technology, and miniaturization. As a result, "in many, many centers all around the world, endourology is slowly replacing shockwave lithotripsy," Dr Traxer reported.
The European Urology Association issued new guidelines this year that recommend ureteroscopy for most stones, although lithotripsy is considered the first choice for small stones in the proximal ureter, he said.
"Shockwave lithotripsy is slowly dying," Dr Traxer said. "If shockwave lithotripsy technology doesn't improve in terms of stone treatment," he noted, "it will be completely retired very soon and replaced with endourology."
The technologic advances in endoscopic equipment have made lithotripsy practically obsolete, said Glenn Preminger, MD, from Duke University in Durham, North Carolina, adding his voice to the con side of the debate.
He cited the reasons he thinks lithotripsy should be retired. With lithotripsy, the stone-free rate depends on stone size and the procedure is reliant on renal anatomy for effective stone elimination. In contrast, endoscopy has a lower retreatment rate and is more cost-effective, and ureteroscopy no longer requires a stent for placement.
"Shockwave lithotripsy is a lot like sex; it might feel good and it might be a lot of fun, but is it right?" said Dr Preminger, who was quoting another clinician.
Dr Clayman explained that he does not view lithotripsy as an either/or proposition.
Currently, about 30% of procedures involve extracorporeal shockwave lithotripsy, down from 70%. That could decline further, he said, although that might not be the right thing.
"The future is going to be very much dependent upon the reinvention of shockwave lithotripsy and the training of our future urologists," Dr Clayman said.
Dr Clayman reports that he has an investment interest in Applied Urology, and financial relationships with Boston Scientific, Cook Urological, Greenwald Inc., and Complete Orthopedic Services. Dr Denstedt reports that he is an owner of Cook Urology and is involved in product development, and that he has a leadership and publishing position with the Endourological Society. Dr Lingeman reports that he is an owner of Beck Analytical Laboratories and is involved in product development; is a consultant or advisor to Boston Scientific Corporation and Lumenis; has an investment interest in Midstate Mobile Lithotripsy and is involved in product development; and is involved in a trial with Richard Wolf Instruments. Dr Traxer has disclosed no relevant financial relationships. Dr Preminger reports that he is a consultant or advisor to Boston Scientific and Retrophin; a meeting participant for Olympus; a leader of the Endourological Society; and is involved in health publishing with UpToDate.
American Urological Association (AUA) 2015 Annual Meeting. Presented May 15, 2015.
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Cite this: Extracorporeal Shockwave Lithotripsy Falling Out of Favor - Medscape - Jun 04, 2015.
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