Shockwaves work better than surgery for smaller kidney stones trapped in the ureter

November 18th, 2010 in Medicine & Health / Other

Different techniques should be used to remove single stones that have become lodged in the distal ureter after being expelled by the kidney, depending on whether they are under or above one centimetre, according to the December issue of BJUI.

Surgeons from the Department of Urology at University Federico II, Naples, Italy, believe that extracorporeal shockwave lithotripsy (ESWL) - which uses a non-invasive acoustic pulse to break down ureteric stones - should be the treatment of first choice in patients with a stone of up to 1cm. Patients with a stone over 1cm should be treated using uretoscopy (URS), where a ureteroscope is passed into the distal ureter to remove the stone.

"ESWL and URS are both accepted treatments for distal ureteric stones, but there is a lot of discussion about which surgical technique should be used as a first-line strategy for this condition" explains co-author Professor Vincenzo Mirone.

"Approximately one in three adults with will have a distal ureteric stone at some point in their lives. Most stones with a diameter of up to 0.5cm will be expelled spontaneously when the patient urinates without requiring any active intervention. For larger stones that get stuck in the ureter, spontaneous expulsion is very difficult and requires active intervention."

The Italian team studied 273 patients with single distal ureteric stones ranging from 0.5cm to 1.5cm, in what they believe is the first prospective randomised study comparing ESWL using an electromagnetic lithotripter and URS.

There were no significant differences between the groups, which had an average age of 50 and were equally split between males and females.

Most of the ESWL treatments (98%) were performed on an outpatient basis and none of the patients required or sedation. Patients received 120 shockwaves, with an average of 3,200 per session. Treatment sessions ranged from 29 to 42 minutes, averaging just under 34 minutes.

The majority of the URS treatments (96%) were performed on an inpatient basis, with 22% of patients receiving general anaesthesia, 66% receiving local anaesthesia and 12% just receiving . Surgery time ranged from 22 to 52 minutes, averaging just under 34 minutes.

Overall results included:

"These results clearly indicate that ESWL should be the first choice for patients with stones of 1cm and under and URS should be the first choice for patients with stones exceeding 1cm" concludes Professor Mirone.

More information: Extracorporeal shockwave lithotripsy vs uteroscopy as first-line therapy for patients with single, distal ureteric stones: a prospective randomized study. Verze et al. BJUI. 106, pp 1748-1752. (December 2010). DOI: 10.1111/j.1464-410X.2010.09338.x

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"Shockwaves work better than surgery for smaller kidney stones trapped in the ureter." November 18th, 2010. http://phys.org/news/2010-11-shockwaves-surgery-smaller-kidney-stones.html