Kidney stones: Size matters

NAPLES, Italy, Nov. 23 (UPI) -- An Italian researcher says size may be decisive when it comes to the best way to remove kidney stones trapped in the ureter.

Dr. Vincenzo Mirone of the University Federico II in Naples advises kidney stones under 1 centimeter -- less than one-half inch -- in size be removed using shockwaves -- non-invasive acoustic pulses, also known as extracorporeal shockwave lithotripsy.

Mirone, co-author of a study published in the British Journal of Urological Surgeons, suggested surgery be used for stones larger than 1 cm -- a procedure known as ureteroscopy -- where a ureteroscope is passed into the distal ureter to remove the stone.

Mirone and colleagues randomly assigned these therapies to 273 patients with single distal ureteric stones ranging in size from 0.5 cm to 1.5 cm. Overall, the two groups -- average age of 50 and equally divided between men and women -- showed few differences.

"However, there were clear differences in both groups when we divided them into patients with stones of up to 1 cm and stones of more than 1 cm," Mirone said in a statement. "These results clearly indicate that extracorporeal shockwave lithotripsy should be the first choice for patients with stones of 1 cm and under, while ureteroscopy should be the first choice for patients with stones exceeding 1 cm."