Asymptomatic lower pole small renal stones: shock wave lithotripsy, flexible ureteroscopy, or observation? A prospective randomized trial

Abstract

Objective: To present the outcomes of flexible ureteroscopy (F-URS), shock wave lithotripsy (SWL), and observation in the management of asymptomatic lower calyceal stones.

Methods: A total of 150 patients with asymptomatic lower calyceal stones were randomized into F-URS (group 1), SWL (group 2), and observation (group 3) groups. The main criteria for patient enrollment were having asymptomatic single lower pole stones <1 cm.

Results: In F-URS, the mean stone-free rate was 92% (46 of 50). The mean number of sessions for the SWL group was 1.48 ± 0.65. Stone-free rate was 90% (45 of 50). In the observation group, patients were followed up for a mean of 21.02 ± 3.65 months. Three stones passed spontaneously without any symptoms. Pain developed in 3 patients during follow-up, and 2 of them passed a stone and responded to analgesics without further treatment. Complication rates for groups 1 and 2 were similar, but group 2 had higher Clavien grades.

Conclusion: For asymptomatic small-sized lower calyceal stones, SWL and F-URS are established treatment modalities. However, with low auxiliary treatment rates, observation may be an option for the management of nonsymptomatic small-sized lower pole kidney stones.