Introduction: The benefit of endoscopically removing small ( = 6 mm) asymptomatic renal stones is unknown. AUA guidelines leave the decision to the urologist and patient. A prospective study with shock wave lithotripsy and some retrospective studies favor observation. However, several studies quoted in AUA guidelines show about half of small renal stones cause a stone event within 5 years. We performed a randomized, controlled trial (ClinicalTrials.gov number, NCT02210650) of removing small asymptomatic renal stones at the time of ureteral or contralateral stone surgery and hope to discuss the results with the AUA community. Methods: In a multi-center, randomized, controlled trial, 38 patients had their small asymptomatic renal stones removed, and 35 patients (Control group) did not, during endoscopic removal of ureteral or contralateral renal stones. The primary outcome was relapse measured by future emergency department (ED) visits, surgeries, and stone growth. Results: After a mean follow up duration of 4.2 years, the Treatment group had longer relapse time than the Control group (P <0.0001, logrank test). The restricted mean time-to-relapse was 75% longer in the Treatment group (1631.6 (standard error 72.8) days vs. 934.2 (121.8)). Relapse risk was 82% lower in the Treatment group (hazard ratio 0.18, 95% confidence interval 0.07-0.44) with 16% vs. 63% of subjects relapsing. Treatment added a median of 25.6 (interquartile range 18.5-35.2) minutes to surgery. ED visits within 2 weeks of surgery were 5 in the Treatment group and 4 in the Control group. Eight Treatment and 10 Control subjects reported passing stones. Conclusions: Removal of small, asymptomatic renal stones during surgery for ureteral or contralateral renal stones reduced relapse. Treatment increased surgery duration but did not increase surgical returns to the ED or passing stones. As surgical tools and techniques continue to improve, the balance may further tilt toward early intervention. SOURCE OF Funding: Supported by NIH NIDDK grant P01 DK043881 and from resources through the Veterans Affairs Puget Sound Health Care System.
