Flexible Ureterorenoscopy Versus Shock Wave Lithotripsy for Kidney Stones < 2 Cm: Results from a Single Centre Randomized Controlled Trial

Background: No clear recommendations are available on whether retrograde intrarenal surgery (RIRS) via flexible ureterorenoscopy or shockwave lithotripsy (SWL) should be preferred for kidney stones <= 2 cm, except for lower-pole stones. Objective: To compare outcomes between RIRS and SWL. Design, setting, and participants: This was a single-center randomized controlled trial from March 2015 to May 2018. Patients with a single 6-20-mm kidney stone were enrolled (NCT02645058). Intervention: Patients were randomized to RIRS or SWL. Outcome measurements and statistical analysis: The primary endpoint was the singleprocedure stone-free rate (SFR) at 1 mo. Two levels of success were set: fragments <= 4 mm (SFR-4) and no residual fragments (SFR-0). Secondary endpoints were the SFR at 6 mo and 1 yr and rates of complications and further treatments. Results and limitations: A total of 138 patients underwent treatment (70 RIRS vs 68 SWL). In comparison to SWL, RIRS SFR results were higher at 1 mo (SFR-4 70.0% vs 45.6%; p = 0.004; SFR-0 50.0% vs 26.5%; p = 0.004) and 6 mo (SFR-4 79.7% vs 63.6%; p = 0.038; SFR-0 59.4% vs 40.9%; p = 0.032). There was no difference in SFR measures between the groups at 1 yr (SFR-4 p = 0.322; SFR-0 p = 0.392). Overall complications were comparable (p = 0.207), but the complication rate for stones >10 mm was higher for the SWL group (p = 0.021). The need for further treatment was comparable (p = 0.368). In terms of patient satisfaction, 86.8% and 77.1% of patients would choose SWL and RIRS again, respectively (p = 0.24). Conclusions: RIRS achieved better SFRs in comparison to SWL at 1 and 6 mo, but not at 1 yr. The RIRS complication rate was lower for stones >10 mm. SWL remains a viable alternative, especially for 6-10-mm stones, providing comparable results to RIRS in the long term. Patient summary: We compared outcomes for the treatment of kidney stones <= 2 cm with two techniques: flexible ureteroscopy, in which a flexible telescope is passed through the urethra and bladder to reach the ureter between the bladder and kidney; and shockwave lithotripsy, in which shockwaves are applied to the skin over the location of the kidney stone. Ureteroscopy achieved better stone-free results at 1 and 6 months, but not at 1 year. (c) 2022 European Association of Urology. Published by Elsevier B.V. All rights reserved.