Comparison of stone-free rate between percutaneous nephrolithotomy and retrograde intrarenal surgery

Background: The management of urolithiasis in the kidney has been drastically changed in the era of endourology, mainly consisting of three surgical procedures: extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), and retrograde intrarenal surgery (RIRS). Since ESWL is usually less invasive via ambulatory clinic routes, this study aimed to examine the stone-free rate (SFR) between PCNL and RIRS. Methods: We retrospectively reviewed patients who had renal stones and were treated with either PCNL or RIRS from June 2016 to June 2018. Staghorn stones, stones with diameters <1 cm, and stones with diameters >2 cm were excluded. Patients who underwent multiple surgeries for bilateral renal stones and those with graft kidney stones were excluded from the study. X-ray, sonography, and/or computed tomography (CT) were used to calculate the size of the stones. Follow-up was evaluated by the same image examination within three months after surgery. Stone-free was defined as no residual stone or the presence of asymptomatic calculi <4 mm. The operation time was defined as a skin-to-skin interval. Results: Following exclusion criteria, there were 39 patients in each arm, with no difference in age, sex, or any other demographic data. The average stone size in the PCNL and RIRS groups was 16.3 and 14.0 mm, respectively (p = 0.009). There was no significant difference in SFR (71.8% vs 61.5%, p = 0.337); the operation time was significant longer (p < 0.001), and the hospital stay was significantly shorter (p < 0.001) in the RIRS group. Conclusion: PCNL and RIRS are both feasible options for managing kidney stones. However, the initial stone size might affect the selection of operation. The SFR in the PCNL group was numerically but not statistically higher. The RIRS group, on the other hand, had a longer operation time but a shorter hospital stays.