Comparison of Shock Wave Lithotripsy and Flexible Ureterorenoscopy in the Treatment of 10–20 mm Lower Pole Stone: Prospective Non-randomized Study

Introduction: The objective of the study is to clarify the efficiency, safety, and limitations of shock wave lithotripsy (SWL) and flexible ureterorenoscopy (f-URS) in the management of lower pole stones (LPS). Methods: The present study was planned prospectively in a non-randomized manner. Patients who had LPS between 10 and 20 cm in size were enrolled in the study. Patient demographic characteristics, stone-related parameters, complications, and success were noted. Patients who underwent SWL and patients who underwent f-URS were compared according to demographic characteristics, procedure-related parameters, complications, and success rate. Results: A total of 82 patients matched the study inclusion criteria, with 44 patients treated with SWL and 38 patients treated with f-URS. The time between diagnosis and the end of the treatment was 29.2 days in the SWL group and 15.2 days in the f-URS group (p = 0.001). The success rate was 89.5% with f-URS and 72.7% with SWL (p = 0.036). Receiver operating curve analysis revealed that a stone size larger than 14 mm in the lower pole was significantly associated with SWL failure (area under the curve [AUC]: 0.711, p = 0.033), and a stone size larger than 16 mm was a predictive factor for f-URS failure. Conclusion: The present study found that f-URS had a significantly higher stone-free rate in the management of 10-20 mm LPS compared to SWL. For the first time, this study showed that the time between diagnosis and the end of treatment was significantly shorter with f-URS. Moreover, LPS larger than 14 mm and 16 mm were predictive factors for SWL and f-URS failure, respectively.