The Impact of Stone Density on Operative Complications of Retrograde Intrarenal Surgery: A Multicenter Study with Propensity Score Matching Analysis

Abstract

Background: The aim of the study was to evaluate the impact of stone density on operative complication rates in retrograde intrarenal surgery (RIRS).Materials and Methods: A total of 473 consecutive patients undergoing RIRS for the treatment of upper tract urinary stones were included. To adjust for baseline confounders, one-to-one propensity score matching was performed. After matching, the patients were divided into two groups according to stone density (low density [LD] group, <= 970 Hounsfield unit [HU]; high density [HD] group, >970 HU). The patients' demographics, stone-related features, stone-free rates, and intraoperative and postoperative complication rates were compared between the groups. The primary objective was to evaluate whether the intraoperative and postoperative complication rates were higher in patients whose stone density was greater than 970 HU.Results: After propensity score matching, 170 of 210 LD and 170 of 263 HD patients undergoing RIRS were included. The baseline characteristics did not differ significantly between the groups. There were no significant differences between LD and HD patients with respect to intraoperative (5.9% and 8.8%, respectively; P = .29), postoperative (10.6% and 15.3%, respectively; P = .14), and overall complication rates (15.2% and 21.1%, respectively; P = .16). Stone-free status was achieved in 143 patients (84.1%) in the LD group and 148 patients (87%) in the HD group; the difference was not statistically significant (P = .27).Conclusion: Our results show that RIRS is a safe and effective minimally invasive procedure for the treatment of upper urinary tract stones, even in HD stones.