Multi-aspect Analysis of Ureteral Access Sheath Usage in Retrograde Intrarenal Surgery: A RIRSearch Group Study

Objective:To evaluate the effect of ureteral access sheath (UAS) use and calibration change on stone-free rate and complications of retrograde intrarenal surgery (RIRS).Methods:Data from 568 patients undergoing RIRS for kidney or upper ureteral stones were retrospectively included. Firstly, patients were compared after 1:1 propensity score matching, according to UAS usage during RIRS (UAS used [+] 87 and UAS non-used [-] 87 patients). Then all UAS+ patients (n=481) were subdivided according to UAS calibration: 9.5-11.5 Fr, 10-12 Fr, 11-13 Fr, and 13-15 Fr. Primary outcomes of the study were the success and complications of RIRS.Results:Stone-free rate of UAS+ patients (86.2%) was significantly higher than UAS- patients (70.1%) after propensity score matching (p=0.01). Stone-free rate increased with higher caliber UAS (9.5-11.5 Fr: 66.7%; 10-12 Fr: 87.0%; 11-13 Fr: 90.6%; 13-15 Fr: 100%; p<0.001). Postoperative complications of UAS+ patients (11.5%) were significantly lower than UAS- patients (27.6%) (p=0.01). Complications (8.7%) with 9.5-11.5 Fr UAS was lower than thicker UAS (17.2%) but was not statistically significant (p=0.09). UAS usage was an independent factor predicting stone-free status or peri- and post-operative complications (odds ratio [OR] 3.654, 95% confidence interval [CI] 1.314-10.162; OR 4.443, 95% CI 1.350-14.552; OR 4.107, 95% CI 1.366-12.344, respectively).Conclusion:Use of UAS in RIRS may increase stone-free rates, which also increase with higher caliber UAS. UAS usage may reduce complications; however, complications seemingly increase with higher UAS calibration.