A Comparative Study of Flexible Navigable Vacuum-Assisted Ureteral Access Sheath and Traditional Ureteral Access Sheath in Retrograde Intrarenal Surgery: Evaluating the Impact of Hydronephrosis on Stone-Free Rate and Complications

Background: Retrograde intrarenal surgery (RIRS) is a widely used minimally invasive technique for renal stone management. Recently, flexible navigable vacuum-assisted ureteral access sheaths (FV-UASs) have been introduced to enhance RIRS outcomes. This study aimed to evaluate the efficacy of FV-UAS compared with traditional UAS (T-UAS) in RIRS, with a specific focus on the impact of hydronephrosis. Methods: A retrospective multicenter study was conducted involving 207 patients undergoing RIRS for renal stones. Patients were divided into two groups based on the type of UAS used: FV-UAS (n = 105) or T-UAS (n = 102). Demographic data, stone characteristics, operative time, complications, and stone-free rates (SFRs) were analyzed. The degree of hydronephrosis was assessed using the Society of Fetal Urology grading system. Results: The FV-UAS group demonstrated significantly shorter operative times (median: 50 minutes vs 57.5 minutes, p = 0.039) and a higher SFR at 1-week postoperatively (47.6% vs 23.5%, p < 0.001) compared with the T-UAS group. However, there was no significant difference in SFR at 1 month (75.2% vs 68.6%, p = 0.290). Postoperative fever was significantly lower in the FV-UAS group (3.8% vs 18.6%, p = 0.001). Importantly, the degree of hydronephrosis did not significantly impact the outcomes that performed RIRS with FV-UAS. Conclusion: FV-UAS offers potential advantages over T-UAS in RIRS, including shorter operative times, improved early stone-free status, and reduced postoperative complications. Hydronephrosis did not appear to affect the efficacy of FV-UAS. These findings suggest that FV-UAS may be a valuable tool in optimizing RIRS outcomes.