Second-Look Flexible Ureterorenoscopy: A Technique Proposal to Achieve Real Stone Free Status

Introduction: Residual stone fragments remain a challenging topic for urologists following retrograde intrarenal surgery (RIRS). This study investigates the effectiveness of second-look flexible ureterorenoscopy (URS) to achieve a true stone-free status and decrease stone-related events. Material and Method A total of 176 consecutive patients treated with RIRS for kidney stones were included in the study. Patients were divided into two groups, group 1 receiving the standard of care (n=51) and group 2 receiving second-look flexible URS (n=125). In all cases, one or more calyceal stones of 1 to 4 mm were extracted with a basket at the time of stent removal. Unless earlier intervention was necessary, patients were followed up every six months to determine if they had experienced SREs. Results The mean follow-up time for the whole group was 21±11.1 months. The mean number of stones in group 1 and group 2 was 1.25±0.11 and 1.56±0.19, respectively. Postoperative stone-free rate after RIRS for group 1 and group 2 were 37.25% (n=19/51) and 40.8% (n=51/125), respectively. The SFR improved to 93.6% (n=117/125) in group 2. Multivariable analysis showed that type of intervention, stone size, and body mass index were independent prognostic factors for SREs. When group 2 was taken as a reference, the odds ratio for SREs was 8.48 (95% CI: 2.95–24.42) in group 1. Conclusion This study found that second-look flexible URS increased the SFRs and diminished the number of SREs. We propose performing second-look flexible URS following RIRS in the presence or suspicion of RSFs to provide better treatment results, less radiation exposure, and greater patient satisfaction. Key Words Retrograde Intrarenal Surgery, Flexible Ureteroscopy, Stone-free Rate, Residual stone Fragments, Stone-Related Event, Second-look Flexible Ureteroscopy.