Effectiveness of Second-look Flexible Ureteroscopy to Achieve A True Stone-Free Status in Retrograde Intrarenal Surgery

Objective:Residual stone fragments remain a challenging topic for urologists following retrograde intrarenal surgery (RIRS). This study aimed to investigate the effectiveness of second-look flexible ureteroscopy (URS) to achieve a true stone-free status and decrease stone-related events.Materials and Methods:The study included 176 consecutive patients treated with RIRS for kidney stones between October 2013 and December 2017. Patients were divided into two groups. Group 1 included patients who underwent only one session of RIRS (n=51) and group 2 included patients who undergo a second-look flexible URS after RIRS (n=125). Both groups were compared for stone-free rates and potential risk factors associated with stone-related events. Stone-related events were defined as urinary infection, renal colic, stone enlargement, and any additional intervention with shock wave lithotripsy or reoperation.Results:Stone-free rate after RIRS for groups 1 and 2 were 37.25% (n=19/51) and 40.8% (n=51/125), respectively. The stone-free rates improved to 93.6% (n=117/125) in group 2 after the second-look flexible URS. The multivariable analysis revealed that type of intervention, stone size, and body mass index were independent prognostic factors for stone-related events. When group 2 was taken as a reference, the odds ratio for stone-related events was 8.48 (95% confidence interval: 2.95-24.42) in group 1.Conclusion:Second-look flexible ureterorenoscopy increased the stone-free rates and diminished the number of stone-related events. We argue that performing second-look flexible ureterorenoscopy in the early period following RIRS in the presence or suspicion of residual stone fragments provides better treatment results.