Does having an asymptomatic renal stone increase morbidity after radical cystectomy?

Background: Asymptomatic renal stones identified before radical cystectomy (RC) and urinary diversion (UD) pose a potential treatment dilemma. This study aims to evaluate the outcomes of these asymptomatic stones managed by observation and their natural history after surgery.

Methods: This longitudinal cohort study included patients referred for RC and UD between 2015 and 2023 at a single institution. Preoperative CT scans were reviewed to identify patients with asymptomatic renal stones. Exclusion criteria included prior stone treatment, additional ureteric stones, and lack of postoperative radiological follow-up. 90-day postoperative complications, stone-related adverse events and spontaneous stone passage (SSP) were the primary endpoints over a postoperative follow-up. Kaplan-Meier curves and regression models were performed.

Results: Among 606 RC patients, 47 patients with 52 renal units met the inclusion and exclusion criteria. The mean stones burden was 4.5 mm (SD ± 2.75). The lower pole was the most frequent location to harbor stones (48%), while renal pelvis was the least one (12%). There were no differences in baseline characteristics or postoperative complication rates between patients with and without asymptomatic renal stones (Overall complications: 60% vs. 61%; Major complications: 17% vs. 18%). The 1-year cumulative incidence of stone-related adverse events and SSP were 10% and 47%, respectively. Higher BMI was a significant predictor of SSP (p < 0.001), with an optimal cutoff of 28 kg/m². Larger stones were associated with stone-related adverse events (p = 0.03).

Conclusion: Observation is a viable strategy for preoperative asymptomatic renal stones among RC and UD patients, with most stones passing spontaneously and few adverse events after the surgery.