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

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.

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.

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).

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.