Early versus delayed ureterolithotripsy following obstructive acute pyelonephritis treatment.

Background And Objectives: There is no recommendation on the timing of ureterolithotripsy after the treatment of obstructive acute pyelonephritis (APN). The effect of early and delayed ureterolithotripsy on postoperative urinary tract infection (UTI) and other complications was investigated.

Methods: Patients who underwent ureterolithotripsy after obstructive APN treatment between February 2017 and August 2021 were divided into two groups, those operated during hospitalization and those operated within 3 months after discharge. Two groups were compared in terms of stone-free status, postoperative complications, postoperative UTI, and urosepsis rates.

Results: Of the 91 patients included in the study, 68 were in the early ureterolithotripsy group, while 23 patients were in the delayed ureterolithotripsy group. The postoperative UTI rate was significantly higher in patients who underwent early ureterolithotripsy (29.4% vs 8.7%,  = 0.045). Patients with postoperative UTI had a higher moderate/severe perinephric fat stranding (PFS) on non-contrast CT at hospital admission (52.2% vs 29.4%,  = 0.048). Among the laboratory parameters, white blood cells were significantly higher in the group with postoperative UTI (21604.5 vs 14728.9,  = 0.042). In the multivariate analysis, early ureterolithotripsy and moderate/severe PFS were independent predictors for postoperative UTI. In the created model, the probability of postoperative UTI after ureterolitripsy after obstructive APN treatment was 3.5% in patients without risk factors, while this rate was 51.9% in patients with both risk factors.

Conclusion: There is no consensus on the timing of stone removal after treatment of obstructive APN. Early ureterolithoripsy and moderate/severe perinephric fat stranding on non-contrast CT are risk factors for postoperative UTI.