History of Obstructive Pyelonephritis Treated Without Drainage as a Risk Factor for Febrile Urinary Tract Infection After Ureteroscopic Lithotripsy: A Retrospective Study From Three Institutions.

Purpose: Preoperative obstructive pyelonephritis (OP) increases the risk of febrile urinary tract infection (fUTI) after ureteroscopic lithotripsy (URSL). This study aimed to investigate the effect of a history of OP treated without drainage on post‑URSL fUTI.

Methods: We retrospectively reviewed the medical records of 343 consecutive patients who underwent URSL at three institutions between January 2021 and April 2024. Risk factors for post‑URSL fUTI were analyzed, and frequencies were compared among patients with a history of OP treated without drainage, those with a history of OP treated with ureteral stent (US) placement, and those without a history of OP.

Results: Of the 343 patients, 29 (8.5%) developed post‑URSL fUTI. Multivariate logistic regression analysis revealed that a history of OP (p < 0.001) and preoperative positive urine culture (p = 0.043) were independent risk factors for post‑URSL fUTI. The incidence of post‑URSL fUTI was significantly higher in patients with OP treated with drainage than in those without a history of OP (p < 0.001). Moreover, the incidence of post‑URSL fUTI in patients with OP treated without drainage was significantly higher than that in patients treated with US placement (p = 0.030).

Conclusion: In this study, the incidence of post‑URSL fUTI in patients with OP treated without drainage was significantly higher than that in those treated with US placement. A history of OP treated without drainage might represent the highest risk factor for post‑URSL fUTI. Therefore, calculous pyelonephritis probably should be managed with drainage to mitigate this risk.