Endourology & Stone Disease(구연) (E-166) 요로 결석으로 유발된 폐쇄성 급성 신우신염이 있는 환자에서 요관경하 쇄석술 후 전신성 염증반응증후군의 예방을 위한 술 전 항생제 치료의 최적 기간 ¹연세의대 강남세브란스병원, ²동국대학교 경주병원 유정우¹, 이광석¹, 정병하¹, 권세윤², 서영진², 이경섭², 구교철¹ OBJECTIVES: There is no consensus on the optimal duration of preoperative antibiotic treatment prior to ureteroscopic lithotripsy in patients presenting with urolithiasis-induced obstructive acute pyelonephritis (APN). We aimed to identify perioperative surgeon-modifiable factors associated with postoperative systemic inflammatory response syndrome (SIRS). MATERIALS & METHODS: This multicenter retrospective study evaluated 115 patients who presented with urolithiasis-induced obstructive APN between January 2008 and December 2019. All patients were administered empirical antibiotics until antibiotic sensitivity confirmation or until ureteroscopic lithotripsy. Data were collected for: age, sex, diabetes mellitus, Eastern Cooperative Oncology Group performance status, duration of preoperative antibiotic treatment, stone size, multiplicity, hydronephrosis grade, preoperative drainage, preoperative antibiotic sensitivity confirmation, inflammatory serum markers, and operative time. Sensitivity analysis using Youden’s index and the logistic regression analysis were used to assess risk factors for postoperative SIRS. RESULTS & CONCLUSION: Postoperative SIRS was observed in 32 (27.8%) patients. The incidence of postoperative SIRS was higher in patients who received preoperative antibiotic treatment for lesser than 14 days (38.8% vs. 12.5%; p = 0.001). Preoperative drainage was carried out by retrograde ureteral stent placement (n = 32; 27.8%) or percutaneous nephrostomy (n = 45; 39.1%). Patient age and the proportion of patients who received preoperative drainage were higher in patients who received preoperative antibiotic treatment for more than 14 days. Multivariable analysis revealed age (odds ratio [OR] = 0.913; p = 0.020), maximal stone diameter ≥15 mm (OR = 14.27; p = 0.041), duration of preoperative antibiotic treatment <14 days (OR = 19.40; p = 0.037), and preoperative C-reactive protein (CRP) ≥6 mg/L (OR = 20.37; p = 0.028) to be independent predictors of postoperative SIRS. Patients with urolithiasis-induced obstructive APN planned for ureteroscopic lithotripsy should be postponed with at least 14 days of preoperative antibiotic administration and until serum CRP level reaches below 6 mg/L in order to minimize the risk of postoperative SIRS. keywords : anti-bacterial agents, SIRS, urolithiasis