Abstract: Objective To investigate the value of preoperative systemic immune-inflammation index (SII) in predicting postoperative urosepsis after flexible ureteroscopic lithotripsy,and establish a preoperative nomogram prediction model.Methods The clinical data of 329 patients who underwent flexible ureteroscopic lithotripsy in Shanghai Fourth People’s Hospital affiliated to Tongji University from August 2020 to October 2021 were retrospectively analyzed.According to the occurrence of urinary sepsis, the patients were divided into sepsis group and non-sepsis group.The independent risk factors of postoperative urosepsis for upper urinary calculi were evaluated by univariate and multivariate Logistic regression analysis.We drew receiver operating characteristic (ROC) to find the cut-off value of risk factors and calculated the area under curve (AUC) to evaluate its diagnostic power.The R software was used to establish a nomogram model for predicting the occurrence of postoperative urosepsis and calculate the c-index.And its accuracy was evaluated by the calibration curve.

Key words: systemic immune-inflammation, urosepsis, flexible ureteroscopic lithotripsy, nomogram