The ROI-modified mayo adhesive probability score as a predictor of postoperative fever after retrograde intrarenal surgery.

In our study, we investigated the predictive value of the region of interest (ROI)-modified Mayo Adhesive Probability (MAP) score which objectively assesses perirenal fat density for postoperative fever following retrograde intrarenal surgery (RIRS), as well as its comparative performance against the conventional MAP score. This retrospective study included 318 patients who underwent RIRS with a sterile urine culture between January 2021 and May 2025. Demographic, stone, and procedure-related data were recorded. Both scores were calculated from non-contrast computed tomography (CT) images prior to surgery; independent risk factors for postoperative fever were identified using logistic regression models and compared via receiver operating characteristic (ROC) analysis. Postoperative fever developed in 41 patients (12.9%). In the model including the conventional MAP score, diabetes mellitus (DM) (odds ratio [OR] = 3.475, p = 0.002), recurrent urinary tract infection (UTI) (OR = 3.567, p = 0.039) and MAP ≥ 3 (OR = 2.707, p = 0.006) were identified as independent risk factors. In the model including the ROI-MAP score, DM (OR = 2.953, p = 0.008) and ROI-MAP ≥ 3 (OR = 7.057, p < 0.001) were identified as independent predictors. The ROI-MAP score demonstrated statistically significantly higher predictive accuracy compared to the conventional MAP score (area under the curve [AUC]: 0.789 vs. 0.709; p = 0.011). The ROI-modified MAP score, which reduces interobserver variability through Hounsfield unit (HU)-based measurement of perirenal fat density, may serve as a potentially useful adjunct for identifying patients at risk of fever following RIRS during the preoperative period.