Avoiding radiation exposure during retrograde intrarenal surgery; a RIRSearch score for predicting longer fluoroscopy times

The aim of this study was to identify preoperative and perioperative predictors of radiation exposure during retrograde intrarenal surgery and to develop a scoring system to estimate intraoperative fluoroscopy time. Data from 753 patients who underwent retrograde intrarenal surgery for renal stones were obtained from a multicenter database. All procedures were performed under general anesthesia using fluoroscopy. Fluoroscopy time, recorded in seconds, was the primary outcome. Ordinal regression analysis was applied to evaluate the association between clinical variables and fluoroscopy duration. A predictive score was developed based on statistically significant factors. The performance of the score was tested using receiver operating characteristic curve analysis and a calibration plot.The mean fluoroscopy time was 58 seconds, while the median was 5 seconds. In 140 procedures, fluoroscopy time exceeded 120 seconds. Six parameters were independently associated with longer fluoroscopy use: absence of preoperative ureteral stenting, low stone density (<1000 Hounsfield units), small stone burden (<250 cubic millimeters), multiple stone localizations, failure of ureteral access sheath insertion, and use of large-caliber sheaths (>= 10-12 French). Each parameter was assigned a weighted value, generating a score ranging from 0 to 15. The scoring system demonstrated excellent discriminatory ability (area under the curve: 0.901). A score of 10 or more predicted fluoroscopy duration above 120 seconds with 87.5% sensitivity and 86.2% specificity.The RIRSearch Score is a practical tool for anticipating prolonged radiation exposure before retrograde intrarenal surgery. Surgeons may use this model to minimize unnecessary fluoroscopy and enhance occupational safety.