Value of the modified Resorlu-Unsal renal stone scoring system for the evaluation of renal stone clearance after FURL

Objectives: To investigate the feasibility of the modified Resorlu-Unsal renal stone scoring (RUSS) system in predicting postoperative renal stone clearance after ureteral flexible lithotripsy (FURL). Methods: Patients with renal stones who underwent FURL were retrospectively analysed as study subjects, preoperative stone status was scored using the modified RUSS in the stone removal and stone retention groups, independent risk factors for the effect of renal stone removal after FURL were analysed using a logistic multifactorial regression model, and the predictive value of postoperative renal stone clearance was evaluated using a subject operating characteristic (ROC) curve. Results: The stone area, number of renal calyces involved, and CT value of stones in the stone removal group were smaller than those in the stone remnant group, and the number of stones with maximal diameter grade 1 was significantly more than that in the stone remnant group, and the modified RUSS score score was lower than that in the stone remnant group (P < 0.05). It was also found that stone area, multiple stones, IPA < 45°, and modified RUSS score were independent risk factors for stone clearance after FURL (P < 0.05). The AUC of the modified RUSS score was found to be greater than that of stone area, multiple stones by ROC graph (P < 0.05). Conclusion: The modified RUSS scoring system predicted renal stone clearance after FURL more accurately than stone area and multiple stones.