To assess the factors influencing the stone-free rate (SFR) of LCS after FURL, and establish a practical, convenient, and accurate scoring system.

149 patients underwent FURL between September 2020 and December 2022, were divided into two groups based on the results of NCCT of the kidney performed 1 month after surgery: Group A (stone clearance group) with 112 patients and Group B (residual stone group) with 37 patients. Variables with P values less than 0.1 from univariate analysis were incorporated into binary unconditional multivariate logistic regression analysis. The degree of correlation was assessed based on the odds ratio of independent risk factors. The optimal cutoff value for the early warning scoring system was determined using the Youden index.

According binary unconditional multivariate logistic regression analysis, stone length (P=0.003), stone CT value (P=0.043), IPA (P=0.031), IW (P=0.043), CPH (P=0.006), and renal pelvis morphology (P=0.036) were identified as independent risk factors. Each factor was assigned 1 point based on OR values, resulting in a total score of 6 points. The area under the curve of the ROC curve was 0.859, and the cut-off value was 1.5. When the total score was less than 2, the overall SFR was 96.20%; however, when the total score was ≥ 2, this rate significantly decreased to 49.32%.

Stone length, stone CT value, renal pelvis shape, IPA, IW, and CPH were identified as independent factors influencing the SFR of LCS after FURL. Each factor was assigned a score of 1, resulting in a prediction scoring system with a total score of 6 points. A total score exceeding 2 was associated with a significantly reduced SFR. FURL was strongly recommended for scores of 0-1, used with caution for scores of 2-3, and contraindicated for scores of 4-6.