Background: To evaluate the predictive ability of the RIRS scoring system and the RUSS in
predicting stone-free rate (SFR) after retrograde intrarenal surgery (RIRS).
Methods: This prospective study was conducted on patients who underwent RIRS for kidney
stones. Two scoring systems were used to determine the degree of procedure difficulty: the
RIRS scoring system and the RUSS. We assessed the predictive ability of the two scoring
systems utilizing receiver operating characteristic (ROC) analysis and calculated the sensitivity
and specificity of each system. Additionally, we analyzed the association between the scoring
systems and the stone-free outcome using a multivariate logistic regression model.
Results: One hundred seventy-one patients were incorporated into this study with a mean age
of 43 years, and 65.5% were male. The results showed a significant AUC of 0.868 for the RIRS
score (P < 0.001, 95% CI = 0.813–0.924). The sensitivity and specificity were 72% and 93.7%,
respectively. In contrast, the RUSS score revealed a non-significant unsatisfactory AUC of 0.480
(P = 0.660), with a 95% confidence interval ranging from 0.384–0.576.
Conclusion: The RIRS scoring system showed a better predictive ability for SFR after RIRS than
the RUSS. Additionally, RIRS was a significant predictor of SFR, controlling for age, gender, body
mass index, and previous renal surgery.