External validation of the current scoring systems and development of a novel scoring system to predict stone-free rates after retrograde intrarenal surgery in patients with cumulative stone diameter of 2-4 cm Validación externa de los sistemas de puntuación actuales y desarrollo de un nuevo sistema de puntuación para la predicción de la tasa libre de cálculos tras la cirugía intrarrenal retrógrada en pacientes con un diámetro acumulado del cálculo de 2-4 cm

Polat S., Danaciolgu Y., Yarimoglu S., SOYTAŞ M., Erdogan A., TEKE K., ...More

Actas Urologicas Espanolas, vol.47, no.4, pp.211-220, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 47 Issue: 4
  • Publication Date: 2023
  • Doi Number: 10.1016/j.acuro.2022.04.011
  • Journal Name: Actas Urologicas Espanolas
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, EMBASE, Gender Studies Database, MEDLINE, DIALNET
  • Page Numbers: pp.211-220
  • Keywords: Flexible ureterorenoscopy, Large renal stones, Lithotripsy, Scoring system, Urolithiasis
  • Istanbul Medipol University Affiliated: Yes


Objective: Our primary aim is to perform the external validation of the current scoring systems in predicting stone-free status (SFS) after retrograde intrarenal surgery (RIRS) for renal stones 2-4 cm and develop a novel scoring system by re-examining possible predictive factors related to SFS. Methods: Patients who underwent RIRS due to renal stones with a cumulative stone diameter of 2-4 cm between January 2017 and March 2021 were retrospectively screened. Residual stones ≤ 2 mm were defined as clinically insignificant, and these cases were considered to have SFS. Possible predictive factors related to SFS were examined using the multivariate logistic regression analysis. A nomogram and a scoring system were developed using independent predictive variables. The prediction ability of the previous and the new scoring system were evaluated with the ROC analysis. Results: The existing scoring systems were found to be insufficient in predicting SFS (AUC < 0.660 for all). The independent predictors of SFS were identified as stone surface area (OR: 0.991, p < 0.001), stone density (OR: 0.998, p < 0.001), number of stones (OR: 0.365, p = 0.033), and stone localization (p = 0.037). Using these predictive markers, a new scoring system with a score ranging between 4 and 15 was developed. The AUC value for this scoring system was 0.802 (0.734-0.870). Conclusion: The RUSS, S-ReSC and RIRS scoring systems and Ito's nomogram failed to predict SFS in stones > 2 cm. The SFS predictive ability of our new scoring system was higher in > 2 cm stones compared to the other scoring systems.