External validation of Ito’s nomogram and T.O.HO. scoring system in flexible ureterorenoscopy

Abstract

Abstract Purpose This study aims to assess stone-free rates after flexible ureterorenoscopy (fURS) using the T.O.HO. (Tallness, Occupied lesion, Hounsfield unit evaluation) scoring system and Ito’s nomogram. Materials and methods In the study conducted with 484 patients, the following parameters were analyzed: age, sex, comorbidities, hospitalization, affected side, extracorporeal shock wave lithotripsy (ESWL) history, stone length, stone density, number of stones, location, and presence of hydronephrosis. Results Multivariate logistic regression analysis revealed that stone length, stone number, and lower pole stone location were associated with the prediction of stone-free status. The cut-off value for Ito’s score was determined to be 13.5 points, with an AUC of 0.792 (sensitivity, 0.609; specificity, 0.821) and a 95% confidence interval of (0.752–0.832) (Fig. 1). The cutoff for the T.O.HO. score was 6.5 points, with an AUC of 0.744 (sensitivity 0.738, specificity 0.602) and a 95% confidence interval of (0.699–0.789). Conclusion In conclusion, T.O.HO. scoring system and the Ito’s nomogram are promising tools to predict stone-free status (SFS) after fURS in preoperative evaluation. In addition, the success of scoring systems in predicting SFS preoperatively appears promising and offers a potentially valuable approach.

Keywords

• Flexible ureterorenoscopy
• Ito’s nomogram
• T.O.HO. Score
• Urolithiasis