Comparative analysis of STONE, TOHO, and ITO stone scoring systems for predicting stone-free status following flexible ureteroscopy in patients with renal stones: a prospective study.

Objective: This study aimed to compare the predictive capabilities of three stone scoring systems (STONE, TOHO, and ITO stone score) in determining outcomes, stone-free status, and complications following flexible ureteroscopy (fURS) in patients with renal stones.

Patients And Methods: This prospective study included 300 patients with renal stones treated at the Urology Department of Benha University Hospital from January 2023 to June 2024, all managed with flexible ureteroscopy (fURS). Eligible participants had renal calculi measuring up to 2.5 cm. For each patient, the three evaluated stone scores were calculated by the same surgeon and an expert radiologist.

Results: This study revealed significant negative correlations between stone-free rates (SFR) and the STONE and TOHO scores (P < 0.05), while there were significantly positive correlations between SFR and ITO scores (P value < 0.05). The SFR at 1 month was 87%. In terms of postoperative complications, colic was reported in 57 patients (19%), fever in 66 patients (22%), and hematuria in 30 patients (10%). According to the study findings, the three scoring systems effectively predicted the outcomes of flexible ureteroscopy, with area under the curve (AUC) values of 0.805 for STONE, 0.903 for TOHO, and 0.856 for ITOscore.

Conclusion: The three studied scoring systems are valid tools for predicting stone-free rates following flexible ureteroscopy in patients with renal stones. The significant correlations observed between these scores and the stone-free rates (87% at 1 month) highlight their effectiveness in assessing surgical outcomes.