The Stone Score: A New Preoperative Assessment Tool to Predict Stone Free Rate Following Ureterolithotripsy

Abstract

Background: Ureteric stones are a common cause of urinary tract obstruction and can lead to significant morbidity if not managed effectively. Ureteroscopy has become a widely used minimally invasive treatment option for ureteric calculi, offering high success rates with fewer complications. The STONE scoring system, based on radiological features, has been developed to help estimate the complexity of ureteric stones. This quasi-experimental study was designed to assess the STONE score's predictability in stone-free rate on ureterolithotripsy from preoperative imaging features (NCCT of KUB). Methods: This hospital-based quasi-experimental study took place in the Department of Urology, NIKDU (National Institute of Kidney Disease and Urology), Sher-E-Bangla Nagar, Dhaka, Bangladesh, from January 2020 to June 2020. A total of 30 subjects were included in the study by a purposive sampling technique. Statistical analyses were carried out by using the Statistical Package for Social Sciences version 23.0. Result: In this study of 30 patients (mean age 35.83±12.71 years; 63.33% male), lower STONE scores (5–8) were associated with a 100% stone-free rate and minimal complications, while higher scores showed reduced clearance and more complications. The mean STONE score was significantly lower in stone-free patients (9.39±1.86) versus those with residual stones (12.33±1.03, p<0.05). Logistic regression confirmed higher scores significantly reduced stone-free chances (OR 0.448, p=0.043), with no significant impact on operative time or hospital stay. Conclusion: The STONE score is a significant predictor of stone-free status after ureteroscopy, with lower scores (5–8) linked to 100% stone clearance and fewer complications. Stone-free patients had a significantly lower mean score than those with residual stones. Logistic regression confirmed that higher STONE scores reduce the chance of stone clearance, while operative time and hospital stay were not significantly affected. Thus, the STONE score effectively predicts ureteroscopy outcomes.