The Role of Scoring Systems in Predicting Surgical Success in Percutaneous Nephrolithotomy: Results from a Single Center

Abstract

Objective: In this study, we aimed to determine the effectiveness of Guy’s score, S.T.O.N.E score, and CROES nomogram, the most widely used models in percutaneous nephrolithotomy (PNL) for predicting stone-free status, and to determine which model predicts stone-free status more successfully. Materials and Methods: The data of patients older than 18 years of age who underwent PNL for kidney stones at our tertiary academic center between 2009 and 2018 were retrospectively analyzed. Examined parameters included the demographic data of patients, stone characteristics, Guy’s score, S.T.O.N.E. score, CROES nomogram, surgical duration, transfusion rate, length of stay, and stone-free status. Prediction values for stone-free status were determined using receiver operating characteristic (ROC) curve analysis. Results: A total of 200 patients were included in the study. The mean age of the patients was 43.7 ± 14.6 years. The mean stone scores of the patients were as follows: Guy’s score: 2.11 ± 1.01; S.T.O.N.E. score: 7.54 ± 1.73; and CROES nomogram: 194 ± 62.7. The stone-free rate was determined to be 66%. The Guy’s and S.T.O.N.E. scores were significantly higher, and the CROES nomogram was significantly lower in non-stonefree patients compared to stone-free patients (p<0.001, p<0.001, and p<0.001, respectively). The cut-off value and area under curve (AUC) were 2.5 and 0.770 for Guy’s score, 7.5 and 0.722 for S.T.O.N.E score, and 185 and 0.843 for CROES nomogram, respectively. Conclusion: Guy’s score, S.T.O.N.E score, and CROES nomogram are effective models in predicting stonefree status in PNL.