Abstract

INTRODUCTION

Currently, there is no consensus on an ideal predictive model that characterizes the complexity of renal stones and predicts surgical results after percutaneous nephrolithotomy (PCNL). The aim of this study is to compare the accuracy of the S.T.O.N.E.nefrolithometry scoring system and CROES nephrolithometric nomogram in predicting stone-free rate and complications of PCNL results.

METHODS

Data from 50 renal units (45 patients) who underwent PCNL operation by the same surgeon between March 2016 and January 2019 for > 2 cm kidney stones were retrospectively analyzed. Preoperative clinical and radiological data and postoperative features of the patients were recorded. Postoperative complications were classified according to the modified Clavien scoring system. S.TO.N.E. and CROES nephrolithometry scores were calculated on preoperative CT images for each patient, and their relationship with stone-free status and complications was evaluated by logistic regression analysis.

RESULTS

The mean stone burden was 778.6 ± 665.4 mm2, the mean Hounsfield Unit was 990.6 ± 335.1 HU, the mean operation time was 125 ± 34 minutes, the mean hospitalization time was 4.7 ± 2.71 days. The mean S.T.O.N.E score was 8.76 ± 2.03, and the mean CROES score was 134.26 ± 67.36. Complete stone-free was achieved in 21 (42%) of the cases. In cases with residual stones, the stone burden was statistically significantly higher compared to cases without stone-free (p = 0,000). There is a positive correlation between the S.T.O.N.E. score and the operation time (r = 0.487, p = 0.000). But, there was a negative correlation between the operation time with the CROES score (r = -0.514, p = 0.000) and the nephrostomy time (r = -0.29, p = 0.04). The relationship between both scoring systems and stone-free rates were statistically significant (p = 0,000). There was a statistically significant relationship between the presence of complications and only the CROES scoring system (p = 0.032).

DISCUSSION AND CONCLUSION

S.T.O.N.E. and CROES scoring systems have predictive value for stone-free status after PCNL. The CROES nephrolithometry nomogram is more effective in predicting complications after PCNL.