Background: Various nephrolithometry scoring systems (NSS) are proposed to determine the structural configuration of kidney stones. Nevertheless, evidence of the comparison among these scoring systems in anticipating postoperative outcomes after percutaneous nephrolithotomy (PCNL) are limited.

Objective: To compare the correlation of four NSS with stone-free rates and perioperative results following PCNL.

Materials and Methods: The authors examined a retrospective study of patients with kidney stones who received PCNL. One hundred seventy-two patients admitted for surgery at Ramathibodi Hospital were assessed. Four NSS were compared, Guy’s Stone Score (GSS), the Clinical Research Office of the Endourological Society nephrolithometric nomogram (CROES), S.T.O.N.E. Nephrolithometry (STONE), and the Seoul National University Renal Stone Complexity (S-ReSC) scoring system. The authors evaluated the correlations between these four scoring systems with stone-free rates and postoperative outcomes.

Results: The stone-free status was 53.5%. There were significant differences in the mean scores of the four systems between the stone-free group and the not stone-free group (1.97 versus 3.70, p<0.05 in GSS; 242.40 versus 159.28, p<0.05 in CROES; 6.64 versus 9.08, p<0.05 in STONE; and 3.44 versus 8.41, p<0.05 in S-ReSC). Multivariate analysis revealed only S-ReSC as independent preoperative factors for PCNL success (p<0.001). Moreover, each scale had a significant correlation with blood loss, length of hospital stay, and operative time. Three scoring systems, all except STONE, were significantly associated with percentage change in estimated glomerular filtration rates (eGFR). There was no significant association among all four scoring systems with postoperative complications.

Conclusion: All four NSS represent excellent predictors for stone-free rates and correlate well with surgical outcomes.

Keywords: GSS, CROES, STONE, S-ReSC, Percutaneous nephrolithotomy

DOI: doi.org/10.35755/jmedassocthai.2020.08.10687

Received 30 Sep 2019 | Revised 15 Jan 2020 | Accepted 16 Jan 2020