Comparison of Guy’s vs S.T.O.N.E. nephrolithometry scoring systems in predicting the success rate of PCNL

Abstract

Introduction and objective:

The aim of the present study was to compare the accuracy of the Guy’s and S.T.O.N.E. scoring systems in predicting percutaneous nephrolithotomy (PCNL) outcomes.

Methods:

This prospective study was carried out in the Department of Urology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, between August 2013 and September 2015 in collaboration with the Department of Radiodiagnosis and Imaging. A total of 100 cases of renal calculi operated on with PCNL were considered in the study on the basis of CT morphodensitometry. The study was approved by the institute’s ethical committee. Guy’s and S.T.O.N.E. scoring systems were calculated. Regression analysis and ROC curves were performed.

Results:

A total of 100 PCNLs were operated on. The overall stone-free rate was 90% with a complication rate of 17%. When compared to patients with residual fragments, stone-free patients had significantly lower Guy’s grade (3.5 vs 2; p < 0.001) and S.T.O.N.E. score (9.1 vs 7.5; p = 0.023). Logistic regression analysis showed that both Guy’s and S.T.O.N.E. systems were significantly associated with stone-free status, OR 0.96 (p < 0.001) and OR 0.94 (p < 0.001), respectively. Furthermore, both scoring systems were significantly associated with estimated blood loss (p = 0.02 and p = 0.004). There was good correlation between both scoring systems and operative time (r = 0.2, p < 0.002 and r = 0.3, p < 0.002) and length of hospital stay (r = 0.1, p = 0.002 and r = 0.2, p < 0.002). There were significant associations between both scoring systems and complications (p < 0.001 and p = 0.004). There was no significant difference in the areas under the curves for the Guy’s and S.T.O.N.E. scoring systems (0.96 (95% CI 0.92–0.99) vs 0.94 (95% CI 0.89–1.001); p < 0.001).

Conclusion:

Both Guy’s and S.T.O.N.E scoring systems have comparable accuracies in predicting post-PCNL stone-free status. Other factors not included in either scoring system may need to be incorporated in the future to increase their accuracy.

Keywords

Percutaneous nephrolithotomy scoring method renal calculi

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References

Preminger

Assimos

Lingeman

et al . AUA guideline on management of staghorn calculi: Diagnosis and treatment recommendations. J Urol 2005; 173: 1991–2000.

Opondo

Gravas

Joyce

et al . Standardization of patient outcomes reporting in percutaneous nephrolithotomy. J Endourol 2014; 28: 767–774.

Thomas

Smith

Hegarty

et al . The Guy’s stone score – grading the complexity of percutaneous nephrolithotomy procedures. Urology 2011; 78: 277–281.

Vicentini

Marchini

Mazzucchi

et al . Utility of the Guy’s stone score based on computed tomographic scan findings for predicting percutaneous nephrolithotomy outcomes. Urology 2014; 83: 1248–1253.

Ingimarsson

Dagrosa

Hyams

et al . External validation of a preoperative renal stone grading system: Reproducibility and inter-rater concordance of the Guy’s stone score using preoperative computed tomography and rigorous postoperative stone-free criteria. Urology 2014; 83: 45–49.

Okhunov

Friedlander

George

et al . S.T.O.N.E. nephrolithometry: Novel surgical classification system for kidney calculi. Urology 2013; 81: 1154–1159.

Okhunov

Helmy

Perez-Lansac

et al . Interobserver reliability and reproducibility of S.T.O.N.E. nephrolithometry for renal calculi. J Endourol 2013; 27: 1303–1306.

Rosette

Opondo

Daels

et al . Categorisation of complications and validation of the Clavien score for percutaneous nephrolithotomy. Eur Urol 2012; 62: 246–255.

Labadie

Okhunov

Akhavein

et al . Evaluation and comparison of urolithiaisis scoring systems in percutaneous kidney stone surgery. J Urol 2015; 193: 154–159.

10.

Noureldin

Elkoushy

Andonian

Which is better? Guy’s versus S.T.O.N.E. nephrolithometry scoring systems in predicting stone-free status post-percutaneous nephrolithotomy. World J Urol 2015; 33: 1821–1825.

11.

Tailly

Okhunov

Nadeau

et al . Multicenter external validation and comparison of stone scoring systems in predicting outcomes after percutaneous nephrolithotomy. J Endourol 2016; 30: 594–601.

12.

Choi

Bae

et al . Prediction of stone-free status and complication rates after tubeless percutaneous nephrolithotomy: A comparative and retrospective study using three stone-scoring systems and preoperative parameters. World J Urol. Epub ahead of print 12 July 2016.

13.

Choi

Bae

et al . Prognostic impact of stone-scoring systems after percutaneous nephrolithotomy for staghorn calculi: A single center’s experience over 10 years. J Endourol 2016; 30: 975–981.

14.

Sfoungaristos

et al . Percutaneous nephrolithotomy for staghorn stones: which nomogram can better predict postoperative outcomes? World J Urol 2016; 34: 1163–1168.

15.

Mandal

Goel

Kathpalia

et al . Prospective evaluation of complications using the modified Clavien grading system, and of success rates of percutaneous nephrolithotomy using Guy’s Stone Score: A single-center experience. Indian J Urol 2012; 28: 392–398.