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
After obtaining ethics approval, medical records of patients undergoing PCNL between 2009 and 2013 at a tertiary stone center were retrospectively reviewed. Guy’s and S.T.O.N.E. scoring systems were calculated. Regression analysis and ROC curves were performed.
Results
A total of 185 PCNLs were reviewed. The overall stone-free rate was 71.9 % with a complication rate of 16.2 %. When compared to patients with residual fragments, stone-free patients had significantly lower Guy’s grade (2.7 vs. 2; p < 0.001) and S.T.O.N.E. score (8.3 vs. 7.4; p = 0.004). Logistic regression analysis showed that both Guy’s and S.T.O.N.E. systems were significantly associated with stone-free status, OR 0.4 (p < 0.001), and OR 0.7 (p = 0.001), respectively. Furthermore, both scoring systems were significantly associated with the estimated blood loss (p = 0.01 and p = 0.005). There was good correlation between both scoring systems and operative time (r = 0.3, p < 0.001 and r = 0.4, p < 0.001) and length of hospital stay (r = 0.2, p = 0.001 and r = 0.3, p < 0.001). However, there were no significant associations between both scoring systems and complications (p = 0.7 and p = 0.6). There was no significant difference in the areas under the curves for the Guy’s and S.T.O.N.E. scoring systems (0.74 [95 % CI 0.66–0.82] vs. 0.63 [95 % CI 0.54–0.72]; p = 0.06).
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.
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Abbreviations
- AUA:
-
American Urological Association
- AUC:
-
Area under curve
- BMI:
-
Body mass index
- CI:
-
Confidence interval
- EBL:
-
Estimated blood loss
- LOS:
-
Length of hospital stay
- NCCT:
-
Non-contrast computed tomography
- PCNL:
-
Percutaneous nephrolithotomy
- PCS:
-
Pelvi-calyceal system
- ORs:
-
Odds ratios
- ROC:
-
Receiver operating characteristic
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Acknowledgments
This work was supported by Grants from Fonds de la Recherche en Santé du Québec (FRSQ) to Dr Sero Andonian.
Conflict of interest
All authors declare no conflict of interest.
Ethical standard
This study was conducted in accordance with the Declaration of Helsinki and its amendments after both Institutional Review Board (No. 14-050-GEN) and Director of Professional Services (McGill University Health Centre) approvals were obtained.
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Noureldin, Y.A., Elkoushy, M.A. & Andonian, S. 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 33, 1821–1825 (2015). https://doi.org/10.1007/s00345-015-1508-5
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DOI: https://doi.org/10.1007/s00345-015-1508-5