Endourology and StonesExternal 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
Section snippets
Material and Methods
In accordance with the approval of our institutional review board, the medical charts of 166 consecutive patients who underwent PCNL by a single fellowship trained endourologist at our institution between July 2008 and February 2013 were retrospectively reviewed. Inclusion criteria included stones located in the kidney (solitary ureteral stones were excluded) identified on preoperative CT imaging, and the presence of postoperative imaging (low-dose CT or abdominal x-ray) on postoperative day 1.
Results
GSS inter-rater concordance was good, with 130 of 166 cases (78%) categorized the same by both raters (κ = 0.72, 95% confidence interval 0.61-0.80). Although the rating only differed by 1 grade in 25 cases (15%), in 11 cases (7%) there was a 2 category difference between raters.
As shown in Table 2 the most common disagreement (10/36, 27%) occurred between grades I and II. Most cases of disagreement (20/36, 56%) resulted from the absence of clear definitions for “abnormal anatomy” as well as
Comment
The current study validates the GSS as a simple and reliable tool for predicting stone clearance, using preoperative CT evaluation and rigorous endpoints (0 mm) for stone clearance regardless of imaging modality. The GSS was also validated for CT using stone free cutoffs of <2 mm and <4 mm, but this did not hold true using abdominal x-ray, which is a less sensitive examination for small fragments. The simple design of the GSS makes it potentially useful for counseling patients regarding the
Conclusion
The GSS is a straightforward grading system of the complexity of renal stones. When applied to preoperative CT scans, it offers good inter-rater concordance and is associated with rigorous end points of stone clearance. The inter-rater concordance could be further improved by explicit definitions of abnormal anatomy partial vs complete staghorn stones, and the size of a calculus that constitutes a separate stone.
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Is Guýs stone score useful for predicting outcomes in percutaneous nephrolithotomy?
2022, Actas Urologicas EspanolasComparing different kidney stone scoring systems for predicting percutaneous nephrolithotomy outcomes: A multicenter retrospective cohort study
2020, International Journal of SurgeryCitation Excerpt :Meanwhile, ROC curves and the AUC of each method also appear to suggest that none of the five methods capable of predicting postoperative complications (Fig. 2, Table 3). PNCL has become the gold standard, first-line treatment for large and complex renal stones; although, previous evidence has shown that calculi complexities, greatly influences outcomes [2,10,18,19]. Therefore, rigorous retrospective analysis of preoperative patient demographics, clinical data and outcomes should be performed to provide accurate risk estimates which could enable clinicians to accurately predict PCNL outcomes.
Morphometry scores: Clinical implications in the management of staghorn calculi
2020, Asian Journal of UrologyPredictive ability of Guy's stone score in pediatric patients undergoing percutaneous nephrolithotomy
2018, Journal of Pediatric UrologyUtility of the Guy's Stone Score in predicting different aspects of percutaneous nephrolithotomy
2018, African Journal of UrologyCitation Excerpt :The significant positive correlation of complication with increasing the grade of GSS is still a matter of debate. Thomas et al. [7] who described the GSS failed to find any positive correlation between either overall rate or severity of complications and GSS, Ingimarsson et al. [17] and Noureldin et al. [19] also in their studies did not find any significant correlation with complications. In contrast Mandal et al. [10] in their big study on 221 renal units that mainly evaluated this issue, found a significant relation between GSS and rate of complication, this positive correlation has also been proved in the studies of Sinha et al. [16] and Vicentini et al. [3].
Financial Disclosure: The authors declare that they have no relevant financial interests.