Using the Modified Clavien Grading System to Classify Complications of Percutaneous Nephrolithotomy

Purpose

A modified Clavien classification system has been proposed to grade perioperative complications. We share our experience in grading the complications of percutaneous nephrolithotomy (PNL), according to this new classification.

Methods

A total of 809 PNLs performed between 2010 and 2014 were reviewed retrospectively. The modified Clavien classification system, which classifies the perioperative complications into 5 grades, was applied. Grade wise comparison of complications between the patients with simple and complex calculi was done. We also carried out a univariate analysis of different predictors of complications after surgery.

Results

A total of 253 perioperative complications were observed in 237 (29.29%) patients. Most complications were related to bleeding and urinary leakage. Patients with complex calculi had significantly more number of complications across all Clavien groups. In a univariate analysis, positive preoperative urine culture and multiple access for stone clearance were identified to be the independent predictors of complications.

Conclusion

The modified Clavien system is a simplistic grading system for classification of postoperative complications. However, it suffers from various shortcomings. Therefore, till the proposition of a more comprehensive classification system, the modified Clavien system is useful for reporting the complications and short-term outcomes of PNL.

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

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.