1532 PREDICTION OF SINGLE PROCEDURE SUCCESS RATE USING S.T.O.N.E. NEPHROLITHOMETRY SURGICAL CLASSIFICATION SYSTEM WITH STRICT CRITERIA FOR SURGICAL OUTCOME

Evaluation of various nephrometric scoring system for nephrolithiasis to predict stone free status after percutaneous nephrolithotomy: A comparative study

BACKGROUND

The CROES Nephrolithometry nomogram, S.T.O.N.E. Nephrolithometry Score and Guy's stone score were introduced for stratification of kidney stones disease on the basis of quantitative stone burden and its distribution. Till date there has been very limited data on head to head comparison of the existing scoring systems. Comparison and analyses among the scoring system helps in further refinement of these systems along with development of new more effective and broadly acceptable nomogram.

OBJECTIVE

Predictability of the stone-free status (SFS) and post-operative complication after PCNL by various scoring systems (The CROES nomogram, S.T.O.N.E. nephrolithometry score and Guy's stone score).

MATERIALS AND METHODS

Total 100 adult patients underwent PCNL after considering inclusion and exclusion criteria. All patients underwent Preoperative NCCT scan, investigations of blood (Hb%, PCV, bleeding and coagulation profile, urea, and creatinine), and urine (RE/ME and C/S), Postoperative X ray KUB/NCCT.

RESULTS

ROC curves were developed for each scoring system to determine the accuracy to predict stone free status. We found CS had significantly higher AUC than other scoring systems [p-value for CS vs GSS = 0.0091 & CS vs SS = 0.000]. So CS has higher accuracy to predict stone free status. None of the scoring system had shown significantly higher AUC than other scoring system in predicting complication.

CONCLUSION

CROES Nephrolithometry nomogram is most accurate to predict preoperative stone-free rate. All scoring systems can equally predict perioperative complications and other variables.

Contemporary assessment of renal stone complexity using cross-sectional imaging

Recently, several scoring systems have been proposed to predict outcomes of percutaneous nephrolithotomy, objectively and quantitatively assessing kidney calculi complexity using cross-sectional imaging. These scoring systems are promising new tools that can guide surgical decision making, predict surgical outcomes, counsel patients undergoing stone surgery, and improve standardized academic reporting in percutaneous kidney stone surgery. In this article, we review features of each of these systems, their similarities and differences, and their applicability in clinical practice and relevance in academic reporting.

Evaluation and comparison of urolithiasis scoring systems used in percutaneous kidney stone surgery

PURPOSE

Contemporary predictive tools for percutaneous nephrolithotomy outcomes include the Guy stone score, S.T.O.N.E. nephrolithometry and the CROES nephrolithometric nomogram. We compared each scoring system in the same cohort to determine which was most predictive of surgical outcomes.

METHODS

We retrospectively reviewed the records of patients who underwent percutaneous nephrolithotomy between 2009 and 2012 at a total of 3 academic institutions. We calculated the Guy stone score, the S.T.O.N.E. nephrolithometry score and the CROES nephrolithometric nomogram score based on preoperative computerized tomography images. A single observer at each institution reviewed all images and assigned scores. Univariate and multivariate analysis was done to determine the most predictive scoring system.

RESULTS

We enrolled 246 patients in study. In stone-free patients vs those with residual stones the mean Guy score was 2.2 vs 2.7, the mean S.T.O.N.E. score was 8.3 vs 9.5 and the mean CROES nomogram score was 222 vs 187 (each p <0.001). Logistic regression revealed that the Guy, S.T.O.N.E. nephrolithometry and CROES nomogram scores were significantly associated with stone-free status (p = 0.02, 0.004 and <0.001, respectively). The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss (p <0.0001 and 0.03) and length of stay (p = 0.03 and 0.009, respectively). The CROES nomogram did not predict estimated blood loss or length of stay.

CONCLUSIONS

All scoring systems and the stone burden equally predicted stone-free status. The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss and length of stay. A single scoring system should be adopted to unify reporting.