Percutaneous nephrolithotomy for staghorn stones: Which nomogram can better predict postoperative outcomes?

Purpose: To identify independent predictors for postoperative stone-free status after percutaneous nephrolithotomy (PCNL) for staghorn stones and to compare Guy's, CROES and STONE nomograms regarding their predictive ability and accuracy specifically for staghorn stones.

Methods: Data of 286 patients who underwent PCNL in our department were collected and analyzed. Several parameters, including the three nomograms, were analyzed to reveal independent predictors for postoperative stone-free status. The area under the curve was used to assess the predictive ability of the independent predictors.

Results: A total of 73 staghorn calculi were identified with mean stone burden of 1253.5 mm(2). Mean Guy's, CROES and STONE score was 3.34, 125.8 and 9.95, respectively. Postoperative stone-free rate was 65.8 %. In univariate analysis, all three nomograms were significantly associated with stone-free status. However, STONE was the only significant independent predictor in multivariate analysis. STONE also revealed the highest predictive accuracy compared to Guy's and CROES nomogram.

Conclusions: STONE nephrolithometry was found to be the only predictor for stone-free rate after PCNL for staghorn stones compared to Guy's and CROES nomograms.