[The use of S.T.O.N.E. scale in patients undergoing percutaneous nephrolithotomy]

The aim of this study was to apply the S.T.O.N.E. scale on our patients undergoing PCNL to predict stone free rate and complications using the modified Clavien scale.

A historical cohort of patients undergoing PCNL was analyzed. All patients with computed tomography to assess stone-free rate with the S.T.O.N.E. scale and complications were evaluated by the modified Clavien scale.

In 102 patients 104 procedures were performed; the mean age was 48.4 years and 71% were women. The distribution of cases were classified as mild: 6.7%, moderate: 63.5% and severe: 29.8%. The stone free rate after the first procedure globally reached 58% and by grade was: mild 85.7%, moderate 71.2% and severe 25%. The RR for residual stones after the first procedure was 2.4 for moderate grade (CI 0.3 to 15, p=0.03) and 4.9 for severe grade (CI 0.7 - 30.9, p=0.08). The overall complication rate was 33%, separately Clavien 1: 14.4%, 2: 9.6%, 3a: 2.9%, 3b: 2.9% 4:1.9%, 5:1%.

The S.T.O.N.E. scale applied in our population can predict accurately and easily stone free rate in patients undergoing PCNL. We found no predictive association for this scale on complications.