Correlation between S.T.O.N.E score and channel size selection in percutaneous nephrolithotomy

The S.T.O.N.E. score was significantly associated with tract size selection in PCNL. Among patients with high S.T.O.N.E. scores, SPCNL yielded higher stone-free rates and shorter operative times with similar safety compared to MPCNL, supporting the use of standard tracts in this group. In low-score patients, SPCNL and MPCNL demonstrated comparable efficacy, whereas MPCNL resulted in fewer complications. Multivariable analysis identified the S.T.O.N.E. score and operative time as independent risk factors for residual stones, while larger tract size was an independent protective factor. These findings suggest that the S.T.O.N.E. score may guide personalized tract size selection in PCNL.