S.T.O.N.E. nephrolithometry: novel surgical classification system for kidney calculi.

Area of Science:

• Urology
• Nephrology
• Medical Imaging

Background:

• Current methods for predicting percutaneous nephrolithotomy (PCNL) outcomes are limited.
• There is a need for a validated, clinically useful scoring system for PCNL.

Purpose of the Study:

• To introduce a novel scoring system, S.T.O.N.E. nephrolithometry, for standardizing PCNL reporting.
• To assess the system's ability to predict stone-free rates and perioperative parameters in PCNL.

Main Methods:

• Developed the S.T.O.N.E. score using five preoperative CT variables: stone size (S), tract length (T), obstruction (O), number of involved calices (N), and stone density (E).
• Included 117 patients undergoing PCNL.

Main Results:

• The S.T.O.N.E. score correlated significantly with postoperative stone-free status (P=.001).
• Lower scores predicted successful stone removal (6.8 vs 9.7, P=.002).
• The score also correlated with estimated blood loss, operative time, and hospital stay (P=.001 for all).

Conclusions:

• The S.T.O.N.E. nephrolithometry system effectively predicts PCNL treatment success and complication risk.
• Standardized CT-derived parameters can enhance preoperative counseling, surgical planning, and outcome evaluation.