Objective: To evaluate the predictive value of volumetric stone measurements including manually calculated stone volume and 3D software–derived volume on stone-free outcomes following mini-percutaneous nephrolithotomy (mini-PCNL), and to assess their relationship with perioperative parameters and commonly used nephrolithometry scoring systems.
Materials amd Methods: This retrospective study was conducted with patients who underwent primary mini-PCNL between January 2024 and January 2025. Preoperative non-contrast computed tomography scans were used to determine the longest stone diameter, surface area, manually calculated stone volume, and 3D software–derived stone volume. Patients were categorized into two groups according to postoperative imaging: stone-free (Group 1) and residual stone (Group 2). Demographic characteristics, stone features, operative parameters, stone complexity scores (GUY’s and STONE) and complication rates were compared between groups.
Results: Of the 80 patients, 61.3% were stone-free postoperatively. Group 2 demonstrated significantly higher manually calculated stone volumes (p = 0.02) and S.T.O.N.E. scores (p = 0.005). Manually calculated and 3D-derived stone volumes both showed significant positive correlations with stone diameter, surface area, nephrolithometry scores, operative time, and laser usage parameters. ROC analysis identified a manually calculated stone volume threshold of 746.9 mm³ for predicting residual fragments (AUC = 0.656, p = 0.02). In the multivariate model, manual stone volume was significantly associated with stone-free status (OR 18.71, p = 0.042).
Conclusion: This study demonstrates a significant association between stone volume and stone-free outcomes after mini-PCNL. While volumetric measurements may provide additional information beyond conventional parameters. Therefore, stone volume should be considered as a complementary parameter rather than a standalone predictor in clinical decision-making.
Keywords: percutaneous nephrolithotomy, stone volume, surface area, stone-free rate
Abstract
Objective: To evaluate the predictive value of volumetric stone measurements including manually calculated stone volume and 3D software–derived volume on stone-free outcomes following mini-percutaneous nephrolithotomy (mini-PCNL), and to assess their relationship with perioperative parameters and commonly used nephrolithometry scoring systems.
Materials amd Methods: This retrospective study was conducted with patients who underwent primary mini-PCNL between January 2024 and January 2025. Preoperative non-contrast computed tomography scans were used to determine the longest stone diameter, surface area, manually calculated stone volume, and 3D software–derived stone volume. Patients were categorized into two groups according to postoperative imaging: stone-free (Group 1) and residual stone (Group 2). Demographic characteristics, stone features, operative parameters, stone complexity scores (GUY’s and STONE) and complication rates were compared between groups.
Results: Of the 80 patients, 61.3% were stone-free postoperatively. Group 2 demonstrated significantly higher manually calculated stone volumes (p = 0.02) and S.T.O.N.E. scores (p = 0.005). Manually calculated and 3D-derived stone volumes both showed significant positive correlations with stone diameter, surface area, nephrolithometry scores, operative time, and laser usage parameters. ROC analysis identified a manually calculated stone volume threshold of 746.9 mm³ for predicting residual fragments (AUC = 0.656, p = 0.02). In the multivariate model, manual stone volume was significantly associated with stone-free status (OR 18.71, p = 0.042).
Conclusion: This study demonstrates a significant association between stone volume and stone-free outcomes after mini-PCNL. While volumetric measurements may provide additional information beyond conventional parameters. Therefore, stone volume should be considered as a complementary parameter rather than a standalone predictor in clinical decision-making.
Keywords: percutaneous nephrolithotomy, stone volume, surface area, stone-free rate