Abstract
<jats:p>Introduction: Accurate preoperative characterization of renal tumor anatomy is essential for partial nephrectomy. Although the R.E.N.A.L. nephrometry score is widely used to assess tumor complexity, its interpretation using conventional computed tomography (CT) may vary among observers. We evaluated whether three-dimensional (3D) reconstruction improves the consistency of preoperative R.E.N.A.L. score assessment. As a secondary objective, perioperative outcomes were compared between patients planned with CT plus 3D reconstruction and those planned with CT alone. Materials and Methods: A retrospective observational study included 55 patients who underwent partial nephrectomy between March 2023 and March 2025. Three experienced urologists independently assigned R.E.N.A.L. nephrometry scores using conventional CT and CT-based 3D reconstructions. Interobserver and intraobserver agreement were assessed using Pearson correlation coefficients, weighted Cohen's kappa, and Fleiss' kappa. Perioperative outcomes were analyzed in a comparable control cohort planned using CT alone. Results: Three-dimensional reconstruction demonstrated greater interobserver agreement than CT alone for both numerical R.E.N.A.L. scores (57% vs. 43%) and risk categorization (72% vs. 62%). Fleiss' kappa indicated very good agreement with 3D reconstruction (κ=0.804) compared with moderate agreement using CT (κ=0.562). Intraobserver agreement between CT and 3D reconstruction was moderate. No significant differences were observed in operative time, warm ischemia time, blood loss, postoperative renal function, or complication rates. Hospital stay was slightly longer in the 3D group. Conclusions: Three-dimensional reconstruction may represent a valuable complementary tool for improving the consistency of preoperative R.E.N.A.L. nephrometry score assessment. Although greater agreement did not translate into measurable perioperative benefits in this cohort, more reproducible anatomical characterization may contribute to a more standardized framework for surgical planning before partial nephrectomy.</jats:p>