Exploratory Evaluation of Combined RENAL Nephrometry and Mayo Adhesive Probability Scores for Perioperative Outcomes in Radical Nephrectomy

Background: The RENAL Nephrometry Score evaluates renal tumor complexity, while the Mayo Adhesive Probability (MAP) score predicts Adherent Perinephric Fat during nephrectomy. Although both are useful in partial nephrectomy planning, their role in radical nephrectomy (RN) remains unclear. This study assessed whether combining the RENAL and MAP scores improves the prediction of perioperative outcome after RN. Methods: In this retrospective study, 52 patients who underwent radical nephrectomy for presumed renal malignancy at a tertiary care hospital in Saudi Arabia between January 2024 and June 2025 were analyzed. RENAL and MAP scores were calculated from preoperative CT scans. Primary outcomes included intraoperative complications, operative time, and length of hospital stay. Associations were evaluated using Spearman correlation, ROC curve analysis, and logistic regression. Given the limited sample size and low event rate, all analyses were considered exploratory. Results: Only clinically significant complications, classified as Clavien–Dindo Grade IIIb, were observed, representing 11.5%. Neither RENAL nor MAP scores, alone or combined, showed significant associations with intraoperative complications, blood loss, or operative duration. The RENAL score demonstrated a modest correlation with length of hospital stay (r = 0.294, p = 0.035), whereas the MAP score showed a weaker, non-significant correlation (r = 0.191, p = 0.175). ROC analysis indicated limited predictive performance for complications (RENAL AUC = 0.377, p = 0.330; MAP AUC = 0.732, p = 0.067; combined AUC = 0.638, p = 0.276). Logistic regression revealed that neither score nor key clinical variables were independent predictors. Conclusions: RENAL and MAP scores were not statistically significantly associated with perioperative outcomes in this exploratory cohort.