Mayo Adhesive Probability Score Adds Predictive Value Beyond PADUA and RENAL to Predict Surgical Complexity in Patients Undergoing Single Port Robotic Partial Nephrectomy: A Multi-Institutional Study

Background and Objective: Standard nephrometry scores characterize renal tumor anatomy but not adherent perinephric fat, which may influence exposure during single-port (SP) robot-assisted partial nephrectomy (RAPN). We evaluated whether Mayo Adhesive Probability (MAP) score is associated with operative difficulty and adds value beyond PADUA and RENAL scores. Methods: Retrospective multi-institutional analysis of 325 patients in the SP Advanced Research Consortium undergoing SP-RAPN with imaging and operative data. MAP was calculated from posterior perinephric fat thickness and perinephric fat stranding. Primary outcome: operative time; secondary outcomes: estimated blood loss (EBL), warm ischemia time (WIT). Log-linear regression adjusted for nephrometry score, age, BMI, and surgical approach. Incremental model fit was assessed by likelihood-ratio testing and Akaike Information Criterion (AIC) in fully adjusted nested models, with additional center-adjusted sensitivity analyses. Results: Each 1-point MAP increase was independently associated with longer operative time in RENAL-adjusted (+9.5%, 95% CI: 6.1–13.0; p < 0.001) and PADUA-adjusted (+6.5%, 95% CI: 3.6–9.5; p < 0.001) models. After center adjustment, these associations persisted (+5.0% and + 6.6% per point, respectively; both p < 0.001). MAP was associated with greater EBL in the primary model (+11.2%, 95% CI: 2.6–20.6; p = 0.010), but this association was attenuated after center adjustment (+6.0%, 95% CI: −2.4% to 15.1%; p = 0.168). MAP was not associated with WIT. Adding MAP improved model fit beyond RENAL (AIC reduction 28.7) and PADUA (AIC reduction 17.6; both p < 0.001). Postoperative complications occurred in 14.2%, major complications in 3.1%, and 30-day readmission in 8.3%. Conclusions: MAP complements nephrometry by capturing the perinephric dissection environment. Incorporating MAP into SP-RAPN assessment may provide complementary information for planning, counseling, and risk adjustment.