Anatomy and patient comorbidity in robotic partial nephrectomy: predictors of complexity and outcomes

Robotic partial nephrectomy is the standard nephron-sparing approach for localised renal tumours. Whether the PADUA score continues to capture surgical complexity in the robotic era, and how patient comorbidity contributes, is uncertain. Retrospective analysis of 197 consecutive patients undergoing transperitoneal robotic partial nephrectomy by a single surgeon at two NHS sites between 2017 and 2024. The primary endpoint was trifecta achievement (warm ischaemia time ≤ 25 min, negative surgical margins, no perioperative complications). Continuous outcomes were tested with Spearman correlation and multivariable linear regression with a formal PADUA × Obesity interaction. Trifecta failure was modelled with multivariable logistic regression. Renal functional recovery was assessed with a linear mixed-effects model. Trifecta achievement was 76.1% (95% CI 69.7 to 81.6) with no significant gradient across PADUA tiers (low 80.6%, moderate 77.4%, high 71.9%; Cochran-Armitage p = 0.339). PADUA correlated with warm ischaemia time (Spearman ρ = 0.20, p = 0.007), operative duration (ρ = 0.17, p = 0.024) and length of stay (ρ = 0.19, p = 0.009). On multivariable regression PADUA independently predicted ischaemia time (β = 0.74 min per point, 95% CI 0.16 to 1.32, p = 0.013); the formal PADUA × Obesity interaction term was non-significant (β = 0.34, 95% CI - 0.88 to 1.56, p = 0.585). Mean eGFR fell at 6 months (75.4 to 71.7 mL/min/1.73 m²; paired n = 135, p < 0.001) and at 12 months (73.5 to 70.3; paired n = 60, p = 0.035), with greater decline in diabetic patients. PADUA predicts ischaemic burden, operative duration and length of stay after robotic partial nephrectomy. Obesity and diabetes contribute additively. An integrated anatomical-patient framework should accompany nephrometry in preoperative assessment, with patient-specific comorbidity profiling informing operative planning, anaesthetic risk and postoperative functional surveillance.