Comparison of functional outcomes of robotic and open partial nephrectomy in patients with pre-existing chronic kidney disease: a multicenter study

Background: We compared renal functional outcomes of robotic (RPN) and open partial nephrectomy (OPN) in patients with chronic kidney disease (CKD), a definite indication for nephron-sparing surgery. Methods: A multicenter retrospective analysis of OPN and RPN in patients with baseline ≥ CKD Stage III [estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2] was performed. Primary outcome was change in eGFR (ΔeGFR, mL/min/1.73 m2) between preoperative and last follow-up with respect to RENAL nephrometry score group [simple (4–6), intermediate (7–9), complex (10–12)]. Secondary outcomes included eGFR decline > 50%. Results: 728 patients (426 OPN, 302 RPN, mean follow-up 33.3 months) were analyzed. Similar RENAL score distribution (p = 0.148) was noted between groups. RPN had lower median estimated blood loss (p < 0.001), and hospital stay (3 vs. 5 days, p < 0.001). Median ischemia time (OPN 23.7 vs. RPN 21.5 min, p = 0.089), positive margin (p = 0.256), transfusion (p = 0.166), and 30-day complications (p = 0.208) were similar. For OPN vs. RPN, mean ΔeGFR demonstrated no significant difference for simple (0.5 vs. 0.3, p = 0.328), intermediate (2.1 vs. 2.1, p = 0.384), and complex (4.9 vs. 6.1, p = 0.108). Cox regression analysis demonstrated that decreasing preoperative eGFR (OR 1.10, p = 0.001) and complex RENAL score (OR 5.61, p = 0.03) were independent predictors for eGFR decline > 50%. Kaplan–Meier analysis demonstrated 5-year freedom from eGFR decline > 50% of 88.6% for OPN and 88.3% for RPN (p = 0.724). Conclusions: RPN and OPN demonstrated similar renal functional outcomes when stratified by tumor complexity group. Increasing tumor age and tumor complexity were primary drivers associated with functional decline. RPN provides similar renal functional outcomes to OPN in appropriately selected patients.