The Impact of Zero Ischemia Versus Standard Warm Ischemia on Long-Term Renal Function in Robotic Partial Nephrectomy: A Retrospective Cohort Study

Abstract

Objective: The aim of this study was to evaluate and compare the perioperative, oncological and long-term renal functional outcomes of the zero ischemia (off-clamp) and standard warm ischemia (on-clamp) approaches in patients undergoing robotic partial nephrectomy (RPN).Materials and Methods: This retrospective cohort study examined 56 consecutive patients who underwent RPN for renal masses. The patients were divided into two groups: a zero ischemia group (n = 26) and a warm ischemia group (n = 30). Preoperative demographics, tumour characteristics (RENAL, PADUA and C-index) and perioperative data were recorded. Renal function was assessed using serum creatinine levels and estimated glomerular filtration rates (eGFR) before surgery, on the first day after surgery, and after one year.Results: There were no differences in demographic variables or tumour complexity scores (RENAL, PADUA) between the groups. The C-index score was significantly higher in the zero ischemia group (median 3.1 vs. 1.86, p = 0.001), indicating a more peripheral tumour location. Although postoperative complication (p = 0.494) and positive surgical margin (PSM) (p = 0.140) rates were comparable, estimated blood loss (300 ml vs. 100 ml, p < 0.001) and hospital stay (4 days vs. 3 days, p = 0.001) were higher in the zero ischemia cohort. Both groups experienced an initial deterioration in renal function, but the zero ischemia group’s eGFR and creatinine levels recovered to baseline within one year (p = 0.970). In contrast, the warm ischemia group experienced a significant decline in eGFR that persisted at one year (p = 0.001).Conclusion: The zero ischemia approach in RPN may offer functional advantages, particularly in selected patients, in terms of complete long-term preservation of renal function compared to standard warm ischemia. Despite slightly increased intraoperative bleeding, this approach demonstrates comparable PSM rates, particularly for anatomically suitable, peripherally located tumours.