Comparative Outcomes between Off-Clamp and On-Clamp Nephron-Sparing Surgery – A Retrospective Analysis

Objective: To compare perioperative and functional outcomes between off-clamp and on-clamp techniques during nephron-sparing surgery (NSS). Methods & Materials: A retrospective study of 70 patients who underwent NSS for renal tumors between January 2020 and July 2025. Patients were divided into two groups: Off-Clamp NSS (Group A, n=34) and On-Clamp NSS (Group B, n=36). Data on operative time, estimated blood loss (EBL), warm ischemia time (WIT), complications, and renal functional outcomes (eGFR changes) were analyzed. Results: Group A showed significantly higher EBL (p=0.02) but better postoperative renal function preservation (mean eGFR drop: 5.6% vs 11.4%, p<0.001). Group B had shorter operative times and less intraoperative bleeding. No significant difference was observed in complication rates or oncologic margin positivity. Conclusion: Off-clamp NSS offers superior renal functional preservation compared to on-clamp NSS at the expense of higher blood loss. Patient selection remains crucial, and off-clamp NSS may be particularly beneficial in younger patients with baseline impaired renal function.