Off-Clamp Robotic-Assisted Partial Nephrectomy: Retrospective Comparative Analysis from a Large Italian Multicentric Series.

Objective: To evaluate the perioperative outcomes, functional impact, and oncologic efficacy of off-clamp robotic-assisted partial nephrectomy (RAPN) in patients with renal masses across multiple high-volume centers.

Materials And Methods: We conducted a retrospective multicenter study including 563 patients (group 1) who underwent clampless RAPN between January 2018 and December 2024. Patients with solitary kidneys, tumors >7 cm, or prior renal surgery were excluded. The standardized surgical technique involved tumor resection without clamping of the renal artery, followed by the use of hemostatic agents and standard/selective suturing of the resection bed on demand. Patients in group 1 were compared to 244 consecutive patients treated in the same centres and treated with RAPN with an on-clamp procedure (group 2). Primary outcomes included operative time, blood loss, and complications, while secondary outcomes assessed renal function preservation and oncologic control at an at least 12-month follow-up.

Results: The median operative time was 118 min (IQR: 100-140 min), and median estimated blood loss was 150 mL (range: 50-400 mL). The overall complication rate was 9.2%, with most classified as Clavien-Dindo Grade I-II. No intraoperative conversions to open surgery were recorded. Renal function was well preserved, with a median estimated glomerular filtration rate (eGFR) decline of 4.1% at three months ( > 0.05), and no cases of acute kidney injury. Oncologic outcomes were favorable, with a positive surgical margin rate (PSM) of 2.4% and two cases of tumor recurrences (0.36%) documented at a 12-month follow-up.

Conclusions: The off-clamp RAPN is a safe and effective nephron-sparing approach, offering significant renal function preservation while maintaining oncologic efficacy. This technique minimizes ischemia-reperfusion injury and post-surgical fibrosis, providing a viable alternative to on-clamp RAPN. Further prospective trials are warranted to confirm long-term benefits and refine patient selection criteria.