Off-clamp Versus On-clamp Robot-assisted Partial Nephrectomy: A Propensity-matched Analysis

Area of Science:

• Urology
• Nephrology
• Surgical Oncology

Background:

• Partial nephrectomy is the standard treatment for small renal masses.
• On-clamp partial nephrectomy risks renal function loss due to ischemia.
• Off-clamp partial nephrectomy aims to minimize ischemia for better renal function preservation, but its efficacy is debated.

Purpose of the Study:

• To compare perioperative and functional outcomes of off-clamp versus on-clamp robot-assisted partial nephrectomy (RAPN).
• To evaluate the impact of clamping strategy on renal function preservation after RAPN.

Main Methods:

• Prospective data from the Vattikuti Collective Quality Initiative (VCQI) database for RAPN.
• Propensity score matching was used to compare outcomes between off-clamp and on-clamp RAPN groups.
• Key outcomes included intraoperative and postoperative complications, need for blood transfusion, conversion to radical nephrectomy, and changes in estimated glomerular filtration rate (eGFR).

Main Results:

• After propensity matching, 205 patients (102 off-clamp, 103 on-clamp) were analyzed.
• No significant differences were observed in intraoperative or postoperative complications between the groups.
• The off-clamp group showed significantly higher rates of blood transfusion (2.9% vs 0%) and conversion to radical nephrectomy (10.2% vs 1%).
• Renal function, assessed by creatinine and eGFR, showed no significant difference between the groups at the last follow-up, with equivalent mean eGFR decline.

Conclusions:

• Off-clamp RAPN does not offer superior renal functional preservation compared to the on-clamp technique.
• The off-clamp approach is associated with an increased risk of blood transfusion and conversion to radical nephrectomy.
• The study suggests that the benefits of off-clamp RAPN in renal function preservation are not evident in this large, multinational cohort.