Comparison of safety and feasibility of on-clamp versus off-clamp robotic partial nephrectomy

Robot-assisted partial nephrectomy (RAPN) is currently the gold standard for localized renal tumors. The surgical approach can be performed using either an on-clamp or off-clamp technique. The aim of the study is to evaluate differences in positive surgical margins (PSMs) and perioperative complications between on-clamp and off-clamp approaches of RAPN, at all levels of tumor complexity.

We retrospectively enrolled 478 patients who underwent RAPN between 1/2020 and 6/2024 and divided into two groups: A (on-clamp) and B (off-clamp). We stratified tumor complexity according to the RENAL score and analyzed all perioperative and oncological outcomes: PSMs, post-operative creatinine changes, intra- and post-operative complications, duration of procedures. For multivariate statistical analysis we used the Chi-square test.

In 83 procedures clamping of the main renal artery was performed (in no case was selective clamping performed). Median value for duration of clamping was 16 minuts. In patients who have undergone ischemia, the duration of ischemia is correlated with the increase in postoperative creatinine (p < 0.001). There was a significant difference in the duration of the procedures between the two groups: group A (median value 90'), group B (median value 120') (p < 0.001) while no difference regarding perioperative complications (p = 0.34) or PSMs (p = 0.73).

Both the on-clamp and off-clamp approaches are considered safe and feasible, provided there is adequate surgical experience. The complication rate was similar, as were the oncological outcomes and but post-operative creatinine increases proportionally to the duration of ischemia. In on-clamp procedures the increase in postoperative creatinine is directly related to the duration of ischemia. The off-clamp procedure is shorter with no difference in surgical and oncological outcomes.