On-clamp vs off-clamp robot-assisted partial nephrectomy for achieving modified trifecta: inverse probability of treatment weighting analysis from a high-volume tertiary robotic center

Abstract

On-clamp partial nephrectomy for the surgical treatment of renal masses poses the risk of ischemia and greater post-operative renal function loss. Conversely, the off-clamp technique might enhance renal function preservation by avoiding any ischemia time. Nevertheless, the debate persists regarding the efficacy of the on- versus off-clamp partial nephrectomy in achieving better surgical, functional, and oncological outcomes. We retrospectively assessed the data from patients undergoing Robot-Assisted Partial Nephrectomy (RAPN) from 2016 and 2023 in a tertiary robotic center. Inverse probability of treatment weighting (IPTW) was used to account for selection bias in treatment allocation. The main objective of the study was assessing the achievement rates of a modified trifecta within the two groups. Multivariable logistic regression analysis (MLRA) was employed to assess the predictors of trifecta achievement. 532 patients were included in the analysis, of whom 74.1% vs. 25.9% underwent on- and off-clamp, respectively. Balancing the two groups for the main predictors of on-clamp surgery, there were no significant differences between on- and off-clamp in terms of estimated blood loss, transfusion rate, intra- and post-operative complications, positive surgical margins, and post-operative mean reduction of eGFR. Finally, no differences were found in the rate of "trifecta" achievement between on-clamp and off-clamp RAPN (24.6% vs. 21%, p = 0.82). At MLRA, off-clamp technique was not a predictor of trifecta achievement compared to the on-clamp technique (off-clamp vs. on-clamp, aOR 1.24, 95% CIs [0.65-2.36], p = 0.58). Our study revealed that clamping technique does not imply clinically relevant differences in reaching trifecta outcomes.

Keywords: Off-clamp; On-clamp; Robot-assisted partial nephrectomy; Trifecta.