On-clamp versus off-clamp robotic partial nephrectomy: A systematic review and meta-analysis

Background: The debate on the pros and cons of robot-assisted partial nephrectomy performed with (on-clamp) or without (off-clamp) renal artery clamping is ongoing. The aim of this meta-analysis is to summarize the available evidence on the comparative studies assessing the outcomes of these two approaches. Material and methods: A systematic review of the literature on PubMed, ScienceDirect (R), and Embase (R) was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement (PRISMA). Only comparative and case-control studies were submitted to full-text assessment and meta-analysis. RevMan 5.3 software was used. Results: From the initial retrieval of 1937 studies, 15 fulfilling inclusion criteria were selected and provided 2075 patients for analysis (702 off-clamp, 1373 on-clamp). Baseline tumor's features showed a significant difference in size (weighted mean difference: -0.58 cm; 95% confidence interval: [-1.06, -0.10]; p = 0.02) and R.E.N.A.L. score (weighted mean difference: -0.53; 95% confidence interval: [-0.81, -0.25]; p = 0.0002), but not in the exophytic property, the location, and the PADUA score. Pooled analysis revealed shorter operative time (p = 0.02) and higher estimated blood loss (p = 0.0002) for the off-clamp group. Overall complication and transfusion rates were similar, while higher major complication rate was observed in the on-clamp approach (5.6% vs 1.9%, p = 0.03). No differences in oncological outcomes were found. Finally, functional outcomes (assessed by estimated glomerular filtration rate at early postoperative, 3 month, 6 month, and last available follow-up) were not statistically different. Conclusion: This meta-analysis shows that off-clamp robot-assisted partial nephrectomy is reserved to smaller renal masses. Under such conditions, no differences with the on-clamp approach emerged.