Higher risk of intraoperative bleeding in right-sided renal tumors compared to left-sided tumors in robot-assisted partial nephrectomy.

Objective: To compare intraoperative blood loss in robot-assisted partial nephrectomy (RAPN) between the right and left sides.

Methods: The data of patients who underwent RAPN at a single institution between 2013 and 2021 were retrospectively analyzed. Using propensity score matching, we compared estimated blood loss (EBL) between right- and left-sided tumors.

Results: This study included 1006 patients who underwent transperitoneal RAPN (N = 726) and retroperitoneal RAPN (N = 280). Through matching, 303 patients were selected for each group. The mean tumor size was 3.1 ± 1.4 cm. The RENAL score was 4-6 in 270 (44.5%), 7-9 in 263 (43.3%), and 10-11 in 73 (12.0%) cases. The EBL on the right side was significantly higher than on the left side (102 vs 70 mL, P = .02). The most experienced surgeon showed significant differences in EBL (116 vs 73 mL, P = .024) and blood transfusion rate (2.5 vs 0%, P = 0.025) between the right and left sides. In the retroperitoneal RAPN, 104 patients were selected in each group through matching. The EBL was significantly higher on the right side than on the left side (50 vs 24 mL, P = 0.02). Operative time was longer on the right side than on the left side (120 vs 109 min, P = .05).

Conclusion: Right-sided tumors had a significantly larger EBL than left-sided tumors in RAPN. The difference was evident in the most experienced surgeon who performed RAPN for larger and complicated cases. This information may help surgeons decide whether to clamp the renal artery and vein during tumor resection in large and complicated right-sided tumors.