Retroperitoneal versus transepritoneal robot-assisted partial nephrectomy for postero-lateral renal masses: an international multicenter analysis

Purpose To assess the outcomes of retroperitoneal robot-assisted partial nephrectomy (r-RAPN) in a large cohort of patients with postero-lateral renal masses comparing to those of transperitoneal RAPN (t-RAPN). Methods Patients with posterior (R.E.N.A.L. score grading P) or lateral (grading X) renal mass who underwent RAPN in six high-volume US and European centers were identified and stratified into two groups according to surgical approach: r-RAPN (“study group”) and t-RAPN (“control group”). Baseline characteristics, intraoperative, and postoperative data were collected and compared. Results Overall, 447 patients were identified for the analysis. 231 (51.7%) and 216 (48.3%) patients underwent r-RAPN and t-RAPN, respectively. Baseline characteristics were not statistically significantly different between the groups. r-RAPN group reported lower median operative time (140 vs. 170 min, p < 0.001). No difference was found in ischemia time, estimated blood loss, and intraoperative complications. Overall, 47 and 54 postoperative complications were observed in r-RAPN and t-RAPN groups, respectively (20.3 vs. 25.1%, p = 0.9). 1 and 2 patients reported major complications (Clavien-Dindo ≥ III grade) in the retroperitoneal and transperitoneal groups (0.4 vs. 0.9%, p = 0.9). There was no difference in hospital re-admission rate, median length of stay, and PSM rate. Trifecta criteria were achieved in 90.3 and 89.2% of r-RAPN and t-RAPN, respectively ( p = 0.7). Conclusion r-RAPN and t-RAPN offer similar postoperative, functional, and oncological outcomes for patients with postero-lateral renal tumors. Our analysis suggests an advantage for r-RAPN in terms of shorter operative time, whereas it does not confirm a difference in terms of length of stay, as suggested by previous reports.