Initial Experience With Robot‐Assisted Nephroureterectomy Using the Hugo Robot‐Assisted Surgery System via a Retroperitoneal Approach: Clinical Comparison With the Transperitoneal Approach

INTRODUCTION: To determine optimal port placement for retroperitoneal robot-assisted radical nephroureterectomy (RANU) using the Hugo robot-assisted surgery system (HRS) and to compare perioperative outcomes and arm interference between transperitoneal and retroperitoneal approaches. METHODS: We retrospectively analyzed 21 patients who underwent RANU for upper tract urothelial carcinoma with HRS at our institution between 2023 and 2025 via a transperitoneal (n = 13) or retroperitoneal (n = 8) approach. For clinical retroperitoneal RANU, four robotic ports were placed 3 cm lateral to the erector spinae and spaced 8 cm medially. We compared patient demographics, perioperative metrics, and the rates of arm interference and system-caused errors from log data. Continuous variables were analyzed using the Mann-Whitney U test, whereas categorical variables were analyzed using the chi-squared test or Fisher's exact test. RESULTS: Total operative, console, and dissection times; blood loss; and transfusion and complication rates were comparable between approaches. One transperitoneal case required conversion to da Vinci because of HRS malfunction. The median number of removed lymph nodes was significantly lower in the retroperitoneal group (p = 0.049). The time from incision to roll-in was shorter in the transperitoneal group (p = 0.015), whereas the time from roll-in to console start favored the retroperitoneal approach (p = 0.045). Arm-interference errors were significantly less common for the retroperitoneal approach (p = 0.011), whereas the frequency of system-caused errors did not differ between the groups. CONCLUSION: Retroperitoneal HRS-RANU was feasible in our cohort and may reduce arm interference; larger studies are needed to confirm this.