Cystoscopic submucosal indocyanine green marking in robot-assisted radical nephroureterectomy: a multicenter cohort study

Background Distal ureter and bladder cuff dissection can be difficult during robot-assisted radical nephroureterectomy (RA-RNU) for upper tract urothelial carcinoma (UTUC), particularly in the deep pelvis where tactile feedback is limited. We evaluated cystoscopic submucosal indocyanine green (ICG) marking around the ureteral orifice as a navigation aid for this step. Methods Adults who underwent RA-RNU with formal bladder cuff excision for clinically localized UTUC (≤T3, M0) at three centers between January 2019 and November 2024 were retrospectively analyzed. Outcomes were compared between submucosal ICG-guided and conventional non-ICG procedures. The primary endpoint was video-derived distal ureter and bladder cuff identification time; postoperative care-process measures were descriptive, and other perioperative and oncological outcomes were exploratory. Results The analysis included 82 patients (43 ICG, 39 non-ICG). The ICG group was older, and the largest baseline imbalances by SMD involved age and pathological T stage. Median identification time was 9.0 min with ICG and 19.3 min without ICG (p < 0.001). In the primary parsimonious model, the geometric mean ratio was 0.49 (HC3 95% CI 0.45–0.53; p < 0.001). No statistically significant between-group difference was observed in Clavien–Dindo grade. During exploratory follow-up, intravesical recurrence occurred in 1/43 versus 2/39 patients and extravesical recurrence in 3/43 versus 8/39; event counts were insufficient for comparative inference. Conclusions Submucosal ICG marking around the ureteral orifice was associated with faster distal ureter and bladder cuff identification during RA-RNU. Prospective studies are needed to confirm reproducibility and evaluate injection-specific safety and longer-term oncological outcomes.