Evaluation of indocyanine green fluorescence guidance in minimally invasive partial nephrectomy stratified by tumor anatomical complexity: a single-center retrospective study

Objectives To evaluate the impact of indocyanine green (ICG) fluorescence guidance on surgical efficiency and renal function during partial nephrectomy (PN), across different tumor anatomical complexities. Methods We retrospectively reviewed 77 consecutive patients with renal cell carcinoma who underwent minimally invasive PN (MIPN, predominantly robot-assisted, n = 76) between April 2024 and August 2025. Patients were grouped into ICG ( n = 31) and non-ICG ( n = 46) cohorts. Outcomes were compared for the whole cohort and stratified by RENAL score (low-complexity < 9 vs. moderate-to-high complexity ≥ 9). Multivariable linear regression and Pearson correlation analyses were performed. Results Baseline characteristics were comparable. Overall, operative time was significantly shorter in the ICG group in unadjusted (139.84 vs. 163.57 min; P = 0.017) and multivariable regression analyses adjusted for tumor size, RENAL score, and surgical approach ( B = −23.808, 95% CI: −41.685 to −5.931, P = 0.010). In the low-complexity subgroup (RENAL score < 9), ICG significantly reduced operative time ( P = 0.038), but this association attenuated after adjusting for tumor size ( P = 0.099). In moderate-to-high complexity cases, no significant difference was detected in unadjusted ( P = 0.357) or adjusted ( B = −28.960, P = 0.067, 95% CI: −60.086 to 2.166) analyses, while larger tumor size independently predicted longer operative time ( B = 12.100, P = 0.014, 95% CI: 2.306 to 21.894). Furthermore, in this high-complexity cohort, shorter operative time was significantly correlated with higher preservation of estimated glomerular filtration rate (eGFR) on postoperative day 1 ( B = −0.002, P = 0.029, 95% CI: −0.003 to −1.920 × 10⁻⁴). Warm ischemia time, blood loss, and complications were similar between groups (all P > 0.05). Conclusion The primary value of ICG fluorescence guidance in MIPN lies in optimizing intraoperative surgical efficiency and shortening operative time; exploratory stratified analyses showed significant operative time reduction with ICG in low-complexity tumors, whereas no significant difference occurred in high-complexity cases. The operative efficiency benefit of ICG in complex cases remains unconfirmed due to limited statistical power. Whether ICG guidance effectively preserves or improves early postoperative renal function remains unknown and requires further investigation.