Indocyanine green fluorescence angiography for prevention of anastomotic leak in colorectal surgery: a graded systematic review and meta-analysis with trial sequential analysis of randomized controlled trials.

BACKGROUND: Anastomotic leak (AL) is a major driver of morbidity after colorectal resection. Indocyanine-green fluorescence angiography (ICG-FA) provides real-time intraoperative perfusion assessment, but its impact across randomized trials remains debated. This review aims to evaluate the efficacy and safety of ICG-FA compared with conventional intraoperative assessment in preventing AL in colorectal surgery. METHODS: A systematic review and a meta-analysis was conducted in accordance with the PRISMA guidelines, including RCTs comparing ICG-FA with conventional assessment. The primary outcome was overall AL; secondary outcomes included leak grade, anatomic location, operative metrics, and change in surgical plan (CISP). Pooled risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CI) were calculated using random- or fixed-effects models. Trial sequential analysis (TSA) was used to evaluate evidence sufficiency. RESULTS: Eight RCTs (n = 4712) met the inclusion criteria. ICG-FA reduced overall AL versus control (risk ratio [RR] 0.68, 95% CI 0.58-0.81; I2 = 0%). The absolute risk reduction was 3.6%, yielding a number needed to treat of around 24 to prevent one leak. TSA crossed the superiority boundary for the primary endpoint, indicating sufficient evidence of the assumed control risk and effect size. Benefits were more apparent for left-sided anastomoses and for lower-grade leaks (A and A + B), whereas severe (Grade C) leaks and reoperation did not differ significantly. Overall complications showed a small relative reduction, but TSA indicated insufficient information size. Other safety outcomes (surgical site infection, ileus, mortality) were similar between groups. CONCLUSIONS: High-certainty evidence demonstrates that ICG-FA reduces overall and low-grade AL, principally in left-sided resections, without prolonging operative time. ICG-FA should be considered an evidence-based adjunct to optimize perfusion assessment in colorectal surgery. REGISTRATION: PROSPERO CRD420251139372.