Systematic review, meta-analysis and trial sequential analysis of randomized controlled trials on the impact of indocyanine green fluorescence angiography for anastomotic leakage in colorectal surgery

Background Fluorescence angiography (FA) is increasingly used to reduce AL in colorectal surgery, yet conclusive evidence on its protective effect remains limited. This systematic review with meta-analysis and trial sequential analysis (TSA) of randomized controlled trials (RCTs) aimed to assess the effectiveness of FA using indocyanine green (ICG) in reducing anastomotic leakage (AL) and determine whether current evidence is sufficient to draw definitive conclusions. Methods A systematic review was conducted following PRISMA guidelines, with a comprehensive search of PubMed, Embase, Scopus, and Cochrane databases up to March 1, 2026. All RCTs evaluating intraoperative ICG use for AL prevention in colorectal surgery were included. The natural logarithm of the risk ratio [log(RR)] was calculated using random-effects models. The risk of bias was assessed with RoB2, and evidence quality was evaluated using the GRADE framework. Results Seven RCTs involving 4636 patients (2318 ICG, 2318 controls) were included. The AL rate was 7.9% in the ICG group versus 11.6% in the control group (RR 0.69; 95% CI 0.58–0.82; p < 0.001), with negligible heterogeneity (I2 = 0%). TSA demonstrated that the cumulative Z-curve crossed the monitoring boundary for benefit, indicating that the required information size had been reached. Subgroup analysis showed a significant reduction in AL in low colorectal or coloanal anastomoses (RR 0.63; 95% CI 0.51–0.76; p = 0.002). FA significantly reduced both grade A leaks (RR 0.54; 95% CI 0.32–0.92; p = 0.006) and grade B+C leaks (RR 0.67; 95% CI 0.48–0.93; p = 0.006). Postoperative complications were modestly reduced in the ICG group (RR 0.90; 95% CI 0.82–0.99; p = 0.035), while no significant differences were observed in operative time, length of hospital stay, or reoperation rate. Conclusion FA significantly reduces AL rate in colorectal surgery. TSA confirms that the required information size has been reached for the overall analysis, supporting the robustness of this finding. However, the subgroup analysis of low anastomoses has not yet reached the required information size, and further targeted trials are warranted to confirm the benefit in specific subgroups.