Purpose <p>Anastomotic leak is a potentially life-threatening complication of colorectal surgery, with perfusion and height of anastomoses considered important risk factors. Indocyanine green (ICG) is commonly used in fluorescence angiography (FA) for perfusion assessment though techniques vary. This is a network meta-analysis comparing use of ICG-FA and height of anastomosis for left sided colorectal anastomoses and rates of anastomotic leak.</p> Methods <p>A systematic review was performed including all adult clinical studies using ICG-FA in colorectal anastomoses. A network meta-analysis was performed to compare high and low anterior resections and the use of ICG for the outcome of anastomotic leak.</p> Results <p>Of some 333 studies retrieved during review, 31 studies were included, totalling 6431 patients. In a meta-analysis to compare high and low anterior resection, with and without ICG, odds of anastomotic leak were greater in low compared to high anastomoses, and ICG is protective in both, OR of 0.38 (0.20–0.73) for high and OR of 0.41 (0.30–0.54) in low anastomoses, with ICG compared to without.</p> Conclusion <p>There is benefit of ICG for both HAR and LAR in reducing anastomotic leak. While there is no consensus on the application, dosage and timing of ICG during anterior resection, pooled results and most studies have shown that the use of ICG to check for tissue perfusion of anastomosis reduces leak. ICG should be considered as part of a surgeon’s armamentarium for intraoperative anastomotic check to reduce the risk of postoperative anastomotic leak.</p>