The use of indocyanine green for colorectal anastomoses: a systematic review and meta-analysis.

Introduction: Anastomotic leak is a relatively common and debilitating complication. Colorectal leak rates vary widely in the literature, ranging from 1% to 20%. In modern surgical practice, there is much emphasis on the use of indocyanine green (ICG). This is a fluorescent dye administered intravenously to locate and predict an adequate line of anastomosis. We sought to analyse the current literature and supporting evidence behind the use of ICG in the context of elective colorectal surgery.

Methods: A literature search was conducted for papers published between January 1991 and December 2022 concerning the use of ICG in colorectal surgery. Data on anastomotic leak, overall complication rate, operative time and involvement of artificial intelligence (AI) were compared.

Results: A total of 24 studies were selected, including 3 randomised controlled trials. There was an anastomotic leak rate of 4.3% in cases with ICG administration compared with 9.5% in the control group (p<0.00001). Seven studies mentioned overall complication rates. These were lower in the ICG cohort than in the control group (15.5% vs 24.5%). There was no significant correlation between ICG use and operative time (p=0.78). Five studies looked at AI, with results suggesting that use of AI leads to much better accuracy in ICG metric analysis. However, the current literature is still inconclusive.

Conclusions: While there is strong evidence behind ICG use in the existing literature, more randomised controlled trials are required for better recommendations. AI in ICG metric interpretation has proved to be difficult owing to interpatient variability. Nevertheless, new data suggest better understanding and standardisation.