Intraoperative use of indocyanine green fluorescence imaging in rectal cancer surgery: The state of the art.

Indocyanine green (ICG) fluorescence imaging is widely used in abdominal surgery. The implementation of minimally invasive rectal surgery using new methods like robotics or a transanal approach required improvement of optical systems. In that setting, ICG fluorescence optimizes intraoperative vision of anatomical structures by improving blood and lymphatic flow. The purpose of this review was to summarize all potential applications of this upcoming technology in rectal cancer surgery. Each type of use has been separately addressed and the evidence was investigated. During rectal resection, ICG fluorescence angiography is mainly used to evaluate the perfusion of the colonic stump in order to reduce the risk of anastomotic leaks. In addition, ICG fluorescence imaging allows easy visualization of organs such as the ureter or urethra to protect them from injury. This intraoperative technology is a valuable tool for conducting lymph node dissection along the iliac lymphatic chain or to better identifying the rectal dissection planes when a transanal approach is performed. This is an overview of the applications of ICG fluorescence imaging in current surgical practice and a synthesis of the results obtained from the literature. Although further studies are need to investigate the real clinical benefits, these findings may enhance use of ICG fluorescence in current clinical practice and stimulate future research on new applications.