Near-Infrared Indocyanine Green-Enhanced Fluorescence and Minimally Invasive Colorectal Surgery: Review of the Literature.

Background: Leakage of the anastomosis after colonic/rectal surgery is a serious complication. One of the most important causes of anastomotic leakage is impaired vascularization. A microvascular tissue deficit is very often not intraoperatively de visu detectable under white light. Near-infrared indocyanine green (ICG)-enhanced fluorescence is a cutting-edge technology that may be useful for detecting microvascular impairment and potentially preventing anastomotic leakage.
Aim: The aim of this narrative review was to evaluate the feasibility and the usefulness of intraoperative assessment of vascular anastomotic perfusion in colorectal surgery using an indocyanine green (ICG) fluorescent tracer.
Material and Methods: A PubMed/MedLine, Embase, and Scopus narrative literature review was performed, in which "colorectal surgery" and "indocyanine green" were used as key words. The inclusion criteria were 1) manuscripts written in English; 2) full text is available; 3) topic related to the use of ICG fluorescence for the assessment of tissue perfusion during laparoscopic or robotic colorectal surgery; and 4) sample: adult patients, benign or malignant disease. Exclusion criteria included 1) case reports; 2) topic not related to the use of ICG fluorescence for the evaluation of tissue perfusion during laparoscopic or robotic colorectal surgery; 3) manuscripts that focused solely on other applications of ICG technology; and 4) any study type not showing original data. Results and Critical Discussion: The intraoperative visual assessment of tissue viability under white light may lead to an underestimation of microvascular blood flow impairment. ICG can be safely used in cases of minimally invasive colonic surgery and also low anterior resections. This technology may be useful when deciding whether to intraoperatively change a previously planned resection/anastomotic level, which could decrease theoretically the occurrence of anastomotic leakage.
Conclusions: Near-infrared ICG technology is a very useful approach. Multiple preliminary studies suggest that this technique may be used to predict anastomotic leakage. However, evaluation of the ICG signal is still too subjective. Some reliable scoring/grading parameters related to the ICG signal need to be defined. Additionally, more prospective, randomized, and adequately powered studies are required to completely reveal the true potential of this surgical technological innovation.