An Overview of Near Infrared Fluorescent Cholangiography with Indocyanine Green during Cholecystectomy

Laparoscopic cholecystectomy (LC) is one of the most common surgical procedures performed globally but continues to carry to an unacceptably high risk of iatrogenic bile duct injury (BDI). In recent years several centres have proposed Near Infrared Fluorescent Cholangiography (NIRFC) with Indocyanine Green (ICG) as a potential method of dynamic intraoperative extra hepatic bile duct mapping. We provide an overview of the current problem of BDI during laparoscopic cholecystectomy including the incidence, aetiology and medico legal ramifications. We also provide a short summary of the enduring argument for and against routine intraoperative cholangiogram (IOC) and we discuss the new technology of NIRFC with ICG in detail. We provide an informative summary of the small number of highly heterogeneous clinical trials of NIRFC with ICG currently available and briefly discuss limitations of the technology. a potential method of dynamic intraoperative extra hepatic bile duct mapping. ICG is exclusively excreted in the bile after intravenous administration. It rapidly accumulates in the extra hepatic biliary anatomy, which can be visualized with several of the commercially available Near Infrared laparoscopes on the market. NIRFC is convenient to use and could potentially negate the radiation dose and rates of cystic duct injury associated with standard Intraoperative Cholangiogram (IOC). However, data is limited; the published studies are all small, with highly variable methodology, outcome measures and interpretation of results, this is insufficient for a systematic review at the current time. The principles of fluorescence A fluorophore is defined as a substance capable of absorbing and emitting light energy. In the simplest terms, fluorescence is a three-step process of excitation, “relaxation” and emission. Fluorophores exist in a low energy unexcited “ground state” until excited by light of an appropriate wavelength. Once irradiated to the high energy state the fluorophore rapidly start to relax partially dissipating the absorbed energy as vibration or heat energy. The partially relaxed fluorophore then enters the emission phase of fluorescence, releasing the photon of energy as a detectable fluorescent signal of a longer wavelength. Unless, “photo bleached”, irreversible structural damage from high intensity light excitation, or quenched by molecular interaction ABBREVIATIONS BDI: Bile Duct Injury; DLC: Delayed Laparoscopic Cholecystectomy; FL: Fluorescent Light; HCC: Hepatocellular Carcinoma; IALC: Index Admission Laparoscopic Cholecystectomy; ICG: Indocyanine Green; ICGR-15: Indocyanine Green Retention Rate at 15 min; IOUS: Intraoperative Ultrasound; IV: Intravenous; LC: Laparoscopic Cholecystectomy; NICE: National Institute for Health and Care Excellence; NIR: Near Infrared; NIRFC: Near Infrared Fluorescent Cholangiography; OR: Odds Ratio; RCT: Randomized Controlled Trial; RR: Relative Risk; WL: White Light