What is the role of Indocyanine Green (ICG) in cholecystectomy?

Role of Indocyanine Green (ICG) in Cholecystectomy

Indocyanine green fluorescence cholangiography (ICG-C) is a valuable adjunctive tool for visualizing biliary structures during laparoscopic cholecystectomy, providing real-time imaging that may help reduce the risk of bile duct injuries, though it is not yet recommended for routine use to reduce bile duct injury rates. 1

Mechanism and Administration

ICG is cleared by the liver and excreted exclusively into bile, making it ideal for biliary visualization. Following intravenous injection, ICG is rapidly bound to plasma protein (primarily albumin at 95%) and taken up almost exclusively by hepatic parenchymal cells 2. The optimal administration protocol involves:

• Intravenous injection of 0.1 mg/kg ICG approximately 30 minutes before surgery 3
• The dye remains visible in the biliary system for approximately 2 hours after administration 4
• No significant adverse reactions have been reported with low-dose ICG administration 3

Benefits in Laparoscopic Cholecystectomy

ICG fluorescence cholangiography offers several advantages:

• Provides real-time, non-invasive imaging of extrahepatic biliary structures 1
• Enables earlier visualization of the common bile duct and cystic duct compared to conventional imaging 4
• Reduces operative time compared to traditional intraoperative cholangiography (from 117.9 to 86.9 minutes) 3
• Particularly valuable in difficult cases with inflammation, obesity, or anatomical variations 3
• May help establish the critical view of safety (CVS) more efficiently 5

Comparison with Other Techniques

When compared to traditional intraoperative cholangiography (IOC):

• ICG-C is non-invasive and does not require radiation exposure 1
• Studies comparing ICG-C to IOC found no significant differences in visualization of the cystic duct, common bile duct, or common hepatic duct 1
• ICG-C is quicker to perform and easier to integrate into the surgical workflow 4

Impact on Bile Duct Injury Prevention

Bile duct injury (BDI) is the most feared complication during laparoscopic cholecystectomy, occurring in approximately 0.4% of elective procedures and 0.8% of emergency procedures 1:

• Recent systematic reviews suggest ICG shows a trend toward lower BDI rates compared to conventional white light, though the difference has not reached statistical significance 6
• The "Critical View of Safety Plus" approach (combining traditional CVS with ICG fluorescence) may improve surgeon confidence in identifying biliary structures before clipping and cutting 5
• The greatest benefits are observed in anatomically challenging cases 6

Alternative Application Methods

While standard practice involves preoperative intravenous administration, alternative techniques include:

• Direct gallbladder ICG injection: The gallbladder is punctured to aspirate bile, which is then mixed with ICG solution and reinjected to fluoresce the gallbladder, cystic duct, and common bile duct 7
• This technique provides immediate visualization of extrahepatic biliary structures and clarifies the dissection plane between the gallbladder and liver bed 7

Current Guidelines and Recommendations

According to the 2021 World Society of Emergency Surgery (WSES) guidelines:

• ICG-C is considered a promising non-invasive tool to visualize biliary structures during laparoscopic cholecystectomy 1
• However, routine use to reduce the BDI rate is not yet recommended (Weak recommendation, low quality of evidence) 1
• A recent survey of 3,411 experienced surgeons found that the use of adjuncts such as IOC, ICG-C, or intraoperative ultrasound was not significantly associated with a lower risk of BDIs 1

Clinical Considerations and Pitfalls

Important considerations when using ICG fluorescence include:

• Timing of administration is crucial - administering too early or too late may result in suboptimal visualization
• ICG should be considered as an adjunct to, not a replacement for, proper surgical technique and the critical view of safety
• Equipment availability varies between institutions, which may limit implementation
• The technique is most beneficial in difficult cases where anatomy identification is challenging

In conclusion, while ICG fluorescence cholangiography shows promise in improving visualization of biliary anatomy during laparoscopic cholecystectomy, it should be viewed as a complementary tool to established safety practices rather than a standalone solution for preventing bile duct injuries.