Takeaways from International Consensus on Intraoperative Fluorescence Imaging

Intraoperative fluorescence imaging (IFI) is safe, cost-effective, has the potential to enhance patient outcomes, and is useful for training and quality control. That was the initial consensus from a Delphi survey conducted among 19 representatives of the International Society for Fluorescence-Guided Surgery (ISFGS) at its annual meeting in 2019.

More recently, the ISFGS captured the views of 140 international experts, both members and non-members, on the use of IFI in six distinct surgical areas. A consensus was reached on 16 of 29 statements common to all the surveys. These were published at the end of 2022 in the journal Surgery.

“Our main goal for each survey was to identify areas of consensus that could lead to consensus guidelines and those areas of nonconsensus that should drive new research,” says ISFGS President Raul J. Rosenthal, MD, one of three principal investigators leading this effort.

Dr. Rosenthal is Regional Chairman of the Digestive Disease Institute for Cleveland Clinic in Florida and one of the founders of the ISFGS. The society was established in 2014, less than a decade after the first IFI system was approved by the FDA.

“Fluorescence imaging with indocyanine green dye was initially used for eye surgery in the 1950s, but the technique has truly flourished in the last two decades and been applied to a broad range of surgical specialties,” says Dr. Rosenthal.

Areas of focus

Today IFI has four primary functions. It is used to visualize anatomy, assess tissue perfusion, map lymphatic systems, and identify cancer. The Delphi surveys conducted by the ISFGS team focused on its application in six surgical scenarios:

• laparoscopic cholecystectomy
• colorectal surgery
• lymphedema surgery
• gastric cancer surgery
• plastic surgery
• thyroid and parathyroid resections

Consensus achieved

In addition to specialty-specific questions and statements, each survey included generalized statements regarding patient preparation, indocyanine green (ICG) administration, uses, limitations, contraindications, impact, training, and future use. Of those, the following were among the 16 statements that achieved overall consensus defined as ≥70% agreement among responders:

• Allergic reactions to ICG are extremely rare. (99.1%)
• All patients should be asked about possible allergies to iodine, shellfish, or ICG. (95.6%)
• ICG can be used even when informed written consent cannot be provided. (85.4%)
• Fluorescence imaging (FI) significantly enhances anatomical visualization. (95.4%)
• It significantly impacts how procedures are performed. (85.6%)
• It significantly reduces overall procedural risk. (83.7%)

Strong and consistent consensus (95.6%) was observed across all 6 specialties on the statement that the timing of ICG administration is very important. Though opinions were less consistent concerning the importance of ICG dose and concentration, a moderate consensus was achieved as well. There was also general agreement on the need for further research in this area.

The percentage of voters agreeing that IFI with ICG was necessary for all procedures in their surgical scenario varied widely. Routine use was deemed necessary by laparoscopic cholecystectomy, colorectal, and lymphedema surgeons, while selective use was preferred for plastic surgery, gastric cancer surgery, or during thyroid or parathyroid resections.

“Only laparoscopic cholecystectomy experts reached a consensus that IFI is necessary for all cholecystectomy procedures,” noted Dr. Rosenthal. He was not surprised by this particular finding in light of the large international randomized clinical trial he led on near-infrared fluorescent cholangiography (NIFC). The study found NIFC to be statistically superior to white light alone in visualizing extrahepatic biliary structures during laparoscopic cholecystectomy.

Future research

Notably, the one statement to achieve unanimous consensus across every specialty was that the use of fluorescence imaging in clinical practice is destined to increase over the next decade, while 99% agreed the same is true for research.

“The overwhelming message we can take away from these surveys is that intraoperative fluorescence imaging with indocyanine green is extremely safe, broadly useful, and here to stay,” adds Dr. Rosenthal. “They also show us that there is tremendous work to be done in terms of verifying and optimizing this important tool, especially in establishing procedure-specific dosing and timing guidelines.”