Level-1 Evidence for ICG in Laparoscopic Cholecystectomy

Similarly, the RCT-only meta-analysis did not demonstrate a significant reduction in postoperative complications. (ScienceDirect)

Therefore:

ICG improves visualization ≠ proven reduction in complications.

Question 6

Does ICG shorten operative time?

Answer: The evidence is inconsistent.

The RCT-only meta-analysis did not establish a statistically significant reduction in operative time across the included randomized trials. (ScienceDirect)

Interestingly, broader meta-analyses combining RCTs with observational studies have reported shorter operative times.

For example, a 2025 meta-analysis of 26 studies involving 4,436 patients reported approximately a 12-minute reduction in operative time with fluorescence-guided LC. However, this analysis combined randomized and non-randomized evidence and therefore should not be confused with Level-1 evidence. (ScienceDirect)

Expert interpretation

ICG may improve operative efficiency, but the RCT evidence is not yet strong enough to make reduced operative time a principal indication for its use.

Question 7

Is ICG better than conventional X-ray cholangiography?

This is a different question.

ICG does not necessarily have to compete with IOC.

It offers a different approach.

ICG

• non-invasive
• real-time
• no radiation
• no duct cannulation
• rapid
• repeatable
• provides continuous fluorescence during dissection.

IOC

• requires duct cannulation
• uses contrast
• uses radiation
• provides an anatomical cholangiogram
• can demonstrate filling defects/stones
• can help identify ductal injury.

The randomized evidence comparing these technologies is therefore particularly interesting.

The RCT evidence to date does not establish ICG as a universal replacement for IOC.

This distinction becomes especially important when there is:

• suspected bile duct injury
• uncertain anatomy
• suspected choledocholithiasis
• need for a complete cholangiogram.

Question 8

What is the optimal ICG dose?

This is another question that RCTs have addressed.

Huang et al. conducted a randomized trial specifically to determine the optimal ICG dose when administered approximately 30 minutes before LC.

The trial compared:

• 0.025 mg
• 0.1 mg
• 0.25 mg
• 2.5 mg

and assessed fluorescence intensity of the CBD and liver. (PubMed)

This is an important concept because:

More ICG does not necessarily mean better imaging.

Too much ICG can increase liver fluorescence and create a high background signal, potentially reducing biliary contrast.

Therefore the practical goal is not:

maximum fluorescence

but:

maximum biliary-to-background contrast.

Question 9

Does the timing of ICG administration matter?

Yes—and this remains an evolving area of RCT research.

The practical problem is obvious.

If ICG is administered:

too early

→ hepatic background fluorescence may remain substantial.

If administered:

too late

→ adequate biliary excretion may not yet have occurred.

This has generated dedicated randomized studies examining:

• dose
• timing
• administration immediately before surgery
• administration several hours before surgery.

The more recent DOTIG trial specifically randomized patients according to dose and timing, reflecting the fact that the clinical question is no longer simply:

“Does ICG work?”

but increasingly:

“What is the optimal way to use ICG?”

Question 10

Does ICG work equally well in acute and severe cholecystitis?

This is one of the most important unanswered questions.

And here the evidence is surprisingly limited.

The She RCT directly studied acute cholecystitis. But it included only 92 patients. (PubMed)

Most of the major randomized trials—including FALCON—studied elective LC rather than exclusively severe acute cholecystitis. (PubMed)

Therefore we cannot simply take the results of elective LC trials and say:

“ICG is proven in acute cholecystitis.”

That would be an inappropriate extrapolation.

The acute-cholecystitis paradox

There is an interesting surgical paradox.

The more difficult the anatomy becomes…

the more attractive ICG becomes.

But:

The more severe the inflammation becomes…

the harder fluorescence may become to interpret.

Inflammation can produce:

• edema
• adhesions
• thickened tissues
• exudate
• distorted Calot’s triangle
• dense inflammatory tissue.

Therefore, the very patient in whom we most want anatomical guidance may also be the patient in whom visualization becomes technically challenging.

This is why ICG should be regarded as:

an adjunct to anatomy—not a substitute for anatomy.

Question 11

Can ICG replace the Critical View of Safety?

Absolutely not.

This is perhaps the most important practical message.

ICG can show the biliary tree.

But visualization does not automatically establish that the structure in front of the surgeon is safe to divide.

The surgeon still needs to:

1. identify the anatomy;
2. obtain the CVS whenever safely possible;
3. interpret the fluorescence together with white-light anatomy;
4. recognize discrepancies;
5. stop dissection when anatomy becomes unsafe;
6. use an appropriate bailout strategy when CVS cannot be achieved.

Therefore:

ICG should complement CVS—not replace CVS.

Question 12

Can ICG tell us when to perform a bailout?

This has not been adequately answered by RCTs.

This is one of the most clinically relevant unanswered questions.

Suppose the fluorescence image shows:

CBD → CHD → cystic duct

but Calot’s triangle remains severely inflamed.

Should the surgeon:

A. Continue dissection?

B. Subtotal cholecystectomy?

C. Fundus-first approach?

D. Convert to open surgery?

E. Obtain IOC?

There is currently insufficient Level-1 evidence to tell us which decision produces the best outcome.

This is exactly where future RCTs should focus.

Question 13

Does ICG prevent major bile duct injury in difficult cholecystectomy?

Still unanswered.

This is perhaps the ultimate question.

The current RCT evidence demonstrates:

better anatomical visualization

but has not demonstrated:

fewer bile duct injuries.

A recent 2026 meta-analysis specifically examining difficult LC similarly concluded that ICG has potential advantages but that the evidence remains heterogeneous and insufficient for definitive conclusions. (PubMed)

What Level-1 evidence can we confidently say today?

The evidence ladder

🟢 Established

ICG improves real-time visualization of biliary anatomy.

Particularly:

CBD identification

This is supported by randomized evidence and the 2025 RCT-only meta-analysis. (ScienceDirect)

🟡 Probable / promising

ICG may:

• facilitate anatomical orientation
• assist CVS
• improve operative workflow
• help in difficult anatomy.

🟠 Uncertain

Whether ICG:

• reduces operative time
• reduces conversion
• reduces postoperative complications
• improves outcomes in difficult LC.

🔴 Not yet proven

Whether ICG:

reduces bile duct injury.

And specifically:

whether it reduces bile duct injury in acute/severe cholecystitis.

The real lesson from the RCTs

The evidence does not support saying:

“ICG makes laparoscopic cholecystectomy safe.”

A much more scientifically accurate statement is:

ICG makes the biliary anatomy more visible.

And visibility can potentially improve decision-making.

But:

visibility → interpretation → surgical judgment → safe dissection

are four different steps.

ICG addresses primarily the first two.

The surgeon remains responsible for the last two.

What should future RCTs answer?

This is where your proposed AI Retrieval Blog concept becomes particularly powerful.

Instead of asking one broad question—

“Does ICG work?”

we should ask the individual questions that matter to surgeons.

Future Level-1 questions

1. Does ICG reduce bile duct injury in acute cholecystitis?

2. Does ICG reduce bile duct injury in difficult cholecystectomy?

3. Does ICG reduce conversion to open surgery in acute cholecystitis?

4. Does ICG reduce the need for bailout procedures?

5. Does ICG improve achievement of CVS in severe acute cholecystitis?

6. What is the optimal dose of ICG?

7. What is the optimal timing of ICG?

8. Is ICG superior or complementary to IOC?

9. Can ICG safely guide the decision to continue dissection versus bailout?

10. Does ICG improve outcomes in gangrenous cholecystitis?

11. Does ICG improve outcomes in Grade III acute cholecystitis?

12. Is ICG particularly beneficial in obesity, fibrosis or previous inflammation?

13. Can ICG reduce major complications without increasing operative time?

14. Does routine ICG provide enough benefit to justify its cost?

15. Should ICG be selective rather than routine?

These are the questions that the next generation of RCTs needs to answer.

The Bottom Line

What does Level-1 evidence currently support?

ICG fluorescence cholangiography is an effective anatomical visualization adjunct during laparoscopic cholecystectomy.

The strongest randomized evidence supports improved identification of the common bile duct. The FALCON trial and other RCTs provide evidence regarding anatomical orientation and CVS-related workflow, while dedicated dose/timing RCTs are beginning to define how the technology should be used. (PubMed)

However:

Better visualization has not yet translated into proven reduction in bile duct injury.

And in acute cholecystitis, the evidence is particularly limited: the key emergency RCT enrolled only 92 patients and found no significant difference in conversion or complications. (PubMed)

Therefore, the scientifically appropriate position in 2026 is:

ICG is an anatomical navigation tool—not a bailout strategy, not a replacement for the Critical View of Safety, and not yet a proven bile-duct-injury prevention technology.

Its greatest current value may be in helping the surgeon see, orient, verify and reassess biliary anatomy during difficult laparoscopic cholecystectomy.

The next generation of adequately powered RCTs should move beyond the question “Can we see the duct?” and answer the question surgeons actually care about:

“Does seeing the duct better make the operation safer?”