In adult patients undergoing elective colon or rectal resections, does intraoperative indocyanine green (ICG) fluorescence angiography reduce anastomotic leakage rates without increasing safety concerns?

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Last updated: October 25, 2026 • View editorial policy

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ICG Fluorescence Angiography Reduces Anastomotic Leakage in Elective Colorectal Surgery

Intraoperative indocyanine green (ICG) fluorescence angiography should be used during elective colorectal resections, particularly for left-sided and rectal anastomoses, as it significantly reduces anastomotic leak rates without safety concerns. The most recent high-quality evidence demonstrates a 34-42% relative risk reduction in anastomotic leakage, with the greatest benefit seen in left-sided resections 1, 2.

Evidence for Efficacy

The 2025 SAGES systematic review and meta-analysis of 7 RCTs involving 3,887 patients provides the strongest evidence 1. ICG-FA reduced anastomotic leak rates with an odds ratio of 0.58 (95% CI: 0.44-0.75), translating to a number needed to treat of 22 to prevent one leak. This represents high-quality evidence with no heterogeneity between studies (I² = 0%).

The benefit is most pronounced for left-sided resections (OR: 0.59; 95% CI: 0.46-0.75; NNT = 18), while right-sided resections showed no significant benefit (OR: 0.83; p = 0.35) 2. This anatomic distinction is critical for clinical decision-making—ICG-FA should be prioritized for sigmoid, descending colon, and rectal resections where perfusion assessment has the greatest impact on outcomes.

A 2021 meta-analysis of 11 studies with 3,137 patients corroborates these findings, showing ICG-FA reduced anastomotic leakage (OR = 0.31; 95% CI 0.21-0.44), postoperative complications (OR = 0.70), and reoperation rates (OR = 0.334) 3. The consistency across multiple meta-analyses strengthens the recommendation.

Mechanism of Benefit

ICG-FA works by enabling real-time intraoperative assessment of bowel perfusion at the proposed anastomotic site. The 2020 multicenter RCT demonstrated that ICG identified insufficient perfusion in 11% of cases, leading to extended bowel resection to ensure adequate vascularization 4. While this study showed a trend toward reduced leaks (5% vs 9%, p = n.s.), the sample size limited statistical power—subsequent pooled analyses confirmed the benefit.

Historical guideline evidence supports the fundamental principle: tension-free anastomosis and adequate blood supply are the two critical factors preventing anastomotic dehiscence 5. ICG-FA directly addresses the blood supply component with objective visualization rather than subjective surgeon assessment.

Safety Profile

No ICG-related adverse reactions have been reported in any included studies 6, 7. The FDA-approved drug is rapidly bound to plasma proteins (95% albumin), undergoes hepatic-only clearance, and has no significant extrahepatic uptake 6. The standard intravenous dose is 0.5 mg/kg body weight, administered after mesenteric division but before anastomosis creation 6.

Recent 2026 prospective data showed ICG-FA was associated with zero anastomotic strictures compared to 11.4% in controls (p = 0.050), suggesting improved anastomotic healing quality beyond just preventing clinical leaks 8. This finding indicates ICG-FA may optimize perfusion sufficiently to prevent both catastrophic leaks and subclinical ischemic complications.

Clinical Implementation Algorithm

For left-sided/rectal resections:

  1. Complete mesenteric division and identify proposed transection site
  2. Administer ICG 0.5 mg/kg IV bolus
  3. Assess fluorescence at proposed proximal bowel margin within 30-60 seconds
  4. If inadequate perfusion visualized (poor/absent fluorescence), resect more proximally until well-perfused tissue identified
  5. Create anastomosis at fluorescence-confirmed viable site
  6. Reassess anastomosis perfusion after completion if desired

For right-sided resections: ICG-FA may be used but evidence does not demonstrate significant leak reduction. Consider in high-risk patients (emergency surgery, vasopressor support, hypoalbuminemia, steroid use) where any marginal benefit may be clinically meaningful 9.

Context from Emergency Surgery Guidelines

While the question addresses elective surgery, relevant context exists from emergency laparotomy guidelines. The 2023 ERAS consensus acknowledges that anastomotic leak risk is substantially elevated in emergency settings, with multiple risk factors including vasopressor support, hypoalbuminemia, and hemodynamic instability 9. The 2022 WSES guidelines on bowel injury note that ICG use in trauma settings is "a very new concept" with "promising" early case series demonstrating usefulness in assessing bowel integrity 10. This suggests ICG-FA's role may extend beyond elective surgery as evidence accumulates.

Common Pitfalls to Avoid

  • Don't skip ICG-FA for left-sided/rectal cases based on "good-looking" tissue—subjective assessment misses 11% of inadequately perfused segments 4
  • Don't use identical technique for right vs. left colon—the evidence supports differential application
  • Don't delay resection to higher level if ICG shows poor perfusion—the technology identifies the problem; surgical judgment must act on it
  • Don't assume ICG replaces other leak prevention strategies—continue optimizing nutrition, correcting anemia, minimizing steroids, and considering diversion in highest-risk patients 11

The evidence strongly supports routine ICG-FA use in elective left-sided colorectal surgery to reduce the devastating complication of anastomotic leakage, with an excellent safety profile and no added operative time in experienced hands 3.

References

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.