Indocyanine Green Fluorescence in Esophagectomy

Indocyanine green fluorescence is an intraoperative imaging technique used to assess blood flow during esophagectomy. After intravenous administration, the dye circulates through vessels and emits near-infrared fluorescence when viewed with a compatible surgical camera. This can help the team judge whether the planned gastric conduit has adequate perfusion before it is joined to the remaining esophagus.

The technique has attracted interest because anastomotic leakage remains one of the most serious complications after esophageal resection. It may support clinical judgement, but it does not replace careful conduit construction, sound surgical technique, haemodynamic management, or postoperative surveillance. Evidence presented through international education forums such as the ISDE congress has helped frame fluorescence imaging as a decision-support tool rather than a stand-alone test.

How The Imaging Works

Indocyanine green binds rapidly to plasma proteins and remains largely within the vascular compartment. Once excited by near-infrared light, it produces a fluorescent signal that can be displayed on the operating monitor. The surgeon may assess how quickly and evenly the signal reaches the gastric conduit and intended anastomotic site.

The image is generally qualitative or semi-quantitative. Bright fluorescence suggests better relative inflow, while delayed or weak enhancement can raise concern about marginal perfusion. The result is influenced by blood pressure, cardiac output, vasopressor use, tissue thickness, camera settings and the interval since injection.

Why Conduit Perfusion Matters

The stomach is commonly fashioned into a narrow conduit and brought into the chest or neck. Its blood supply depends heavily on the right gastroepiploic arcade after other vessels are divided. Excessive tension, twisting, venous congestion or an overly long conduit can compromise the anastomosis.

Poor perfusion is associated with impaired healing and a higher risk of anastomotic leakage, which can lead to mediastinitis, sepsis, prolonged hospitalisation and additional procedures. Fluorescence may reveal a transition zone where the conduit should be shortened, although the appropriate threshold for resection is not universally established.

Use During The Operation

Imaging can be performed after conduit mobilisation, before final division, after the stomach has been positioned, or immediately before anastomosis. A repeat injection may be considered when the anatomy or haemodynamic state changes, although cumulative dosing and local protocols must be respected.

The operating team should interpret the image alongside conduit length, absence of twisting, tension, visible vessel preservation and the planned anastomotic technique. A segment that fluoresces slowly may prompt a change in the transection point, but the final decision remains a surgical judgement.

Reading The Signal Carefully

A fluorescence image is not a direct measurement of tissue oxygenation or guaranteed healing. A conduit can show an apparently adequate signal and still develop leakage because of mechanical stress, infection, impaired venous drainage or patient-related factors. Conversely, a low signal may reflect technical or physiological conditions rather than irreversible tissue damage.

The team should record the timing of injection, dose, observed perfusion pattern and any change to the operative plan. Clear documentation is useful for morbidity review and research, particularly when different imaging platforms produce different intensity scales.

Evidence And Practical Limits

Studies have reported reductions in anastomotic leakage when fluorescence findings are used to guide the resection margin, but results are variable. Many studies are observational, use different definitions of abnormal perfusion and include different surgical approaches. Randomised evidence and standardised quantitative thresholds remain limited.

The method also adds equipment, staff training and workflow considerations. It may be less informative in severe hypotension, marked vasoconstriction or unexpected bleeding. Iodine-related hypersensitivity, liver dysfunction and pregnancy require appropriate clinical review, while a previous reaction to contrast-related agents should be discussed before administration.

Considerations In Australian Hospitals

In Australia, esophagectomy is concentrated in specialist upper gastrointestinal units in cities such as Sydney, Melbourne, Brisbane, Perth and Adelaide. Public hospitals may need to coordinate access to fluorescence-capable theatre systems, while private hospitals and device suppliers may follow different procurement and maintenance arrangements. Local credentialling and theatre policies therefore matter.

The dye’s availability, product information and regulatory status should be checked through the Therapeutic Goods Administration and the hospital pharmacy. Use may also be affected by formulary rules, informed-consent processes and whether the procedure is being performed under a public hospital pathway or private insurance arrangement. Medicare funding should not be assumed to cover every equipment or consumable cost.

Long travel distances from regional Queensland, Western Australia or the Northern Territory can delay referral to high-volume centres and complicate postoperative review. Shared-care pathways, telehealth follow-up and clear discharge instructions are particularly relevant when patients return home after surgery.

Building A Safe Workflow

A practical protocol can reduce variation between surgeons, anaesthetists, nurses and perfusion-imaging staff.

• Confirm camera compatibility, sterile covers and image recording before incision.
• Check the prescribed dose, allergy history, liver status and local pharmacy requirements.
• Agree on when fluorescence will be assessed and who will document the findings.
• Optimise blood pressure and avoid interpreting images during major haemodynamic instability.

Useful documentation may include:

• Injection time and dose.
• Time to visible conduit enhancement.
• Relative fluorescence at the proposed anastomotic site.
• Any change in transection level or reconstruction plan.

Training should use recorded cases and multidisciplinary review rather than relying on a single operator’s visual impression. Australian centres can also contribute to registries and collaborative studies that examine leakage rates, cost-effectiveness and outcomes across metropolitan and regional referral networks.

What The Evidence Means For Patients

Patients should understand that fluorescence imaging is an adjunct to established surgical assessment. It may help the surgeon choose a better-perfused anastomotic site, but it cannot eliminate the risk of leakage or other complications. Recovery still depends on nutrition, respiratory care, infection prevention and early recognition of deterioration.

The most useful role for indocyanine green is within a structured pathway that combines objective imaging with experienced judgement and consistent postoperative care. The key point to remember is that fluorescence can improve information at a critical moment, but safe esophagectomy still depends on the whole clinical team and the fundamentals of sound surgery.