Indocyanine green fluorescence angiography (ICG-FA) is increasingly used during reconstructive surgery to provide real-time visualisation of tissue perfusion. In deep inferior epigastric perforator (DIEP) flap breast reconstruction, this information can help surgeons identify poorly perfused areas that may be at greater risk of postoperative complications.
A newly published study by Hayasaka and colleagues takes this application a step further. Rather than using ICG-FA solely to identify tissue that should be removed, the investigators incorporated fluorescence findings into a structured intraoperative algorithm to determine whether an additional vascular anastomosis was required.
The findings illustrate how ICG fluorescence imaging can help translate perfusion assessment into an immediate surgical decision—with the objective of safely using a larger proportion of the available flap while minimising the risk of fat necrosis.
Why Flap Perfusion Matters
DIEP-flap reconstruction uses skin and fat from the lower abdomen to reconstruct the breast while preserving the abdominal muscles. The transferred tissue is supplied through selected perforating blood vessels, which are connected to recipient vessels in the chest.
A key challenge is ensuring that blood flow from the selected perforator adequately reaches all the tissue required for the reconstruction. Where perfusion is insufficient, part of the transferred fat may subsequently undergo necrosis.
Fat necrosis can result in firm areas within the reconstructed breast, discomfort, additional imaging or investigations, and, in some cases, further treatment or surgery. Surgeons must therefore balance the desire to retain sufficient flap volume against the risk of including inadequately perfused tissue.
A Structured ICG-FA Algorithm
The study included 50 patients undergoing unilateral breast reconstruction with a DIEP flap.
After the flap had been elevated, the surgical team performed ICG fluorescence angiography to assess the distribution of blood flow from the main perforating branch. These findings were then used to determine whether the flap could be supported by the primary vascular connection or whether an additional arterial and/or venous anastomosis should be performed.
This approach is important because it moves beyond a simple binary assessment of whether tissue appears perfused. The fluorescence information was incorporated into a defined decision-making process addressing:
- how much of the flap demonstrated blood flow through the principal perforator;
- how much tissue was required for the reconstruction;
- whether the intended flap volume could be used safely; and
- whether an additional vascular connection was needed to support a more extensive flap.
Almost Half of Patients Required an Additional Anastomosis
Based on the ICG-FA algorithm, an additional anastomosis was performed in 24 of the 50 patients—48% of the study population.
The likelihood of requiring an additional anastomosis increased significantly when more than 70% of the flap was needed for reconstruction.
This suggests that fluorescence assessment may be particularly valuable in patients requiring a larger flap volume, where relying on a single perforator may not provide adequate perfusion across the entire intended flap.
The investigators identified seven different additional-anastomosis configurations, demonstrating that the technique could be adapted to the individual vascular anatomy and intraoperative findings. The contralateral deep inferior epigastric artery and vein were the vessels used most frequently.
Supporting Greater Flap Utilisation
One of the study’s most notable findings was the difference in the proportion of available flap tissue that could be used.
Average flap utilisation was:
- 78.4% in patients receiving an additional anastomosis
- 53.5% in patients not requiring an additional anastomosis
The difference was statistically significant (p < 0.001).
These figures should not be interpreted as a direct comparison of two alternative treatments, as the decision to perform an additional anastomosis was based on the individual patient’s perfusion pattern and reconstructive requirements. However, the findings indicate that the algorithm enabled surgeons to retain and use a larger proportion of the flap when additional vascular support was needed.
This may be particularly relevant where greater tissue volume is required to achieve the desired reconstructive result.
Low Incidence of Fat Necrosis Reported
Only one localised case of postoperative fat necrosis was reported among the 50 patients. This occurred in a patient who had undergone an additional anastomosis.
The authors concluded that their ICG-FA algorithm was useful in minimising fat necrosis while supporting the use of extensive DIEP flaps. It therefore offered a practical means of tailoring the vascular strategy to the perfusion characteristics and tissue requirements of each reconstruction.
What Does This Mean for Clinical Practice?
This study demonstrates a broader role for ICG fluorescence angiography in reconstructive surgery.
ICG-FA was not used simply to identify poorly perfused tissue for removal. It provided information that helped the surgical team decide whether to modify the vascular reconstruction by creating an additional anastomosis.
When incorporated into a structured intraoperative algorithm, ICG fluorescence imaging may help surgeons to:
- assess perfusion across the intended DIEP flap;
- identify when a single vascular pedicle may be insufficient;
- select patients who may benefit from an additional anastomosis;
- retain a greater proportion of the available flap;
- support individualised reconstructive planning; and
- potentially reduce the risk of postoperative fat necrosis.
The study involved only 50 patients and did not include a non-ICG control group, so larger comparative studies will be needed to validate the algorithm and determine its wider reproducibility. Nevertheless, it provides a valuable example of fluorescence imaging being used not only to assess perfusion, but to guide a specific and potentially consequential intraoperative intervention.
The findings reinforce the evolving role of ICG-FA as a decision-support tool in reconstructive surgery—helping surgeons move from visualising perfusion to acting on that information in real time.
Reference
Hayasaka R, Tanakura K, Kuramoto Y, et al. Indocyanine green fluorescence angiography algorithm for determining additional anastomosis in deep inferior epigastric perforator flap for breast reconstruction. Breast Cancer. Published online 3 August 2026. doi: 10.1007/s12282-026-01901-z.
