We have read with interest the article published in your journal by Morales-Conde et al, “Fluorescence and markers in surgery: The future ahead”.1 We believe it is appropriate to expand on the information given by sharing our experience in breast surgery. Various applications of indocyanine green (ICG) have been described. However, there are 2 main applications: the identification of the sentinel lymph node (SLN) and the evaluation of flap perfusion.
As the authors indicated,1 the molecular characteristics of ICG make it a promising tracer for sentinel lymph node biopsy (SLNB). This dye matches or improves the results of patent blue and radioisotopes,2–4 mitigating their drawbacks and providing a real-time map of lymph node drainage, even before the incision is made. However, there are 2 scenarios where its use may be limited. The first is in obese patients, since the light emitted by the contrast medium can only be captured up to 1 cm deep, making identification of the SLN difficult. The second is single-incision surgery, where there is a great distance between the surgical incision and the axilla.5 Here, there is also a greater risk of contamination with contrast when dividing lymphatic ducts between the incision and the axilla, thereby making it difficult to identify the SLN.
The second application is the evaluation of tissue perfusion in breast reconstruction surgery. ICG can assist in the identification of tissues with poor perfusion and risk of necrosis after a skin- and nipple-sparing mastectomy,6–8 as well as the selection of perforators for reconstruction with autologous tissue. We have recently published the preliminary results of the gBREAST-22 study,9,10 in which we demonstrated the usefulness of ICG in complex breast surgery due to the high negative predictive value of angiography, thus preserving tissues whose viability was questioned during the initial surgical planning. However, angiography with ICG also has its limitations. There is no objective parameter to define and/or quantify tissue ischemia, and it may differ depending on the patient’s characteristics or interobserver variability.6 In addition, the joint use of ICG for angiography and lymphography for SLN is complex since the subcutaneous injection area used for lymphography can lead to overestimating the perfusion of the flap or the NAC. The authors’ recommendation is to perform the injection of contrast for SLN close to the axilla in order to reduce the artifact during angiography.
In conclusion, ICG is a promising tool in many areas of breast surgery. However, it is necessary to expand the scientific evidence and objectify its interpretation to standardize its application and be able to apply it safely.
