Endoscopic assessment of free flap perfusion in the upper aerodigestive tract using indocyanine green: a pilot study

Malfunction of microvascular anastomoses is the main reason for free-flap failures. The aim of this investigation was to prove the feasibility of endoscopic free-flap perfusion measurements in the upper aerodigestive tract (UADT) using indocyanine green (ICG).

Twenty-five patients undergoing free-flap reconstruction of the UADT were included. At least three ICG angiographies (0 h, 24 h and 72 h) were performed per participant. The sequences were subjectively judged online. The data were subsequently analysed, the results compared to clinical outcome and a survey with clinical staff (n = 21) performed.

All 25 flaps survived. The ICG angiographies were tolerated well, showing a delayed fluorescence gain in transplanted tissue compared to surrounding but comparable final maximum fluorescence intensities. Four surgical revisions (two for a true and two for a false indication) could be additionally investigated. The two flaps with a real perfusion compromise showed fluorescence Indices (relative fluorescence maxima of transplant vs. surrounding) of 33% and 37%, whereas these values lay above 60% for all other examinations (including those two flaps that were revised for a false indication). The survey showed that ICG angiography leads to a better discrimination of well- and malperfused flaps compared with conventional inspection.

In this small level IIb study, it was possible to prove the feasibility of endoscopic ICG angiography in patients with free-tissue transfer to the UADT. In difficult situations, it seems a welcome adjunct to conventional screening and might aid in the decision whether to revise a clinically suspect flap.