Indocyanine green fluorescence angiography for free flap monitoring: A pilot study

We evaluated the feasibility and the tolerance of repeated fluorescent indocyanine green angiography in free flap monitoring, and determined the intraoperative predictive values of flap vitality.

The free flap failure rate has been significantly reduced, but free flap loss still occurs and remains a costly disaster. Repeated clinical examinations are commonly used for flap monitoring, but they can be unreliable because of their subjectivity. Laser-induced fluorescence of indocyanine green is a new method for assessing tissue perfusion.

20 patients undergoing microsurgical reconstruction were monitored by indocyanine green fluorescence angiography, intraoperatively, and during 4 days after surgery, with 18 injections. Monitoring was made by clinical examination, and then compared to angiographic findings.

The vascular complication rate was 15% (3/20) with 2 cases of venous thrombosis and one case of partial necrosis of the flap skin paddle. Both cases of venous thrombosis were salvaged by secondary surgery. There was no total flap loss. ICG angiography allowed detecting each intra and postoperative complication, earlier than clinical examination. The mean per-operative intensity of fluorescence was significantly lower in flaps with vascular complications (23.8 GL/ms; p = 0.008). The postoperative slope (p = 0.02) and amplitude (p = 0.03) of the fluorescent signal were both significantly lower than for uncomplicated flaps, before surgical revision. These 2 parameters came back to normal values after secondary surgery. There was no adverse effect of ICG despite the repeated injections.

ICG angiography is a feasible and safe technique for the detection of free flap vascular complications.