Skin Tattoo Interference of Indocyanine Green Fluorescence Angiography and Near Infrared Spectroscopy in Free Flap Reconstruction: A Case Report

A plethora of flap monitoring modalities are available as adjuncts to clinical assessment. Indocyanine green fluorescence angiography (ICGFA) has proven to be sensitive in assessing tissue perfusion intraoperatively. Near-infrared spectroscopy (NIRS) allows accurate real-time monitoring of flap perfusion in the postoperative period. Tattoos are increasingly common in our patient population, but their effects on ICGFA and NIRS have not been well established in the literature. A 30-year-old patient with a Gustilo 3C open left tibia-fibular fracture underwent reconstruction with an anterolateral thigh free flap. The thigh donor site had extensive black ink tattooing, which resulted in absent light-up on ICGFA and reduced NIRS reading. Based on our observations, we conclude that black ink tattoos obscure ICGFA and result in a falsely low NIRS reading. We recommend placing flap monitoring probes away from tattooed sites or monitoring tattooed flaps with conventional clinical examination and Doppler modalities instead.