Perfusion dynamics in pedicled and free tissue reconstruction: Infrared thermography and laser fluorescence video angiography

Objective: Preoperative planning, design, and perioperative monitoring of microsurgical free flaps is of paramount importance to successful reconstruction. Infrared Thermography provides an indirect method by which vascular perfusion may be monitored and has previously shown efficacy in detection of cutaneous perforators. In a proof-of-concept study, we assessed the utility of infrared thermography in delineating angiosomes and monitoring for adequate tissue perfusion in the preoperative, intraoperative, and postoperative setting. This technology was compared to conventional indocyanine green fluorescence angiography (ICG-FA). Method: Four patients undergoing locoregional pedicled or free flap reconstruction were assessed using ICG-FA and Forward-looking infrared (FLIR) thermography in standardized conditions. Monitoring of flap angiosomes and tissue perfusion using both fluorescent pixel intensity and thermography was then performed implementing proprietary software. Conclusion: Our study is unique in that tissue perfusion intraoperatively was assessed with both thermography and indocyanine green fluorescence angiography (ICG-FA), which represents a previously established system. We demonstrate that smartphone compatible thermal cameras may be used as an adjunct to clinical exam, as well as other monitoring technologies, providing further information in not only selection of perforators, in the operative setting, but also in the early detection of poor flap viability secondary to microvascular compromise allowing for timely salvage.