Infrared Temperature Monitoring in Vascularized Flaps with Simulated Arterial and Venous Thrombosis: An Animal Study

Early recognition of postoperative vascular compromise is critical for the success of vascularized free tissue transfer, with vascular thrombosis occurring in approximately 10% of cases. This study aimed to evaluate whether a portable infrared camera (FlirOne; FO) can detect skin surface temperature changes following simulated vascular occlusion in an animal model. Secondary objectives were to assess agreement between FO and an intracutaneous thermistor and to compare temperature patterns following arterial versus venous occlusion.

A pedicled groin flap was raised in 32 female Sprague-Dawley rats. Animals were divided into four groups with simulated arterial or venous occlusion. The right side served as the intervention side, while the left acted as either a positive or negative control. Skin surface temperature was recorded at predefined time points before and after vessel ligation using FO and an intracutaneous thermistor.

Venous thrombosis was associated with an increase in flap temperature, whereas a consistent temperature decrease following arterial occlusion was not observed. The agreement between FO and the intracutaneous thermistor was moderate.

Infrared temperature monitoring demonstrated a tendency toward temperature elevation in venous congestion, while temperature changes associated with arterial ischemia appeared to develop more slowly. These findings suggest that infrared thermography may be more sensitive to venous than arterial vascular compromise in this experimental model.