Projected augmented reality and dynamic infrared thermography enhances profunda artery perforator flap perforator mapping.

[BACKGROUND] Preoperative perforator mapping of the Profunda Artery Perforator (PAP) flap is hindered by challenges in aligning preoperative images with the intraoperative lithotomy position of the leg. Dynamic Infrared Thermography (DIRT) is a real-time, quick, and non-invasive imaging modality that is increasingly explored for preoperative perforator mapping. This feasibility study demonstrates the application of Projected Augmented Reality to project thermal images of DIRT directly on the skin for the identification of perforators before PAP flap breast reconstructions.

[METHODS] A portable self-aligning projection device (Anatomy Projector) was integrated with a thermal sensor to obtain thermal information and automatically project thermal images onto the patient's medial thigh before PAP flap dissection. Projected DIRT hotspots were evaluated with hand-held Doppler (HHD) and compared to locations of intraoperative perforators following a Cartesian coordinate system.

[RESULTS] Preoperative DIRT examination yielded a projection of 127 DIRT hotspots in 20 PAP flaps. All projected hotspots could be verified with Doppler (100 %) and 82.1 % of intraoperative perforators correlated with a projected DIRT hotspot within a 3 cm radius. Notably, 30.4 % of these matches involved the first appearing DIRT hotspot, and 82.6 % of these matches involved a DIRT hotspot within the first 5 appearing hotspots.

[CONCLUSION] This feasibility study pioneers the use of Projected Augmented Reality for the display of thermal images of DIRT directly on the skin for the preoperative perforator identification before PAP flap harvest. High resemblance with HHD and intraoperative perforators was found. Future research should examine the further applications in the intraoperative and postoperative setting.