Mobile Smartphone Thermal Imaging Characterization and Identification of Microvascular Flow Insufficiencies in Deep Inferior Epigastric Artery Perforator Free Flaps.

[BACKGROUND] Mobile smartphone thermal imaging (MTI) devices correlate with blood flow, which makes them appealing adjuncts during reconstructive surgery. MTI was assessed in the setting of deep inferior epigastric artery perforator (DIEAP) free flaps. We hypothesized that MTI can be a surrogate for blood flow to identify microvascular flow insufficiencies.

[METHODS] Nineteen patients underwent 30 DIEAP flaps for breast reconstruction. Images were obtained preoperatively, intraoperatively, and at instances of concern for flap viability. Three groups were evaluated: normal DIEAP flaps (NDFs), flaps with arterial insufficiency (AI), and flaps with venous congestion (VC).

[RESULTS] All flaps were successful. There were significant temperature increases from max ischemia (24.5 ± 2.1°C) to 1 min after anastomosis (27.2 ± 1.6°C, P < 0.001). NDFs continued to warm until the final MTI was taken when leaving the operating room. There were no differences between MTI flap temperatures before transfer to the chest and after completion of microanastomosis. With questionable flap viability, VC and AI temperatures were found to be significantly colder than the NDF group (28.3 ± 1.9°C versus 32.2 ± 1.8°C, P = 0.003) in the VC group and (27.2 ± 0.7°C versus 32.2 ± 1.8°C, P = 0.001) in the AI group. After correction of the identified flow insufficiency, VC and AI rewarmed and temperatures were no different compared with NDF.

[CONCLUSIONS] MTI recognizes microanastomotic failure and is a practical adjunct in the evaluation of free flap perfusion.