Mobile Smart-Phone Thermal Imaging Accurately Predicts Perforator Location and Microvascular Flow Insufficiencies
Cody J. Phillips1, Morgan R. Barron, MD1, John Kuckelman, DO1, Michael Derickson, MD1, Vance Sohn, MD1, Keith Paige, MD2, Kevin Beshlian, MD3.
1Madigan Army Medical Center, Tacoma, WA, USA, 2Swedish Cancer Institute, Seattle, WA, USA, 3The Polyclinic, Seattle, WA, USA.
Background: Mobile smart-phone 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 perforators preoperatively and microvascular flow insufficiencies postoperatively.
Methods: Nineteen patients underwent 30 DIEAP free flaps for breast reconstruction. Operating surgeons were blinded to MTI images. Images were obtained preoperatively, intraoperatively, and at instances of concern for ﬂap viability. Preoperative MTI mapping of perforators was correlated to operative perforator selection. Three groups were established for comparison: normal DIEAP flaps (NDF), flaps with arterial insufficiency (AI) and flaps with venous congestion (VC). Images were reviewed for temperature differences.
Results: All flaps were successful. Pre-operative MTI correlated with operative perforator selection in 25 of 30 (83.3%) of flaps. There were significant increases in temperature from max ischemia (24.5 ±2.1⁰C) to one minute after anastomosis (27.2±1.6 ⁰C, P < 0.001). NDF continued to warm until the final MTI taken when leaving the operating suite. Free flap temperatures were similar between the three groups prior to transfer to the chest and after completion of the microsurgical anastomosis. Flaps with VC and AI were found to be significantly colder than the NDF group, (28.3±1.9⁰C vs. 32.2±1.8⁰C, p=0.003) in the VC group and (27.2±0.7⁰C vs. 32.2±1.8⁰C, p=0.001) in the AI group (Figure1). After correction, VC and AI groups rewarmed and temperatures were no different compared to the NDF group. General characteristics were compared and no statistically significant differences were observed for age, co-morbidities, ASA classification, or flap ischemia times.
Conclusion: MTI accurately identiﬁes perforators suitable for DIEAP ﬂaps and is useful in planning. MTI recognizes early microanastomotic failure and is a practical advancement in the evaluation of free ﬂap perfusion compared to current assessment methods.
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