Post-operative monitoring of free flaps using a low-cost thermal camera: a pilot study

Abstract

Background Careful post-operative monitoring of free flaps is important in flap survival; immediate action increases flap salvage rate. Although various methods are available, room for improvement remains. Thermal cameras have proven their value in medicine and are nowadays readily available at low costs. The objective of this study was to evaluate the potential of an affordable infrared thermal camera and software in the detection of failing free flaps during post-operative monitoring. Methods Free myocutaneous rectus abdominis flaps were harvested in 16 female landrace pigs and replanted after several hours of storage. All flaps were assessed with indocyanine green fluorescence angiography as well as hourly clinical assessment of skin colour, turgor and capillary refill. Furthermore, thermal photographs were taken simultaneously with the FLIR One thermal camera smartphone module. These photographs were processed in MATLAB and evaluated on their additional value as an indicator for flap failure. Results Out of 16 flaps, three flaps failed due to arterial failure and one flap developed venous congestion. The mean flap temperature compared to adjacent control skin proved to be most indicative for flap failure. All unsuccessful flaps showed lower temperatures after failure compared to the uncompromised free flaps. Conclusions An affordable thermal camera module can potentially contribute to post-operative free flap monitoring. Vascular compromise in free flaps can be distinguished by investigating relative temperature differences between the flap and reference skin. Until the FLIR One camera has been extensively investigated in a human population, it should be used in conjunction with conventional monitoring techniques.

Evaluation of infrared thermography findings in postoperative follow-up in dogs with pyometra

“…Postoperative wound care is one of the essential steps of clinical recovery. In animal studies, thermographic monitoring is used after burns, thrombosis formations, various malformations, oncological surgical interventions, and flap applications (Casas-Alvarado et al, 2020;Hummelink et al, 2020;Kraemer et al, 2011). Research in this area has high standardization and precision in median incision line examination results.…”

Utility of Thermal Imaging in Predicting Superficial Infections in Transfemoral Osseointegrated Implants

“…Thermal imaging has proven to be an effective adjunct for diagnosing SSIs as well as for monitoring postoperative flap viability. [13][14][15] Additionally, this method is noninvasive, cheap, and provides real-time feedback regarding a patient's surgical site/flap via an infrared camera that captures radiation from a scanned subject and transforms the data into a visible image. Thermal imaging has been used to predict infection and flap failure, as changes in temperature surrounding the surgical site are correlated with perfusion of the scanned area.…”

Continuous intraoperative perfusion monitoring of free microvascular anastomosed fasciocutaneous flaps using remote photoplethysmography

“…Techniques like laser Doppler flowmetry 12 , 13 , microdialysis 14 , oximetry 15 , CO 2 monitoring 16 , measurement of temperature 17 , glucose and lactate 18 , nuclear medicine 19 , pH measurement 20 , hydrogen clearance 21 and tomographic approaches 12 , 13 are similarly characterized by invasiveness and stationary or complex handling, with the need of either additional expensive hardware or techniques. Promising non-invasive, non-contact and non-ionizing methods as hyper/multispectral 22 – 26 , laser speckle 27 , 28 and thermal imaging 29 – 31 require additional (cost-intensive) equipment and hyperspectral imaging has limited intraoperative capability due to insufficient real-time ability 32 .…”