Role of Infrared Thermography in Planning and Monitoring of Head and Neck Microvascular Flap Reconstruction

Abstract

Background: Reconstruction using microvascular free flaps has become the standard of care in head and neck cancer surgery, and their success lies in appropriate planning, adequate revascularization, and early detection of flap compromise so that prompt salvage is possible. This study evaluates the role of infrared thermography in the planning, execution, and postoperative monitoring of microvascular flaps in head and neck reconstructions. Methods: This is a single institutional, prospective observational study conducted at a tertiary care hospital in South India for 13 months. Twenty patients were included, and their thermographic images were captured in the preoperative, intraoperative, and postoperative settings using the infrared camera FLIR T400. These images were analyzed along with the Doppler, and clinical monitoring findings in all the settings and the temperature difference were calculated postoperatively. Results: Hotspot perforator marking was made using infrared camera, and perforator marking was made using hand-held Doppler preoperatively, which correlated in 93% of cases. Intraoperatively, flap rewarming was successfully demonstrated in 19 of 20 cases. Postoperatively, flap compromise was observed on infrared thermography during the first 24 hours but not on clinical monitoring in three cases. The temperature difference values recorded were 5.4°C, 2.4°C, and 4.9°C. The mean of temperature difference of the healthy flaps was 1.0°C (range 0.1°C–1.8°C). Conclusion: Infrared thermography provides simple and reliable imaging, which can be used in perforator marking and flap designing preoperatively and checking the flap perfusion and vascular anastomosis patency intra- and postoperatively.

Free Flap Monitoring Using Infrared Thermography: An Objective Adjunct to Clinical Monitoring

“…With IRT statistically significant difference was found in mean ∆T between viable and compromised flap. Chava 13 et al reported range of temperature difference of 0.1 to 1.8°C (mean 1°C) in viable flaps, while compromised flaps showed temperature from 2.4 to 5.4°C. Pappilon 14 et al reported temperature difference of 1.5°C in viable flaps and 3.7°C in compromised flaps in a study of 47 free flaps.…”

“…23 Taking temperature difference (ΔT) rather than absolute value minimizes these influences. 11,13 Thermal sensitivity of the imaging device is another concern, more with the lowresolution thermal devices. 24 Initially IRT devices were cumbersome, nonportable, and costly but smartphone-based thermal camera is promising in accessibility and cost-effectiveness.…”