Serial Static Infrared Thermography for Intraoperative and Postoperative Surface-Temperature Monitoring of Free-Flap Skin Islands in Paediatric Craniofacial Reconstruction: A Technical Feasibility Study

Abstract

Background/Objectives: This single-patient retrospective study evaluated the technical feasibility of serial infrared thermography (IRT) for intraoperative and postoperative surface-temperature documentation of free-flap skin islands and its descriptive concordance with clinical and vascular assessments. Methods: A 9-year-old boy with Nager syndrome undergoing bilateral temporomandibular joint reconstruction and soft-tissue reconstruction with an anterolateral thigh free flap divided into two skin islands was monitored intraoperatively and postoperatively. Thermograms were acquired using a FLIR T1020 camera (emissivity 0.98) under documented environmental conditions. Intraoperative and postoperative observations were interpreted separately, without normalisation between settings. Mean temperatures within manually delineated regions of interest and inter-island differences were analysed retrospectively and compared descriptively with documented clinical assessment, Doppler ultrasonography, and computed tomography angiography (CTA) findings. Results: Pallor prompted Doppler ultrasonography, followed by CTA; these showed absent right-perforator flow and non-visualisation of that perforator, respectively. The skin did not bleed after puncture. Thermography was performed after these tests and was not taken into account when making the decision about reoperation. IRT demonstrated temperature changes in both skin islands. At 49 h after the initial flap measurement, the mean surface temperature was 26.6 °C in the right skin island and 32.7 °C in the left (absolute difference, 6.1 °C). A focal area of relatively increased surface temperature “hot spot” was identified retrospectively within the viable left skin island; this qualitative observation was exploratory and was not based on a prespecified thermal threshold. Conclusions: Serial IRT was feasible and provided contactless thermal information retrospectively concordant with multimodal perfusion assessment. These findings are hypothesis-generating and do not establish earlier detection, diagnostic accuracy, or a universal thermal threshold; larger prospective studies are required.