title: Monitoring of microvascular free flaps following oropharyngeal reconstruction using infrared thermography: first clinical experiences.
abstract: The aim of this study is to investigate static and dynamic infrared (IR) thermography for intra- and postoperative free-flap monitoring following oropharyngeal reconstruction. Sixteen patients with oropharyngeal reconstruction by free radial forearm flap were included in this prospective, clinical study (05/2013-08/2014). Prior ("intraop_pre") and following ("intraop_post") completion of the microvascular anastomoses, IR thermography was performed for intraoperative flap monitoring. Further IR images were acquired one day ("postop_1") and 10 days ("postop_10") after surgery for postoperative flap monitoring. Of the 16, 15 transferred free radial forearm flaps did not show any perfusion failure. A significant decreasing mean temperature difference (∆T: temperature difference between the flap surface and the surrounding tissue in Kelvin) was measured at all investigation points in comparison with the temperature difference at "intraop_pre" (mean values on all patients: ∆T intraop_pre = -2.64 K; ∆T intraop_post = -1.22 K, p < 0.0015; ∆T postop_1 = -0.54 K, p < 0.0001; ∆T postop_10 = -0.58 K, p < 0.0001). Intraoperative dynamic IR thermography showed typical pattern of non-pathological rewarming due to re-established flap perfusion after completion of the microvascular anastomoses. Static and dynamic IR thermography is a promising, objective method for intraoperative and postoperative monitoring of free-flap reconstructions in head and neck surgery and to detect perfusion failure, before macroscopic changes in the tissue surface are obvious. A lack of significant decrease of the temperature difference compared to surrounding tissue following completion of microvascular anastomoses and an atypical rewarming following a thermal challenge are suggestive of flap perfusion failure.
authors.affiliation: Clinic of Otolaryngology, Head and Neck Surgery and Department of Head Medicine and Oral Health, University of Leipzig, Liebigstr. 10-14, 04103, Leipzig, Germany.
authors.forename: Maren
authors.initials: M
authors.lastname: Just
authors.affiliation: Innovation Center Computer Assisted Surgery, ICCAS, University of Leipzig, Leipzig, Germany.
authors.forename: Claire
authors.initials: C
authors.lastname: Chalopin
authors.affiliation: Innovation Center Computer Assisted Surgery, ICCAS, University of Leipzig, Leipzig, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Unger
authors.affiliation: Clinic of Maxillo-Facial-Surgery and Department of Head Medicine and Oral Health, University of Leipzig, Leipzig, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Halama
authors.affiliation: Innovation Center Computer Assisted Surgery, ICCAS, University of Leipzig, Leipzig, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Neumuth
authors.affiliation: Clinic of Otolaryngology, Head and Neck Surgery and Department of Head Medicine and Oral Health, University of Leipzig, Liebigstr. 10-14, 04103, Leipzig, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Dietz
authors.affiliation: Clinic of Otolaryngology, Head and Neck Surgery and Department of Head Medicine and Oral Health, University of Leipzig, Liebigstr. 10-14, 04103, Leipzig, Germany. milos.fischer@medizin.uni-leipzig.de.
authors.forename: Miloš
authors.initials: M
authors.lastname: Fischer
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D058752:Free Tissue Flaps / Q000098:blood supply*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009959:Oropharyngeal Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011446:Prospective Studies; D019651:Plastic Surgery Procedures / Q000379:methods; D012881:Skin Temperature; D013817:Thermography
keywords: Dynamic infrared thermography; Free tissue transfer; Free-flap monitoring; Microsurgery; Perfusion failure; Thermal imaging