title: Endoscopic assessment of free flap perfusion in the upper aerodigestive tract using indocyanine green: a pilot study.
abstract: BACKGROUND
  Malfunction of microvascular anastomoses is the main reason for free-flap failures. The aim of this investigation was to prove the feasibility of endoscopic free-flap perfusion measurements in the upper aerodigestive tract (UADT) using indocyanine green (ICG).
  
  
  METHODS
  Twenty-five patients undergoing free-flap reconstruction of the UADT were included. At least three ICG angiographies (0 h, 24 h and 72 h) were performed per participant. The sequences were subjectively judged online. The data were subsequently analysed, the results compared to clinical outcome and a survey with clinical staff (n = 21) performed.
  
  
  RESULTS
  All 25 flaps survived. The ICG angiographies were tolerated well, showing a delayed fluorescence gain in transplanted tissue compared to surrounding but comparable final maximum fluorescence intensities. Four surgical revisions (two for a true and two for a false indication) could be additionally investigated. The two flaps with a real perfusion compromise showed fluorescence Indices (relative fluorescence maxima of transplant vs. surrounding) of 33% and 37%, whereas these values lay above 60% for all other examinations (including those two flaps that were revised for a false indication). The survey showed that ICG angiography leads to a better discrimination of well- and malperfused flaps compared with conventional inspection.
  
  
  CONCLUSIONS
  In this small level IIb study, it was possible to prove the feasibility of endoscopic ICG angiography in patients with free-tissue transfer to the UADT. In difficult situations, it seems a welcome adjunct to conventional screening and might aid in the decision whether to revise a clinically suspect flap.
authors: Department of Otorhinolaryngology, Head & Neck Surgery, Klinikum der Universität München, Ludwig Maximilian University, Großhadern Medical Campus, Marchioninistr. 15, D-81377 Munich, Germany. christian.betz@med.uni-muenchen.de
authors: Christian Stephan
authors: CS
authors: Betz
authors: Sven
authors: S
authors: Zhorzel
authors: Hilmar
authors: H
authors: Schachenmayr
authors: Herbert
authors: H
authors: Stepp
authors: Christoph
authors: C
authors: Matthias
authors: Colin
authors: C
authors: Hopper
authors: Ulrich
authors: U
authors: Harréus
mesh_terms: D000368:Aged; D000714:Anastomosis, Surgical / Q000379:methods; D004396:Coloring Agents; D004724:Endoscopy; D005260:Female; D058752:Free Tissue Flaps / Q000098:blood supply*; D006258:Head and Neck Neoplasms / Q000601:surgery*; D006801:Humans; D007208:Indocyanine Green; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D019651:Plastic Surgery Procedures / Q000379:methods*
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green