title: Luminescence ratiometric oxygen imaging (LROI) in microvascular anastomosed fibular and radial forearm flaps.
abstract: BACKGROUND
  In a preliminary trial, we were able to show first promising results in the analysis of perioperative and postoperative perfusion of free flaps by means of a new monitoring system for detecting thrombotic vessel occlusion before clinical signs become evident.
  
  
  OBJECTIVE
  We investigated whether flap monitoring by measuring perfusion-dependent parameters differs between radial forearm and fibular free flaps and whether a threshold value requiring anastomosis revision could be determined.
  
  
  METHODS
  37 radial forearm flaps (RF) and 15 fibular flaps (FF) were harvested and transplanted. Perfusion was determined by measuring a fluorescent oxygen sensor foil covering a flap's skin surface with a handheld fluorescence microscope. The sensor contained an oxygen reservoir, which was consumed by the tissue corresponding to the perfusion status of the flap. Measurements were done before explantation, after successful anastomosis and one day after surgery.
  
  
  RESULTS
  We found a significant difference (p < 0.005) in the relative transdermal oxygen consumption (RTOC) between clinically well-perfused grafts (RF: mean: 0.13 ± 0.08; FF: mean: 0.15 ± 0.07) and clinically poorly perfused grafts (RF: mean: 0.40 ± 0.09; FF: mean: 0.55 ± 0.28). A threshold RTOC value of 0.3 for differentiating between well-perfused and poorly perfused flaps was confirmed for both RF and FF.
authors.affiliation: Department of Cranio-Maxillo-Facial Surgery, University Medical Centre Regensburg, Regensburg, Germany.
authors.forename: J K
authors.initials: JK
authors.lastname: Meier
authors.forename: L
authors.initials: L
authors.lastname: Prantl
authors.forename: S
authors.initials: S
authors.lastname: Geis
authors.forename: S
authors.initials: S
authors.lastname: Mueller
authors.forename: M
authors.initials: M
authors.lastname: Hullmann
authors.forename: G
authors.initials: G
authors.lastname: Liebsch
authors.forename: M
authors.initials: M
authors.lastname: Gosau
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015374:Biosensing Techniques / Q000379:methods; D005260:Female; D005360:Fibula / Q000098:blood supply* / Q000601:surgery; D031541:Fluorescence Resonance Energy Transfer; D005542:Forearm / Q000098:blood supply* / Q000601:surgery; D006801:Humans; D008163:Luminescent Measurements / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000032:analysis* / Q000097:blood; D010313:Partial Pressure; D013524:Surgical Flaps / Q000098:blood supply*
chemical_list: D010100:Oxygen
keywords: FRMI; Free flap; fluorescent optical sensor; microvascular; pO$_2$ imaging