title: Real-time navigation by fluorescence-based enhanced reality for precise estimation of future anastomotic site in digestive surgery.
abstract: BACKGROUND
  Fluorescence-based enhanced reality (FLER) is a technique to evaluate intestinal perfusion based on the elaboration of the Indocyanine Green fluorescence signal. The aim of the study was to assess FLER's performances in evaluating perfusion in an animal model of long-lasting intestinal ischemia.
  
  
  METHODS
  An ischemic segment was created in 18 small bowel loops in 6 pigs. After 2 h (n = 6), 4 h (n = 6), and 6 h (n = 6), loops were evaluated clinically and by FLER to delineate five regions of interest (ROIs): ischemic zone (ROI 1), presumed viable margins (ROI 2a-2b), and vascularized areas (3a-3b). Capillary lactates were measured to compare clinical vs. FLER assessment. Basal (V 0 ) and maximal (V max) mitochondrial respiration rates were determined according to FLER.
  
  
  RESULTS
  Lactates (mmol/L) at clinically identified resection lines were significantly higher when compared to those identified by FLER (2.43 ± 0.95 vs. 1.55 ± 0.33 p = 0.02) after 4 h of ischemia. Lactates at 2 h at ROI 1 were 5.45 ± 2.44 vs. 1.9 ± 0.6 (2a-2b; p < 0.0001) vs. 1.2 ± 0.3 (3a-3b; p < 0.0001). At 4 h, lactates were 4.36 ± 1.32 (ROI 1) vs. 1.83 ± 0.81 (2a-2b; p < 0.0001) vs. 1.35 ± 0.67 (3a-3b; p < 0.0001). At 6 h, lactates were 4.16 ± 2.55 vs. 1.8 ± 1.2 vs. 1.45 ± 0.83 at ROI 1 vs. 2a--2b (p = 0.013) vs. 3a-3b (p = 0.0035). Mean V 0 and V max (pmolO2/second/mg of tissue) were significantly impaired after 4 and 6 h at ROI 1 (V 0 (4h) = 34.83 ± 10.39; V max (4h) = 76.6 ± 29.09; V 0 (6h) = 44.1 ± 12.37 and V max (6h) = 116.1 ± 40.1) when compared to 2a--2b (V 0 (4h) = 67.1 ± 17.47 p = 0.00039; V max (4h) = 146.8 ± 55.47 p = 0.0054; V 0 (6h) = 63.9 ± 28.99 p = 0.03; V max (6h) = 167.2 ± 56.96 p = 0.01). V 0 and V max were significantly higher at 3a-3b.
  
  
  CONCLUSIONS
  FLER may identify the future anastomotic site even after repetitive assessments and long-standing bowel ischemia.
authors.affiliation: IHU, Minimally Invasive Image-Guided Surgical Institute, Strasbourg, France, michele.diana@ircad.fr.
authors.forename: Michele
authors.initials: M
authors.lastname: Diana
authors.forename: Peter
authors.initials: P
authors.lastname: Halvax
authors.forename: Bernard
authors.initials: B
authors.lastname: Dallemagne
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nagao
authors.forename: Pierre
authors.initials: P
authors.lastname: Diemunsch
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Charles
authors.forename: Vincent
authors.initials: V
authors.lastname: Agnus
authors.forename: Luc
authors.initials: L
authors.lastname: Soler
authors.forename: Nicolas
authors.initials: N
authors.lastname: Demartines
authors.forename: Veronique
authors.initials: V
authors.lastname: Lindner
authors.forename: Bernard
authors.initials: B
authors.lastname: Geny
authors.forename: Jacques
authors.initials: J
authors.lastname: Marescaux
mesh_terms: D000714:Anastomosis, Surgical; D000818:Animals; D013505:Digestive System Surgical Procedures / Q000379:methods*; D005260:Female; D005456:Fluorescent Dyes; D007090:Image Interpretation, Computer-Assisted; D007208:Indocyanine Green; D007421:Intestine, Small / Q000098:blood supply*; D007511:Ischemia / Q000175:diagnosis*; D019344:Lactic Acid; D008297:Male; D012044:Regression Analysis; D013050:Spectrometry, Fluorescence / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D034421:Sus scrofa
chemical_list: D005456:Fluorescent Dyes; D019344:Lactic Acid; D007208:Indocyanine Green