title: Near-infrared imaging of face transplants: are both pedicles necessary?
abstract: BACKGROUND
  Facial transplantation is a complex procedure that corrects severe facial defects due to traumas, burns, and congenital disorders. Although face transplantation has been successfully performed clinically, potential risks include tissue ischemia and necrosis. The vascular supply is typically based on the bilateral neck vessels. As it remains unclear whether perfusion can be based off a single pedicle, this study was designed to assess perfusion patterns of facial transplant allografts using near-infrared (NIR) fluorescence imaging.
  
  
  METHODS
  Upper facial composite tissue allotransplants were created using both carotid artery and external jugular vein pedicles in Yorkshire pigs. A flap validation model was created in n = 2 pigs and a clamp occlusion model was performed in n = 3 pigs. In the clamp occlusion models, sequential clamping of the vessels was performed to assess perfusion. Animals were injected with indocyanine green and imaged with NIR fluorescence. Quantitative metrics were assessed based on fluorescence intensity.
  
  
  RESULTS
  With NIR imaging, arterial perforators emitted fluorescence indicating perfusion along the surface of the skin. Isolated clamping of one vascular pedicle showed successful perfusion across the midline based on NIR fluorescence imaging. This perfusion extended into the facial allograft within 60 s and perfused the entire contralateral side within 5 min.
  
  
  CONCLUSIONS
  Determination of vascular perfusion is important in microsurgical constructs as complications can lead to flap loss. It is still unclear if facial transplants require both pedicles. This initial pilot study using intraoperative NIR fluorescence imaging suggests that facial flap models can be adequately perfused from a single pedicle.
authors.affiliation: Division of Plastic and Reconstructive Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Nguyen
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Ashitate
authors.forename: Vivek
authors.initials: V
authors.lastname: Venugopal
authors.forename: Florin
authors.initials: F
authors.lastname: Neacsu
authors.forename: Frank
authors.initials: F
authors.lastname: Kettenring
authors.forename: John V
authors.initials: JV
authors.lastname: Frangioni
authors.forename: Sylvain
authors.initials: S
authors.lastname: Gioux
authors.forename: Bernard T
authors.initials: BT
authors.lastname: Lee
mesh_terms: D000818:Animals; D005145:Face / Q000098:blood supply* / Q000601:surgery*; D054445:Facial Transplantation / Q000379:methods*; D005260:Female; D005453:Fluorescence; D008866:Microsurgery / Q000379:methods; D023421:Models, Animal; D009333:Neck / Q000098:blood supply; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013524:Surgical Flaps / Q000098:blood supply*; D034421:Sus scrofa; D020858:Tissue and Organ Harvesting / Q000379:methods; D014184:Transplantation, Homologous
keywords: Composite tissue allotransplantation; Face transplantation; Near infrared imaging