title: Role of ischemic gradient in neovascularization of interpolated skin flaps.
abstract: OBJECTIVE
  To investigate the significance of the ischemic gradient between interpolated skin flaps and the recipient bed and to determine its role in flap viability.
  
  
  METHODS
  Bilateral interpolated skin flaps were elevated in 10 pigs and intravenous fluorescein was used to define a border of pedicle perfusion. Flaps were assigned to 1 of 2 groups: proximal flaps, which were contained within the fluorescein border, or distal flaps, which extended 3 cm beyond the fluorescein border. Flaps were then transferred to an adjacent cutaneous defect and pedicles were divided after 2 weeks. The flap and pedicle portions were evaluated separately and viability was quantified.
  
  
  METHODS
  Ten adolescent pigs with bilateral flaps. None were withdrawn.
  
  
  METHODS
  Intravenous fluorescein (20 mg/kg) to determine extent of perfusion in the flaps.
  
  
  RESULTS
  Proximal flaps (n = 10) maintained excellent viability with the pedicles attached. After pedicle division, however, partial flap and pedicle necrosis developed. Distal flaps (n = 10) promptly showed signs of ischemia and congestion but soon showed improved vascularity. A statistically significant improvement was seen in mean percent viability of the distal group compared with the proximal group (P < .05) (Student t test).
  
  
  CONCLUSIONS
  The more ischemic flap-pedicle complex resulted in greater viability after pedicle division. The ischemic gradient seemed to represent a potent angiogenic stimulus to the recipient bed.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Virginia Medical Center, Charlottesville, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Park
authors.forename: G T
authors.initials: GT
authors.lastname: Rodeheaver
authors.forename: P A
authors.initials: PA
authors.lastname: Levine
mesh_terms: D000818:Animals; D005260:Female; D019793:Fluorescein; D005452:Fluoresceins; D006085:Graft Survival; D007511:Ischemia / Q000503:physiopathology*; D018919:Neovascularization, Physiologic; D012867:Skin / Q000098:blood supply*; D013524:Surgical Flaps; D013552:Swine
chemical_list: D005452:Fluoresceins; D019793:Fluorescein