title: Laser-assisted indocyanine green dye angiography accurately predicts the split-thickness graft timing of integra artificial dermis.
abstract: BACKGROUND
  The use of an artificial dermal substitute such as Integra-a bilaminate combination of thin silicone and cross-linked bovine tendon collagen and chondroitin-6-sulfate-has become a popular method to address large surface area wounds or smaller, complex wounds devoid of a vascular bed. The incorporation of Integra depends on a vascular wound bed or periphery and can take 4 weeks or longer to occur. If the Integra has not fully incorporated at the time of placement of the split-thickness graft, complete graft loss may result. The availability of a minimally invasive method to assess the incorporation of Integra would be of great value.
  
  
  METHODS
  Two 5 × 10-cm paraspinal full-thickness wounds were created on 3 female swine. Wounds were randomly assigned full-thickness skin graft or Integra (Plainsboro, NJ) treatment. Both types of grafts were placed after the application of fibrin glue (Tisseel, Deerfield, Ill) to the wound bed. Laser Doppler imaging (LDI) (Moor), indocyanine green dye (ICG) angiography (LifeCell SPY), and clinical scoring were performed weekly for a period of 8 weeks after grafting. At 4 weeks, the silicone layer of the Integra was removed, and a culture of autologous keratinocytes was applied. A 4-mm punch biopsy sample of each graft was taken 1, 2, 4, 6, 7, and 8 weeks postoperatively for histologic analysis.
  
  
  RESULTS
  Both ICG angiography and LDI perfusion measurements noted an increase in perfusion at the Integra graft site that peaked 3 weeks after grafting, corresponding with the start of neovascularization and the optimal time for the application of a split-thickness skin graft. indocyanine green dye angiography measurements exhibit greater reproducibility between animals at late time points as compared with LDI. This decrease in LDI precision is directly related to increases in scar tissue thickness of greater than 5 mm as determined via histologic analysis and corresponds with the accepted maximum penetration depth of the LDI laser.
  
  
  CONCLUSIONS
  Indocyanine green dye angiography may provide valuable information as to graft integrity and split-thickness skin graft timing at late time points. Range of LDI seems to be insufficient for split-thickness graft timing or late time point accuracy. Future exploration of ICG angiography potential will involve tracking Integra graft delay in porcine models.
authors.affiliation: From the *Stony Brook University Medical Center, Stony Brook, NY; †The Feinstein Institute for Medical Research, Manhasset, NY; and ‡University of California at San Francisco, San Francisco, CA.
authors.forename: Mitchell S
authors.initials: MS
authors.lastname: Fourman
authors.forename: Brett T
authors.initials: BT
authors.lastname: Phillips
authors.forename: Jason R
authors.initials: JR
authors.lastname: Fritz
authors.forename: Nicole
authors.initials: N
authors.lastname: Conkling
authors.forename: Steve A
authors.initials: SA
authors.lastname: McClain
authors.forename: Marcia
authors.initials: M
authors.lastname: Simon
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Dagum
mesh_terms: D000818:Animals; D002809:Chondroitin Sulfates; D003094:Collagen; D005260:Female; D005456:Fluorescent Dyes; D007208:Indocyanine Green; D018919:Neovascularization, Physiologic; D061848:Optical Imaging / Q000379:methods*; D011897:Random Allocation; D012867:Skin / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000293:injuries; D016038:Skin Transplantation / Q000379:methods*; D017768:Skin, Artificial; D013552:Swine; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler; D014945:Wound Healing
chemical_list: D005456:Fluorescent Dyes; C114835:integra artificial skin; D002809:Chondroitin Sulfates; D003094:Collagen; D007208:Indocyanine Green