title: Application of topical negative pressure (vacuum-assisted closure) to split-thickness skin grafts: a structured evidence-based review.
abstract: BACKGROUND
  Significant controversy surrounds the effectiveness of negative pressure wound therapy although it has been in use for decades. Although many clinicians favor this modality in relation to its practicality, ease of use especially in complex wounds, it has faced the same challenges as other dressings in relation to evidence base of efficacy in relation to a number of outcome measures. In view of the current financial pressures on health care systems worldwide, this structured review systematically challenges the evidence for perioperative application of topical negative pressure (TNP) to split-thickness skin grafts (STSGs) through evidence-based critical appraisal, and extrapolate the mechanisms of action on the mechanisms through which TNP may aid wound healing. Weighted evidence-based recommendations regarding the impact of TNP on split skin graft quality and quantity of take as outcomes.
  
  
  METHODS
  Phase 1: Structured literature search. Phase 2: Retrieved articles were critically appraised for rigor and methodological validity by 3 independent authors, then stratified according to a validated "levels of evidence" framework. Graded "current best evidence" recommendations could therefore be proposed.
  
  
  RESULTS
  Of the 220 studies retrieved in the initial search, 38 studies satisfied our quality of evidence criteria. Current best evidence supports 2 complementary trends explaining the mechanisms whereby STSG benefits from TNP. Active stimulation of epithelial mitosis: TNP creates mechanical stretch which stimulates multiple signaling pathways up-regulating growth- and mitosis-associated epithelial transcription factors. Topical negative pressure also promotes microcirculatory flow (graft and wound edge), stimulates angiogenesis and basement membrane integrity (grade C). Prevention of complications: significant reduction of graft lift-off by edema, exudates, subgraft hematoma, and reduction of shear when compared to traditional dressings (grade B). Topical negative pressure promotes significant qualitative improvement in the final STSG result studies (level 1B). The role of TNP in prevention of infection is, however, equivocal and further research is required. No evidence of harm from TNP application was reported.
  
  
  CONCLUSIONS
  Topical negative pressure increases quantity and quality of split skin graft take compared to traditional bolster dressings. The advantages are increased in irregularly contoured, technically difficult wounds and suboptimal recipient wound beds where it seems to be the best modality currently available. Large-scale randomized clinical controlled trials remain scanty in all areas of wound dressing research including negative pressure therapy.
authors.affiliation: Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff, United Kingdom.
authors.forename: Ernest Anthony
authors.initials: EA
authors.lastname: Azzopardi
authors.forename: Dean E
authors.initials: DE
authors.lastname: Boyce
authors.forename: William A
authors.initials: WA
authors.lastname: Dickson
authors.forename: Elayne
authors.initials: E
authors.lastname: Azzopardi
authors.forename: James Hamish Ellsworth
authors.initials: JH
authors.lastname: Laing
authors.forename: Iain S
authors.initials: IS
authors.lastname: Whitaker
authors.forename: Kayvan
authors.initials: K
authors.lastname: Shokrollahi
mesh_terms: D006085:Graft Survival; D006801:Humans; D054843:Negative-Pressure Wound Therapy; D011183:Postoperative Complications / Q000517:prevention & control; D016038:Skin Transplantation / Q000379:methods*; D014945:Wound Healing / Q000502:physiology