title: Current Thoughts on Fat Grafting: Using the Evidence to Determine Fact or Fiction.
abstract: BACKGROUND
  Autologous fat grafting is an increasingly popular procedure used for facial rejuvenation and body contouring. The purpose of this article is to perform an evidence-based review to determine fact from fiction for the hot topics in autologous fat grafting.
  
  
  METHODS
  A comprehensive literature search was performed. The following key words were then searched: "fat grafting," "autologous fat grafting," "autologous fat transfer," "lipotransfer," "liposculping," and "lipofilling." The authors then assessed each modality individually for the level of evidence that exists and whether the majority of evidence supports or refutes it.
  
  
  RESULTS
  A review of the literature demonstrated that there is no standard test for determining fat viability or volume augmentation after grafting. Furthermore, there is no difference in cell viability seen between syringe aspiration and liposuction pump aspiration harvest techniques (Level II). The decision to wash or centrifuge the fat plays very little role in fat graft survival (Level III). There is no difference between cell viability as a function of harvest location (Level IV). Nearly all studies show no significant effect of local anesthesia on adipocyte cells (Level IV). There are excellent data that support the fact that low-shear devices maintain fat structural integrity (Level IV). There is quality evidence that supports longevity of fat grafted to the breast (Level III). Two studies support large-volume fat grafting longevity but fail to prove their results using objective measures or with sufficiently large sample sizes (Level IV). External preexpansion devices improve total graft survival rate (Level IV). There is quality evidence to support that fat should be injected soon after harvesting, as properties of fat begin to change after processing (Level IV). Microneedling (preconditioning) before fat grafting has been demonstrated to improve fat survival (Level III).
  
  
  CONCLUSIONS
  Currently, the highest levels of evidence derive from human studies of clinical trials and animal studies using human fat. The evidence presented here helps to address the need for accurate and quantitative viability assays. These assays would facilitate a systematic evaluation of each procedural step during fat graft harvest, processing, and grafting to improve the overall viability and predictability of fat grafts.
authors.affiliation: New York, N.Y. From the Department of Plastic Surgery, New York University; and the Department of Plastic and Reconstructive Surgery, Lenox Hill Hospital.
authors.forename: Sammy
authors.initials: S
authors.lastname: Sinno
authors.forename: Stelios
authors.initials: S
authors.lastname: Wilson
authors.forename: Nicholas
authors.initials: N
authors.lastname: Brownstone
authors.forename: Steven M
authors.initials: SM
authors.lastname: Levine
mesh_terms: D050153:Abdominal Fat / Q000637:transplantation*; D000273:Adipose Tissue / Q000637:transplantation*; D003357:Cosmetic Techniques; D004954:Esthetics; D019317:Evidence-Based Medicine; D005260:Female; D006085:Graft Survival; D006801:Humans; D007271:Injections, Intradermal; D015187:Lipectomy / Q000379:methods*; D008297:Male; D012060:Rejuvenation / Q000502:physiology*; D020858:Tissue and Organ Harvesting / Q000379:methods; D014182:Transplantation, Autologous; D016896:Treatment Outcome