title: Studies in fat grafting: Part II. Effects of injection mechanics on material properties of fat.
abstract: BACKGROUND
  Although fat grafting can address many soft-tissue deficits, results remain inconsistent. In this study, the authors compared physical properties of fat following injection using an automated, low-shear device or the modified Coleman technique.
  
  
  METHODS
  Lipoaspirate was obtained from nine patients and processed for injection using either a modified Coleman technique or an automated, low-shear device. Fat was passed through a 2-mm cannula and compared with minimally processed fat. A rheometer was used to measure the storage modulus and shear rate at which tissues began to lose their solid-like properties. Viscosity was also measured, and gross properties of treatment groups were evaluated qualitatively with a glass slide test.
  
  
  RESULTS
  Fat injected through an automated, low-shear device closely matched physical properties of minimally processed fat. The storage modulus (G') of fat for the device group was greater than for the modified Coleman group, and the onset of breakdown was delayed. Similarly, viscosity measurement of fat from the automated device closely matched minimally processed fat and was greater than that of othe modified Coleman group.
  
  
  CONCLUSIONS
  The physical properties of lipoaspirate processed using an automated, low-shear device with a 2-mm cannula preserved the intactness of fat more than the modified Coleman technique. The authors' rheologic data demonstrate less damage using an automated device compared with the modified Coleman technique and potentially support its use for improved fat graft integrity.
authors.affiliation: Stanford, Menlo Park, and Palo Alto, Calif. From the Hagey Laboratory for Pediatric Regenerative Medicine, Department of Surgery, Plastic and Reconstructive Surgery Division, and the Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine; the Departments of Materials Science and Engineering and Bioengineering, Stanford University; the TauTona Group; and the Plastic Surgery Center of Palo Alto.
authors.forename: David
authors.initials: D
authors.lastname: Atashroo
authors.forename: Jordan
authors.initials: J
authors.lastname: Raphel
authors.forename: Michael T
authors.initials: MT
authors.lastname: Chung
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Paik
authors.forename: Andreina
authors.initials: A
authors.lastname: Parisi-Amon
authors.forename: Adrian
authors.initials: A
authors.lastname: McArdle
authors.forename: Kshemendra
authors.initials: K
authors.lastname: Senarath-Yapa
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Zielins
authors.forename: Ruth
authors.initials: R
authors.lastname: Tevlin
authors.forename: Chris
authors.initials: C
authors.lastname: Duldulao
authors.forename: Graham G
authors.initials: GG
authors.lastname: Walmsley
authors.forename: Michael S
authors.initials: MS
authors.lastname: Hu
authors.forename: Arash
authors.initials: A
authors.lastname: Momeni
authors.forename: Brian
authors.initials: B
authors.lastname: Domecus
authors.forename: Joe R
authors.initials: JR
authors.lastname: Rimsa
authors.forename: Lauren
authors.initials: L
authors.lastname: Greenberg
authors.forename: Geoffrey C
authors.initials: GC
authors.lastname: Gurtner
authors.forename: Michael T
authors.initials: MT
authors.lastname: Longaker
authors.forename: Derrick C
authors.initials: DC
authors.lastname: Wan
mesh_terms: D000273:Adipose Tissue / Q000637:transplantation*; D001696:Biomechanical Phenomena; D006801:Humans; D007267:Injections / Q000295:instrumentation / Q000379:methods*