Fat grafting of the face is a very common plastic surgery procedure done to add or restore volume for a variety of aesthetic and reconstructive needs. There are a variety of techniques contained within fat grafting that are believed to affect the outcome. (how well the injected fat survives) How the fat is harvested, donor site selection, how the fat is prepared for injection and the injection technique are the four major considerations, all of which have undergone considerable study.
The one fat grafting consideration that has undergone the most investigative research is graft preparation/concentration. Since the fat harvest process introduces extraneous fluid and trauma to the tissues, it is understandable that eliminating these non-essential aspiration components would create a concentrate that is largely cellular . Numerous concentration methods have been advocated of which mechanized centrifugation provides the most rapid and assured separation of the liposuction harvest into usable and nonusable layers.
But an equally acceptable fat concentration method is that of gravity decantation. For the smaller volumes of fat needed for facial fat injections, this method of decantation offers a convenient and device-free concentration method. As decantation refers to the separation of liquid suspensions into layers of different densities, gravity will spare the oil and water layers of the liposuction aspirate. The less dense oil layer (fat cells and free lipid) will form on top of the more dense water layer. This top layer is then easily pulled off for injection.
The key in gravity decantation is time. It takes about 30 minutes for these layers to fully separate. Thus after the harvest other procedures are done awaiting the full decantation process.
Dr. Barry Eppley