Fat appears to be a near ideal material for facial volume restoration or augmentation. Known as lipofilling, it is a very safe and relatively inexpensive method of adding volume to either the aging or lipodystrophic face. While injecting fat into the face is straightforward, the important question becomes how to ensure that most of it will survive. Post-injection resorption is a well known problem with fat injections. There are undoubtably many factors that influence survival, but one of the most obvious is its preparation prior to injection.
Despite many espoused methods of fat preparation, which all boil down to how it is processed, no ideal method has yet been proven. The most commonly used methods include either filtration/washing and centrifugation of the fat. Filtration is done through a fine mesh screen which is washed with saline prior to placement into a syringe. Centrifugation is a more sophisticated method of machine separation which appears more effective at isolating pure fat. It is the basis of ‘structural fat grafting’. Is one way really better than the other?
In the June 2011 issue of Plastic and Reconstructive Surgery, a study was published comparing the clinical results obtained using filtered and washed fat with that of centrifuged fat in facial transplantation. In a prospective double-blind study of 25 patients over a six month period, fat injections into the face were assessed after a 12 month follow-up based on before and after photographs. The authors concluded that there was no significant difference between the two fat-processing methods based on their assessment of implanted hemifacial regions.
While one would assume that centrifuged fat should survive better, due to higher concentrations of fat cells, this study done by experienced fat injectors refutes that claim. On the one hand, this probably brings joy to those plastic surgeons who do not employ centrifugation due to the extra time and expense to do so. Centrifugation does involve a lot more effort and potential expense given the equipment needed to do it. It is an arduous step that one hopes is really worth that effort. To those who are devout believers of fat centrifugation, they can argue that this is a limited study based on the number of patients and uses only a very subjective method of postoperative evaluation.
Despite arguments that can be made on both sides, the ideal method for fat preparation remains yet unknown. This is also conflicted by the likely fact that the survival of fat cells depends on many other factors as well including the anatomic source of the fat, its method of harvest and the qualities of the recipient bed into which it is implanted. Since there is no way to control all of these variables, we are unlikely to know anytime soon how to best inject fat. For now, I will continue to use filtered/washed preparation method for facial fat injections as it offers the shortest time between harvest and implantation.
Dr. Barry Eppley
Indianapolis, Indiana