Enhancement of the buttocks is most consistently done with a gluteal implant. Despite its predictable improvement in the size and shape of the buttocks, buttock implants are not without complications. Intramuscular implant placement makes recovery more uncomfortable and having to sit on the implant predisposes it to positional shifting and the formation of fluid collections and possible infection.
Because of these concerns, the alternative treatment of fat injections or free fat grafting has emerged. Fat grafting to the buttocks has numerous potential advantages such as the elimination of the need for a synthetic implant, the use of a patient's own body tissues, an easier recovery with few limitations, a simultaneous benefit of cosmetic enhancement of the donor site, and a very low risk of bleeding or infection. All of these advantages of free fat fat grafting is counterbalanced by one significant disadvantage. . . . an unpredictability of after surgery shape and size. How much fat survives and is retained is widely variable. No plastic surgeon can guarantee or predict with 100% accuracy how much fat will survive on a consistent basis. I prefer to inject no more than about 300cc per buttock as I think much volume than that results in greater volume loss.
The burning question through the past several decades is. . . how to make fat grafting work better. The injection technique is, of course, important but is only half of the answer. How the fat is prepared after harvest in the operating room is the other half. Everyone agrees that concentration is very important after harvest. This is the mechanical process of removing the liquids from the more solid fat components. Whether this is done by a centrifuge or passing the fat aspirate through a strainer or sieve are two methods of which one has not been proven to be better than the other. Additives to the fat are theoretically appealing but there is no universal magical additive. Currently, I add platelet-rich plasma (PRP) to the concentrated fat prior to injection. Whether this aids fat survival is not proven but since it is a product of the patient, there is no risk in so doing. PRP is a concentrate of a patient's own blood done at the time of surgery. While there is no standardized amount of PRP to add to fat, I typically use 3cc of PRP per buttock graft site.
If a patient opts for buttock augmentation with fat injections, they must accept that the amount of fat that will survive is unpredictable. It may require more than one injection session to obtain the best result. Most fat grafting methods will not achieve the degree of volume enhancement that a gluteal implant will.
Dr Barry Eppley is a board-certified plastic surgeon in private practice in Indianapolis, Indiana at Clarian Health Systems. (http://www.eppleyplasticsurgery.com ) He writes a daily blog on plastic surgery, spa therapies, and medical skin care at http://www.exploreplasticsurgery.com