Excellent question with no definitive answer. Depending on the study your review fat grafts will survive anywhere from an average of 30-50%. There are also schools of thought that believe few fat cells survive and the success is attributable to stem cells that are transferred along with the fat cells. Survival can depend on the age and health of the patient, donor site, method of harvest/processing/transfer, as well as post-oeprative care.
The survival of grafted fat is variable from procedure to procedure. As it is essentially impossible to quantify the survival of grafted fat as a percentage of the total amount of fat that was transferred, I instead tend to look at it in terms of what percentage of the overall improvement (that is seen early postoperatively) is still persistent at four months postop. If it's still there at four months, then it has a blood supply and will persist long-term. In my experience, most patients show a 50-80% persistence of the early improvement at four months. If less than 50% of the improvement has persisted, most patients need and want a secondary fat grafting procedure. We perform such fat grafting 'touchup' procedures at a significantly reduced cost compared to the initial procedure, and patients are advised of the potential expense before they have their initial surgery. Once in a great while we have a patient who experiences limited fat survival and who has very little long-term change in their appearance following their fat grafting procedure, and for such patients we offer a secondary procedure at no charge. Another way to look at this issue is to ask 'what percentage of patients require a secondary fat grafting procedure in order to get the result they are looking for?'. Because my approach to fat grafting is conservative, I have a fairly high number of patients who return for a second procedure. I would much prefer to have a patient like what they get and return for more, than to have a patient who is unhappy because they feel that their fat grafting was overdone. If you look at reviews posted by fat grafting patients who have had a very negative experience with the procedure, you find an abundance of patients that feel that an excessive amount of fat was placed in their face. They're not just unhappy - they feel disfigured. So a conservative approach is absolutely critical to success with facial rejuvenation by means of structural fat grafting. To be worth a patient's time and money, fat grafting needs to look natural, and not like a trip to the operating room.
