Why can't more fat be transferred in a single surgery?

Thank you for your question. I generally perform high-volume fat transfer in one session. It is not clear to me why you were, as you describe it, under-grafted. Unfortunately, lots of plastic surgeons perform fat transfer that have little to no experience with the procedure. While I am not suggesting that this is the case with you, it is always in your best interest to make sure that the person you are seeing for FFG has a lot of experience in this very specialized procedure. It is possible that secondary sessions are necessary to give the desired volume. This is because the body can only retain so much fat in one session. There is some unpredictability to fat transfer. To improve the viability of the fat transfer, it is always best to make sure you see someone who performs a lot of these procedures because the viability (hence, results) of the transfer depends mainly on the way the fat is harvested, processed, and injected.

Despite of significant knowledge about fat grafts, we still can not predict how much of injected fat would take after 1-1.5 years. That depends of many factors including area of augmentation, age of patient, grafting technique, to mention only few. In hour 25 years of facial fat grafting we could say that around 30% of fat injected in the cheeks, around eyes, forehead would survive, in average. For breasts and buttocks/hips ,it is about 50%. In general. areas that move more (lips, eyelids) have lower retention of fat grafts. Over-grafting in the face is not recommended since it can create unpredictable lumps and shape change that is difficult to manage secondarily. For that reason, fat grafting in the facial areas is, in general, more conservative and may need additional procedure (12 months plus after first procedure) to keep control of result. Hope this helps.

When fat is transferred from one part of the body to other part of body they don't have blood supply. So if you put small amount of fat,it will receive nutrition from surrounding cells.But ,if we transfer big volume of fat at same place,the fat cells lying on the center or away from the normal surrounding tissue will be deprived of nutrition and might die. That is the reason ,we can't inject high volume of fat at one sitting.

There are basically 2 reasons why you may need more than one session of fat grafting. First is the experience of your surgeon. Fat grafting is very different than filler injection. You cannot inject it in one place to fill the area but have to spread it among the tissues in layers to maintain blood supply to the grafted fat. Many physicians doing fat grafting do not understand this and get a poor take of the injected fat which does not maintain the fullness you desire as most of the injected fat is absorbed. The second reason is similar to the first. You have to have enough area with good blood supply to support the amount of fat needed to achieve the desired fill. In many cases you need more than one session if you need a significant amount of volume addition. I, in fact, tell most of my patients that it may take more than one session if they wish more than a little volume increase.