Understanding Fat Grafting / Fat Transfer
Fat grafting, or fat transfer, is an increasingly popular procedure in many plastic surgery practices locally and around the world, and is one of the most requested procedures in my practice. One can see why this is so, as it fulfils a dual purpose within one surgical setting - the removal of fat cells from a location in the body to another location in the body or face where he or she desires more volume.
“Killing two birds with one stone” is an extremely attractive proposition that draws many patients to this procedure. Here, I would like to address the various aspects of the fat transfer procedure, the risks and benefits of doing it, as well as what to expect after having it done.
How is fat grafting done and what are the underlying principles?
Fat grafting essentially comprises of 3 separate procedures done in 1 surgical setting, first there is the fat harvest, which is a liposuction or liposuction-like procedure, followed by the purification and centrifugation of the aspirated liposuction material (lipoaspirate), and lastly, the injection of the purified fat component into the recipient areas of the face or body.
The first step is usually a liposuction procedure if a large amount of fat is required, thus necessitating general anaesthesia with an anaesthetist present. It is performed just like a full liposuction surgery. If a smaller amount of fat is required, such as for fat grafting to the under eyes or to the laugh lines, then this is performed under local anaesthesia with a fine cannula via a tiny 2-3mm opening in the belly button area; this isn’t a liposuction procedure in the sense that no more than 10-20cc of fat is drawn out and there is no change in the overall appearance or size of the abdominal skin area.
After collecting the lipoaspirate, the next step is to purify it as many components of the lipoaspirate are not desirable. That includes the tumescent fluid (used in liposuction), plasma, the red blood cells, the lipid/oily layer and fibrous tissue. If the purification is not done, then all these excess components injected would be very quickly reabsorbed by the body, resulting in a much greater percentage of volume loss than expected. This is especially key in areas where small volumes of fat graft are injected - a high percentage of fat loss would mean a much less optimal aesthetic result. The centrifugation of the fat is done at a specific setting to maximise the purification of the fat with minimisation of trauma to the fat cells, allowing for a maximal retention rate of the grafted fat in the recipient site. At the same time, there should also be minimal handling of the fat as well as minimal exposure of the fat to air.
The last step would be the injection of the purified fat to the recipient site. I subscribe to a modified version of the Coleman technique of fat transfer, as popularised by Dr Sydney Coleman, where small aliquots of fat are deposited using 1cc syringes each time with a fine Tulip cannula. This allows for a finer, more even deposition of the fat, thus reducing the possibilities of irregularities and lumpiness. It also enhances the fat survival rate as thin layers of fat tend to vascularised a lot better - a key step for fat survival.
The fat that is grafted from another location comes without its own blood supply, which means there is a crucial period it must undergo after being transferred to survive for the long term. There are a few theories on how this occurs. The first theory suggests that the fat cells, just like other grafts such as skin grafts, depend on the ingrowth of new blood vessels at the recipient site, bringing to it nutrients and oxygen. This, therefore, implies that a good healthy well-vascularised recipient site would ideally result in the best percentage of fat survival. The second theory suggests that most the transferred fat cells die off in the early period, and it is the transferred cells (more accurately, the adipocyte-derived mesenchymal cells) that eventually differentiate and grow into the new fat cells. This may go some way into explaining why fat survival rate is boosted by the addition of certain additives, such as stromal vascular fraction (SVF). In my opinion, it is probably a combination of both, with initial partial fat survival with the ingrowth of new blood vessels, and then longer-term differentiation of the cells into fat cells (adipocytes).
Where is the fat usually harvested from?
The donor site of the body where I harvest the fat from depends on the volume of fat I require as well as the gender of the patient. Typically, for small volumes of less than 100cc, which is usual for fat transfer procedures to the face, I will harvest the fat from the lower abdomen area using a tiny 2-3mm opening hidden inside the umbilicus, such like that for keyhole surgery, except smaller. Harvest of the fat is done manually using 10cc syringes and a fine Tulip harvesting cannula. This is regardless of gender.
If the amount of fat required is larger, for example for transfer to the breasts or the buttocks, then a full liposuction procedure is carried out with the liposuction machine, cannulas and fat collector. This is performed under general anaesthesia and involves sculpting of the donor areas, not simply just fat collection. For ladies, I typically harvest the fat from the thighs, whereas for the men, I usually harvest from the love handles, back and tummy areas; the reason for this is that fat deposition in the body is predetermined by gender and genetics, and the gender-specific deposition of fat is usually in those areas specified. In my experience, fat taken from the thigh area also seems to survive better when transferred to the breasts, with a higher percentage remaining.
Where is the fat usually transferred to?
The most common areas of fat transfer to the face are the under eye and cheek area, the nasolabial folds (laugh lines), the forehead, temples as well as the chin. In particular, the under-eye area (tear trough and lid cheek junction) tend to get very sunken with age and weight loss, producing a haggard and tired appearance.
Fat grafting to that triangular area of the tear trough and the mid-cheek gives a very youthful and full appearance and is the most common area I fat graft to. This is often done in combination with an eye bag removal procedure.
Fat transfer to the face replaces the volume loss that occurs in the face due to ageing, which is a result of a loss of fatty tissue, skeletal tissue and to some extent, muscular tissue. Besides the full appearance of youth, it also results in a lifting effect as the increased volume in areas such as the malar, temples and mid-cheek take up the skin slack that occurs due to volume loss. In a subset of patients, the cells in the fat graft also result in a reduction in skin pigmentation issues as well as fine wrinkles in the months that follow the procedure.
The breasts are the most common body region that fat grafting is requested for. It results in a volume increase as well as an improvement in the overall shape of the breasts. In post-breastfeeding patients, they also provide a small degree of lifting. There are, however, a few aspects that I discuss in detail with my patients:
- It will never be the same as an implant in terms of shaping and lifting; nor can fat grafting achieve the size that can be achieved with implants in one sitting.
- Although the fat is alive and is permanent after the initial 3-6 week resorption period, it responds to ageing and weight loss and weight gain, just as natural fat would. In other words, if you lose weight, the breasts will get smaller; similarly, it will sag and get smaller with age.
- There must be enough fat for me to transfer. The average volume of fat I transfer in my practice is 350cc to 400cc per breast for a total of 700cc to 800cc of pure fat. This means that I would need to remove via liposuction around 1.3L of lipoaspirate, as around 40% of the aspirate composes of undesirable substances, such as tumescent fluid.
The buttock is the other area for body fat grafting, commonly called a Brazilian Butt Lift (BBL). The concept is similar, with the use of volume in the upper buttock to lift and shape a saggy bottom. The volumes used for a BBL is even greater than that for breasts, due to the higher loss rate, with an average volume of 400-450cc each side.
What are some of the complications and risks of fat grafting?
- Infection: This is the biggest issue with fat grafting, as it results in a much larger volume loss in the fat transferred and a longer recovery time in terms of hardening. Fortunately, this is often easily treated with antibiotics and local drainage.
- Irregularity & pigmentation: When performing a full liposuction for the fat harvesting, complications at the donor area such as contour irregularity and pigmentation is present.
- Asymmetrical and extreme fat resorption: The average percentage of fat graft retention after being transferred is between 40-60%. Many factors affect this, including patient genetics, smoking, intermittent fasting and low carbohydrate diets, too early return to cardiovascular exercise and the region that it is being transferred to.
- In 10-15% of my patients, there is significant resorption of fat beyond 60%, despite controlling all the above factors. This and the possibility of slight volume differences (left and right) are aspects that one must be aware of before embarking on the fat grafting journey.
How do my patients prepare for the surgery?
I usually advise them to eat well to have the best possible reservoir of fat for me to harvest. Also, they are instructed to avoid certain foods and supplements 1 week before the procedure to minimise the degree of swelling and bruising after the surgery.
What is the post-surgery recovery like?
The surgery is performed as a day surgery procedure in my centre. I do not put drainage tubes; my patients only need to wear a compression garment for the donor site for around 3-4 weeks. In terms of pain, my patients only require oral painkillers, of which a significant number do not even require or take. The breast fat grafting is usually far more comfortable than a breast augmentation procedure, for example.
In terms of returning to work, my patients are given hospitalisation leave of around 1 week, although many go back even sooner. As for exercises like pilates/yoga and strenuous physical activity, I usually advise my patients to wait a month after the surgery.
How can I maximise my chances of fat graft survival?
The main advice I give to my patients is to take it easy and eat well. Stop all low carbohydrate or intermittent fasting diets for 1 month after the surgery as well as to reduce high-intensity physical workouts for the same period. Cessation of smoking will also help as it reduces the blood supply to the fat graft.
I also advise no prolonged pressure to the area for the first month if possible, so tight bras are out, as is sleeping on the side for the first week.
How much is a Fat Transfer procedure? Is it Medisave and insurance covered?
For the surgery to fulfil the criteria for Medisave and insurance claims, it has to be done for medical reasons, such as for reconstruction after a traumatic incident or after cancer removal.
Cost of surgery is dependent on the following factors: surgeon’s fees, anaesthesia fees, facility fees, medication, garment and the equipment/medical consumables. GST is of course the last factor.
1.Strong AL, Cederna PS, Rubin JP, Coleman SR, Levi B. The Current State of Fat Grafting: A Review of Harvesting, Processing, and Injection Techniques. Plast Reconstr Surg. 2015 Oct;136(4):897-912.
2.Coleman SR. Structural fat grafting: more than a permanent filler. Plast Reconstr Surg. 2006 Sep;118(3 Suppl):108S-120S.
3.Egro FM, Coleman SR. Facial Fat Grafting: The Past, Present, and Future. Clin Plast Surg. 2020 Jan;47(1):1-6.
4.Coleman SR, Lam S, Cohen SR, Bohluli B, Nahai F. Fat Grafting: Challenges and Debates. Atlas Oral Maxillofac Surg Clin North Am. 2018 Mar;26(1):81-84.
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