Fat grafting: why part of it is reabsorbed, and why that is normal

Fat grafting is one of the most versatile resources in current plastic surgery. Your own tissue is taken by liposuction, processed and placed where volume is missing: face, breasts, buttocks, contour defects.

And it has a limitation worth putting first, because it explains almost every disappointment.

Not all grafted fat survives

Between thirty and fifty per cent is reabsorbed during the first three months.

That is not a complication: it is how a graft behaves. Transplanted fat needs new blood vessels to grow around it in order to stay alive, and whatever does not get them goes.

That is why a calculated excess is placed, and why a second session is sometimes planned from the outset. Anyone who does not know this beforehand lives those three months as a loss of the result, ringing anxiously every fortnight.

You leave theatre with more volume than you are going to end up with. It is deliberate, and the real result is judged at six months.

What it does have going for it

Fat is your own tissue: it causes no rejection, it is not a foreign body and, when it takes, it behaves like the rest of the fat in your body. That has a consequence worth knowing: if you put on a lot of weight, that fat grows too.

In the face it restores volume to the areas that empty with age. In the breast it corrects asymmetries and contour defects. And in depressed scars or irradiated areas it does something no synthetic filler does: as well as filling, it improves the quality of the skin covering them.

What improves survival

It is not chance. It depends on how the fat is harvested — at low pressure, with fine cannulas — how it is processed and, above all, how it is placed: in multiple small passes and in different planes, never as one large bolus, so that each particle ends up close to a vessel that can feed it.

On the patient's side, what matters most is not smoking. Tobacco compromises the microcirculation, which is exactly what the graft taking depends on.

The safety point: the buttock

Here it is necessary to be explicit. In the buttock, the serious risk is fat embolism from intramuscular injection, and it is avoided by placing the graft exclusively in the subcutaneous plane, above the muscle.

This is not a minor technical detail or a matter of preference: it is the difference between a safe procedure and one that has caused deaths. If you are considering buttock augmentation with fat, ask which plane it is placed in. There is only one correct answer.

The practical side

One to three hours, local anaesthesia with sedation or general depending on the extent, as a day case, normal life in seven to fourteen days. There are two areas to look after: the donor site, which behaves like a small liposuction, and the recipient site.

At the recipient site, the instruction most often broken is not to lean on or press the area for the first weeks. In the buttock that means not sitting as you normally would for a time, and it is uncomfortable, and it is what decides how much graft survives.

What is not promised

No exact volume is promised and no total survival of the graft. What is promised is a procedure using your own tissue, a plan that accounts for reabsorption from the start, and a second session if one is needed.