Fat grafting the buttock: facts and myths

1. There is a place for fat grafting into buttocks. 2. Fat embolism occurs during fat harvest but is unlikely to cause death and more likely to be apparent as a confused state up to two days postoperatively. 3. Fatal fat embolism is more likely by venous inoculation of fat under pressure into the sub-gluteal space [7]. It is estimated that the risk of mortality from massive fat graft to buttock is 1 in 3000. 4. It is unlikely, in my opinion, that macroscopic fat embolism results from a direct cannulation of gluteal veins, as suggested by some authors [7], in these cases, because under tissue tension we should expect the gluteal veins to collapse and the cannulae are larger than 3mm, making direct cannulation difficult. I suggest that it is more likely that there is tension avulsion of the gluteal veins as they are stretched in the sub-gluteal space resulting in direct access to fat embolism. 5. Fat graft into the gluteus maximus provides better fullness in the upper and mid buttock regions. Fat injected into subcutaneous tissue gives a broad but flatter buttock. 6. Only 200 to 300mls of fat maximum should be injected into each buttock and under no tension using a 3mm or larger diameter cannula, with as few passages as possible to avoid trauma to veins. The cannula is inserted, a pull back on the syringe plunger excludes direct venous cannulation, and fat is injected whilst slowly withdrawing with a thin subcutaneous tissue layer the space for multiple separated passages is narrow therefore fewer are possible. 7. Staged small volume injection of fat graft may give a better result with less risk. Injecting fat under tension is against the principles and understanding of basic wound healing and tissue revascularisation. 8. The mid and upper buttock give a more precise fullness if the fat is injected intramuscularly. This fat must not be injected under pressure and never from the inferior buttock crease.