October 2015 issue of Plastic and Reconstructive Surgery Journal was full of stuff I want to know. I centrifuge my fat, as there are studies to indicate it improves fat survival. As time goes on, and newer ways of processing fat come out, I always want to know: Can I do this better?
This article was a review of the literature looking at fat processing. The title is catchy, “Roll, Spin, Wash, or Filter? Processing of Lipoaspirate for Autolgous Fat Grating: An Updated, Evidence Based Review of the Literature.”
Why do we filter? It is thought that contaminants- oil, blood, dead cells- can lead to inflammation. Inflammation is thought to cause poorer fat retention. There are some things in fat grafting like stem cells which we think help fat survive, but attracting host cells and making new blood vessels.
Their conclusion, not so helpful. “The authors failed to find compelling evidence to advocate a single technique.” We need more high quality data. But I did find some interesting things in the body of the paper. (Yes, I read the entire article, not just the summary.)
Some of the new stuff out there is not proven:
- Newer technologies don’t have human studies yet. Puregraft was done in the lab, showing more viable fat cells. No in vivo study was done.
- Revolve is a closed system which washes the specimen and agitates it. It showed less blood and lower free oil, but when the fat was harvested, there was no difference in fat retention or histology compared to centrifuge.
- Tissue Trans Filtron system was compared against gauze, centrifuge, and gravity. They found the gauze rolling with the best survival.
- There are filters to get the vascular stroma and stem cells out. But these have not been translated to in vivo studies for how to be used clinically.
There is no superior method, but there are some consistent findings.
- Gravity separation has the largest number of intact fat cells, but it also has the largest amount of contaminants. There is less survival of this fat relative to centrifuged or washed fat, thought due to higher inflammation.
- Cotton gauze rolling makes good grafts, with few contaminants, but it is labor intensive and not applicable to larger amounts.
- Centrifuge is the most widely used technique, ala Syd Coleman, who does 1200g (3000rpm) for 3 minutes, and then getting rid of the oil layer. There are new studies which demonstrate lower rates of graft viability after centrifuge relative to washing, but “soft” centrifuge 400g for 1 minute has shown equal or better results to washing.
- Washing preserves stem cells and fat cells. These are promising, but not proven yet.
- Filter methods get rid of contaminants and keep the fat cells. Again, promising but not proven.