Posted on April 17, 2014
Journal time! This March 2014 Plastic & Reconstructive Surgery Journal had an article by Dr. Khouri et al discussing “Megavolume Autologous Fat Transfer: Part I. Theory and Principles.” As you know, I love fat transfer, and any pearls or insights I like to share with you.
Principles of Graft Survival.
- Graft to Recipient Interface. Fancy way of stating how does the fat we removed get planted into the “soil” in the new location?
- small portions – smaller than 2mm radius can live by plasma imbibition (drinking the surrounding fluid in the tissue) until a new blood supply forms.
- no fat cell should be more than 2mm away from its recipient caillary network.
- it has 2 days to form new connections
- this translates to 1cc per pass from a 10cm long cannula with a radius of .2cm
- create microribbons of fat, laid down in a 3d pattern of rows that do not overlap or coalesce.
- avoid grafting into cavities. I love his next line. “Cavity is the enemy, where grafts die and turn into necrotic cyts.” This is why we can’t graft into an old implant space.
- Interstitial Fluid Pressure Limit. When you stretch the skin (as happens when you are injecting fat into the new space), the skin stretches and stretches and then BAM you will hit skin tension. As he says in doctor speak, “The compliance of the tissue rapidly decreases and interstital fluid pressure suddenly increases.”
- When pressure rises, the blood circulation in the little tiny capillaries drops, which reduces oxygen delivery, new blood vessel formation and graft survival.
- BRAVA pre expansion helps improve tissue stretching
- this is a good area to think about things: how good is your skin tone? how old are you? what ethnicity? have you had kids? breastfed? are you grafting into skin or muscle? have you had radiation?
- Alternate Theory of fat grafting: All the fat you graft dies, but it leaves stem cells and those grow. For this reason, many are trying to enrich fat transfer with stem cells. “However none of the methods involving stem cell enriched grafts have been clinically proven to be more effective and safe.”
See the next blog to talk about the recipient site (ie where we are grafting into, like the face or breast.)