I just got my Plastic and Reconstructive Surgery Journal, with PRS Global Open, “Best Papers of 2015.” The geek I am, I love it! The first article was written by a favorite doctor of mine, Dr. Khouri. The title isn’t flashy (as in most scientific papers), “Diffusion and Perfusion: The Keys to Fat Grafting.” Khouri is a mentor of mine, and a leader in the field of fat transfer. His studies give science to our quest of how to improve fat transfer and the survival and predictability of fat.
Why did they write it? They talk about how fat grafting has unpredictable long term effects. Fat is a living substance, so it must get oxygen to live. At first it receives the oxygen through diffusion, and then with new blood vessel formation.
Study:
They created three models using different variables of oxygen delivery and graft survival.
What did they find?
- “Microribbons” of fat maximize oxygen transfport.
- The site you inject into should be large, stretchy, and have good blood vessel supply.
- Any fat size injected over 0.16cm in radius will have a central area of necrosis (dead fat)
- If you go over pressure of 9mm, then any additional fluid will reduce blood flow, and therefore oxygen, to the tissue.
- Tissue can usually accommodate about 60% of its weight in interstitial fluid before reaching critical pressure of 9mm.
- Remember this 60% is approximate and changes with the stretchiness of the tissue you inject.
- BRAVA (or other stretching devices) cause edema and angiogenesis (new blood vessel formation). They are helpful prior to implanting new fat to have a more vascular bed.
Good scientific data. It supports using certain cannulas to harvest the fat, which are the ideal fat globule size. It shows injecting the fat diffusely in microribbons is the best technique. And it reaffirms not to overfill the area. In fat grafting more is not better.