Fat Injections have gone by several names including Structural Fat Grafting and Lipostructure. Although the technique was first reported by Miller in 1926, it was uncommon until the 1980s when it was popularized by Illouz and Fournier and subsequently refined in the 1990s by Sydney Coleman. The fat is harvested via a liposuction type approach. Tissue infiltration is done according to a so-called “wet-technique” using a physiological solution, adrenaline and local anesthesia.
The procedure is usually performed in the outpatient office theatre under conscious sedation, but can be done under general anesthesia in hospital if required.A specifically designed fat harvesting cannula attached to a 10ml syringe, is use for “gentle” liposuction harvest of fat. I personally use a Tonnard-type cannula designed by Tulip Medical. The fat is “purified” by centrifugation at 3000 r.p.m. for 3 min, which separates the fat into 3 layers – an upper oil layer of ruptured adipocyte contents, a middle layer of viable fat cells, and a lower layer of blood and wetting solution. This is shown below. The oil layer is poured or wicked off, and the lower layer is decanted by removing the syringe cap. The viable fat cell layer is transferred into 1ml syringes. Exposure to air is limited by capping and special transfer devices.
The process of structural fat grafting is done by infiltrating multiple levels of the area to be augmented / filled with a special blunt side-hole cannula on withdrawal by gentle plunger pressure. Extremely small amounts are deposited with each pass – typically 0.1 cc. Hundreds of passes are thus required. This ensures that each “parcel” of fat is separated from the others, and no cell is further than 1mm from recipient tissue to ensure maximal integration. Overcorrection is not performed. Many levels are infiltrated: just above periosteum, intramuscular and subcutaneously. Direct subdermal placement is done in specific cases only. Post-operative care includes 24h of antibiotics, analgesia, head elevation and compression to limited swelling. Utilizing this technique, fat grafts can be biocompatible, non-detectable, predictable and stable. Many consider this to represent the ideal filler.
The complications of this technique are low, and the use of a blunt cannula has circumvented many complications previously associated with this technique. Infection rates are also very low. One of the major benefits of this technique is that once the final result is appreciated (usually at about 12 weeks) there will be little change in the long term volume. Generally, fat grafting has less “lift” capacity than HA filler and significant more fat volume is require to achieve the same effect as HA filler. Typical facial injection volumes are between 12 and 30 cc, while typical HA volumes are between 1 and 6 cc. These differences are shown below.