One guiding principle of reconstructive plastic surgery is short and simple: "Replace like with like." Specifically, where tissue is missing, restore the defect with the same tissue whenever possible. If bone is missing, use a bone graft. If muscle is missing, use a muscle flap. So if fat is missing, the ideal solution is obvious.
Whether the goal is to restore volume to the lips or cheeks or temples, or to fill in a crease or depression such as the nasolabial folds or marionette lines (or all of the above), the ideal material is quite clearly the material that one wishes were there in greater abundance in the first place: your own fat. To be the ideal filler material it must also make sense from a cost perspective, which it does. The fat supply, from the standpoint of the volumes required for facial enhancement, is essentially limitless. A multi-area facial enhancement by fat grafting costs about the same as several syringes of ArteFill, Radiesse or Sculptra. And fat has the distinct advantages of not inciting an immune response, producing a more natural soft tissue consistency, and being well tolerated immediately below the skin (even within the deep dermis itself). So in my practice, there really is no place for the 'semi-permanent' soft tissue fillers.
The process is actually quite straightforward: fat is harvested from the abdomen, thighs, hips or buttocks using specially-designed instruments and a specialized technique, processed (by centrifugation, which eliminates all components of the harvested material which are not viable fat), and meticulously introduced into the facial areas to be enhanced using a second, smaller set of fat transfer cannulas. This procedure does not require an operating room and deep sedation or anesthesia - it can be performed in the office procedure room under local anesthesia and oral sedation.
A number of terms are currently used to describe varying techniques for harvesting and delivering fat in small quantities to produce long-lasting soft tissue augmentation: structural fat grafting, microfat grafting, lipostructure, orbital pearl fat grafting, etc. These terms all describe techniques for harvesting living fatty tissue with minimal trauma, refining the fat (in most cases) in some manner such as by centrifugation, and meticulously introducing the fat into the recipient area a small amount at a time to produce new soft tissue structure.
In patients who have developed deep 'tear troughs' at the junction of the lower lid and cheek, adjacent to the side of the nose, the meticulous grafting of fat harvested from the patient's abdomen, hips or thighs can build this area back up and nicely restore a more youthful contour. In some blepharoplasty patients this depression or 'hollow' extends horizontally across the entire junction of the lower lid and cheek, and this must be corrected to obtain the ideal postoperative result.