Autologous Facial Fat Grafting Study

Autologous fat grafting is a very common standard of care procedure in plastic surgery, used for both aesthetic and reconstructive applications across the entire body.1 Facial fat grafting, in particular, is the most common site for use of autologous fat. The American Society of Plastic Surgeons (ASPS) statistics report showed 133,720 cases of facial fat grafting for cosmetic indications in 2020.2 This is mainly due to the fact that humans lose facial fat during the aging process, and that loss of volume leads to characteristic signs of aging.3 It is also well known that when autologous fat grafting is used for facial cosmetic injections, increasing the amount of fat in the dermal/subdermal region has very positive effects on the appearance of the skin.4-6 This is because adding more padding beneath the skin gives the appearance of suppleness and smoothness and mitigates the "deflated" appearance that patients complain of. Additionally, as the adipose graft tissue heals, it tends to increase vascularization in the region which also has a positive effect on the skin. This can improve fine and course wrinkles, and color tone and pigmentary variation can also improve.7-9 Facial fat grafting is commonly performed by surgeons at UPMC and throughout the Pittsburgh region, consistent with national practice patterns. Autologous fat grafting is a minimally invasive procedure that involves harvest of fat tissue with a liposuction cannula. In many cases, the cannula is attached to a 10 mL syringe and negative pressure applied by withdrawing the syringe plunger during aspiration.1 In other cases, a mechanical aspiration machine is used to generate negative pressure.1 Either way, all of this equipment is standard in most operating rooms across the country. The aspirated material consists of small particles of adipose tissue, measuring between three and five mm in diameter.10 Once harvested into sterile vessels, the aspirate can be gently centrifuged or strained to separate and remove the aqueous and oil layers. If washed, a sterile saline solution would be used to perform the washing procedure. The material is often transferred between syringes using a Luer Lock connector and the graft material is then injected from syringes. Passing the tissue multiple times between Luer Lock connectors has become a very common method of breaking up clumps of tissue and enabling a more flowable graft material that can be injected through smaller gauge cannula without clogging.11 Controversy exists in the plastic surgery community as to the most beneficial preparation methods in the operating room.12 Different surgeons use a number of methods alone or in combination that include filtering or straining fat, gentle centrifugation, separation of fluid and oil layers by gravity, and rinsing/washing with sterile saline. All of these methods are well accepted as within standard of care and represent minimal manipulation of the tissue grafts. A national survey of the plastic surgery community, published by our group revealed that 28% of surgeons use a saline wash during their fat graft processing.13 The rationale for a saline wash is that it may decrease any residual free lipid/oil, as well as residual red cells, both of which can potentially cause irritation of the local tissues. However, opponents of washing often cite that there washing adds an extra step without clinical benefit. Hypothesis: We hypothesize that a saline washed fat graft injectate will have improved appearance of facial skin. We speculate that the reduced free lipid and reduced red cell fraction will be beneficial in the healing process. Significance: This study will provide evidence that may directly impact clinical practice for a common procedure in plastic surgery. Regardless of whether the null hypotheses is accepted or rejected, the data will be of direct clinical use and impact practice in the operating room. Treatment Period: Autologous fat graft injections will be performed on Day 0 of the study period after eligibility determination has been made, and after baseline data collection. Subjects will be followed over a 12-month time period.