Fat Resorption after Autologous Fat Transfer
We have fat cells located everywhere on the body but not always where it’s wanted for beautiful curves and contours. Fat transfer is a relatively new technique that is growing in popularity each year, due to the beautiful, natural results it produces, and the multiple benefits the procedure offers. Patients who are dissatisfied with the volume and contour of the buttocks, face, hips, breasts, or abdomen can have their own fat (autologous fat) transferred to these areas, improving the appearance of both areas in the process. Fat is a filler with ideal properties: it naturally integrates into tissues, is autologous, and is 100% biocompatible(1). Fat that manages to establish itself in the treated areas and survive after the procedure is considered permanent. This is typically true for the vast majority of the cells transferred during the treatment. However, since not all the fat injected will survive, the results are only considered permanent after approximately 6 months, when all the fat that did not survive it has been disposed of by the body. Therefore, patients will need to wait to see the final volume they can expect from the procedure.
In 2009, the American Society of Plastic Surgeons task force determined that autologous fat grafting was a safe procedure with a relatively low rate of complications. In addition, they stated that artifacts could be identified and distinguished from malignancy in early breast cancer screenings (2). The popularity of autologous fat transfer is supported by a remarkably low risk of complications, minimal scars, and readily available donor sites. Fat grafts are easily available, biocompatible, associated with low donor-site morbidity, and provide a natural appearance. The abdomen is the most common site of fat harvesting; the second is the trochanteric region (saddlebags) and the inner thighs. Recent developments have minimized fat resorption after fat autologous fat transfer (AFT), allowing plastic surgeons to deliver near permanent results. Long term results after autologous fat grafting are achieved with the following critical factors: 1) Gentle liposuction techniques; 2) purification of fat prior to re-injection; 3) meticulous fact injection int the buttocks and hips, and 4) patients’ compliance with pre and post-operative protocols.
Recent studies published by Stanford University about fat harvest techniques used in AFT concluded that laser-assisted liposuction reduced viability of graft material, when comparing suction-assisted liposuction with laser-assisted liposuction. Fat that is removed in laser liposuction cannot be re-used as the fat cells are destroyed by the heat from the laser. It’s important noticing that fat cells treated and removed during VASER Liposuction procedures are typically of high quality (in contrast with the ones extracted via Smart Lipo) and are viable to re-introduce into the body (3). Two recent, independent studies have confirmed the viability of fat removed with VASER Liposuction: Cytori Therapeutics conducted a multi-site study that confirmed the viability of VASER-treated fat at 85% and regenerative cells at 87%, and the University of Pittsburgh Medical Center found the viability of VASER-treated fat to be over 80%, six weeks post re-injection (4).
Certain donor or liposuction sites such as the lower back and flanks also boast high survival rate of fat grafts due to their proximity to the buttocks and hips. However, in 2004, a study conducted by the Department of Plastic Surgery of the University of Texas examined fat harvested from 4 body parts: the abdomen, the flank, the thigh, and the medial knee. They determined that there was no significant effect on adipocyte viability or survival based on harvest site (5). This information is beneficial because it allows the plastic surgeon more versatility to harvest based on tissue availability and patient aesthetic preferences without compromising the outcomes.
Moreover, clinical studies had shown that fat transfer procedures success is dependent on factors during the removal of the fat, such as the aspiration pressure used, and the cannula’s size used. In this respect, the VASER Liposuction system was designed to maintain the integrity of fat cells, by using ultrasound energy to selectively target and dislodge fats cells from the fatty tissue matrix. Atraumatric VentX cannulas give you the ability to fine tune suction pressure to remove the treated fat. Typically, 2.9mm to 3.7mm precision cannulas are used, depending on the donor site, and the pressure utilized to extract the fat with VASER Liposuction system is minimal (around 15 inch Hg) as opposed to the standard 25 inch Hg, which can affect the viability of the fat cells harvested. Research concluded that breaking apart adipose tissue prior to aspiration allows the use of atraumatic cannula and lower vacuum levels, which prevent the fat from tearing or shearing during aspiration.
The method of processing (purification of the fat) is the second key factor that plastic surgeons can use to maximize fat survival. The preparation process clears the donor fat of blood, pain killers and other unwanted elements that could cause infections or other undesirable complications. Separation from excess fluid ensures that the plastic surgeon is injecting only purified and stable fat cells will be re-injected into the buttock area. After the fat selection process is completed, only 10cc to 100cc will be injected in the face, 25cc to 400cc will be injected in each breast, and 500cc to 1500cc will be injected into each buttock (6).
Furthermore, high success rates of fat survival can be achieved by choosing a proper method of placement. During surgery, fat grafts should be placed in a way that simulates naturally occurring fats. Micro-droplets of fat (a mere 0.01cc) are disperse through meticulous fat injections. By all means, fat placement requires slow injection techniques and is time consuming (7). The use of micro-droplet technique ensures smooth skin surface and natural buttock contour. It creates small compartments of fat in which blood vessels can grow. It is important noticing that blood supply is essential for the long-term survival of fat grafts, the same way it is crucial in skin grafts and organ transplants.
Patients can also contribute on the success of autologous fat grafting surgery and the longevity of the results by closely following their plastic surgeon’s pre and post-operative instructions. Plastic surgeons typically suggest their patients avoiding cigarettes and heavy drinking because these habits reduce circulation throughout the body, leading to the degradation of new cells. Smoking causes vasoconstriction, which limits the blood flow to the newly transplanted fat cells. The fat needs that blood supply to survive and give you the best outcome possible. In the case of fat transfer to the buttocks (BBL), a fundamental measure is wearing specialized compression garments around the clock. Additionally, at least ten lymphatic drainage massage sessions are required to eliminate excess lymph fluid, alleviate swelling and discomfort, and also prevent complications such as seromas (fluid collection), and contour irregularities (indentations, and/or fibrosis).
(1) Simonacci, Francesco. “Procedure, applications, and outcomes of autologous fat grafting”. National Center for Biotechnology Information, US National Library of Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5491488/
(2) Landau, Mark. “Proposed Methods to Improve the Survival of Adipose Tissue in Autologous Fat Grafting”. Plastic and Reconstructive Surgery - Global Open. https://journals.lww.com/prsgo/Fulltext/2018/08000/Review__Proposed_Methods_to_Improve_the_Survival.18.aspx
(3) Schafer, M.E. “Acute Adipocyte Viability After Third-Generation Ultrasound-Assisted Liposuction”. Aesthetic Surgery Journal. 2013 Jul; 33(5):698-704.
(4) Fisher, C. “Comparison of Harvest and Processing Techniques for Fat Grafting and Adipose Stem Cell Isolation. Plastic Reconstructive Surgery. 2013 Aug; 132(2):351-61.
(5) Rohrich RJ, Sorokin ES, Brown SA. “In search of improved fat transfer viability: a quantitative analysis of the role of centrifugation and harvest site”. Plastic Reconstructive Surgery. 2004;113:391–395; discussion 396.
(6) “What do you expect out of Brazilian Butt Lift”. The Bioplasty International Center. https://www.internationalsurgery.com/what-do-you-expect-out-of-brazilian-butt-lift/
(7) Strong, Amy L. “The Current State of Fat Grafting: A Review of Harvesting, Processing, and Injection Techniques”. National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov