Commentary on: Facial Hypertrophy as a Complication of Weight Gain in Autologous Fat Graft Patients: Considerations and Recommendations

See the Original Article here. Fat graft hypertrophy after systemic weight has been reported anecdotally since the advent of liposuction and the first attempts by surgeons to inject suctioned fat.1 Over the years, various authors have speculated about the phenomenon and have presented their individual experiences.2 The scientific basis for this problem is that grafted tissue tends to maintain its original phenotypic characteristic when moved from one part of the body to another. For example, a full-thickness skin graft transferred from the back to the face will never look like normal facial skin. Similarly, when subcutaneous fat survives after being grafted elsewhere in the body, its own inherent characteristics are preserved. When the host organism gains or loses weight, individual fat cells increase and decrease in size. In humans, the most visible manifestation of weight gain is the increased volume of subcutaneous fat, which happens to be the most popular donor material used for facial fat grafting. The authors of this systematic review looked at 714 papers and selected 6 in the English language literature that met their requirements.3 They have identified commonalities in these papers and conclude with some certainty that significant weight gain can result in the hypertrophy of grafted fat in the face. They also determined that this hypertrophy can lead to poor aesthetic outcomes requiring surgical correction. The 6 papers forming the basis for this systemic review all deal with a specific case or a narrow subset of patients. These include a single case of hemifacial atrophy,4 a case of lower lid cancer resection,5 a group of Asian patients with temporal hollowing,6 and a series of periorbital augmentation.7 One series included staged injections of cryopreserved fat or a cocktail of tissue plus fat.8 However, for most plastic surgeons, facial fat grafting is a procedure done with fresh fat as part of age-related rejuvenation surgery—most commonly a facelift.9 Personally, I have found volume augmentation with injected fat to be the single most significant advance in facial rejuvenation that has come along during my 35-year career, and I do facial fat grafting in almost all facelift cases. Interestingly, the authors of this review found no paper that looked specifically at fat graft hypertrophy in this cohort of patients. This may indicate a lack of such a problem in these older patients, or it may represent a lack of reporting. In a systematic review, authors can only assess what has been published. Germane to this issue are the 2 main theories for fat graft survival. The host replacement hypothesis suggests that grafted fat cells die and are replaced by cells from the host that become new fat cells.10 The cell survival theory suggests that the fat cells survive.11 The graft replacement theory describes 3 zones: one with fat cell survival, a second with stem cell survival, and a third where all grafted cells are replaced by host cells.12 Conceptually, the survival theory is most compatible with hypertrophy of grafted fat after weight gain, but all theories could be implicated if the “new fat cells” generated by the body behave the same way as the grafted fat. This science is yet to be elucidated. Seeking a solution to the problem, the authors found a lack of evidence to select one donor site over another. However, they speculate, quite reasonably in my opinion, that fat graft hypertrophy is more likely to occur when fat is harvested from an area prone to hypertrophy during weight gain. Every patient has areas where they tend to “put on weight.” The authors therefore suggest harvesting fat for facial injection not from these labile fat stores, but rather from fat stores that tend to be more stable over time. One problem with this review, correctly identified by the authors, is the lack of any papers dealing with the pediatric age group. This is important because patients tend to gain weight through their adult years, particularly after menopause for women.13 A number of pediatric conditions, such as Parry-Romberg syndrome, are well suited for treatment with fat graft. Also, young adults requesting a “permanent filler” may undergo facial fat grafting. Most of these children and young adults are destined to gain weight later in life, which puts them at risk of fat graft hypertrophy. Fortunately, the typical facelift patient receiving facial fat graft for volume restoration is a middle-aged or older person and, in that setting, the prospect for significant weight gain in the future is much less likely. Also, in my experience, injected fat graft takes better in younger patients, whereas in the older patient with a deflated face, the percentage of graft take appears to be less certain. As a result, in the facial rejuvenation age group, facial fat grafting is a more forgiving procedure than in younger patients. The request to add more fat in these older patients is more likely than the need to remove hypertrophic fat caused by weight gain. Another factor not mentioned in this paper is the importance of the location of the fat graft if it becomes hypertrophic. When fat is placed deep, such as along the periosteum over the zygomatic body, there is a considerable margin of error before fat hypertrophy becomes a visible deformity. By contrast, fat graft placed more superficially, such as along the infraorbital rim to treat the tear trough, is easier to see and will be much more visible in the setting of systemic weight gain. This fact is likely the underlying factor behind several of the papers reviewed by the authors.6,7 Perhaps the most problematic issue introduced by this review is the difficulty in removing previously injected fat in the setting of hypertrophy secondary to weight gain. The authors note that liposuction and surgical excision have been reported in the literature, although in the clinical setting, both approaches are difficult to achieve without damaging surrounding tissue. With modern techniques for facial fat grafting, miniscule droplets of fat are injected throughout a given area and its survival is based on blood supply from surrounding soft tissue. Consequently, the fat becomes integrated and surgically removing it can result in the inadvertent removal of some surrounding soft tissue. The take-home message from this systematic review is that until we can influence the biology of fat the hypertrophy of injected fat graft will continue to be a potential problem if patients gain weight. This is more likely to be an issue in younger people where it can lead to aesthetic deformities that require surgical correction. Facial hypertrophy associated with weight gain should be included as part of the informed consent for facial fat graft. I tell all my patients that when fat harvested from their abdomen is grafted into their face, that fat “thinks it’s abdominal fat” and will enlarge in volume if they gain a lot of weight. Patients are often surprised by this, but on reflection, they universally understand and accept it, creating yet another reason for our patients to avoid excessive weight gain. The author receives royalties from Elsevier (Amsterdam, the Netherlands). The author received no financial support for the research, authorship, and publication of this article.

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