April 2020 HSC Section 4 - Plastic and Reconstructive Problems

The Journal of Craniofacial Surgery

Volume 30, Number 3, May 2019

Future of Facial Fat Grafting

metabolic rates are lower than mature adipose cells rendering them more resistant to the burden of hypoxia which follows grafting. 27 Consequently, the concept of nanofat grafting is rapidly developing. Tonnard et al described their results in 2013. Their study involved the complete emulsification of abdominal fat such that no viable adipocytes were evident. This strategy is not intended for volume augmentation, but rather to both mechanically concentrate the ASCs and also create a more flowable graft material that can be applied with a narrow gauge injection cannula or needle. Emulsifi- cation was achieved by passing fat between two 10cc syringes connected by a luer-lok followed by filtration through a nylon cloth. The effluent collected was considered the ‘‘nanofat’’ sample. Nonmulsified fat was also used as a control (referred to as microfat if taken via a small multiport cannula with sharp 1-mm side-holes or macrofat if taken via a standard 3-mm cannula). Histologic staining confirmed the presence of viable adipocytes in macrofat and microfat samples and the absence of these in the nanofat sample. The stromal vascular fraction (SVF) was separated from the lipoas- pirates and cultured for 7 days after which CD34 positive cells were identified. Neither the morphology (fibroblast in nature) nor the CD43 positive cells to SVF ratio differed significantly between nanofat, microfat, and macrofat lipoaspirates. A further 10 days in an adipogenic medium yielded cells which were round and lipid filled (again no difference was seen between the 3 lipoaspirate types either in quantity or quality). Grafting occurred in 67 patients, of which the greatest facial indication was perioral skin rejuvenation, followed by glabellar skin and dark lower eyelids. 28 Three patients with images were selected by Tonnard et al which are displayed in Figure 1. Uyulmaz and colleagues published their experience in a total of 52 patients with scars (n ¼ 40), discoloration (n ¼ 6), and wrinkles (n ¼ 6) treated with nanofat injections. The processing method was

FIGURE 2. Top row shows a 52-year female with irregular, hyperpigmented lesion of the cheek before (A) and 4 months after nanofat injection (B). Bottom row shows a 49-year-old patient with periorbital hyperpigmentation before (A) and 1 month after nanofat injection (B). 29 Adapted from ‘‘Nanofat Grafting for Scar Treatment and Skin Quality Improvement’’ by S Uyulmaz et al, 2018, Aesthetic Surgery Journal , 38, p. 424-425. Copyright 2018 by the American Society for Aesthetic Plastic Surgery.

the same as that described by Tonnard et al. The average volume of injected lipoaspirate was 4.6 mL. Pre- and postoperative photo- graphs were judged by a panel of 3 physicians; a plastic surgeon, a general surgeon and a dermatologist who graded their outcomes independently as good, satisfactory or no change. In 66% of patients they judged the outcome to be good, with only 7% receiving a ‘‘no change’’ rating. Scars were judged to be highly improved (88% receiving a ‘‘good’’ grading) while wrinkles and discoloration had more equivocal results though as noted above, the sample sizes of these last 2 categories were small. 29 Selected patient images before and after nanofat injection are shown in Figure 2. Nanofat grafting represents a shift in thinking as regards the application of fat grafting. 28 Traditional grafting relies on the volume which can be achieved through the implantation of mature adipose tissue. Long-term viability relies on the maintenance of this tissue vitality though the preservation of tissue architecture and the insertion of small ‘‘packets’’ to ensure vascularization and preser- vation of volume and consistency. Nanofat grafting relies on none of this, but instead utilizes the stem-cell population within the SVF to achieve rejuvenation of native tissue, resolution of scars, and reversal of aging signs. In the regulatory framework, this mechani- cal processing is still considered minimal manipulation and falls under the umbrella of a surgical procedure. Facial fat grafting has traditionally been utilized to augment volume in the various compartments of the face. 11,30 In youth, adipose tissue in the face is abundant, diffuse, and balanced; however, as the face ages, there is increasing imbalance which develops in volume; some compartments become hypertrophied while others become atrophied. 30 The SVF is the product of lipoaspirate after collagenase degra- dation. This leads to 2 distinct phases; a floating mature adipocyte fraction and a lower, aqueous fraction containing cellular compo- nents. 31 Separation of the aqueous component of the degradation product yields a heterogenous mixture of cells including ASC, endothelial precursor cells, macrophages, smooth muscle cells, lymphocytes, pericytes, and preadipocytes. 31 Stromal Vascular Fraction-Enriched Fat Grafting

FIGURE 1. Sun damaged skin in a 41-year-old female (top row), bulging and pigmentation of the lower eye-lids in a 36-year-old female and perioral rhytides in a 61-year-old female. Left-hand images show preinjection state and right- hand images show state 7 months after nanofat injection. 26 Adapted from ‘‘Nanofat grafting: basic research and clinical applications’’ by P. Tonnard et al, 2013, Plastic and Reconstructive Surgery 132, p. 1023-1024. Copyright 2013 by the American Society of Plastic Surgeons.

# 2019 Mutaz B. Habal, MD

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