Fat Graft Survival After Recipient Site Pretreatment With Fractional Carbon Dioxide Laser

Preconditioning Strategies for Improving the Outcome of Fat Grafting

Autologous fat grafting is a common procedure in plastic, reconstructive, and aesthetic surgery. However, it is frequently associated with an unpredictable resorption rate of the graft depending on the engraftment kinetics. This, in turn, is determined by the interaction of the grafted adipose tissue with the tissue at the recipient site. Accordingly, preconditioning strategies have been developed following the principle of exposing these tissues in the pretransplantation phase to stimuli inducing endogenous protective and regenerative cellular adaptations, such as the upregulation of stress-response genes or the release of cytokines and growth factors. As summarized in the present review, these stimuli include hypoxia, dietary restriction, local mechanical stress, heat, and exposure to fractional carbon dioxide laser. Preclinical studies show that they promote cell viability, adipogenesis, and angiogenesis, while reducing inflammation, fibrosis, and cyst formation, resulting in a higher survival rate and quality of fat grafts in different experimental settings. Hence, preconditioning represents a promising approach to improve the outcome of fat grafting in future clinical practice. For this purpose, it is necessary to establish standardized preconditioning protocols for specific clinical applications that are efficient, safe, and easy to implement into routine procedures.

Heating Pretreatment of the Recipient Site Enhances Survival of Transplanted Fat in a Mouse Model

BACKGROUND

Despite several studies about the preparation of the recipient site in fat grafting, optimizing techniques with clinical usefulness is still necessary. Through previous animal studies reporting that heat can increase tissue vascular endothelial growth factor and vascular permeability, the authors hypothesize that pretreatment heating of the recipient site will increase retention of grafted fat.

METHODS

Twenty 6-week-old female BALB/c mice had two pretreatment sites on their back, one for the experimental temperatures (44°C and 48°C) and the other for the control. A digitally controlled aluminum block was used to apply the contact thermal damage. Human fat (0.5 mL) was grafted on each site and harvested on days 7, 14, and 49. The percentage volume and weight, histologic changes, and peroxisome proliferator-activated receptor gamma expression, a key regulator of adipogenesis, were measured by the water displacement method, light microscopy, and quantitative real-time polymerase chain reaction, respectively.

RESULTS

The harvested percentage volumes were 74.0% ± 3.4%, 82.5% ± 5.0%, and 67.5% ± 9.6% for the control, 44°C-pretreatment, and 48°C-pretreatment groups, respectively. The percentage volume and weight of the 44°C-pretreatment group was higher than the other groups ( P < 0.05). The 44°C-pretreatment group exhibited significantly higher integrity with fewer cysts and vacuoles than the other groups. Both heating pretreatment groups showed markedly higher rates of vascularity than the control group ( P < 0.017), and also increased the expression of peroxisome proliferator-activated receptor gamma over two-fold.

CONCLUSION

Heating preconditioning of the recipient site during fat grafting can increase the retention volume and improve the integrity, which is partly explained by increased adipogenesis in a short-term mouse model.

CLINICAL RELEVANCE STATEMENT

Tanning could be an alternative pretreatment for fat grafting.

Fat Grafting: Basic Science, Techniques, and Patient Management

In this review, a summary of the rich history of autologous fat grafting is provided, and a comprehensive summary of the science and theory behind autologous adipocyte transplantation, as well as the techniques commonly used is described. These include recipient site preparation, harvesting, processing, and engraftment. In addition, important considerations for preoperative and postoperative management are discussed to maximize graft retention. Special considerations in grafting to the breast, face, and buttocks are also summarized.

Photobiomodulation with polychromatic light (600-1200 nm) improves fat graft survival by increasing adipocyte viability, neovascularization, and reducing inflammation in a rat model

OBJECTIVES

Unpredictability with the final volume and viability of the graft are the major concerns in fat grafting. An experimental study was conducted to increase graft retention using photobiomodulation (PBM) with polychromatic light in near-infrared region (600-1200 nm) by utilizing its stimulatory effects on angiogenesis, neovascularization, adipocyte viability, and anti-inflammatory properties.

METHODS

A total of 24 rats were divided into four groups (n = 6) according to the applied polychromatic light protocol to the recipient site (none, before fat transfer, after fat transfer, and combined). In all groups, inguinal fat pad was excised, measured for volume and weight, and transferred to the dorsum of the rat. At the end of the experiment, fat grafts were harvested from the recipient site for volume and weight measurements, histological, and immunohistochemical evaluation.

RESULTS

Intergroup comparison revealed that fat graft retention regarding weight and volume, was significantly superior in Group IV (p = 0.049 and p = 0.043, respectively), which polychromatic light was applied both before and after transfer of the graft. Hematoxylin-eosin and Masson's trichrome stained sections showed absence of necrosis, fibrosis, inflammation, cyst formation, and increased vascularization of both inner and outer zones of the grafts in Group IV. Also, immunohistochemical staining scores for perilipin (indicator for adipocyte viability), CD31 and VEGF (indicators for angiogenesis and neovascularization) were significantly higher (p < 0.001). Ki67 scores were significantly lower in this group because of anti-inflammatory environment (p < 0.001).

CONCLUSIONS

Application of PBM to the recipient site before and after fat transfer improved outcomes in rats at 56 day after fat grafting by means of volume retention, increased neovascularization and adipocyte viability and reduced necrosis, fibrosis and inflammation.

Surgical Decision Making in Autologous Fat Grafting: An Evidence-Based Review of Techniques to Maximize Fat Survival

Autologous fat grafting is an important tool in plastic surgery and is widely used for a variety of applications, both aesthetic and reconstructive. Despite an ever-increasing list of indications and extensive research over many years into improving outcomes, fat grafting remains plagued by incomplete and often unpredictable graft survival. Decisions made at each stage of surgery can potentially contribute to ultimate success, including donor site selection and preparation, fat harvest, processing, and purification of lipoaspirate, recipient site preparation, and delivery of harvested fat to the recipient site. In this review, we examine the evidence for and against proposed techniques at each stage of fat grafting. Areas of consensus identified include use of larger harvesting and grafting cannulas and slow injection speeds to limit cell damage due to shearing forces, grafting techniques emphasizing dispersion of fat throughout the tissue with avoidance of graft pooling, and minimizing exposure of the lipoaspirate to the environment during processing. Safety considerations include use of blunt-tipped needles or cannulas to avoid inadvertent intravascular injection as well as awareness of cannula position and avoidance of danger zones such as the subgluteal venous plexus. We believe that using the evidence to guide surgical decision-making is the key to maximizing fat grafting success. Level of Evidence: 4.

Isolated Fat Grafting for Reconstruction of Lower Face Volumetric Asymmetry in Skeletally Immature Patients: A Clinical Outcome Study

BACKGROUND

The purpose of this study was to assess the objective and subjective outcomes of lower face volumetric (contour) asymmetry correction with isolated fat grafting in skeletally immature patients.

METHODS

A prospective analysis was conducted of skeletally immature patients (n = 73) with craniofacial microsomia and Parry-Romberg syndrome who underwent isolated fat grafting (with no previous or concomitant bone surgery) using anatomical surgical principles (facial subunits and fat compartments) for the reconstruction of lower face volumetric asymmetry. Objective ultrasound and photogrammetric lower face symmetry analyses were blindly performed preoperatively and at 3 and 12 months postoperatively. A panel assessment of blinded surgical professionals and laypersons was also obtained to grade the subjective lower face symmetry.

RESULTS

There were significant (all P < 0.05) postoperative objective and subjective lower face symmetry enhancements (preoperative < postoperative) after isolated fat grafting, with no differences (all P > 0.05) between 3 versus 12 months' postoperative comparisons.

CONCLUSIONS

Growing patients with unilateral lower face volumetric asymmetries presented with improvement of objective and subjective symmetry after a single isolated fat grafting procedure.

Monopolar radiofrequency treatment for facial laxity: Histometric analysis

BACKGROUND

A monopolar radiofrequency device can be used in facial tightening. The device targets the dermis and fibrous septae, and the treatment results in immediate collagen contraction and the induction of subsequent collagen remodeling.

AIMS

We aimed to evaluate the histometric change of the subjects treated with a monopolar radiofrequency device using a novel tip.

MATERIALS AND METHODS

Eleven subjects with skin types III and IV participated in the study. They received a single session of a monopolar radiofrequency on the face, and biopsies were performed before treatment, and 2 and 6 months after the treatment. Hematoxylin and eosin, Masson trichome, and Victoria blue stains were used. An image analysis was performed using the Image J software. The dermal density of collagen and elastic fiber, and the coherency of collagen fibers were assessed in the papillary, upper reticular, and lower reticular dermises, respectively.

RESULTS

The monopolar radiofrequency treatments led to improvements in collagen fiber density and coherency. In the Masson trichome staining, the collagen fiber densities were 0.736 ± 0.06 and 0.652 ± 0.063 before treatment and increased to 0.773 ± 0.044 (P = .018) and 0.686 ± 0.05 (P = .045) in the papillary and lower reticular dermises, respectively. The density of the elastic fibers in all parts of the dermis showed a tendency to increase after treatment, though not statistically significantly. The mean coherency was higher after than before treatment.

CONCLUSIONS

In this in vivo study, we found that the collagen and elastic fiber densities and architectural structures were improved after treatment.