Background: The processing of harvested fat for transplantation is critical to fat graft performance. In breast reconstruction, larger volumes of fat are being grafted and, in some clinical cases, are being implanted within radiated tissue. This preclinical animal study evaluated the effects of radiation on retention volume and fat graft quality after processing by decantation or REVOLVE™ technology (Allergan Aesthetics, an AbbVie Company), a filtration-based device that can process lipoaspirates and remove unwanted contaminants prior to grafting. Methods: Lipoaspirate was collected from human donors (n = 6), processed using either REVOLVE™ technology or decantation, and implanted (0.5 cc) into 60 athymic mice for 4 weeks with or without a single 35-Gy radiation dose 12 weeks prior. Volume composition, MRI, and weight-based volumetric assessment of grafted fat were performed and compared between radiated and non-radiated mice. Results: Volume composition analysis demonstrated significantly higher fat content and lower aqueous fluid with REVOLVE™ technology than with decantation, with minimal cellular debris and free oil. MRI-based and weight-based volume analysis demonstrated a significantly higher percent retention with REVOLVE™ technology than decantation in nonirradiated and irradiated sites, respectively. Pathology scoring showed a significant decrease in fibrosis within grafts processed with REVOLVE™ technology in nonirradiated sites. Conclusions: Results suggest that fat processed using REVOLVE™ technology provides better early volume retention and quality of fat grafts compared to decantation, both in healthy and radiation-treated surgical sites.

Autologous fat grafting is increasingly used in plastic, reconstructive, and esthetic surgery. Cryopreservation offers a promising solution for the long-term storage of adipose tissue, enabling multiple grafting sessions while minimizing patient discomfort associated with repeated liposuction for fat harvesting. This systematic review aims to analyze the current literature focusing on factors that influence the outcome of cryopreservation, including the use of cryoprotectants, the cooling and warming rate, the storage temperature, and the enrichment of cryopreserved fat grafts. A systematic search of the PubMed/MEDLINE database up to November 2024 was performed, including original preclinical and clinical studies written in English describing the cryopreservation of unprocessed or mechanically processed adipose tissue (macrofat, microfat, or nanofat). Eligible articles needed to describe the applied cryopreservation protocol, at least the storage temperature. Studies on cryopreservation of adipose-derived stem cells (ASCs), stromal vascular fraction, microvascular fragments, and other isolated components of adipose tissue were excluded. Data on cryoprotectants, cooling and warming rates, storage temperature, and eventual supplementation or enrichment of frozen fat were collected. Of the 679 records identified, 59 met the inclusion criteria. Adipose tissue cryopreservation at -80°C with a cryoprotectant, controlled slow cooling, and fast warming represented the most often applied protocol with encouraging outcomes in maintaining tissue survival and histological structure. Several studies indicated that the supplementation of frozen adipose tissue with ASCs improves tissue survival. Taken together, existing studies present diverse, and to some extent, conflicting results regarding cryopreservation protocols and their effects on adipose tissue viability. Hence, the ideal cryopreservation protocol for autologous fat remains to be established. Moreover, tailored protocols may be necessary for the cryopreservation of fat derivatives, such as nanofat.

The use of fat grafting has expanded to include cell and tissue regeneration, necessitating investigations to ensure the viability of stromal and adipose-derived mesenchymal stem cells (ASCs) within the transferred fat parcels. This study explored the impact of harvesting technique and centrifugation on the viability of stromal cells and ASCs in lipoaspirate.

Fat was harvested from patients undergoing fat grafting using 2 types of liposuction cannula: (A) a 3-mm blunt tip cannula with 3 smooth holes and (B) a 2.4-mm, sharp point port, multihole blunt tip cannula. Fat from cannula B underwent different processing methods: no centrifugation, 300g, 600g, and 900g centrifugation. Stromal cells were isolated, quantified, and evaluated for viability. ASCs were cultured from these samples to confirm survival.

Lipoaspirates from 21 patients were analyzed. The mean stromal cell counts were 0.937 × 109 ± 0.346 × 109/mL for cannula A and 0.734 × 109 ± 0.266 × 109/mL for cannula B (P = 0.684), with viabilities of 98.79% and 98.22% (P = 0.631), respectively. ASCs isolated and after 2-passage culture were also higher for cannula A. Stromal cell quantification and viability were lowest in the noncentrifuged group (P < 0.05) and highest in the 600g centrifugation group.

Fat harvesting using cannulas A and B showed no significant difference in stromal cell yield or viability. Handheld syringe liposuction preserved stromal vascular fraction cell and ASC viability. Centrifugation at different speeds did not significantly affect stromal cell viability.

Autologous fat grafting has been widely adopted in cosmetic and reconstructive procedures recently. With the emerging of negative-pressure-assisted liposuction system, the harvesting process of fat grafting is more standardized, controllable, and efficient. Each component in the system could influence the biomechanical environment of lipoaspirate. Several reviews have studied the impact of negative pressure on fat regeneration. As the initial part of the harvesting system, cannulas possess their unique mechanical parameters and their influence on lipoaspirate biomechanical characters, biological behaviors, and regeneration patterns remains unclear. Basic in vivo and in vitro studies have been performed to determine the possible mechanisms. Instant in vivo studies focus on adipocytes, stromal vascular fraction cells, fat particles, and growth factors, while in vivo grafting experiments analyze the graft retention rate and histology. Understanding the different regeneration patterns of lipoaspirate and the mechanisms behind may facilitate the choice of harvesting cannulas in clinical practice.

Large-volume fat grafting is emerging as a promising technique in plastic and reconstructive surgery. However, the unpredictable graft volume retention rate remains a critical challenge. To address this issue, we need a profound understanding of the survival mechanisms following large-volume fat transplantation. This review summarizes known survival mechanisms and strategies to enhance graft retention.

This review comprehensively examines the current literature on the survival mechanisms and retention strategies in large-volume fat grafting. A thorough literature search was conducted using PubMed, Medline and Google Scholar databases, focusing on studies published from 2009 to 2023.

In the current research on fat survival mechanisms, few have focused on large-volume fat grafting. This review provides an overview of the survival mechanisms specific to large-volume fat grafting and identifies a survival pattern distinct from that of small-volume fat grafting. Additionally, we have summarized existing strategies to improve graft retention across five stages (harvesting, processing, enrichment, grafting and post-graft care), analyzed their advantages and disadvantages and identified some of the most promising strategies.

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Three-dimensional (3D) printing is dramatically improving breast reconstruction by offering customized and precise interventions at various stages of the surgical process. In preoperative planning, 3D imaging techniques, such as computer-aided design, allow the creation of detailed breast models for surgical simulation, optimizing surgical outcomes and reducing complications. During surgery, 3D printing makes it possible to customize implants and precisely shape autologous tissue flaps with customized molds and scaffolds. This not only improves the aesthetic appearance, but also conforms to the patient's natural anatomy. In addition, 3D printed scaffolds facilitate tissue engineering, potentially favoring the development and integration of autologous adipose tissue, thus avoiding implant-related complications. Postoperatively, 3D imaging allows an accurate assessment of breast volume and symmetry, which is crucial in assessing the success of reconstruction. The technology is also a key educational tool, enhancing surgeon training through realistic anatomical models and surgical simulations. As the field evolves, the integration of 3D printing with emerging technologies such as biodegradable materials and advanced imaging promises to further refine breast reconstruction techniques and outcomes. This study aims to explore the various applications of 3D printing in breast reconstruction, addressing current challenges and future opportunities.

Currently, the definition of large-volume liposuction is the removal of 5 L or more of total aspirate. Higher volumes of lipoaspirate come into consideration with higher BMIs, because more than 5 L is often required to achieve a satisfactory aesthetic result. The boundaries of what lipoaspirate volume is considered safe are based on historical opinion and are constantly in question.

Because to date there have been no scientific data available to support a specific safe maximum volume of lipoaspirate, the authors discuss necessary conditions for safe high-volume lipoaspirate extraction.

This retrospective study included 310 patients who had liposuction of ≥5 L over a 30-month period. All patients had 360° liposuction alone or in combination with other procedures.

Patient ages ranged from 20 to 66 with a mean age of 38.5 (SD = 9.3). Average operative time was 202 minutes (SD = 83.1). Mean total aspirate was 7.5 L (SD = 1.9). An average of 1.84 L (SD = 0.69) of intravenous fluids and 8.99 L (SD = 1.47) of tumescent fluid were administered. Urine output was maintained above 0.5 mL/kg/hr. There were no major cardiopulmonary complications or cases requiring blood transfusion.

High-volume liposuction is safe if proper preoperative, intraoperative, and postoperative protocols and techniques are employed. The authors believe that this bias should be modified and that sharing their experience with high-volume liposuction may help guide other surgeons to incorporate this practice with confidence and safety for better patient outcomes.

Fat injection laryngoplasty (FIL) is a common procedure used to correct glottic insufficiency. Nevertheless, few studies have discussed potential treatments for cases with poor voice recovery after FIL.

Eighteen patients with unfavorable vocal outcomes from FIL were analyzed. Each of these patients presented persistent dysphonia for more than 2 months following FIL, together with bulging vocal folds and poor mucosal wave. We applied microsurgery as the standard treatment to remove excessive fat. Vocal fold steroid injection (VFSI) was administered to patients that were hesitant or declined to undergo microsurgery. Voice outcomes were evaluated using the Voice Handicap Index-10 (VHI-10), grade-roughness-breathiness (GRB) scores, and smoothed cepstral peak prominence (CPPs).

Six patients underwent microsurgery directly, 6 patients received only VFSIs as a salvage treatment, and the remaining 6 patients received 1 to 3 courses of VFSIs before the decision to undergo microsurgery. Pathology reports were available for 10 patients, and contained 5 instances of adipose tissues, 3 of fat necrosis, 1 of chronic inflammation, and 1 of fibrosis. Seventeen patients reported satisfactory or improved outcomes. We found remarkable improvements in VHI-10, GRB, and CPPs (all P < .05) after salvage treatments for FIL. Subgroup analyses showed comparable voice outcomes for patients undergoing direct microsurgery, VFSI alone, and VFSI followed by microsurgery (P > .05).

This study demonstrated that fat overinjection and/or fibrotic change in the injected vocal folds may cause poor voice outcomes after FIL. Both microsurgery and VFSI could be applied as salvage treatments with good voice recovery profiles.

Level 4.

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.

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.

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.

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.

Tanning could be an alternative pretreatment for fat grafting.

Fat tissue has been widely used as a filler material during plastic surgery, but unpredictable fat retention remains a significant concern. Fat tissue is vulnerable to ischemia and hypoxia, but it always has waiting time before injection in the operation theater. Apart from transferring fat tissue as quickly as possible after harvesting, washing the aspirate with cool normal saline is often used. However, the mechanisms of cool temperature acting on adipose tissue have yet to be fully elucidated. Herein, this study aims to explore the effect of preservation at different temperatures on the inflammatory profile of adipose tissue. Inguinal adipose tissue of rats was collected and cultured in vitro under 4°C, 10°C, and room temperature for 2 hours. The proportion of damaged adipocytes and an array of cytokines were determined. We observed that the damage rate of the adipocyte membrane was slightly higher at room temperature, but there was no significant difference, while we noticed increased IL-6 and MCP-1 levels in adipose tissue at room temperature ( P ＜0.01). The 4°C and 10°C cool temperatures may offer protection against proinflammatory states during the adipose tissue preserved in vitro.

Determining the most appropriate cannula diameter for lipoaspirate harvesting is important, both in terms of the quality and composition of the material obtained, and the ease of practical use of the cannula. The size of the cannula is one of the main factors affecting the qualitative characteristics of the obtained lipoaspirate sample for further use of adipose tissue. The purpose of the investigation was to clinically and histomorphometrically determine the optimal cannula diameter for lipoaspirate samples collection from rabbit inguinal fat pad in an experimental study. The methods of Animal models, Surgical procedures, Macroscopic examination, Histological examination, and Morphometric study were applied. There is a direct correlation between the percentage of connective tissue fibres in the lipoaspirate and the diameter of the cannula. The lack of clear criteria for selecting a lipoaspiration cannula is one of the limitations to obtaining generally accepted lipoaspiration protocols with subsequent use of adipose tissue. In this study, the animal experiment determined the most ideal cannula diameter suitable for collecting the largest amount of lipoaspirate for subsequent use.

Autologous fat grafting is a technique that can be used for cosmetic and reconstructive indications such as oncologic defects, aging, trauma, and congenital malformations. However, there is no standardized technique, and one of the main challenges is the unpredictable rate of fat resorption. When using fat grafting, it is crucial to understand the different factors that contribute to adipocyte viability. A literature search, using PubMed, was conducted in 2022 with variations of the terms "autologous fat grafting," "fat harvesting," "fat processing," and "fat injection." Articles in the English language that presented original data about different factors that may affect adipocyte viability for fat grafting were included in this review. Syringe suction harvests (lower pressures), compared with other methods with higher pressures, were found to have increased adipocyte counts and viability, but this did not translate clinically during in vivo studies. The studies have shown that, despite our efforts in optimizing fat harvest, processing, and injection, no statistical or clinical differences have been found. Additional studies are still needed to determine a universal protocol for optimal fat graft survival.

Adipose tissue (AT) is composed of a heterogeneous population which comprises both progenitor and differentiated cells. This heterogeneity allows a variety of roles for the AT, including regenerative functions. In fact, autologous AT is commonly used to repair soft tissue defects, and its cryopreservation could be a useful strategy to reduce the patient discomfort caused by multiple harvesting procedures. Our work aimed to characterize the cryopreserved AT and to validate its storage for up to three years for clinical applications. AT components (stromal vascular fraction-SVF and mature adipocytes) were isolated in fresh and cryopreserved samples using enzymatic digestion, and cell viability was assessed by immunofluorescence (IF) staining. Live, apoptotic and necrotic cells were quantified using cytometry by evaluating phosphatidylserine binding to fluorescent-labeled Annexin V. A multiparametric cytometry was also used to measure adipogenic (CD34+CD90+CD31-CD45-) and endothelial (CD34+CD31+CD45-) precursors and endothelial mature cells (CD34-CD31+CD45-). The maintenance of adipogenic abilities was evaluated using in vitro differentiation of SVF cultures and fluorescent lipid staining. We demonstrated that AT that is cryopreserved for up to three years maintains its differentiation potential and cellular composition. Given our results, a clinical study was started, and two patients had successful transplants without any complications using autologous cryopreserved AT.

Autologous fat grafting has gained increasing popularity used in plastic surgery as a strategy to improve functional and aesthetic outcome. However, variable augmentation results have concerned surgeons in that volume loss of grafted fat reported fluctuates unsteadily.

An optimal technique that clinically maximizes the long-term survival rate of transplantation is in urgent need to be identified.

The PubMed/MEDLINE database was queried to search for animal and human studies published through March of 2022 with search terms related to adipose grafting encompassing liposuction, adipose graft viability, processing technique, adipose-derived stem cell, SVF and others.

45 in vivo studies met inclusion criteria. The principal of ideal processing technique is effective purification of fat and protection of tissue viability, such as gauze rolling and washing-filtration devices. Cell-assisted lipotransfer including SVF, SVF-gel and ADSCs significantly promotes graft retention via differentiation potential and paracrine manner. ADSCs induce polarization of macrophages to regulate inflammatory response, mediate extracellular matrix remodeling and promote endothelial cell migration and sprouting, and differentiate into adipocytes to replace necrotic cells, providing powerful evidence for the benefits and efficacy of cell-assisted lipotransfer.

Based on the current evidence, the best strategy can not be decided. Cell-assisted lipotransfer has great potential for use in regenerative medicine. But so far mechanically prepared SVF-gel is conducive to clinical promotion. PRP as endogenous growth factor sustained-release material shows great feasibility.

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Autologous fat transplantation has been used for breast nearly 40 years, but there are two main problems: the volume retention rate is unpredictable, leading to too many operations, and various complications, such as nodules, necrosis and calcification, occur.

The author proposed "function-preserving fat grafting" (FPFG) and reviewed the clinical data of patients from October 2002 to December 2020.

A total of 1218 patients underwent surgery, and 767 patients were followed up for more than half a year. Their ages ranged from 22 to 61 (31.9±10.1) years, and the BMI values ranged from 16.1 to 28.2 (20.6±2.73) kg/m2. Group I included 703 cases of breast aesthetic augmentation, group II included 38 cases of breast reconstruction after mastectomy (10 cases after radiotherapy and 7 cases after the Brava device was worn) and group III included 26 cases of simultaneous implant exchange with fat.

At 6 months after the operation, 89.8% of the patients were satisfied with the outcome. For these patients, aesthetic augmentation required 1.9±0.73 procedures, and the unilateral breast injection volume was 180-380 ml (265.5±46.6); breast reconstruction required an average of 3.4±0.71 procedures, and the unilateral injection volume was 140-370 ml (233.9±67.7). The simultaneous implant exchange volume with fat was 160-320 ml (241.3±35.8 ml). There were 9 cases (1.2%) of palpable nodules, 3 cases of infection (0.39%), and no other severe complications.

FPFG has the advantages of requiring few operations; leading to few necrosis, oil cysts and nodules; and leading to high postoperative satisfaction.

Autologous fat transfer can be safely offered for total breast reconstruction after nipple-sparing mastectomy. The aim of this study was to extend a fat transfer protocol to smokers and compare the long-term results among them and irradiated and nonirradiated patients.

One hundred seventeen breasts after nipple-sparing mastectomy were prospectively enrolled and stratified in group A (25 irradiated), group B (21 smokers), or group C (71 controls). A standardized fat transfer protocol was used. Data collected were patient demographics, surgery information, and aesthetic analysis. Continuous and categorical variables were analyzed with the Kruskal-Wallis test, and the Cohen Kappa test was used to test interrater variability for the aesthetic analysis.

Groups were homogeneous for demographics ( p > 0.05) but significantly different in number of fat transfer sessions ( p < 0.001), mean volume of the first two treatments ( p = 0.003), and mean total volume of injected fat ( p = 0.002). Volume, shape, position of the breast mound, inframammary fold, and scar location subscales obtained high score evaluations without a significant difference among groups ( p > 0.05), whereas skin texture subscale showed a lower score evaluation in group A ( p = 0.003). Although a significant difference for total subscales was worse in group A ( p = 0.004), the global score had a high rate evaluation in all groups ( p = 0.145). Interrater reliability showed substantial agreement among all categories.

Although further investigation is required, the authors confirm the efficacy of their fat transfer protocol for both irradiated and nonirradiated nipple-sparing mastectomy patients and propose its indication to smokers with comparable clinical and aesthetic results.

Risk, II.

Unilateral vocal fold paralysis (UVFP) after thyroid surgery often leads to significant morbidity including dysphonia, dysphagia, and aspiration. Injection laryngoplasty (IL) is an effective treatment of UVFP with numerous readily available materials. However, few studies focus on IL for UVFP following thyroidectomy.

This review aims to critically review current literature to determine the timing, materials, methods and outcomes of IL for UVFP after thyroid surgery.

Literature review.

A literature review was performed using the Pubmed, Medline and EMBASE databases. All relevant articles published in English addressing the effect of IL in post thyroid surgery related UVFP were analyzed. Studies using IL for UVFP of multiple etiologies were excluded. Meta-analysis was conducted using fixed and random effect model.

Five original studies were identified, including 214 patients received IL for UVFP following thyroid surgery. Two studies injected autologous fat via direct suspension laryngoscope under general anesthesia, while the other 3 studies injected polyacrylamide, hyaluronic acid, and polymethyl methacrylate from cricothyroid membrane under local anesthesia. All 5 studies reported improved voice outcomes of IL for post-thyroidectomy UVFP. Meta-analysis showed MPT increased for 3.18 s (95% CI: 2.40-3.96, fix effect model) after IL. Another common acoustic parameter, jitter (%) also improved for 1.46 (95% CI: 0.73-2.19, random effects model) after IL for post-thyroidectomy UVFP.

This review supported that IL can improve the voice outcome for post-thyroidectomy UVFP. Autologous fat remains a good augmentation material with a potential longer lasting effect. More research and long-term surveys are needed to document the safety and longevity of other synthetic materials.

Loss of volume is perhaps the most frustrating problem of fat grafting. The process of fat grafting depends on different variables such as harvesting, processing, and injection techniques. Results between studies that evaluate the effect of the cannula size on fat graft survival have been controversial. However, the role of the fenestration area of the cannula has not been described.

Four custom-made cannulas with a single fenestration were used for this study. Cannulas vary in diameter and area of the fenestration. Healthy patients seeking primary liposuction of the abdomen for aesthetic reasons were included. Lipoaspiration was performed in a clockwise pattern, and the order of the cannulas was rotated. Negative pressure was maintained at 0.8 atm at all times. Ten ml of fat, obtained from the suction tube, was poured into 20-ml conical centrifugal tubes for further processing. One gram of lipoaspirate was extracted from each sample, and acridine orange stain was added. Adipocytes were extracted, extended in a frotis, and observed by a histologist (masked fashion) under fluorescence microscopy. Viability was reported in percentages per sample.

The overall viability was 64.75% ± 18.58. The viability of the obtained samples ranged from 66.51± 20.66 % to 62.83 ± 18.1. In further analysis, comparing the viability according to the shaft diameter and fenestration area, there was no significant difference among groups.

Neither the diameter of the cannula nor the size of the fenestrations are determining factors to affect the viability of the adipocytes.

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

After more than a century of development, autologous fat transplantation (AFT), a repair method for soft tissue defects and deformities, has the advantages of being simple, rapid, effective and safe, and it is increasingly favoured by plastic surgeons. This article reviews the developmental history of AFT, analyses its clinical application status in the oral and maxillofacial regions, and provides a preliminary summary and discussion of the research progress related to AFT. The hope is that that this technique could be widely applied for oral and maxillofacial diseases as well as facial rejuvenation indications. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Adipose tissue is a compact and well-organized tissue containing a heterogeneous cellular population of progenitor cells, including mesenchymal stromal cells. Due to its availability and accessibility, adipose tissue is considered a "stem cell depot." Adipose tissue products possess anti-inflammatory, anti-fibrotic, anti-apoptotic, and immunomodulatory effects. Nanofat, being a compact bundle of stem cells with regenerative and tissue remodeling potential, has potential in translational and regenerative medicine. Considering the wide range of applicability of its reconstructive and regenerative potential, the applications of nanofat can be used in various disciplines. Nanofat behaves on the line of adipose tissue-derived mesenchymal stromal cells. At the site of injury, these stromal cells initiate a site-specific reparative response comprised of remodeling of the extracellular matrix, enhanced and sustained angiogenesis, and immune system modulation. These properties of stromal cells provide a platform for the usage of regenerative medicine principles in curbing various diseases. Details about nanofat, including various preparation methods, characterization, delivery methods, evidence on practical applications, and ethical concerns are included in this review. However, appropriate guidelines and preparation protocols for its optimal use in a wide range of clinical applications have yet to be standardized.

Most preconditioning techniques before fat grafting require external manipulation. Since nutrition is the main factor maintaining the balance of lipogenesis and lipolysis, we hypothesized that fasting before undergoing autologous fat grafting may increase lipolysis and reduce adipocyte size, thereby improving the fat graft survival rate.

C57BL/6 mice were divided into 24 h starved or fed groups. Adipose tissue lipolysis, adipogenesis, and angiogenesis-related gene expression, in fat from both groups, were analyzed. The volume and weight of the grafted fat at 4-8 weeks postoperatively were measured using micro-computed tomography. Immunohistochemistry staining and mRNA expression analysis were also performed to evaluate the effect of fasting on fat graft survival.

Fasting decreased adipocyte size by inducing adipose tissue lipolysis. Adipogenesis-related genes were remarkably downregulated while lipolysis-related genes and angiogenesis inducer genes were significantly upregulated in the starved adipose tissue. The mice grafted with the fat from the 24 h starved group had approximately 20% larger volumes and considerably heavier weights than those from the fed group. Increased viable adipocytes and vessels, and reduced macrophages in the fat grafts obtained from the 24 h starved group were also observed.

Fasting for 24 h before harvesting fat increased the retention volume of fat graft by increasing angiogenesis via VEGF induction. Therefore, fasting would be a novel and reliable preconditioning strategy to improve graft survival in autologous fat grafting.

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Lipomodelling has become increasingly popular for reconstructive, aesthetic and therapeutic indications. The guidelines summarise available evidence for indications, training, technique, audit and outcomes in lipomodelling and also highlight areas for further research.

Platelet-rich plasma is a useful adjuvant therapy in the treatment of acne scars. Fat is as ideal soft tissue filler.

To compare the efficacy and safety of subcision with autologous fat grafting versus subcision with intradermal Platelet-rich plasma for the treatment of acne scars.

Twenty-four patients were divided into two groups with 12 patients each. One group subjected to single session of subcision with autologous fat grafting. Second group treated with subcision followed by intradermal Platelet-rich plasma monthly once for 3 months. High resolution digital photographs taken before and after every session. Single blinded physician assessment was also done.

In quantitative acne scar assessment scoring, both group of patients showed significant percentage of improvement in acne scars, 61.23 ± 9.48% in patients treated with subcision followed by autologous fat grafting and 44.16 ± 7.28% in patients treated with subcision followed by intradermal PRP. At the time of enrolment, 33.3% (n = 8) of patients had Grade A (milder) scarring, 50% (n = 12) had Grade B (moderate) scarring while 16.7% (n = 4) had Grade C (severe) scarring. After the completion of the treatment, it was found that 75% (n = 18) of patients were in Grade A while 20.8% (n = 5) of patients were in Grade B (p < 0.05; significant).

Both the treatment modalities, i.e., autologous fat grafting and intradermal PRP were effective and safe for the treatment of acne scars and results in each group was significant (p < 0.001). But there were no statistically significant differences between the two treatment groups (p = 0.23).

A low survival rate is one of the main challenges in fat grafting.

This study aimed to evaluate whether microfat obtained by a novel strategy promoted the survival and retention of fat grafts.

A 5-mm-diameter blunt tip cannula with large side holes (~30 mm2/hole) was used to obtain macrofat. A novel strategy based on a newly invented extracorporeal cutting device was then used to cut the macrofat into microfat, which was named adipose-derived progenitor cell enrichment fat (AER fat); Coleman fat was used as the control. Aliquots (0.5 mL) of both types of fat were transplanted into 10 nude mice and analyzed 10 weeks later. Western blotting, flow cytometry, and immunofluorescence were performed to assess the AER fat characteristics and underlying mechanisms.

The retention rate of fat grafts in AER fat-treated animals was significantly higher than that in the Coleman group (mean [standard deviation] 54.6% [13%] vs 34.8% [9%]; P < 0.05) after 10 weeks. AER fat contained more dipeptidyl peptidase-4-expressing progenitor cells (3.3 [0.61] × 103 vs 2.0 [0.46] × 103 cells/mL; P < 0.05), adipose-derived plastic-adherent cells (6.0 [1.10] × 104 vs 2.6 [0.17] × 104 cells/mL; P < 0.001), and viable adipocytes than Coleman fat. Moreover, histologic analysis showed that AER fat grafts had better histologic structure and higher capillary density.

AER fat transplantation is a potential strategy to improve the survival and long-term retention of fat grafts. AER fat contained more dipeptidyl peptidase-4-expressing progenitor cells.

Adipose tissue senescence is implicated as a major player in obesity- and ageing-related disorders. There is a growing body of research studying relevant mechanisms in age-related diseases, as well as the use of adipose-derived stem cells in regenerative medicine. The cell banking of tissue by utilising cryopreservation would allow for much greater flexibility of use. Dimethyl sulfoxide (DMSO) is the most commonly used cryopreservative agent but is toxic to cells. Trehalose is a sugar synthesised by lower organisms to withstand extreme cold and drought that has been trialled as a cryopreservative agent. To examine the efficacy of trehalose in the cryopreservation of human adipose tissue, we conducted a systematic review of studies that used trehalose for the cryopreservation of human adipose tissues and adipose-derived stem cells. Thirteen articles, including fourteen studies, were included in the final review. All seven studies that examined DMSO and trehalose showed that they could be combined effectively to cryopreserve adipocytes. Although studies that compared nonpermeable trehalose with DMSO found trehalose to be inferior, studies that devised methods to deliver nonpermeable trehalose into the cell found it comparable to DMSO. Trehalose is only comparable to DMSO when methods are devised to introduce it into the cell. There is some evidence to support using trehalose instead of using no cryopreservative agent.

Rhinoplasty is a commonly performed cosmetic surgery. Clinicians are facing an increased demand on non-surgical procedures, therefore liquid rhinoplasty is gaining popularity. Given the characteristic of lipofilling to rejuvenate and improve skin texture, fat grafting can be used to reshape the nose in secondary rhinoplasty. Fat was injected in 27 patients with a mean age of 42 years. Volume of fat ranged from 1.5 to 4.5 cc with a mean of 2.2 cc. Patients were seen at 1 week, 3 months, 6 months, and 1 year. Patient satisfaction was measured using the Rhinoplasty Outcome Evaluation questionnaire and plastic surgeons' evaluation. After 1 year follow up, 20 patients were satisfied with the results at 1 year. The aesthetic outcome was noted as very good in 11 patients, good in 9 patients, and poor in 3 patients. Most of the patients had an improvement in skin texture with trophic effect on the skin. No complications were seen in our series According to this study, nasal lipofilling is a safe and efficacious filler in secondary rhinoplasty. However, more studies are needed to assess the indications and limitations of nose lipofilling.

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.

Autologous fat grafting (AFG) has been employed in surgical practice as a filling method. However, controversies remain on the specifics of this technique. So far, few relevant experimental large animal studies have objectively assessed factors related to AFG integration.

This study utilized an experimental, medium-sized animal model to compare the feasibility of AFG collected employing 2 different techniques with instruments of distinct thicknesses.

Twenty minipigs (Sus scropha domesticus) were subjected to AFG harvesting via en bloc resection utilizing 3- (Group I) and 5-mm-diameter (Group II) round punch blades (PBs) and liposuction (LS) with 3- (Group III) and 5-mm-diameter cannulas (Group IV). Both samples were grafted intramuscularly (biceps femoralis). Hematoxylin and eosin staining was employed to identify intact adipocytes, fat necrosis, fibrosis, inflammation, and oil cysts. Immunohistochemical staining (perilipin-A, tumor necrosis factor alfa, and cluster of differentiation number 31) was utilized to quantify the feasibility of adipocytes, tissue necrosis, and neoangiogenesis, respectively.

Hematoxylin and eosin analysis showed that fat necrosis and histiocyte presence were significantly lower in the AFG harvested utilizing a PB than in LS. For perilipin-A, a statistical difference was observed between subgroups I and III (P = 0.001) and I and IV (P = 0.004). Instrument diameter had no effect on graft integration in comparisons between groups II and III (P = 0.059) and II and IV (P = 0.132).

In this experimental study, fat collected utilizing a PB demonstrated higher adipocyte viability than fat collected with LS. The diameter of the collection instruments, whether PB or LS, had no effect on graft integration.

Lipofilling (LF) is a largely employed technique in reconstructive and esthetic breast surgery. Over the years, it has demonstrated to be extremely useful for treatment of soft tissue defects after demolitive or conservative breast cancer surgery and different procedures have been developed to improve the survival of transplanted fat graft. The regenerative potential of LF is attributed to the multipotent stem cells found in large quantity in adipose tissue. However, a growing body of pre-clinical evidence shows that adipocytes and adipose-derived stromal cells may have pro-tumorigenic potential. Despite no clear indication from clinical studies has demonstrated an increased risk of cancer recurrence upon LF, these observations challenge the oncologic safety of the procedure. This review aims to provide an updated overview of both the clinical and the pre-clinical indications to the suitability and safety of LF in breast oncological surgery. Cellular and molecular players in the crosstalk between adipose tissue and cancer are described, and heterogeneous contradictory results are discussed, highlighting that important issues still remain to be solved to get a clear understanding of LF safety in breast cancer patients.

After studying this article, the participant should be able to: 1. Understand the types of tumescence available for liposuction. 2. Explain the various modalities available for liposuction. 3. Describe the patient selection, staging, and complications associated with debulking liposuction. 4. Describe ways to optimize outpatient liposuction.

Liposuction is one of the most common procedures performed by board-certified plastic surgeons and is likely greatly underestimated, given underreporting of office procedures and the number of non-plastic surgeons performing these operations. With the ever-increasing popularity of liposuction, various methodologies and technology have been designed to make this task simpler and faster for the surgeon and hasten the recovery for the patient. In the past 10 years, over 50 devices or techniques have been released to assist, refine, or altogether replace liposuction. With the advent of these newer tools, a thorough Continuing Medical Education study was performed to review the available literature.

Mesenchymal stem cells (MSCs) derived from somatic tissues have been used to promote lipotransfer, a common practice in cosmetic surgery. However, the effect of lipotransfer varies, and the mechanism of action remains vague. To address these questions, we differentiated human embryonic stem cells, a stable and unlimited source, into MSCs (EMSCs). Then we subcutaneously transplanted human fat aspirates together with EMSCs or PBS as a control into the back of nude mice. Within 24 h of transplantation, EMSCs promoted aggregation and encapsulation of injected fat tissues. Afterward, all grafts gradually shrank. However, EMSC-containing grafts were larger, heavier and had fewer dark areas on the surface than the control grafts. Histologically, more live adipocytes, vascular cells, and macrophages and less fibrosis were observed in EMSC-containing grafts than in the controls. Some EMSCs differentiated into vascular cells and adipocytes in the EMSC-containing grafts. RNA sequencing revealed that human RNA was shown to decline rapidly, while mouse RNA increased in the grafts; further, human genes related to extracellular matrix remodeling, adipogenesis, and chemokine (including CCL2) signaling were expressed at higher levels in the EMSC-containing grafts than they were in the controls. CCL2 knockout reduced macrophage migration towards EMSCs in vitro and early macrophage recruitment to the grafts and the pro-engraftment effect of EMSCs in vivo. Treating mice with a macrophage inhibitor abolished the EMSC effects and converted the grafts to heavy masses of cell debris. Together, these data demonstrate that EMSCs promote fat engraftment via enhanced tissue reconstitution and encapsulation of implanted tissues, which was followed by increased angiogenesis and adipocyte survival and reduced fibrosis, in which stimulated CCL2 signaling and mobilized macrophages play pivotal roles.

The autologous lipotransfer represents an established method in the field of Plastic Surgery. As a reliable and safe method for breast reconstruction and breast augmentation it offers an alternative to established methods such as implants and flap surgery.Survival rate of adipose derived stromal cells limits success or failure of fat grafting. Slight changes in the fat grafting process can lead to huge changes in ADSC-survival rate.This review wants to optimize the fat-grafting process to ensure best outcomes.

Nonsurgical rhinoplasty is one choice for cases in which open surgery may be harmful, the deformity is not indicated to correct with open surgery, or in patients who have phobia of general anesthesia or any type of surgery. Autologous fat injection or fillers are most common materials currently available in the market. In this article, we explain the indications, contraindications, methods, and complications of this treatment.

Breast implant removal is becoming a common procedure in light of the current events and controversies with silicone breast implants. The authors believe strongly in informing patients about the indications and options regarding both explantation and the management of the secondary breast deformity.

Relevant literature regarding the management of the explant patient was reviewed and organized to provide an update on prior publications addressing the explant patient population.

Surgical management options after implant removal include breast contouring and volume restoration. Fat augmentation has been used in both aesthetic and reconstructive breast surgery.

The authors review the surgical management for explantation, breast contouring, and autologous fat grafting for volume restoration. In the explant patient, autologous fat grafting serves as a reliable option for volume restoration.

Background It is generally believed that trauma to fat grafts is detrimental and affects the survival of the graft. In addition, it has been shown that smaller fat particle size corresponds to better survival; however, smaller cannula openings correspond to slower and more difficult fat graft harvesting. Objectives This study documents the relationship between cannula size, harvested fat cell size, and injection needle size. A means of reducing fat particle size following aspiration with larger diameter cannulas is also discussed. Methods Fat was harvested from five patients undergoing elective liposuction. Each fat sample was placed in a syringe and injected through progressively smaller needles until obstruction under low pressure was obtained. The minimal needle size was documented for each sample. Results Fat harvested with a liposuction cannula results in different size fat particles ranging up to the size of the cannula. Particles obtained from 3- and 4-mm cannulas can be injected without obstruction through a 16-gauge needle. Particles obtained from a 2-mm cannula can be injected without obstruction through an 18-gauge needle. Particles obtained from a 1-mm cannula can be injected without obstruction through a 20-gauge needle. Particles obtained from a 1-mm cannula could not be injected without obstruction through a 22-gauge needle. Conclusions There is a relationship between cannula opening size and the resultant fat graft size. Fat particles are somewhat compressible but should not be forced through needles or cannulas that are too narrow. It may be beneficial to harvest fat with larger cannulas and cut the particles to smaller sizes for injection.

Human adipose tissue is a great source of translatable biomaterials owing to its ease of availability and simple processing. Reusing discardable adipose tissue for tissue regeneration helps in mimicking the exact native microenvironment of tissue. Over the past 10 years, extraction, processing, tuning and fabrication of adipose tissue have grabbed the attention owing to their native therapeutic and regenerative potential. The present work gives the overview of next generation biomaterials derived from human adipose tissue and their development with clinical relevance.

Around 300 articles have been reviewed to widen the knowledge on the isolation, characterization techniques and medical applications of human adipose tissue and its derivatives from bench to bedside. The prospective applications of adipose tissue derivatives like autologous fat graft, stromal vascular fraction, stem cells, preadipocyte, adipokines and extracellular matrix, their behavioural mechanism, rational property of providing native bioenvironment, circumventing their translational abilities, recent advances in featuring them clinically have been reviewed extensively to reveal the dormant side of human adipose tissue.

Basic understanding about the molecular and structural aspect of human adipose tissue is necessary to employ it constructively. This review has nailed the productive usage of human adipose tissue, in a stepwise manner from exploring the methods of extracting derivatives, concerns during processing and its formulations to turning them into functional biomaterials. Their performance as functional biomaterials for skin regeneration, wound healing, soft tissue defects, stem cell and other regenerative therapies under in vitro and in vivo conditions emphasizes the translational efficiency of adipose tissue derivatives.

In the recent years, research interest has inclination towards constructive tissue engineering and regenerative therapies. Unravelling the maximum utilization of human adipose tissue derivatives paves a way for improving existing tissue regeneration and cellular based therapies and other biomedical applications.

Power-assisted liposuction and lipofilling (PALL) is a simple and reproducible surgical technique for large volume fat grafting.

The authors share their 7-year experience with their large-volume fat transfer technique, PALL.

A total of 417 patients who underwent PALL-related surgeries involving the breast and buttock were evaluated in a retrospective study. Liposculpting and fat harvesting were performed with power-assisted liposuction. Fat was transferred with simultaneous power-assisted vibration and tunnelization to provoke expansion of the recipient site. Following lipofilling, additional external vibration of the recipient site was performed to enhance diffusion of the injected fat.

Liposuction volumes up to 5000 mL were recorded, and injection volumes ranged from 300 to 900 mL per side for each session. Operating times ranged from 45 to 120 minutes. Patients were followed-up for 1 to 4 years. No major complications were recorded.

PALL is an efficient, safe, and reproducible procedure with myriad applications in aesthetic and reconstructive surgery.

Level of Evidence: 4.

Autologous fat grafting has broad applications in reconstructive and aesthetic breast surgery as a natural filler and for its regenerative purposes. Despite the widespread use of fat grafting, there remains no shared consensus on what constitutes the optimal fat grafting technique and its oncological safety. For this reason, the authors of this study have organized a Survey and an International Consensus Conference that was held at the Aesthetic Breast Meeting in Milan (December 15, 2018).

All studies on fat grafting, both for breast aesthetic and reconstructive purposes, were electronically screened. The literature review led to 17 "key questions" that were used for the Survey. The authors prepared a set of 10 "key statements" that have been discussed in a dedicated face-to-face session during the meeting.

The 10 key statements addressed all the most debated topics on fat grafting of the breast. Levels of evidence for the key statements ranged from III to IV with 2 statements (20%) supported by a level of evidence III and 6 statements (60%) by level of evidence IV. Overall consensus was reached for 2 statements (20%) with >75% agreement reached for 7 statements.

The survey demonstrated a diversity of opinion and attitude among the panelists with regard to technique. Clear recommendations for evidence-based clinical practice for fat grafting use both in aesthetic and reconstructive breast surgery could not be defined due to the scarcity of level 1 or 2 studies.

Fat grafting is effectively used in the lower eyelid and periorbital area for rejuvenation of the aging face. Several complications may occur with fat grafting, including volume undercorrection or overcorrection, contour irregularities, prolonged bruising and swelling, infection, granulomas and inflammation, and vascular embolization with visual loss or stroke. In many cases, complications can be effectively treated, although permanent and serious injury can occur. Appropriate surgical techniques help to prevent most of these complications. An understanding of how and why complications of fat grafting of the lower eyelid occur aids in the avoidance and treatment of these complications.