Autologous Fat Grafting in the Breast: Critical Points and Technique Improvements

Effectiveness and Safety of Different Methods of Assisted Fat Grafting: A Network Meta-Analysis

OBJECTIVE

Numerous studies have proposed the utilization of stromal vascular fraction (SVF), adipose-derived stem cells (ADSCs), and platelet products as auxiliary grafting techniques to improve the survival rate of fat grafts. This study aimed to evaluate the efficacy and safety of various fat grafting methods since 2010 through a network meta-analysis, aiming to identify the most effective technique for fat grafting.

METHODS

Clinic trials on assisted fat grafting were searched from Pubmed, Embase, Web of Science, and the Cochrane Library, spanning the period from January 1, 2010 to March 2024. The risk of bias in the included trials was meticulously assessed using the Cochrane risk of bias tool. The survival rate of fat grafts served as the primary evaluation metric for effectiveness, while complications were employed as the indicator for safety.

RESULTS

The study incorporated 31 clinic trials, involving a total of 1656 patients. The findings indicated that the survival rate with assisted fat grafting significantly surpassed that of simple fat grafting (SUCRA, 10.43%). Notably, ADSC-assisted fat grafting exhibited the highest survival rate (SUCRA, 82.17%), followed by Salvia miltiorrhiza (SM)-assisted fat grafting (SUCRA, 69.76%). In terms of safety, the most prevalent complications associated with fat grafting were fat sclerosis and fat necrosis. Adc-assisted fat grafting was correlated with the lowest incidence of complications (SUCRA, 41.00%), followed by simple fat grafting (SUCRA, 40.99%). However, PRP-assisted (SUCRA, 52.86%) and SVF-assisted fat grafting (SUCRA, 65.14%) showed higher complication rates.

CONCLUSION

Various methods of assisted fat grafting can significantly enhance the survival rate, but they often fail to effectively mitigate the incidence of complications. Compared to other methods, adipose mesenchymal stem cells-assisted fat grafting consistently yielded a higher survival rate of grafts and fewer complications. Consequently, this approach represents a relatively effective method for assisting in fat grafting at present.

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 .

CT volumetry study of microfat graft survival from different donor sites in augmenting the enophthalmic socket

PURPOSE

To evaluate autologous fat grafts harvested from the abdomen versus the thigh for treating the enophthalmic socket using CT volumetry.

METHODS

A randomized prospective interventional study including 20 patients suffering from unilateral enophthalmic socket. Pre-operative clinical assessment included photographs, exophthalmometry reading as well as CT volumetry for volume deficit calculations and the harvesting site was randomly allocated (abdomen or thigh). All patients completed 6 months of follow-up. Exophthalmometry change and percentage of retained fat with the globe included and without it at follow-up were measured.

RESULTS

Microfat graft survival showed no statistically significant correlation with sex, age, or donor site. Mean percentage of retained fat with globe and without it were 14.75% and 25.31%, respectively. Difficulty of extraction and degree of volume deficit correlated significantly with percentage of fat retained. Exophthalmometer change correlated significantly with percentage of fat retained.

CONCLUSION

Autologous fat grafting is a safe and effective technique for volume augmentation of enophthalmic sockets regardless of its harvesting site. CT volumetry has an important role in accurately measuring the volume deficit as well as the postoperative results.

Injectable and Self-Adaptive Gel Scaffold Based on Heparin Microspheres for Adipogenesis of Human Adipose-Derived Stem Cells

An injectable and self-adaptive heparin microsphere-based cell scaffold was developed to achieve adipose regeneration. Simultaneously, the cell scaffold exhibited a dynamic architecture, self-regulated glucose levels, sustained insulin delivery, and steady viscoelastic properties for adipogenesis. The dynamic cell scaffold is cross-linked by the boronate-diol interaction among heparin-based microspheres, which have boronate and maltose groups. Because of the boronate-maltose ester bonds, the gelatinous complex would be partially dismantled and readily display glucose-sensitive performance by free glucose via competitive displacement. The dynamic cross-linking heparin microsphere scaffold can deliver the lipogenic drug insulin to enhance lipid filling, which has an impact on fat tissue enhancement. A 4-week in vitro cell culture demonstrated that the dynamic heparin microsphere-based cell scaffold, through loading with insulin, showed significantly higher efficiency in promoting ASC differentiation compared with traditional 3D culture methods. In vivo histological results further demonstrated that there was a significant increase in adipose in the proposed cell scaffold, which proved to be statistically significant compared with traditional biomaterials. Notable stain expression of the FABP4 and PPAR-γ genes was also observed in the dynamic cell scaffold containing insulin, which was more similar to natural fat.

Comparative Analysis of a New Automatic System and Four Existing Techniques for Autologous Fat Grafting

Background

Autologous fat grafting is increasingly used worldwide and is a very attractive technique in many ways. However, treatment duration and postinjection tissue resorption remain problematic elements, which are largely related to the preparation method used. Moreover, few scientific studies objectively compare different fat preparation methods. This study analyzes the efficiency and quality of lipoaspirates prepared with a new filtration/centrifugation system (Adipure) in comparison with several existing techniques.

Methods

Patient lipoaspirates were processed by five different techniques: decantation, centrifugation, Macrofill, Puregraft, and Adipure. Adipose tissue was evaluated in vitro for tissue resorption and oil formation, as well as in vivo after subcutaneous injections in immunodeficient mice. Adipose grafts were collected after 1 month, weighed, and analyzed by histology with a detailed scoring method.

Results

Decanting gives inferior results to all other techniques, in terms of amount of tissue and oil in vitro, or graft weight and histological analysis in vivo. Methods using classical Coleman centrifugation (1200g), or a modified one (400g) associated with washes (Macrofill) produce very similar results, both in vitro and in vivo. Techniques using filtration systems (Puregraft and Adipure) produce less oil overall and have a higher grafting efficiency. The best results regarding grafting efficiency and oil quantity are found with the Adipure device.

Conclusions

A combination of filtration and very low-speed centrifugation potentiates the advantages of these techniques, in terms of graft efficiency. The adipose tissue purification being done in a few minutes, in an automatic way, undoubtedly provides a strong advantage for the use of this new system.

Characterization of Human Subcutaneous Adipose Tissue and Validation of the Banking Procedure for Autologous Transplantation

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.

Adipose Collagen Fragment: A Novel Adipose-Derived Extracellular Matrix Concentrate for Skin Filling

BACKGROUND

Skin filler is an option for treating skin aging and wrinkles; however, currently used fillers are limited by poor biocompatibility, rapid degradation, and possible hypersensitivity reactions. Autologous adipose tissue-derived products have been recognized as promising options for skin rejuvenation.

OBJECTIVES

This study aimed to develop a novel adipose-derived product for skin filling.

METHODS

Adipose collagen fragment (ACF) was prepared through pulverization, filtration, and centrifugation. The macrography, structure, types of collagen, and cell viability of ACF were evaluated by immunostaining, western blotting, and cell culture assays. ACF, nanofat, and phosphate-buffered saline (9 spots/side, 0.01 mL/spot) were intradermally injected in the dorsal skin of 36 female BALB/c nude mice; the skin filling capacity and the collagen remodeling process were then investigated. Twenty-one female patients with fine rhytides in the infraorbital areas were enrolled and received clinical applications of ACF treatment. Therapeutic effects and patients' satisfaction scores were recorded.

RESULTS

The mean [standard deviation] yield of ACF from 50 mL of Coleman fat was 4.91 [0.25] mL. ACF contained nonviable cells and high levels of collagen I, collagen IV, and laminin. Fibroblasts and procollagen significantly increased in ACF and ACF-treated dermis (P < 0.05). Overall, 85.7% of patients were satisfied with the therapy results, and no infections, injection site nodules, or other unwanted side effects were observed.

CONCLUSIONS

ACF significantly improved dermal thickness and collagen synthesis and may serve as a potential autologous skin filler.

Design of an elastic porous injectable biomaterial for tissue regeneration and volume retention

Soft tissue reconstruction currently relies on two main approaches, one involving the implantation of external biomaterials and the second one exploiting surgical autologous tissue displacement. While both methods have different advantages and disadvantages, successful long-term solutions for soft tissue repair are still limited. Specifically, volume retention over time and local tissue regeneration are the main challenges in the field. In this study the performance of a recently developed elastic porous injectable (EPI) biomaterial based on crosslinked carboxymethylcellulose is analyzed. Nearly quantitative volumetric stability, with over 90% volume retention at 6 months, is observed, and the pore space of the material is effectively colonized with autologous fibrovascular tissue. A comparative analysis with hyaluronic acid and collagen-based clinical reference materials is also performed. Mechanical stability, evidenced by a low-strain elastic storage modulus (G') approaching 1kPa and a yield strain of several tens of percent, is required for volume retention in-vivo. Macroporosity, along with in-vivo persistence of at least several months, is instead needed for successful host tissue colonization. This study demonstrates the importance of understanding material design criteria and defines the biomaterial requirements for volume retention and tissue colonization in soft tissue regeneration. STATEMENT OF SIGNIFICANCE: We present the design of an elastic, porous, injectable (EPI) scaffold suspension capable of inducing a precisely defined, stable volume of autologous connective tissue in situ. It combines volume stability and vascularized tissue induction capacity known from bulk scaffolds with the ease of injection in shear yielding materials. By comparative study with a series of clinically established biomaterials including a wound healing matrix and dermal fillers, we establish design rules regarding rheological and compressive mechanical properties as well as degradation characteristics that rationally underpin the volume stability and tissue induction in a high-performance biomaterial. These design rules should allow to streamline the development of new colonizable injectables.

Scarless Composite Breast Reconstruction Utilizing an Advancement Skin Flap, Loops, and Lipofilling

BACKGROUND

Autologous fat grafting has gained popularity in breast reconstructive surgery. To further increase the breast volume and provide a reliable breast shape, a skin flap can be advanced from the upper abdomen and lateral thorax to the breast.

OBJECTIVES

The aim of this study was to propose a method of breast reconstruction utilizing the principles of power-assisted liposuction and lipofilling (PALL) for breast matrix dissociation applied through infiltration, tunnelization, extensive undermining and lipofilling, in combination with loops (PALLL) to recruit a vascularized flap to reshape the breast.

METHODS

A prospective study was performed from January 2014 to January 2019. Demographic data, surgical procedure information (including volumes of the recruited advancement flap and lipofilling, and stages of lipofilling), and complication data were collected. Patient-reported outcomes, including satisfaction and well-being, were measured by a questionnaire.

RESULTS

In total, 37 women (41 breasts) underwent breast reconstruction by PALLL with an average follow-up of 26 months. The mean age of the patients was 54 years, and their mean BMI was 29 kg/m2. The mean recruited flap volume was 197 mL, and the mean lipofilling volumes were 153 mL for the first session, 190 mL for the second session, and 110 mL for the third session. Nine patients needed 3 sessions, 27 patients 2 sessions, and 1 patient only 1 session. Overall, 94% of patients were satisfied with their breast shape. All patients reported sensitive breasts. There were minimal complications.

CONCLUSIONS

Breast reconstruction with PALLL is a minimally invasive alternative to reconstructing and reshaping sensate breasts in which a vascularized skin flap recruited by loops from breast surroundings is combined with fat grafting. This approach provides long-term shape stability with minimal scarring and low complication rates.

LEVEL OF EVIDENCE: 4

Complications and Surgical Treatment of Breast Augmentation Using Autologous Fat Transfer and Fillers

Background

Breast augmentation with autologous fat grafting or hyaluronic acid injection requires minimal loss of healthy tissue. With an increasing trend of breast augmentation with these fillers, accompanying complications have also increased. Patients with complications often complain of induration, cyst formation, calcification, and infection, which require surgical treatment. We will discuss these complications and their surgical treatment through our experience of cases.

Methods

This retrospective study included 20 patients who all required surgical treatment due to breast augmentation complications such as induration, cyst formation, calcification, and infection, and who visited us between May 2007 and June 2018. The patients' ages ranged from 25 to 63, and the mean age was 39.9. The material used for breast augmentation was fat for 17 cases, and hyaluronic acid, paraffin, and silicon for one case each. The results were analyzed through plastic surgeons at our hospital.

Results

We performed a zigzag incision in the peri-areola margin to 17 of 18 patients for complications of autologous fat grafting and hyaluronic acid injection. The one excluded patient required an adipo-fascial flap from an inframammary fold incision. For one patient with silicon injection complication and one patient with paraffin injection complication, each required mammary gland resection.

Conclusions

A zigzag incision in the peri-areolar margin was useful for treating complications of breast augmentation with autologous fat grafting and hyaluronic acid injection. All cases resulted in inconspicuous fine scars, with high patient satisfaction. However, this incision was insufficient to remove injected silicon and paraffin.

Hydrogel from acellular porcine adipose tissue promotes survival of adipose tissue transplantation

Lipofilling is a popular technique for soft tissue augmentation, limited by unpredictable graft survival. This study aimed at exploring the effect of hydrogel from acellular porcine adipose tissue (HAPA) on angiogenesis and survival of adipose tissue used for lipofilling. The effect of HAPA on adipose-derived stem cells (ADSCs) proliferation, adipogenic differentiation, and vascular endothelial growth factor (VEGF) secretion were evaluated in hypoxia and normoxiain vitro. For thein vivostudy, adipose tissue with phosphate buffered saline, ADSCs, and HAPA (with or without ADSCs) were co-injected subcutaneously into nude mice. HAPA-ADSCs mixture (tissue engineering adipose tissue) was also grafted. Gross observation, volume measurement, and ultrasound observation were assessed. For histological assessment, hematoxylin and eosin, perilipin, cluster of differentiation 31 (CD31), Ki67, and transferase-mediated d-UTP nick end labelling (TUNEL) staining were performed. HAPA improved ADSCs proliferation, VEGF secretion, and adipogenic differentiation under normoxia and hypoxia conditionsin vitrostudy. For thein vivostudy, HAPA showed improved volume retention and angiogenesis, and reduced cell apoptosis when compared to ADSCs-assisted lipofilling and pure lipofilling. In conclusion, HAPA could maintain ADSCs viability and improve cell resistant to hypoxia and might be a promising biomaterial to assist lipofilling.

Adjunctive Procedures and Informed Consent with Breast Implant Explantation

BACKGROUND

The use of injectable or implantable materials or devices in the breast for augmentation or reconstruction has a history of innovation and controversy. Staying current in the field of breast implant management today means understanding not just the published literature but also its absence. Cutting edge breast implant treatment also means awareness of patient and media-driven interests and requests.

METHODS

Adjuvant treatments to optimize physical and psychological well-being with breast implant explantation, without replacement, will be addressed through literature review and analysis.

RESULTS

The body of literature demonstrates evidence of variable, and sometimes contradictory, methods to address adjunctive management of systemic concerns, the capsule, soft tissue of the native breast/chest, and treatment timing related to explantation. Few approaches are supported by very strong evidence. Many treatment methodologies are defensible. Any current attempts at optimizing management in patients undergoing explantation will be somewhat impaired by the ongoing nebulousness of related issues, such as breast implant illness. It seems clear, therefore, that plastic surgeons must fulfill their duty as caregivers to provide explantation surgery, either to attempt to improve physical health, mental well-being, or simply to respect patients' wishes. A well-informed surgeon will likely employ a variety of approaches, adapted to the unique patient presentations at hand.

CONCLUSION

It is expected that consultations, incisions, tissue rearrangements, surgical timing, and treatment indications will continue to vary as scientific investigation strives to understand and to optimize treatment of patients experiencing difficulty with breast implants.

Blood Impairs Viability of Fat Grafts and Adipose Stem Cells: Importance of Washing in Fat Processing

BACKGROUND

Fat processing plays a pivotal role in graft survival. Each component of the blood in lipoaspirate affects fat survival in different ways, but the mechanisms are not clear.

OBJECTIVES

The aim of this study was to investigate, by various experimental methods, the effect of blood on the viability of fat grafts and adipose stem cells (ASCs).

METHODS

Blood and fat samples were obtained from 6 female patients undergoing aesthetic liposuction. For the in vivo experiment, we compared fat mixed with normal saline or various ratios of blood in nude mice. The samples were explanted at 2 and 8 weeks to evaluate the gross volume retention and histologic and immunohistochemical characteristics. For in vitro experiments, ASCs were pretreated with hemoglobin at different concentrations and for different times. We then assessed the proliferation, migration, adipogenesis, and reactive oxygen species production of ASCs.

RESULTS

Blood in the graft led to a decrease in graft viability, as evaluated by general observation and histologic and immunohistochemical morphology in vivo. In vitro experiments showed inhibited proliferation, migration, and adipogenesis, and increased reactive oxygen species production in ACSs, after hemoglobin treatment, suggesting impaired ASC viability.

CONCLUSIONS

This study suggests that blood impairs the viability of fat grafts and ASCs and provides evidence that washing to remove blood is important in fat processing.

[Preliminary exploration on the application of hydrogel from acellular porcine adipose tissue to assist lipofilling]

OBJECTIVE

To investigate the effect of hydrogel from acellular porcine adipose tissue (HAPA) on the survival of transplanted adipose tissue.

METHODS

For in vitro study, adipose tissue and HAPA-adipose tissue complex were cultured in normoxia and hypoxia atmospheres for 24 and 72 hours. TUNEL and Perilipin immunofluorescence staining were performed to observe the effect of HAPA on apoptosis and survival of adipocities. For in vivo study, 42 healthy male nude mice (4-6 weeks old) weighing 15-18 g were randomly divided into adipose group (group A), 10%HAPA group (group B), 20%HAPA group (group C), 30%HAPA group (group D), 40%HAPA group (group E), and 50%HAPA group (group F) according to different HAPA/adipose tissue volume ratio ( n=7). For each group, 1 mL adipose tissue or HAPA-adipose tissue complex was injected subcutaneously into the dorsum of the nude mice. At 4 weeks after transplantation, 7 nude mice in each group were sacrificed and grafts were harvested, gross observation, volume measurement, ultrasound examination, and histologic staining (HE staining, CD31 and Perilipin immunofluorescence stainings) were applied.

RESULTS

Hypoxia showed a tendency of promoting adipose tissue necrosis and apoptosis, while HAPA exhibited an obvious effect of inhibiting cell apoptosis in vitro study ( P<0.05). For in vivo study, grafts of all groups had intact fibrocapsule. No obvious signs of infection and necrosis were observed at 4 weeks. Volume shrinkage was observed in all groups, however, the groups A-D had significantly higher volume retention rate than groups E and F ( P<0.05). Ultrasound examination showed that there were no significant difference in the number and volume of liquify area of the grafts in each group ( P>0.05). With the increase of HAPA's volume ratio, HE staining proved an improved fat integrity while a gradually decreased vacuoles and fibrosis. CD31 immunohistochemical staining showed that the number of neo-vascularisation in groups E and F were significantly higher than those in groups A-D ( P<0.05). Perilipin immunofluorescence staining showed that with the increase of HAPA volume ratio, the number of living adipocytes increased gradually, and more new adipocytes could be seen in the field of vision.

CONCLUSION

As the volume ratio of HAPA gradually increased, the survival of transplanted adipose tissue also increased, but the volume retention rate decreased gradually. 30%HAPA was considered the relative optimal volume ratio for its superior adipose tissue survival and volume retation rate.

Comparative technical analysis of lipoaspirate mechanical processing devices

Fat grafting is a well-established procedure in reconstructive, aesthetic, and regenerative medicine, in particular due to the presence in the adipose tissue of a high concentration of mesenchymal stem cells. The need to reduce fat processing times, for an immediate clinical use and regulatory restrictions on the degree of manipulation of human tissues, has led to the development of numerous devices for the mechanical, nonenzymatic processing of adipose tissue. The aim of this study is to describe the state of the art of mechanical devices used for fat processing, performing a technical analysis of the currently commercially available devices. This should facilitate the development of new devices that improve therapeutic results.

Delayed two steps PRP injection strategy for the improvement of fat graft survival with superior angiogenesis

Platelet-rich plasma (PRP) has been widely used to improve the fat retention rate in autologous fat transplantation since it possesses a good angiogenesis capability in vivo. However, due to the short half-life of growth factors released from PRP and its uneven distribution in injected fat tissue, the strategy of PRP in fat transplantation needs further improvement. Since the capillaries started to grow into fat grafts in 1 week and vascular growth peaks in the second week after transplantation, we hypothesized that delayed two-steps PRP injection into the interior of grafts, accompanied with the extent of neovascularization might theoretically promote microvessel growth inside transplanted adipose tissue. 24 nude mice were divided into three groups: Blank group (0.35 mL fat mixed with 0.15 mL saline, N = 8), Single step group (0.35 mL fat mixed with 0.15 mLPRP, N = 8), and Two steps group (0.35 mL fat (day 0) + 0.075 mL PRP (day 7) + 0.075 mL PRP (day 14), N = 8). At 6 and 14 weeks post-transplantation, grafts were dissected, weighted, and assessed for histology, angiogenesis, fat regeneration and inflammation level. The weight and volume of the fat samples revealed no statistical difference among the three groups at 6 weeks after fat transplantation. The weight and volume of the Two steps group fat samples showed significantly higher compared to that in Blank and Single step groups at 14 weeks after fat transplantation (weight: 137.25 ± 5.60 mg versus 87.5 ± 3.90 mg,106.75 ± 2.94 mg, respectively; volume: 0.13 ± 0.01 mL versus 0.08 ± 0.01 mL, 0.09 ± 0.01 mL, respectively). Histological assessments indicated that delayed two-steps PRP injection strategy helps to improve adipose tissue content and reduce the composition of fibrous connective tissue at 14 weeks after fat transplantation. At 6 weeks and 14 weeks after transplantation, CD31 immunofluorescence indicated that delayed two-steps PRP injection strategy helps to improve angiogenesis and significantly higher compared to that in Blank and Single step groups (6 weeks: 28.75 ± 4.54 versus 10.50 ± 2.06, 21.75 ± 1.85; 14 weeks: 21.75 ± 2.86 versus 9.87 ± 2.08, 11.75 ± 1.47, respectively). Preadipocyte count indicated delayed two-steps PRP injection strategy might promote fat regeneration and significantly higher compared to that in Blank and Single step groups at 14 weeks (129.75 ± 6.57 versus 13.50 ± 3.50, 17.12 ± 6.23, respectively). In this study, we demonstrated that the novel delayed two-steps PRP injection strategy remarkably enhanced the long-term fat retention rate and improved the neovascularization extent in the interior of the fat graft. Platelet-rich plasma, Delayed two-steps injection, Angiogenesis, Fat transplantation.

Fat Grafting and the Palpable Breast Mass in Implant-Based Breast Reconstruction: Incidence and Implications

BACKGROUND

Fat grafting is a powerful and increasingly used technique in breast reconstruction. However, fat necrosis can lead to palpable postoperative changes that can induce anxiety and lead to unplanned diagnostic studies. The authors' aim in this study was to evaluate the incidence, type, and timing of these unanticipated studies; the specialty of the ordering provider; and the factors that trigger the ordering process.

METHODS

A retrospective chart review was conducted for patients from 2006 to 2015 who underwent fat grafting as part of implant-based breast cancer reconstruction and had at least 1-year follow-up after fat grafting.

RESULTS

From 2006 to 2015, 166 patients underwent fat grafting as part of implant-based breast reconstruction. Forty-four women (26.5 percent) underwent at least one imaging procedure. Thirteen women (7.8 percent) underwent 17 biopsies. For a palpable mass, the initial imaging test most commonly ordered was ultrasound, followed by mammography/ultrasound. The percentage of patients with a diagnosis of fat necrosis on mammography, ultrasound, and biopsy was 4.2, 12.7, and 5.4 percent, respectively. Seven patients (4.2 percent) had distant metastases. Tissue diagnosis of local recurrence was never identified. Mean follow-up was 2.4 years.

CONCLUSIONS

Fat-grafting sequelae may lead to early unplanned invasive and noninvasive procedures initiated by a variety of providers. In this study, fat grafting had no impact on local recurrence rate. As use of fat grafting grows, communication among breast cancer care providers and enhanced patient and caregiver education will be increasingly important in optimizing the multidisciplinary evaluation and monitoring of palpable breast lesions.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Autologous fat grafting in the treatment of velopharyngeal insufficiency: Clinical outcomes and treatment tolerability survey in a case series of 21 patients

Introduction:

Velopharyngeal insufficiency (VPI) is the inability to close the velopharyngeal sphincter during phonation and/or feeding. VPI is clinically characterised by hypernasal speech and nasal regurgitation. In cases of severe VPI, pharyngoplasty is recommended. Cases of mild-to-moderate VPI can be treated with fat grafting of the posterior pharyngeal wall in addition to speech therapy. The lipofilling can also be useful after pharyngoplasty to improve the outcomes.

Materials and Methods:

Twenty-one patients (14 males and 7 females), ages 4–23 affected by mild-to-moderate VPI and treated with lipofilling were included in this retrospective study. The mean injected fat volume was 7.95 cc (median 6 cc, min 4 cc, max 20 cc and range 16 cc). The follow-up ranged from 6 to 60 months. The pre- and post-operative Borel–Maisonny scores were compared using Wilcoxon test. Moreover, we performed a telephone survey with the aim to assess the parental perception on child's speech and quality of life after the surgical treatment.

Results:

Despite the small sample size, in this case series, we observed a statistically significant Borel–Maisonny score improvement and a parental satisfaction rate of about 85%.

Conclusions:

The augmentation of the posterior pharyngeal wall in addition to speech therapy improved the Borel–Maisonny score and the intelligibility of this case series of patients affected by mild-to-moderate VPI. In these patients, evaluated in a multidisciplinary approach, this technique allowed us to avoid major surgical procedures that would modify the anatomy of the velopharyngeal port. However, prospective comparative studies or randomised controlled trials could be useful to compare fat grafting with velopharyngoplasty techniques, with the aim to clarify indications and to define a specific treatment protocol.

Autologous fat grafting: Harvesting techniques

Autologous fat grafting is widely used for soft-tissue augmentation and replacement in reconstructive and aesthetic surgery providing a biocompatible, natural and inexpensive method. Multiple approaches have been developed in the past years, varying in the location of adipose tissue donor-sites, use of wetting solutions, harvesting, processing and placing techniques. Despite many advances in this subject, the lack of standardization in the protocols and the unpredictability of the resorption of the grafted tissue pose a significant limitation for graft retention and subsequent filling. In this review, we discuss several approaches and methods described over the last years concerning the harvesting of autologous fat grafts. We focus on contents such as the best donor-site, differences between existing harvesting techniques (namely tissue resection, hand aspiration or liposuction techniques), recommended harvesting cannula diameters, pressure application and volume of wetting solution injected prior aspiration. Results and comparisons between methods tend to vary according to the outcome measured, thus posing a limitation to pinpoint the most efficient methods to apply in fat grafting. Additionally, the lack of a standard assay to determine viability or volume augmentation of fat grafting remains another limitation to obtain universally accepted grafting procedures and protocols.

•

Distinct harvesting procedures associate with different outcomes of fat graft take.

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Flank, abdomen, thigh and knee are the more consistently used donor-sites for fat.

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Higher vacuum pressures in liposuction are more traumatic for the tissue.

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The tumescent technique is a safer procedure with improved aesthetic results.

•

Comparing harvesting techniques is a big challenge given the multiple variables.

Short-term post-implantation dynamics of in vitro engineered human microvascularized adipose tissues

Engineered adipose tissues are developed for their use as substitutes for tissue replacement in reconstructive surgery. To ensure a timely perfusion of the grafted substitutes, different strategies can be used such as the incorporation of an endothelial component. In this study, we engineered human adipose tissue substitutes comprising of functional adipocytes as well as a natural extracellular matrix using the self-assembly approach, without the use of exogenous scaffolding elements. Human microvascular endothelial cells (hMVECs) were incorporated during tissue production in vitro and we hypothesized that their presence would favor the early connection with the host vascular network translating into functional enhancement after implantation into nude mice in comparison to the substitutes that were not enriched in hMVECs. In vitro, no significant differences were observed between the substitutes in terms of histological aspects. After implantation, both groups presented numerous adipocytes and an abundant matrix in addition to the presence of host capillaries within the grafts. The substitutes thickness and volume were not significantly different between groups over the short-term time course of 14 days (d). For the microvascularized adipose tissues, human CD31 staining revealed a human capillary network connecting with the host microvasculature as early as 3 d after grafting. The detection of murine red blood cells within human CD31+ structures confirmed the functionality of the human capillary network. By analyzing the extent of the global vascularization achieved, a tendency towards increased total capillary network surface and volume was revealed for prevascularized tissues over 14 d. Therefore, applying this strategy on thicker reconstructed adipose tissues with rate-limiting oxygen diffusion might procure added benefits and prove useful to provide voluminous substitutes for patients suffering from adipose tissue loss or defects.

Complications and Treatment Strategy After Breast Augmentation by Polyacrylamide Hydrogel Injection: Summary of 10-Year Clinical Experience

From 1997 to 2006, polyacrylamide hydrogel (PAAG) was approved for use in China as a permanent filler for breast augmentation, and it is estimated that 200,000 women have undergone PAAG injection since then. After injection, complications such as pain, mass, hematoma, asymmetry, migration, infection, and even cancer continue to emerge. Because of the potential toxicity and unstable nature of the material and the nonstandardized injection layers, complications after PAAG injection breast augmentation are often complex and difficult to treat. The only treatment for these complications is debridement surgery, which includes PAAG evacuation, capsule remove, lesion excision, and mastectomy. Currently, although there are a variety of surgical methods for complications after PAAG injection, there is a lack of consensus regarding the diagnosis and treatment. We systematically review the literature and summarize our experience of diagnosis and treatment of complications after PAAG injection in our hospital over the past 10 years. To date, this is the first attempt to propose a diagnostic classification for PAAG injection breast augmentation and to set out a treatment strategy based on this classification. Although the China Food and Drug Administration withdrew its approval in 2006, PAAG is still being used illegally in some areas, and the patient population is widespread. This study aims to provide a more comprehensive understanding of PAAG complications to drive the standard diagnosis and treatment based on clinical classification, and to provide references for the future development of safer injectable products. Level of Evidence IV 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 .

Nanofat Increases Dermis Thickness and Neovascularization in Photoaged Nude Mouse Skin

OBJECT

To investigate the effects of nanofat injection into photoaged nude mouse skin on dermis thickness, neovascularization, and cell proliferation.

METHODS

Adipose-derived stem cells (ADSCs) and nanofat were prepared from human liposuction aspirates. The photoaged skin model was created using ultraviolet B (UVB) radiation onto BALB/c nude mice. A total of 24 mice were used in this study; 6 mice without treatment (natural aging) served as controls, while 18 mice were irradiated under the UVB lamp and treated with PBS (200 μl per injection area), ADSCs (1 × 10⁶/200 μl ADSCs per injection area), or nanofat (200 μl per injection area) on the dorsal skin. Four weeks after injection, skin specimens were collected. The skin texture of each group was evaluated by general observation. Histological analyses were performed to analyze skin structure, dermis thickness, collagen fiber arrangement, capillary density, and cell proliferation.

RESULTS

Four weeks after injection, no obvious differences were observed between the PBS group, ADSCs group, and nanofat group by skin gross observation. From the histological analyses, the ADSCs group and the nanofat group showed obviously thicker dermis than the PBS group (P < 0.05). More capillaries were observed in skin using anti-CD31 staining in the ADSCs and Nanofat groups than was observed in the PBS group (P < 0.05). No significant differences in the average dermis proliferation index were observed between groups by anti-Ki-67 staining. However, an increased epidermal proliferation index was observed in the ADSCs and Nanofat groups, compared to that in the PBS group (P < 0.05).

CONCLUSIONS

Nanofat increased dermis thickness and neovascularization in photoaged skin.

NO LEVEL ASSIGNED

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 .

Soft tissue fillers for adipose tissue regeneration: From hydrogel development toward clinical applications

There is a clear and urgent clinical need to develop soft tissue fillers that outperform the materials currently used for adipose tissue reconstruction. Recently, extensive research has been performed within this field of adipose tissue engineering as the commercially available products and the currently existing techniques are concomitant with several disadvantages. Commercial products are highly expensive and associated with an imposing need for repeated injections. Lipofilling or free fat transfer has an unpredictable outcome with respect to cell survival and potential resorption of the fat grafts. Therefore, researchers are predominantly investigating two challenging adipose tissue engineering strategies: in situ injectable materials and porous 3D printed scaffolds. The present work provides an overview of current research encompassing synthetic, biopolymer-based and extracellular matrix-derived materials with a clear focus on emerging fabrication technologies and developments realized throughout the last decade. Moreover, clinical relevance of the most promising materials will be discussed, together with potential concerns associated with their application in the clinic.

Adipose-Derived Stem Cells in Novel Approaches to Breast Reconstruction: Their Suitability for Tissue Engineering and Oncological Safety

Adipose-derived stem cells (ADSCs) are rapidly becoming the gold standard cell source for tissue engineering strategies and hold great potential for novel breast reconstruction strategies. However, their use in patients with breast cancer is controversial and their oncological safety, particularly in relation to local disease recurrence, has been questioned. In vitro, in vivo, and clinical studies using ADSCs report conflicting data on their suitability for adipose tissue regeneration in patients with cancer. This review aims to provide an overview of the potential role for ADSCs in breast reconstruction and to examine the evidence relating to the oncologic safety of their use in patients with breast cancer.

Adipose derived delivery vehicle for encapsulated adipogenic factors

Hydrogels derived from adipose tissue extracellular matrix (AdECM) have shown potential in the ability to generate new adipose tissue in vivo. To further enhance adipogenesis, a composite adipose derived delivery system (CADDS) containing single- and double-walled dexamethasone encapsulated microspheres (SW and DW Dex MS) has been developed. Previously, our laboratory has published the use of Dex MS as an additive to enhance adipogenesis and angiogenesis in adipose tissue grafts. In the current work, AdECM and CADDS are extensively characterized, in addition to conducting in vitro cell culture analysis. Study results indicate the AdECM used for the CADDS has minimal cellular and lipid content allowing for gelation of its collagen structure under physiological conditions. Adipose-derived stem cell (ASC) culture studies confirmed biocompatibility with the CADDS, and adipogenesis was increased in experimental groups containing the hydrogel scaffold. In vitro studies of AdECM hydrogel containing microspheres demonstrated a controlled release of dexamethasone from SW and DW formulations. The delivery of Dex MS via an injectable hydrogel scaffold combines two biologically responsive components to develop a minimally, invasive, off-the-shelf biomaterial for adipose tissue engineering.

STATEMENT OF SIGNIFICANCE

Scientists and doctors have yet to develop an off-the-shelf product for patients with soft tissue defects. Recently, the use of adipose derived extracellular matrix (adECM) to generate new adipose tissue in vivo has shown great promise but individually, adECM still has limitations in terms of volume and consistency. The current work introduces a novel composite off-the-shelf construct comprised of an adECM-based hydrogel and dexamethasone encapsulated microspheres (Dex MS). The hydrogel construct serves not only as an injectable protein-rich scaffold but also a delivery system for the Dex MS for non-invasive application to the defect site. The methods and results presented are a progressive step forward in the field of adipose tissue engineering.

The power of fat and its adipose-derived stromal cells: emerging concepts for fibrotic scar treatment

Lipofilling or lipografting is a novel and promising treatment method for reduction or prevention of dermal scars after injury. Ample anecdotal evidence from case reports supports the scar‐reducing properties of adipose tissue grafts. However, only a few properly controlled and designed clinical trials have been conducted thus far on this topic. Also, the underlying mechanism by which lipofilling improves scar aspect and reduces neuropathic scar pain remains largely undiscovered. Adipose‐derived stromal or stem cells (ADSC) are often described to be responsible for this therapeutic effect of lipofilling. We review the recent literature and discuss anticipated mechanisms that govern anti‐scarring capacity of adipose tissue and its ADSC. Both clinical and animal studies clearly demonstrated that lipofilling and ADSC influence processes associated with wound healing, including extracellular matrix remodelling, angiogenesis and modulation of inflammation in dermal scars. However, randomized clinical trials, providing sufficient level of evidence for lipofilling and/or ADSC as an anti‐scarring treatment, are lacking yet warranted in the near future. © 2017 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd

Lower Leg Augmentation with Fat Grafting, MRI and Histological Examination

INTRODUCTION

Nowadays, there is an increasing demand for contouring of the entire lower leg, in addition to corrections at the level of the muscle only. Accordingly, it becomes advantageous to use fat tissue for this purpose, for its availability in high quantities, potential for its easy implantation in all leg parts, biological compatibility, low antigen potential, and minimal donor morbidity.

METHODS

Forty-eight female patients, aged 20-54 (47.1 % younger than 35 and 52.9 % older than 35), underwent lower leg augmentation with autologous fat. We compared pre- and 1, 3, and 6 months postoperative morphological and volumetric characteristics of the recipient region by circumferential measuring of particular parts of the lower legs and evaluating the presence of live transplanted fat by MRI and histological examination.

RESULTS

The augmentation of certain circumferences of the lower leg at the 6-month follow-up examination is significantly related to preoperative circumference as well as to the quantity of infiltrated fat. Therefore, lower the baseline circumference, the greater the augmentation, and the greater the quantity of infiltrated fat, the greater the augmentation.

CONCLUSION

Ensuring adequate technique in the transfer of fat tissue from the donor region to the recipient region of the lower leg is definitely the least invasive method of lower leg contouring. For patients with muscle dystrophies or those with injuries, this technique could become the first choice for its minimal complications. The simplicity of the procedure invites its wide application in plastic surgery.

LEVEL OF EVIDENCE III

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Fat Grafting with Tissue Liquefaction Technology as an Adjunct to Breast Reconstruction

Background

Tissue liquefaction technology (TLT) delivers warmed saline from the liposuction cannula tip at low pressure pulses to disaggregate adipocytes. This technology differs significantly from that used in other liposuction devices including water jet-assisted liposuction. Here we introduce our early experience with this technology in the setting of fat transfer for revision breast reconstruction.

Methods

A retrospective chart review of 136 consecutive patients who underwent fat harvest with TLT and subsequent transfer into 237 breast reconstructions was conducted at a single institution. This two-surgeon series examined donor and recipient site complication rates over a median follow-up of 143 days [87–233].

Results

The overall complication rate was 28.7 %, of which the majority (22.1 %) was fat necrosis at the recipient site as documented by any clinical, imaging, or pathologic evidence. The abdomen served as the donor site for half of the cases. Donor site complications were limited to widespread ecchymosis of the donor site notable in 10.4 % of cases. Twenty-five percent of patients had received postmastectomy radiotherapy prior to fat transfer. Prior to revision with fat transfer, implant-based breast reconstruction was used in 75.5 % of cases, and autologous flaps in the remainder. Fat transfer was combined with other reconstructive procedures 94.1 % of the time.

Conclusions

TLT can be used to harvest adipocytes for fat transfer with donor site morbidity and recipient site complications comparable to other modalities. The efficiency and quality of harvested fat makes this technology appealing for wide spread adoption during fat transfer.

Level of Evidence IV

This journal requires that the 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.