Fat Grafting as Regenerative Surgery: A Current Review.

SUMMARY: Autologous fat grafting has long been regarded as an ideal filler, lauded for its ability to restore soft-tissue contour. In recent times, fat grafting has exhibited regenerative capacity, largely secondary to the action of adipose-derived stem cells and preadipocytes in the stromal vascular fraction of adipose tissue. This has birthed a new field of regenerative surgery with benefits germane to scarring, fibrosis, atrophy, burns, neuropathic pain, and autoimmune disease. The broad clinical applications of regenerative fat grafting have the potential to improve quality of life through functional and aesthetic improvement. Fat grafting has the potential to serve as a regenerative option for difficult clinical problems that cannot be treated effectively at the present time. Fat grafting also exhibits angiogenic and immunomodulatory properties in the context of autoimmune disease. The broad clinical applications of regenerative fat grafting have the potential to improve quality of life both functionally and aesthetically. It may present a less invasive avenue for clinical issues that today necessitate conventional surgical techniques. However, regenerative fat grafting is still in its infancy; further research is required to ascertain evidence-based protocols for the various clinical indications and better understand the precise regenerative mechanisms after fat grafting.

Smoking and Physical Activity Significantly Influence Stromal Vascular Fraction Cell Yield and Viability.

BACKGROUND: Subcutaneous tissue is an abundant source of adipose-derived regenerative cells. It is readily available and easy to extract by means of liposuction, making it one of the most popular sources for tissue engineering and regenerative medical applications. METHODS: The stromal vascular fraction (SVF) cell yield and viability of the lipoaspirate obtained from 43 patients undergoing elective liposuction were examined in correlation with their age, gender, body mass index, smoking status, and physical activity. The lipoaspirate was processed with the Celution® 800/CRS system to isolate the SVF and a few drops of the obtained pellet were used for cell counting with NecleoCounter® NC-100TM. RESULTS: Twenty-eight (65.1%) were men and 15 (34.9%) were women with an average age of 40.7 ± 10.4 years (women) and 38.9 ± 11.8 years (men). Viable SVF cells/g fat was significantly correlated with smoking level (negative correlation, ρ= - 0.312, P < 0.05) and with marginal significance with female gender. Cell viability showed a significant negative correlation with physical activity level (ρ = - 0.432, P < 0.01); borderline significance for correlation of this parameter with smoking level should not be neglected. Other parameters did not influence the cell yield nor the viability of the stromal vascular fraction. CONCLUSION: Many factors may influence SVF cell yield and viability. Our findings indicate that age and smoking significantly influenced SVF cell yield, age positively while smoking negatively. Increased physical activity had a negative correlation with SVF cell viability. LEVEL OF EVIDENCE N/A: 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 .

A 3-step Mechanical Digestion Method to Harvest Adipose-derived Stromal Vascular Fraction.

BACKGROUND: Adipose stromal vascular fraction (SVF) isolation with enzymatic digestion is the gold standard, but is expensive, having practical and legal concerns. The alternative mechanical SVF isolation methods provide lower cell yields as they employ either centrifugation, emulsification, or digestion steps alone. We combined mechanical processing with buffer incubation and centrifugation steps into an isolation method called "mechanical digestion" and compared the cell yields with that of enzymatic digestion. METHODS: A total of 40-mL lipoaspirate was harvested from 35 women undergoing liposuction and was submitted to conventional enzymatic digestion for SVF isolation or mechanical digestion using a closed unit harnessing 3 ports with blades, followed by buffer incubation and centrifugation. Culture of the SVFs and flow cytometry were performed. RESULTS: The SVF cell yield obtained by enzymatic digestion was significantly higher 3.38 × 106/mL (±3.63; n = 35) than that obtained by mechanical digestion 1.34 × 106/mL (±1.69; n = 35), P = 0.015. The average cell viability was 82.86% ± 10.68 after enzymatic digestion versus 85.86% ± 5.74 after mechanical digestion, which was not significant. Mechanical digested SVF expressed 2-fold higher stem cell surface markers compared with enzymatically digested SVF. Mechanical digestion was less time consuming, cost effective, and did not require a specific laboratory environment. CONCLUSIONS: Mechanically digested SVF was comparable to enzymatically digested SVF in terms of stromal cell composition and viability. With mechanical digestion, we can isolate 30%-50% SVF cells of that isolated with enzymatic digestion. Further studies are warranted to determine the clinical outcomes.

An Enzyme-free Method for Isolation and Expansion of Human Adipose-derived Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) are a population of multipotent cells that can be isolated from various adult and fetal tissues, including adipose tissue. As a clinically relevant cell type, optimal methods are needed to isolate and expand these cells in vitro. Most methods to isolate adipose-derived MSCs (ADSCs) rely on harsh enzymes, such as collagenase, to digest the adipose tissue. However, while effective at breaking down the adipose tissue and yielding a high ADSC recovery, these enzymes are expensive and can have detrimental effect on the ADSCs - including the risks of using xenogeneic components in clinical applications. This protocol details a method to isolate ADSCs from fresh lipoaspirate and abdominoplasty samples without enzymes. Briefly, this method relies on mechanical disassociation of any bulk tissue followed by an explant-type culture system. The ADSCs are permitted to migrate out of tissue and onto the tissue culture plate, after which the ADSCs can be cultured and expanded in vitro for any number of research and/or clinical applications.

"Brazilian Butt Lift" Performed by Board-Certified Brazilian Plastic Surgeons: Reports of an Expert Opinion Survey.

BACKGROUND: Gluteal fat augmentation has increased worldwide, and so have major complications. Brazilian plastic surgeons have been performing this procedure for more than 30 years, and more often every year. Therefore, the authors performed a study among board-certified plastic surgeons, members of the Brazilian Society of Plastic Surgery, to evaluate their techniques; identify their preferences, complications, and outcomes with this procedure; and make some recommendations. METHODS: An anonymous Web-based survey consisting of 16 questions was sent to 5655 members in July of 2017. A supplementary survey was subsequently sent to obtain more information about major complications. RESULTS: A total of 853 responses were analyzed. The highest percentage of responses in the different categories were as follows: fat decantation for processing, injection with a 3-mm-diameter cannula, use of superior incisions, subcutaneous fat grafting only, and with a volume of 200 to 399 ml of fat per buttock. The majority of surgeons received training in this procedure during residency. The most common complications were contour irregularities. The estimated mortality rate was one in 20,117 cases, and the rate of nonfatal fat embolism was one in 9530. The risk of death was 16 times greater when fat was injected intramuscularly. CONCLUSIONS: Based on this survey, the authors recommend injecting fat only subcutaneously, by means of superior incisions, using cannulas 3 mm in diameter or more. They find that by following these recommendations, this procedure can be as safe as any other. More research to establish guidelines and increase its safety is necessary.

Assessment of Female Genital Surgery Education in Plastic Surgery Training: Report of an Expert Opinion Survey.

BACKGROUND: Patient demand for aesthetic genital surgery has markedly increased. The International Society of Aesthetic Plastic Surgery reported 95,010 labiaplasties and 50,086 vaginal rejuvenation procedures in 2015. METHODS: We performed an online anonymous survey to evaluate the teaching of female genital procedures in plastic surgery training programs worldwide. RESULTS: A total of 1033 board certified plastic surgeons answered the survey. Most respondents were from the USA, Brazil, Mexico and Colombia. The majority of plastic surgeons performing these procedures were in private practice (77.62%) and (22.38%) in academic settings. Most plastic surgeons (75.63%) did not receive formal education in female genital rejuvenation procedures however 54.31% did receive education in reconstruction procedures. During their training, most were exposed to vaginal reconstruction (15.94%), labia minora reduction (11.9%), vulva reconstruction (11.53%), flaps for vaginal agenesis (11.39%) and monsplasty (7.98%). Additional training for female genital procedures was mostly at meetings and shadowing experts. Sixty-two percent reported that patients seldom requested those procedures, and 63.73% reported these procedures comprised less than 5% of their practice. The most commonly performed procedures were labia minora reduction, labia majora augmentation or reduction and monsplasty. The materials used were mostly fat grafting, hyaluronic acid injections and lasers. CONCLUSION: Additional formal training during residency for aesthetic genital surgery would be beneficial. Additionally, courses at meetings would be useful for plastic surgeons who have had insufficient training. More studies need to be conducted on the different female genital rejuvenation procedures offered in order to evaluate patients' long-term outcomes and satisfaction. LEVEL OF EVIDENCE V: 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 .

Subcutaneous-Only Gluteal Fat Grafting: A Prospective Study of the Long-Term Results with Ultrasound Analysis.

In recent years, gluteal fat augmentation has exhibited some of the most significant growth among all plastic surgery procedures. However, as the popularity of and media attention to gluteal fat augmentation continue to rise, reports of fatalities, largely attributed to fat embolism, have raised valid concerns. Many plastic surgeons inject fat in the intramuscular plane and claim better graft take in the muscles and the possibility of injecting more volume in the gluteal region. Because of the large caliber of vessels, subcutaneous fat augmentation has been a preference of many. However, the long-term outcome of fat injected into the subcutaneous layer has been questionable, and there is a lack of prospective quantitative studies of subcutaneous-only fat grafting. Therefore, the authors evaluated the long-term maintenance of gluteal adipose thickness when fat was injected only subcutaneously. Fifty consecutive female patients were evaluated in this prospective clinical study. All patients underwent gluteal fat augmentation in the subcutaneous plane only. Ultrasound analysis of the adipose tissue thickness of the gluteal region was performed preoperatively, immediately postoperatively, and at 12 months postoperatively. Immediate postoperative measurements revealed an average increase in gluteal subcutaneous layer thickness of 56.51 percent (range, 39.5 to 108.6 percent) (p < 0.0001). At 12 months postoperatively, the gluteal adipose tissue thickness decreased by an average of 18.16 percent (range, 6.8 to 24.8 percent) (p < 0.0001). Subcutaneous-only gluteal fat augmentation is shown to be as effective as previous studies reporting intramuscular fat injection with regard to long-term fat retention in the buttocks. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, IV.

Enzyme-Free Isolation of Adipose-Derived Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) are a population of multipotent cells that can be isolated from various adult and fetal tissues, including adipose tissue. These cells contain enormous clinical and basic research appeal due to their plasticity to differentiate into cells of all germ layers in vitro, cross allogeneic barriers in vivo, and suppress inflammation. Methods to isolate adipose-derived MSCs (ADSCs) primarily rely on enzymatic digestion of the adipose tissue using harsh enzymes such as collagenase. However, these harsh enzymes are expensive and can have detrimental effects on the ADSCs, including risks of using xenograft components in clinical application. This chapter focuses on methods of isolating ADSCs from adipose tissue without enzymatic digestion.

Real-Time Ultrasound-Assisted Gluteal Fat Grafting.

BACKGROUND: The number of gluteal fat augmentation procedures has increased recently and so has the number of complications. Because of the increased risk of morbidity and mortality when fat is injected intramuscularly, not knowing where fat is injected is concerning. We sought to identify the planes in which fat is injected during the procedure. METHODS: We selected 15 consecutive female patients who desired gluteal fat augmentation. All patients had epidural anesthesia and the gluteal region was infiltrated with a vasoconstrictive solution. With the patient in prone position, an ultrasound probe placed on the buttocks was used to identify the fascial layers. While decanted fat was being injected with a blunt cannula, the images were projected wirelessly to a screen, so that the surgeon and assistant could follow the planes in which the cannula was being introduced and the fat injected. RESULTS: The mean volume of harvested fat was 3533 ml and the mean volume of fat injected per gluteal region was 528 ml. The evaluation of the depth and location of the cannula was performed in real time with the ultrasound, accurately and reliably identifying the planes of fat injection. All injections were subcutaneous. The downsides of this technique were the purchase cost of the ultrasound device, increased surgical time, the need for an assistant to follow the cannula and the probe constantly, and the learning curve. CONCLUSION: Real-time ultrasound-assisted gluteal fat grafting is reliable and may avoid injuring the deep vessels, further decreasing the risks of major complications.

Use of Tranexamic Acid to Reduce Blood Loss in Liposuction.

BACKGROUND: The use of tranexamic acid for blood loss prevention has gained popularity in many specialties, including plastic surgery. However, its use in liposuction has not been studied. The authors present a prospective, double-blind, nonrandomized study evaluating the efficacy of tranexamic acid in reducing perioperative blood loss during liposuction. METHODS: Twenty women undergoing liposuction were divided into two cohorts. Group 1 (n = 10) received a standard dose of 10 mg/kg of tranexamic acid intravenously in the preoperative and postoperative periods, whereas group 2 (n = 10) received a placebo. Patient hematocrit levels were evaluated preoperatively and postoperatively. Blood volume in the infranatant of the lipoaspirate was also measured; t tests were used for statistical analysis. RESULTS: Age, body mass index, and volume of lipoaspirate were comparable between the two cohorts. The volume of blood loss for every liter of lipoaspirate was 56.2 percent less in the tranexamic group compared with the control group (p < 0.001). Hematocrit levels at day 7 postoperatively were 48 percent less in group 1 compared with group 2 (p = 0.001). Furthermore, a 1 percent drop in the hematocrit level was found after liposuction of 812 ± 432 ml in group 1 and 379 ± 204 ml in group 2. Thus, the use of tranexamic acid could allow for aspiration of 114 percent more fat, with comparable variation in hematocrit levels. CONCLUSIONS: Tranexamic acid has been shown to be effective for minimizing perioperative blood loss in liposuction. Further large randomized controlled studies are required to corroborate this effect. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

Shift toward Mechanical Isolation of Adipose-derived Stromal Vascular Fraction: Review of Upcoming Techniques.

Standard isolation of adipose stromal vascular fraction (SVF) requires the use of collagenase and is considered more than "minimally manipulated" by current good manufacturing practice requirements. Alternatively, nonenzymatic isolation methods have surfaced using physical forces to separate cells from the adipose matrix. The purpose of this study was to review the literature on the use of mechanical isolation protocols and compare the results. The implication for use as a standard procedure in practice is discussed. METHODS: A systematic review of the literature was performed on mechanical isolation of SVF with a search of six terms on PubMed and Medline databases. One thousand sixty-six articles were subject to evaluation by predetermined inclusion and exclusion criteria. RESULTS: Two level 2 evidence articles and 7 in vitro studies were selected. SVF was isolated using automated closed systems or by subjecting the lipoaspirate to centrifugation only or by shaking or vortexing followed by centrifugation. Six articles reported isolation in laboratory settings and three inside the operating room. Stromal vascular cells expressed CD34, and CD44, CD73, CD90, and CD105, and differentiated along adipogenic and osteogenic lineages. When compared with enzymatic methods, mechanical isolation required less time but yielded fewer cells. Both case-control studies reported improved volume retention with cell-supplemented fat grafts for breast reconstruction. CONCLUSIONS: Mechanical isolation methods are alternatives to circumvent safety issues posed by enzymatic protocols. However, randomized comparative studies with long-term clinical outcomes using mechanically isolated stromal vascular cells are needed to identify their ideal clinical applications.

Fat Grafting for Gluteal Augmentation: A Systematic Review of the Literature and Meta-Analysis.

BACKGROUND: With the increasing demand for gluteal fat augmentation, reports of fatal complications have surfaced. Therefore, the authors proposed to analyze the published techniques and compare different protocols, to identify those of potential concern. METHODS: A systematic review of the literature was performed with a search of 21 terms on the PubMed, MEDLINE, Cochrane, and Scientific Electronic Library Online databases. Nineteen articles meeting our predetermined criteria were analyzed, and data from the different steps of the procedure were classified, allowing evaluation and comparison of techniques. Independent-samples t test and one-way analysis of variance were used for statistical analysis. RESULTS: Seventeen case series and two retrospective studies including 4105 patients were reviewed. Most articles were authored in Colombia, Mexico, and Brazil. Most procedures were performed on adult female patients under general anesthesia. Fat was harvested using a tumescent technique from the lower extremities and the back, with machine-vacuum suction. A mean of 400 ml of decanted lipoaspirate was injected into each gluteal region, mostly subcutaneously and intramuscularly with 60-ml syringes. Most patients rated their results as "excellent." The mean complication rate was 7 percent (6.7 percent minor, 0.32 percent major), with no significant relation to the planes of injection. CONCLUSIONS: Fat grafting is an effective and predictable way to remodel the gluteal region; however, the procedure is not without risks. Avoiding gluteal vessel damage may prevent most feared complications, such as fat embolism. Accurate analysis, systematization of the procedure, and reporting cases in the fat grafting registry may provide the foundation for optimization of outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

The Role of International Volunteers in the Growth of Surgical Capacity in Post-earthquake Haiti.

BACKGROUND: The 2010 Haiti earthquake severely strained local healthcare infrastructure. In the wake of this healthcare crisis, international organizations provided volunteer support. Studies demonstrate that this support improved short-term recovery; however, it is unclear how long-term surgical capacity has changed and what role volunteer surgical relief efforts have played. Our goal was to investigate the role of international surgical volunteers in the increase of surgical capacity following the 2010 Haiti earthquake. METHODS: We retrospectively analyzed the operative reports of 3208 patients at a general, trauma and critical care hospital in Port-au-Prince from June 2010 through December 2013. We collected data on patient demographics and operation subspecialty. Surgeons and anesthesiologists were categorized by subspecialty training and as local healthcare providers or international volunteers. We performed analysis of variance to detect changes in surgical capacity over time and to estimate the role volunteers play in these changes. RESULTS: Overall number of monthly operations increased over the 2.5 years post-earthquake. The percentage of orthopedic operations declined while the percentage of other subspecialty operations increased (p = 0.0003). The percentage of operations performed by international volunteer surgeons did not change (p = 0.51); however, the percentage of operations staffed by volunteer anesthesiologists declined (p = 0.058). The percentage of operations performed by matching specialty- and subspecialty-trained international volunteers has not changed (p = 0.54). CONCLUSIONS: Haitian post-earthquake local and overall surgical capacity has steadily increased, particularly for provision of subspecialty operations. Surgical volunteers have played a consistent role in the recovery of surgical capacity. An increased focus on access to surgical services and resource-allocation for long-term surgical efforts particularly in the realm of subspecialty surgery may lead to full recovery of surgical capacity after a large and devastating natural disaster.