Deep Subcutaneous Gluteal Fat Compartments: Anatomy and Clinical Implications.

BACKGROUND: Advances in gluteal fat grafting have resulted in diminished risks through improved understanding of regional anatomy and technical nuances. No anatomic studies identifying the presence or absence of buttock fat compartments have yet been reported. OBJECTIVES: The aim of this cadaveric study was to identify and characterize the deep subcutaneous gluteal fat compartments to further understand the nuanced differences between deep and superficial subcutaneous fat layers. METHODS: A cadaveric study was performed to identify the fat compartments. Latex injection into the iliac artery and vein was used to prepare 4 fresh (N = 8 hemibuttocks) hydrated cadavers for dissection. Preliminary work identified the likely position of deep gluteal fat compartments. The cannula was positioned under ultrasound guidance in between the superficial and deep gluteal layers. Cadaveric buttocks were infiltrated by the static technique with dyed human fat, dyed applesauce, and dyed saline in an attempt to identify the gluteal deep subcutaneous fat compartments. RESULTS: Dissection identified and characterized 7 discrete deep gluteal fat compartments. These comprise 3 medial fat compartments (superior, middle, and inferior); a central fat compartment; and 3 lateral (superior, middle, and inferior) deep fat compartments. CONCLUSIONS: Seven deep gluteal fat compartments have been identified that have distinct boundaries and maintain injected contents separate from each other above the gluteal muscle fascia. These compartments can be selectively expanded for buttock augmentation. Knowledge of these compartments enables surgeons to perform gluteal augmentation by static infiltration, injecting autologous fat under ultrasound guidance in the deep subcutaneous fat layer, while optimizing aesthetic considerations.

Safety Comparison of Abdominoplasty and Brazilian Butt Lift: What the Literature Tells Us.

BACKGROUND: Although abdominoplasty is a mainstay of the plastic surgeon, the safety of the Brazilian butt lift (BBL) has been questioned, effectively being prohibited in some countries. The central rationale for the safety concern over the BBL stems from a publication stating a mortality rate of one in 3000. The question remains: What is the real safety of these procedures? METHODS: Focusing on mortality, literature searches were performed for BBL and for abdominoplasty. The 2017 Aesthetic Surgery Education and Research Foundation survey data and publication were examined and analyzed. Additional data from the American Association for Accreditation of Ambulatory Surgical Facilities were obtained independently. RESULTS: Abdominoplasty and BBL appear to have similar safety based on mortality; however, the nature of their mortalities is different. Although most abdominoplasty deaths are secondary to deep venous thrombosis/pulmonary embolism-inherent circulatory thrombotic abnormality-BBL mortality is associated with iatrogenic pulmonary fat embolism. BBL mortality rates from more recent surveys on BBL safety demonstrate a mortality of one in 15,000. CONCLUSIONS: Although deep venous thrombosis/pulmonary embolism will always remain an abdominoplasty risk, intraoperative BBL pulmonary fat embolism has the potential to be reduced dramatically with a better understanding of dynamic anatomy, surgical instrumentation, and technique. The authors are now presented with a better lens with which to view a more accurate safety profile of BBL surgery, including its place among other commonly performed aesthetic procedures.

Composite Buttock Augmentation: The Next Frontier in Gluteal Aesthetic Surgery.

BACKGROUND: Despite rapid growth, gluteal fat transplantation has a dismal safety record and often results in inadequate domal projection. Implants alone for gluteal augmentation have also been reported to be less than ideal, with significant complication rates. The idea of combining both implants and fat, as has been described in the breast, was therefore applied to surgery of the buttocks. METHODS: One hundred forty-seven consecutive cases of buttock augmentation were reviewed. Average follow-up was 18 months. The technique of composite buttock augmentation used progressive instrument dissection to precisely define the correct intramuscular plane of the implant pocket with a minimum amount of pocket access dissection. RESULTS: Operating times averaged 1 hour 55 minutes. The average volume of fat inserted was 380 cc. The average implant volume was 300 cc. Complications included implant displacements and implant pocket infections requiring surgical intervention. There were no cases of pulmonary thromboembolism, fat embolism, or death. CONCLUSIONS: Taking a lesson from composite breast augmentation, composite buttock augmentation is a new method for gluteal reshaping that seeks to use the best of both worlds: the reliable core projection of an implant combined with the natural appearance and feel of fat. Progressive instrument dissection seeks to minimize unnecessary dissection and to accurately and safely define the intramuscular pocket. The intramuscular placement of implants instead of fat should eliminate the risk of fatal fat pulmonary embolism in these patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Clinical Implications of Gluteal Fat Graft Migration: A Dynamic Anatomical Study.

BACKGROUND: The intraoperative mortality and overall complication rate for gluteal augmentation with fat transplantation is unacceptably high. The current controversy among experts regarding safety is whether fat should be placed within the gluteus muscle or limited to only the subcutaneous space. The purpose of the present study was to test the hypothesis that under certain pressures, fat injected within the gluteal muscle can actually migrate out of the muscle and into a deeper plane containing critical neurovascular structures, by means of the process of deep intramuscular migration. METHODS: A total of eight human cadaver dissections were performed. Four hemibuttocks were selected for intramuscular fat injection. The patterns of subfascial fat migration were evaluated in three of these hemibuttocks by direct visual inspection and in one hemibuttock by endoscopic evaluation. Four other hemibuttocks were selected for subcutaneous or suprafascial fat injection. RESULTS: Proxy fat was found to migrate through the muscle and into the deep submuscular space with each intramuscular injection. With subcutaneous injection, no proxy fat was found during dissection in the intramuscular septae or submuscular space. CONCLUSIONS: The intramuscular insertion of fat, which up to this point has been considered reasonable to perform in the superficial muscle and even recommended in the literature, is now deemed to be an inexact and risky surgical technique. This technique, because of the migratory nature of injected fat, should be avoided from further use in fat transplantation to the gluteal region.

MBN 2016 Aesthetic Breast Meeting BIA-ALCL Consensus Conference Report.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is an uncommon neoplasia occurring in women with either cosmetic or reconstructive breast implants. The actual knowledge about BIA-ALCL deriving from the literature presents several limits, and it remains difficult to make inferences about BIA-ALCL epidemiology, cause, and pathogenesis. This is the reason why the authors decided to organize an evidence-based consensus conference during the Maurizio Bruno Nava (MBN 2016) Aesthetic Breast Meeting held in Milan in December of 2016. Twenty key opinion leaders in the field of plastic surgery from all over the world have been invited to express and discuss their opinion about some key questions on BIA-ALCL, trying to reach a consensus about BIA-ALCL cause, pathogenesis, diagnosis, and treatment in light of the actual best evidence.

Staying Safe during Gluteal Fat Transplantation.

Gluteal augmentation with fat transplantation is increasing in demand but has been associated with a concerning number of fatality reports. Despite these reports, various surgeons have safely performed gluteal fat transplantation on a large number of patients with no reported mortality. The important aspects of safely performing gluteal fat transplantation are reviewed. Proper patient selection, favorable instrumentation, patient positioning, proper technique, and knowledge of anatomy are critical to improving the safety of this procedure. Adherence to these key principles should allow a reduction in mortality from this procedure, which would safely allow its continued offering in the setting of increasingly high demand.

The graft-to-capacity ratio: volumetric planning in large-volume fat transplantation.

BACKGROUND: Variability in large-volume fat transplantation has been linked to technique. Meanwhile, the recipient-site volume and its relation to the volume of grafted fat have been relatively overlooked. Graft-to-capacity concepts are evidenced in other soft-tissue transplantation procedures such as skin and hair transplantation. The authors define the graft-to-capacity ratio as the volume of grafted fat in relation to the volume of the recipient site. The authors postulate its theoretical limits, and empirically analyze its potential clinical importance in large-volume fat transplantation. METHODS: Thirty cases of large-volume fat transplantation to the breast were reviewed. All patients underwent (1) preoperative quantitative volumetric analysis using three-dimensional breast imaging and (2) large-volume fat transplantation using the large-syringe technique. The volume of fat transplanted into each breast at the time of surgery was noted. Quantitative volumetric breast imaging was repeated 12 months postoperatively. RESULTS: The average graft-to-capacity ratio was 117 percent, with a standard deviation of 22 percent, consistent with deduced theoretical limits. Cases where the graft-to-capacity ratio exceeded 1 SD demonstrated lower percentage volume maintenance. Cases where the graft-to-capacity ratio was lower than 1 SD appeared to demonstrate higher percentage volume maintenance. Univariate linear regression of percentage volume maintenance as a function of the graft-to-capacity ratio demonstrated a significant inverse relationship. CONCLUSION: The graft-to-capacity ratio appears to be a relevant variable in percentage volume maintenance outcomes and may be useful in establishing consistency in large-volume fat transplantation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Mechanisms of action of external volume expansion devices.

BACKGROUND: External volume expansion by suction has been proposed to improve the survival of fat grafting by preparing the recipient site. In previous experimental work, external volume expansion demonstrated the capacity to stimulate cell proliferation, vessel remodeling, and adipogenesis. This study investigated possible mechanisms underlying these observed changes. METHODS: A miniaturized external volume expansion device was applied to the dorsum of mice for 2 hours. Hypoxia during stimulation was assessed with pimonidazole hydrochloride, and tissue perfusion was measured for up to 2 days using hyperspectral imaging. Treated tissues were evaluated by microscopy for edema, inflammation, and the effects on cell proliferation and vessel remodeling. RESULTS: External volume expansion-treated tissues were grossly expanded with 2 hours of stimulation, developing a macroscopic swelling that regressed slowly over the course of hours following stimulus cessation. This gross swelling was reflective of histologic signs of intense edema, persistent for at least 1 hour after external volume expansion. Tissues were hypoxic during stimulation, and hyperspectral imaging demonstrated decreased tissue content of both oxygenated and deoxygenated hemoglobin in the first hour after external volume expansion release. The onset of inflammation was already apparent by the end of stimulation and remained elevated through 2 days after external volume expansion. At this time point, epidermal and dermal cell proliferation and vascular density were significantly increased. CONCLUSION: External volume expansion sets in motion various mechanisms, including mechanical stimulation, edema, ischemia, and inflammation, that over distinct time periods maintain an environment conducive to cell proliferation and angiogenesis, which can be elicited even by a single 2-hour external volume expansion cycle.

Autologous injectable dermis: a clinical and histological study.

BACKGROUND: No perfect solution yet exists for dermal fillers. The authors hypothesized that autologous dermis can be processed in an operator-friendly manner and adopted in selected patients as a filler, following the principle of replacing "like with like." METHODS: The authors designed a prototype "cutting chamber" to morsel dermis into an injectable form. Autologous injectable dermis grafting was performed in 16 patients who underwent lip or labionasal fold correction concomitant with abdominoplasty or cesarean scar correction; patient dermis was used for the donor graft. Furthermore, injectable dermis grafting was performed in the subcutaneous tissue of three patients undergoing multistage reconstructive procedures for obesity. The grafts were harvested and examined histologically at 3, 7, and 12 months. RESULTS: Dermis processing and injection proved feasible with limited effort. All 16 patients presented good volume maintenance by 12 months. Two reported transient palpable firmness for the first 6 months, which subsequently resolved. Histological examination of processed and injected dermis showed volume maintenance over time, effective revascularization of the mass, and structural reorganization with collagen bundles and nested fibroblasts reminiscent of reticular dermis. A transient inflammatory reaction was observed, consistent with the expected healing events. CONCLUSIONS: Use of autologous dermis as a filler substance for both aesthetic and reconstructive procedures appears to be a feasible option. It could be advised for patients requiring filler correction who undergo concomitant procedures involving excision of potential donor dermis.

A report of the ASPS Task Force on regenerative medicine: opportunities for plastic surgery.

In 2011, the American Society of Plastic Surgeons (ASPS) created the Task Force on Regenerative Medicine to address the Society's strong interest in the emerging field of regenerative medicine, particularly cell- and tissue-based therapies applicable to plastic surgery procedures. The Task Force's U.S. Food and Drug Administration's Workgroup is informing ASPS interactions with the U.S. Food and Drug Administration's Center for Biologics Evaluation and Research. Engaging in dialogue with the agency to determine which research protocols will produce scientific data necessary to determine safety and efficacy for regenerative cellular therapies can allow research to be targeted to gather data that prove safety and efficacy of specific categories of therapies and/or products. This article reviews the regulatory backdrop of regenerative medicine, briefly reviews the history of regenerative medicine, and then looks at current research and potential future areas of research and clinical application. The historic ability of plastic surgeons to innovate and apply translational research positions the specialty of plastic surgery as a strong leader in clinical applications of regenerative medicine therapies.

"SIEF"--simultaneous implant exchange with fat: a new option in revision breast implant surgery.

UNLABELLED: A technique of implant exchange is reported using recipient-site preexpansion followed by autologous fat transplantation to the breast in 12 consecutive patients with breast implants who desired implant removal. Recipient-site preexpansion, used 2 weeks before fat grafting, may have both practical and theoretical benefits in increasing the breast subcutaneous space and stimulating the recipient-site microcellular environment overlying the prosthetic implant, allowing the subcutaneous insertion of a sufficient core volume of donor graft at the time of prosthetic explantation. In the cases described, the postexplantation breast volume at 9 months to 1 year postoperatively by quantitative three-dimensional imaging was equal to or greater than the preexplantation composite volume of breast and implant. Preexpansion before implant exchange with fat affords a more abundant space, completely independent from the subglandular or submuscular planes. In this new space, the "third space" of the breast, it is possible to technically place graft into the breast subcutaneous tissue and alleviate breast asymmetry resulting from pocket distortions caused by capsular contracture or by implant pocket drift. Observing breast augmentation with implants and with fat grafting in the same patient affords a unique opportunity to analyze some of the key differences between the two techniques. Recipient-site preexpansion and simultaneous implant exchange with fat (SIEF) should be added to the list of applications where fat grafting to the breasts may have early clinical utility and portends the use of fat used in conjunction with breast implants to achieve better patient outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

External volume expansion increases subcutaneous thickness, cell proliferation, and vascular remodeling in a murine model.

BACKGROUND: Fat grafting is a powerful tool for soft-tissue reconstruction; however, the science behind recipient bed preparation has not been thoroughly explored. External volume expansion using suction before fat grafting has been used clinically to improve reliability and consistency of graft survival. The authors developed a murine model to investigate the underlying mechanism of external volume expansion. METHODS: The authors created an external volume expansion device using a soft-silicone dome connected to a vacuum source (25 mmHg) to treat the dorsum of mice, and the response was compared with treatment with an occlusive dressing. Treated areas were monitored with magnetic resonance imaging. Remodeling of microvasculature was studied with corrosion casting on day 7. Effects on tissue thickness, number of adipocytes, cell proliferation, and blood vessel density were analyzed at 28 days. RESULTS: Macroscopic analysis showed tissue swelling at sites treated with the external volume expansion device by 21 days, without skin damage. On day 28, external volume expansion increased the thickness of the subcutaneous fat layer twofold, consistent with magnetic resonance imaging observations. The proliferation rate in the subcutaneous layer of expansion-treated areas increased twofold, with a net 2.2-fold increase in number of adipocytes in columns; remodeling of the vessels network occurred, with reorientation and increase of vessel diameters shown by corrosion casting and 1.9-fold augmentation of vessels density. CONCLUSIONS: External volume expansion applied to mouse integument induces highly proliferative and vascularized subcutaneous tissue. Recipient-site preparation using external volume expansion devices may be a promising tool to enhance cell and tissue engraftment.

Breast augmentation using preexpansion and autologous fat transplantation: a clinical radiographic study.

BACKGROUND: Despite the increased popularity of fat grafting of the breasts, there remain unanswered questions. There is currently no standard for technique or data regarding long-term volume maintenance with this procedure. Because of the sensitive nature of breast tissue, there is a need for radiographic evaluation, focusing on volume maintenance and on tissue viability. This study was designed to quantify the long-term volume maintenance of mature adipocyte fat grafting for breast augmentation using recipient-site preexpansion. METHODS: This is a prospective examination of 25 patients in 46 breasts treated with fat grafting for breast augmentation from 2007 to 2009. Indications included micromastia, postexplantation deformity, tuberous breast deformity, and Poland syndrome. Preexpansion using the BRAVA device was used in all patients. Fat was processed using low-g-force centrifugation. Patients had preoperative and 6-month postoperative three-dimensional volumetric imaging and/or magnetic resonance imaging to quantify breast volume. RESULTS: All women had a significant increase in breast volume (range, 60 to 200 percent) at 6 months, as determined by magnetic resonance imaging (n = 12), and all had breasts that were soft and natural in appearance and feel. Magnetic resonance imaging examinations postoperatively revealed no new oil cysts or breast masses. CONCLUSIONS: Preexpansion of the breast allows for megavolume (>300 cc) grafting with reproducible, long-lasting results that can be achieved in less than 2 hours. These data can serve as a benchmark with which to evaluate the safety and efficacy of other core technology strategies in fat grafting. The authors believe preexpansion is useful for successful megavolume fat grafting to the breast.