Analysis of local complications following explantation of silicone breast implants

A Pipeline to Understand Emerging Illness Via Social Media Data Analysis: Case Study on Breast Implant Illness

Background

A new illness can come to public attention through social media before it is medically defined, formally documented, or systematically studied. One example is a condition known as breast implant illness (BII), which has been extensively discussed on social media, although it is vaguely defined in the medical literature.

Objective

The objective of this study is to construct a data analysis pipeline to understand emerging illnesses using social media data and to apply the pipeline to understand the key attributes of BII.

Methods

We constructed a pipeline of social media data analysis using natural language processing and topic modeling. Mentions related to signs, symptoms, diseases, disorders, and medical procedures were extracted from social media data using the clinical Text Analysis and Knowledge Extraction System. We mapped the mentions to standard medical concepts and then summarized these mapped concepts as topics using latent Dirichlet allocation. Finally, we applied this pipeline to understand BII from several BII-dedicated social media sites.

Results

Our pipeline identified topics related to toxicity, cancer, and mental health issues that were highly associated with BII. Our pipeline also showed that cancers, autoimmune disorders, and mental health problems were emerging concerns associated with breast implants, based on social media discussions. Furthermore, the pipeline identified mentions such as rupture, infection, pain, and fatigue as common self-reported issues among the public, as well as concerns about toxicity from silicone implants.

Conclusions

Our study could inspire future studies on the suggested symptoms and factors of BII. Our study provides the first analysis and derived knowledge of BII from social media using natural language processing techniques and demonstrates the potential of using social media information to better understand similar emerging illnesses.

Enhanced Regeneration of Vascularized Adipose Tissue with Dual 3D-Printed Elastic Polymer/dECM Hydrogel Complex

A flexible and bioactive scaffold for adipose tissue engineering was fabricated and evaluated by dual nozzle three-dimensional printing. A highly elastic poly (L-lactide-co-ε-caprolactone) (PLCL) copolymer, which acted as the main scaffolding, and human adipose tissue derived decellularized extracellular matrix (dECM) hydrogels were used as the printing inks to form the scaffolds. To prepare the three-dimensional (3D) scaffolds, the PLCL co-polymer was printed with a hot melting extruder system while retaining its physical character, similar to adipose tissue, which is beneficial for regeneration. Moreover, to promote adipogenic differentiation and angiogenesis, adipose tissue-derived dECM was used. To optimize the printability of the hydrogel inks, a mixture of collagen type I and dECM hydrogels was used. Furthermore, we examined the adipose tissue formation and angiogenesis of the PLCL/dECM complex scaffold. From in vivo experiments, it was observed that the matured adipose-like tissue structures were abundant, and the number of matured capillaries was remarkably higher in the hydrogel–PLCL group than in the PLCL-only group. Moreover, a higher expression of M2 macrophages, which are known to be involved in the remodeling and regeneration of tissues, was detected in the hydrogel–PLCL group by immunofluorescence analysis. Based on these results, we suggest that our PLCL/dECM fabricated by a dual 3D printing system will be useful for the treatment of large volume fat tissue regeneration.

Engineering 3D degradable, pliable scaffolds toward adipose tissue regeneration; optimized printability, simulations and surface modification

We present a solution to regenerate adipose tissue using degradable, soft, pliable 3D-printed scaffolds made of a medical-grade copolymer coated with polydopamine. The problem today is that while printing, the medical grade copolyesters degrade and the scaffolds become very stiff and brittle, being not optimal for adipose tissue defects. Herein, we have used high molar mass poly(L-lactide-co-trimethylene carbonate) (PLATMC) to engineer scaffolds using a direct extrusion-based 3D printer, the 3D Bioplotter®. Our approach was first focused on how the printing influences the polymer and scaffold's mechanical properties, then on exploring different printing designs and, in the end, on assessing surface functionalization. Finite element analysis revealed that scaffold's mechanical properties vary according to the gradual degradation of the polymer as a consequence of the molar mass decrease during printing. Considering this, we defined optimal printing parameters to minimize material's degradation and printed scaffolds with different designs. We subsequently functionalized one scaffold design with polydopamine coating and conducted in vitro cell studies. Results showed that polydopamine augmented stem cell proliferation and adipogenic differentiation owing to increased surface hydrophilicity. Thus, the present research show that the medical grade PLATMC based scaffolds are a potential candidate towards the development of implantable, resorbable, medical devices for adipose tissue regeneration.

Management of Capsular Contracture in Cases of Silicone Gel Breast Implant Rupture with Use of Pulse Lavage and Open Capsulotomy

INTRODUCTION

Pulse lavage (PL) irrigation of prosthesis pockets has prior been described for breast implant salvages. However, PL for removal of leaked silicone from prosthesis pockets after implant ruptures has not been studied yet. Since open capsulotomies are regarded as equal treatment of capsular contracture (CC) than capsulectomies, this study analyzed the clinical outcome of PL for silicone removal and subsequent capsulotomy in cases of concurrent CC and breast implant rupture.

METHODS

Between 2012 and 2017, 55 patients (75 breasts) with suspected silicone implant rupture and CC (Baker grade III/IV), after primary breast augmentation or implant-based breast reconstruction, were included in a retrospective, observational study. Mean patient follow-up was 12.2 ± 3.6 months.

RESULTS

In all preoperatively suspected ruptured silicone breast implants, around a quarter were intact. In contrast to previously published data, implant exchanges in cases of implant ruptures did not lead to significantly higher CC recurrence rates (27.6% vs. 22.2% in cases of intact implants, p = 0.682), if the prosthesis pockets were treated with PL irrigation followed by open capsulotomy. PL reduced the amount of encapsulated silicone remnants histologically. The age of patients with CC after failed implant-based reconstruction was significant lower for salvage surgeries with flap reconstruction than for implant exchanges, p < 0.05.

CONCLUSIONS

PL irrigation of prosthesis pockets prior to open capsulotomy is a safe and effective treatment of CC with concurrent silicone leakage. Remaining silicone remnants in breast capsules may affect the development of a recurrent CC. To avoid CC recurrences, patients should consider conversion to autologous tissue.

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 .

Silicone breast prostheses: A cohort study of complaints, complications, and explantations between 2003 and 2015

BACKGROUND

Complications after silicone implantation, with silicone extravasation being the most severe, remain a safety issue in breast implantation surgery. The purpose of our study was to determine the incidence of medium- and long-term postoperative complaints and complications and indications for explantation in patients with a silicone breast implant.

METHODS

This is a retrospective cohort study consisting of patients who received silicone breast implants of the fourth or fifth generation between 2003 and 2015. Long-term outcomes (> 3 months after initial placement) were derived from medical records. The association with indication of breast surgery, method of placement, and type of reconstruction was determined.

RESULTS

In total, 448 patients (n = 738 silicone breast implants) met the inclusion criteria with a median follow-up of 330 days. Overall, 18% of the implants resulted in postoperative complaints, with discomfort or pain being the most common complaint (12%), significantly more frequent in reconstructive cases and significantly associated with subglandular placement in cosmetically augmented breasts. Physical examination revealed in 14% one or more postoperative complications, with capsular contracture being the most common complication. A total of 12% of the implants were eventually explanted within a median time of 568 days. Predominant reasons were cosmetic dissatisfaction, capsular contracture, and pain (in 37%, 21%, and 15%, respectively). Macroscopic leakage was demonstrated in 3% of the explanted prostheses.

CONCLUSIONS

Explantation of breast implants occurred in 12%, within a median time of 1.6 years, wherein macroscopic leakage was rarely seen. Cosmetic dissatisfaction, capsular contracture, and pain were the most common indications.

Follistatin and the Breast Implant Capsule

Supplemental Digital Content is available in the text.

Background:

Breast capsular contracture remains an elusive problem faced by plastic surgeons and is the leading long-term complication after breast implantation. Follistatin (Fst) is a protein with known anti-inflammatory and antifibrotic properties and has the potential to limit the severity of diseases associated with inflammation and fibrosis such as capsular contracture. The aim of this study was to examine the effect of Fst288 on capsular fibrosis around silicone implants in a mouse model.

Methods:

BALB/c mice were implanted subcutaneously with untreated silicone implants (baseline control). In the experimental group, immediately after silicone implant insertion, the implant pocket received either a single injection of 1 µg Fst288 or normal saline (internal control). The animals were killed at 3, 5, 7, 14, 28, and 90 days after surgery, and serum, implants, and the surrounding tissue were removed for histological and immunohistochemical analyses.

Results:

Fst288 treatment resulted in significant decreases in capsule thickness at 28 days (P < 0.05) and 3 months (P < 0.001), decreased collagen production at 14 days (P < 0.05) and 3 months (P < 0.01), decreased angiogenesis at 3 months (P < 0.001), decreased α-smooth muscle actin levels at 3 months (P < 0.05), and a decrease in the number of CD45+ cells at days 5 (P < 0.05) and 7 (P < 0.01), respectively, when compared with control implants.

Conclusions:

A single injection of Fst288 at the time of silicone implant insertion into the mice results in a significant reduction in pericapsular inflammation and capsular fibrosis.

Sonoelastography in the evaluation of capsule formation after breast augmentation - preliminary results from a follow-up study

INTRODUCTION

There are many indications for breast augmentation, including reconstruction after mastectomy, correction of congenital disorders and cosmetic procedures. The most frequent local complication of this surgery is capsule formation due to fibrosis. The aim of the study was to assess the usefulness of sonoelastography in the evaluation of capsule formation around silicone implants.

MATERIAL AND METHODS

The study group included 13 patients aged 20 to 41, who underwent breast augmentation with silicone implants. Their 26 breasts were examined before surgery, 7 and 14 days and a minimum of 8.5 months after surgery. The breast stiffness was assessed with tonometry and shear wave elastography to evaluate elasticity of the breast tissue and capsule formation after surgery.

RESULTS

We assessed the correlation between capsular elasticity measured at successive visits and the Baker scale. There were no significant relationships between any pairs of variables (p > 0.05). We also analyzed the correlation between the time of the follow-up and changes in the tissue elasticity of every region - no significant relationship was found. The greatest decrease in pericapsular elasticity was established in lower and inner quadrants. Moreover, there was a significant difference between the elasticity of the tissue before and 1 week after surgery (p < 0.05) and no significant changes in the elasticity before surgery and at the end of the follow-up.

CONCLUSIONS

Sonoelastography is precise in evaluation of capsule formation after breast augmentation. It may show changes that cannot be assessed using palpation.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

Acute suppression of TGF-ß with local, sustained release of tranilast against the formation of fibrous capsules around silicone implants

We propose the acute, local suppression of transforming growth factor beta (TGF-ß), a major profibrotic cytokine, to reduce fibrosis around silicone implants. To this end, we prepared silicone implants that were able to release tranilast, a TGF-ß inhibitor, in a sustained manner for 5 days or 15 days. We performed histologic and immunohistochemical analyses for 12 weeks after the implantation of the implants in living rats. The capsule thicknesses and collagen densities significantly decreased compared with those around the non-treated silicone implants. Notably, early suppression of TGF-ß affected the fibrogenesis that actually occurs at the late stage of wound healing. This change may be ascribed to the decrease in monocyte recruitment mediated by early TGF-ß during the acute inflammatory reaction. Thus, a significant decrease in differentiated macrophages was observed along with a decrease in the quantity of TGF-ß and fibroblasts during the subsequent inflammation stage; these changes led to a diminished fibrotic capsule formation.

Adipose tissue engineering with human adipose tissue-derived adult stem cells and a novel porous scaffold

We investigated the effect of a novel porous scaffold composed with water-soluble poly(L-glutamic acid) (PLGA) and chitosan (CS) on the attachment, proliferation, and adipogenic differentiation of human adipose tissue-derived adult stem cells (ADSCs) in vitro and in vivo. Scanning electron microscope and fluorescent Dil labeling were used to reveal the attachment and growth of ADSCs on scaffolds; cell proliferation was detected by DNA assay. The adipogenic differentiation potential of ADSCs on the scaffolds was assayed by Oil-red O staining and further confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) for adipogenic gene markers (peroxisome proliferator-activated receptor γ2, lipoprotein lipase, fatty acid-binding protein, adiponectin). Cell-seeded constructs exposed to adipogenic medium for 2 weeks in vitro were implanted in severe combined immunodeficient (SCID) mice for 6 weeks. It was shown that ADSCs attached and spread well on scaffolds with good proliferation behaviors and abundance of extracellular matrix deposition. Oil-red O staining and RT-PCR showed adipogenic differentiation potential of ADSCs on scaffolds. Newly formed adipose-like tissue was confirmed in vivo in SCID mice by Oil-red O staining. PLGA/CS porous scaffolds exhibit good compatibility to ADSCs and can be promising biomaterials for adipose tissue engineering.

Is ultracision knife safe and efficient for breast capsulectomy? A preliminary study

BACKGROUND

Silicone breast implants are used to a wide extent in the field of plastic surgery. However, capsular contracture remains a considerable concern. This study aimed to analyze the effectiveness and applicability of an ultracision knife for capsulectomy breast surgery.

METHODS

A prospective, single-center, randomized study was performed in 2009. The inclusion criteria specified female patients 20-80 years of age with capsular contracture (Baker 3-4). Ventral capsulectomy was performed using an ultracision knife on one side and the conventional Metzenbaum-type scissors and surgical knife on the collateral side of the breast. Measurements of the resected capsular ventral fragment, operative time, remaining breast tissue, drainage time, seroma and hematoma formation, visual analog scale pain score, and sensory function of the nipple-areola complex were assessed. In addition, histologic analysis of the resected capsule was performed.

RESULTS

Five patients (median age, 59.2 years) were included in this study with a mean follow-up period of 6 months. Three patients had Baker grade 3 capsular contracture, and two patients had Baker grade 4 capsular contracture. The ultracision knife was associated with a significantly lower pain score, shorter operative time, smaller drainage volume, and shorter drainage time and resulted in a larger amount of remaining breast tissue. Histologic analysis of the resected capsule showed no apoptotic cells in the study group or control group.

CONCLUSIONS

The results suggest that ventral capsulectomy with Baker grade 3 or 4 contracture using the ultracision knife is feasible, safe, and more efficient than blunt dissection and monopolar cutting diathermy and has a short learning curve.

LEVEL OF EVIDENCE II

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 at www.springer.com/00266.

A clinical study of late seroma in breast implantation surgery

BACKGROUND

The use of mammary implants may lead to a variety of early and delayed complications. The most common delayed complications are capsular contracture and implant failure. Late seroma has seldom been reported. In a long-term prospective observational study, cases of late seroma were assessed and recorded.

METHODS

Between March 2005 and November 2009, suspected cases of late seroma in patients who had undergone breast augmentation or reconstruction with textured implants were evaluated clinically and with instrumental analyses. An ultrasound-guided needle aspiration of the fluid was performed.

RESULTS

In this study, 13 cases of late seroma (8 augmentations and 5 reconstructions) were observed. The overall incidence of this complication was 1.68%. Chemical analyses confirmed the diagnosis of seroma, which recurred in all the patients within days of evacuation. For 12 patients, a reoperation was performed, during which the implant was removed, a total capsulectomy was performed, and in cases of subglandular breast augmentation, the implant pocket was changed to a submuscular placement before a new prosthesis was inserted. One patient underwent a second ultrasound-guided needle aspiration. No seroma recurrence was observed in any of the patients during the follow-up period.

CONCLUSION

In case of unexpected breast enlargement after prosthesis implantation, the physician should first rule out infection, then investigate possible friction irritation from either a fold in the device or rubbing of a textured implant. According to the authors' experience and another report, this complication occurs in 1% to 2% of cases. The inclusion of this complication in the informed consent form should be considered. Long-term studies designed to investigate the underlying causes of late seroma are warranted for the prevention and treatment of this complication.

[Aesthetic breast augmentation]

Breast augmentation has become one of the most popular procedures in aesthetic plastic surgery. In addition to the well-established procedure for breast enlargement with silicone implants, two further procedures have become established in recent years. The use of autologous fat for augmentation is not new but has become more important due to further developments in the sampling method and preparation of fatty tissue. Since 2006 a product based on hyaluronic acid has complemented the available options and offers an additional clinically tested method for breast enlargement. The correct method for each patient must be decided on an individual basis. This article gives a review of the individual procedures for breast enlargement and sketches the known advantages and disadvantages.

A case of late unilateral hematoma and subsequent late seroma of the breast after bilateral breast augmentation

BACKGROUND

A previously unreported case of unilateral recurrent late collections, namely, a hematoma and a subsequent seroma, in an otherwise healthy female patient after breast augmentation is presented.

METHODS

A case is reported together with a review of the world literature published and presented regarding late postoperative breast augmentation complications.

RESULTS

The patient was a 49-year-old woman who underwent bilateral breast augmentation in 2006. Spontaneous swelling of the left breast developed 1 year postoperatively. The patient was taken to the operating theater, where a large hematoma was found and drained and the prosthesis reinserted. No cause for the complication was identified at the operation. The patient's symptoms of left-sided breast swelling with discomfort recurred 9 months later. A large seroma was found at surgery but no blood staining. On both occasions, the implant was extracted and examined, with no fault discovered. Capsulectomy was performed, and the pocket was examined, debrided, and cauterized as necessary. On neither occasion was any remarkable pathology found clinically or in laboratory samples sent for analysis. The patient was investigated for any sensitivities or hematologic abnormalities, with no significant results.

CONCLUSION

A previously unreported case of recurrent late postaugmentation collections, namely, a seroma and a subsequent hematoma, in an otherwise well female patient is reported. The authors found no obvious reason for the recurrence in this patient.

Pectus excavatum reconstruction with silicone implants: long-term results and a review of the english-language literature

Pectus excavatum, or funnel chest, is an anterior chest wall deformity, characterized by a depressed sternum. Frequently used techniques for pectus excavatum repair are extensive thoracic surgical corrections at a young age. At an adult age, custom-made silicone implants can be used as a less extensive surgical option. Thus far, there are only a limited number of reports in the English-language literature concerning this treatment modality. We evaluated our series of 16 patients treated with custom-made silicone implants, assessing complications, patient satisfaction, and aesthetic outcome. Seven patients (44%) had complications, mostly seroma formation (31%). Ten of 12 patients (83%), who were evaluated at the long-term, reported improved patient satisfaction and 9 of 13 patients (69%), in whom aesthetic results were assessed, had a good or excellent aesthetic outcome.Our study, combined with a review of the English-language literature, demonstrates that there is a place for custom-made silicone implants in the treatment of pectus excavatum, especially in less severe cases at an adult age. Preoperative counseling with emphasis on the likelihood of seroma formation is advocated.

Engineered adipose tissue formation enhanced by basic fibroblast growth factor and a mechanically stable environment

Engineered adipose tissue can be used in plastic and reconstructive surgery to augment soft tissue lost due to mastectomy or lumpectomy. The three-dimensional space provided by a scaffold capable of withstanding in vivo compressive forces and neovascularization may promote engineered adipose tissue formation. The objective of this study was to determine whether voluminous adipose tissue can be engineered by combining a mechanically stable environment with basic fibroblast growth factor (bFGF). Mechanical support structures, fabricated from biodegradable synthetic polymers, were placed into subcutaneous pockets of athymic mice. Human preadipocytes, containing fibrin matrix, with (group 1) or without (group 2) bFGF were injected into the space created by the support structures. Additionally, human preadipocytes containing fibrin matrix, with (group 3) or without (group 4) bFGF, were injected into subcutaneous spaces without support structures. Six weeks after implantation, the original implant volume was approximately maintained in groups 1 and 2, whereas groups 3 and 4 showed significant implant shrinkage. Adipogenesis and angiogenesis were more extensive in the group 1 than any other group. The fraction of human nuclear antigen-positive adipocytes in the implant was highest in group 1. Mouse adipocyte-specific genes were also expressed in the implants, again at the highest levels in group 1. Implanted preadipocyte apoptosis was significantly reduced in the groups treated with bFGF (groups 1 and 3) as opposed to those without (groups 2 and 4). This study demonstrates that combining a mechanically stable environment with bFGF can promote voluminous adipose tissue regeneration. This adipogenesis was likely promoted by the mechanically stable three-dimensional space, enhanced neovascularization, implanted cell survival, and host adipogenic cell migration. The method described in this study could be useful to augment adipose tissue used in plastic and reconstructive surgery.

Late intracapsular seroma in subfascial buttock augmentation: a case report

Late intracapsular seroma and hematoma have been described frequently as a complication of breast augmentation surgery. However, there are few reports of late intracapsular seroma in buttock augmentation. Textured and polyurethane implants have been used for subfascial enlargement of the buttocks. In this article, the authors report a large late intracapsular bilateral seroma caused by a retrofascial polyurethane-covered implant used for buttock augmentation: 1,200 ml on one side and 300 ml on the other. This patient's intracapsular seroma was of sudden onset 2 years and 6 months after surgery, and apparently had no relation to any trauma, use of medication, or physical exercise. Local tissues, including the gluteal fascia, were distended such that the implant was replaced inside the muscle and there was no relapse of the seroma. Late intracapsular hematomas or seromas from implants for buttock and breast augmentation may have the same etiology, and textured implants seem to be involved. All the reports on the matter are associated with textured implants. Any late seroma or hematoma caused by a smooth implant is related to an additional factor that may be considered as the etiologic agent. Further studies aimed at a large-scale assessment of the cause and actual incidence of late seromas and hematomas from textured implants are required.

Dual-plane implant positioning for capsular contracture of the breast in combination with mastopexy

OBJECTIVE

This study aims at combined surgical therapy options concerning patients with a clinically relevant and long-established capsular contracture following subglandular breast augmentation in a glandular ptotic breast.

METHODS

This is a review of 23 patients with capsular contracture. Three patients had a revision surgery for capsular contracture and implant dislocation before. The mean implant duration in the case of the twenty patients without any previous revision was 96 months. A revision implant has been re-located in a dual-plane position and further corrective surgery was carried out to adapt the glandular ptotic breast. Between 2001 and 2003, a chart review was performed on all patients for capsular contracture and ptotic breast by using the technique presented in this study.

RESULTS

In each case, the operation was performed as a one-stage procedure. The procedure included the following steps: Removal of the implant and total capsulectomy, preparation of an inferior de-epithelialised skin pedicle above the inframammary crease, release of the inferior origins of the pectoralis major muscle, creation of a new implant pocket by continuous connection of the inferior muscle border with the cranial edge of the inferior skin pedicle (dual-plane), adaptation of the soft-tissue/skin envelope by closing the cranial V over the implant coverage, preservation of the areola by creating a cranial or cranial medial pedicle. There was a follow-up for a period of up to 48 months, and any complication that occurred was documented. At follow-up period, all patients who had been implanted with a new implant pocket were free of a clinically relevant capsular contracture.

CONCLUSIONS

In the cases of a severe capsular contracture and glandular-ptotic breasts, we presented the surgical corrections of the parenchyma/skin envelop as a one-stage procedure following the establishment of a new implant pocket.

Engineering of volume-stable adipose tissues

Autologous adipose tissues have been clinically used for augmentation of soft tissues lost due to mastectomy or lumpectomy in plastic and reconstructive surgery. However, this therapy has problems of absorption and subsequent volume loss of the implanted adipose tissues. In this study, volume-stable adipose tissues were engineered in vivo using mechanical support structures fabricated from biodegradable synthetic polymers. Dome-shaped mechanical support structures were fabricated by reinforcing poly(glycolic acid) fiber-based matrices with poly(L-lactic acid). The support structures were placed into subcutaneous pockets of athymic mice, and human preadipocytes suspended in fibrin matrix were injected into the space under the support structures (group I). Injection of either fibrin matrix without preadipocytes under the support structures (group II) or fibrin matrix containing preadipocytes into subcutaneous spaces with no support structures (group III) served as controls. Six weeks after implantation, the original implant volume was maintained approximately in groups I and II, whereas, group III showed significant implant shrinkage. The compressive modulus of the mechanical support structures did not change significantly over 6-week incubation in phosphate-buffered saline at 37 degrees C. Histological analyses of the implants showed regeneration of adipose tissues in group I. In contrast, groups II and III did not show extensive adipose tissue formation. This study demonstrates that volume-stable adipose tissues can be engineered in vivo using mechanical support structures. This technique offers the potential for augmentation of adipose tissues with volume conservation.