Capsular Contracture In Silicone Breast Implants: Insights From Rat Models

CD248 Regulates Inflammation and Encapsulation in Silicone-Related Capsule Formation

BACKGROUND

Capsular contracture is the most common reason for having a secondary breast implant operation. The failure of the implanted device and discomfort are related to foreign body response, which involves a pathologic encapsulation. An up-regulated expression of CD248 was previously demonstrated to modulate inflammation and fibrosis. The authors hypothesized that CD248 contributes to foreign body reaction and contracture during silicone-stimulated capsule formation.

METHODS

A murine capsular contracture model was established to correlate CD248 with capsular contracture. The timing and site of CD248 expression were characterized by protein analysis and histologic examination. The capsules between wild-type mice and CD248 knockout mice were compared in this model to verify the possible role of CD248 in silicone-related capsule formation.

RESULTS

CD248 was expressed in the peri-silicone implant capsule by stromal fibroblast and perivascular fibroblast. CD248 was overexpressed on day 4 and down to a constant level, but it was still up-regulated through day 21 to day 56 after silicone implantation. The CD248 knockout mice showed a prolonged inflammation period, whereas the wild-type mice developed a thinner but more collagenous capsule.

CONCLUSIONS

In conclusion, an effective murine capsular contracture model was established to study the relationship between CD248 and capsular contracture. CD248 may play a role in inflammation and encapsulation during silicone implantation. CD248 deletion in mice contributed to a loose and irregular collagen bundle in a capsule area, implying a decrease in contracture. Therefore, CD248 could be a potential therapeutic target in capsular contracture.

CLINICAL RELEVANCE STATEMENT

CD248 may play a role in inflammation and encapsulation during silicone implantation. It could be a potential therapeutic target in clinical capsular contracture.

Dysregulated wound healing in the pathogenesis of urogynecologic mesh complications

To test the hypothesis that dysregulated wound healing is associated with Urogynecologic mesh complications, we collected vaginal cell secretions using vaginal swabs after polypropylene mesh implantation in patients with (N = 39) and without (N = 40) complication. A customized multiplex immunoassay measured markers of inflammation (MCP-1, IGFBP-1, IL-2, IL-10, IL-17, PDGF-BB, bFGF, IL-1b, IL-6, IL-12p70, TNF-α), neuroinflammation (IL-1RA, TGF-β, IL-15, IL-18, IL-3, M-CSF), angiogenesis (VEGF), and matrix proteins (fibronectin, tenasin c, thrombospondin-2, lumican) between groups. Patients with complications were younger, heavier, implanted with mesh longer, and more likely to be ever smokers. A 5 kg/m2 BMI increase and ever-smoking were associated with a 2.4-fold and sixfold increased risk of complication, respectively. Patients with the highest tertile of bFGF, fibronectin, thrombospondin-2, TNF-β, or VEGF had an odds ratio (OR) of 11.8 for having a mesh complication while ≥ 3 elevated had an OR of 237 while controlling for age, BMI, and smoking. The highest tertile of bFGF, thrombospondin-2, and fibronectin together perfectly indicated a complication (P < 0.0001). A receiver-operator curve for high bFGF, thrombospondin-2, and fibronectin showed excellent discrimination between complications and controls (AUC 0.87). These data provide evidence of dysregulated wound healing in mesh complications. Modifiable factors provide potential targets for patient counseling and interventions.

Polyetheretherketone (PEEK) as a Potential Material for the Repair of Maxillofacial Defect Compared with E-poly(tetrafluoroethylene) (e-PTFE) and Silicone

Silicone and e-poly(tetrafluoroethylene) (e-PTFE) are the most commonly used artificial materials for repairing maxillofacial bone defects caused by facial trauma and tumors. However, their use is limited by poor histocompatibility, unsatisfactory support, and high infection rates. Polyetheretherketone (PEEK) has excellent mechanical strength and biocompatibility, but its application to the repair of maxillofacial bone defects lacks a theoretical basis. The microstructure and mechanical properties of e-PTFE, silicone, and PEEK were evaluated by electron microscopy, BOSE machine, and Fourier transformed infrared spectroscopy. Mouse fibroblast L929 cells were incubated on the surface of the three materials to assess cytotoxicity and adhesion. The three materials were implanted onto the left femoral surface of 90 male mice, and samples of the implants and surrounding soft tissues were evaluated histologically at 1, 2, 4, 8, and 12 weeks post-surgery. PEEK had a much higher Young's modulus than either e-PTFE or silicone (p < 0.05 each), and maintained high stiffness without degradation long after implantation. Both PEEK and e-PTFE facilitated L929 cell adhesion, with PEEK having lower cytotoxicity than e-PTFE and silicone (p < 0.05 each). All three materials similarly hindered the motor function of mice 12 weeks after implantation (p > 0.05 each). Connective tissue ingrowth was observed in PEEK and e-PTFE, whereas a fibrotic peri-prosthetic capsule was observed on the surface of silicone. The postoperative infection rate was significantly lower for both PEEK and silicone than for e-PTFE (p < 0.05 each). PEEK shows excellent biocompatibility and mechanical stability, suggesting that it can be effective as a novel implant to repair maxillofacial bone defects.

ADM-assisted prepectoral breast reconstruction is not associated with high complication rate as before: a Meta-analysis

Implant-related breast reconstruction can be divided into subpectoral breast reconstruction (SPBR) and prepectoral breast reconstruction (PPBR) according to the different anatomical planes. The previous stereotype was that PPBR had a high complication rate and was not suitable for clinical use. However, with the emergence of acellular dermal matrix (ADM), the clinical effect of PPBR has been improved. To compare the outcomes difference between SPBR and PPBR, We conducted this meta-analysis. Articles on SPBR versus PPBR were searched in PubMed, Web of Sciences, Embase, and Cochrane databases, strictly following the PRISMA guidelines. According to the set criteria, we included the literature that met the requirements. Extracted data were the incidence of adverse events and the duration of drainage. Results show that SPBR has a higher incidence rate in capsular contracture, animation deformity, infection, hematoma and delayed healing wound than PPBR. There are no significant differences in skin flap necrosis, seroma, implant loss, reoperation and duration of drainage between the two groups. Hence, PPBR is no longer a high complication surgical method and can be used in the clinical practice. However, there are few large sample studies at present, so it is necessary to carry out further studies on PPBR.

Progranulin Promotes the Formation and Development of Capsules Caused by Silicone in Sprague-Dawley Rats

Background

Silicone implants are currently the most widely used artificial materials in plastic surgery. Capsule formation following implant application is unavoidable. When the capsule is excessively thick and strongly contracted, it can lead to obvious symptoms, clinically known as capsular contracture. Biological factors have always been the focus of research on the capsule formation. As a growth factor, progranulin (PGRN) plays an important regulatory role in wound healing, tissue fibrosis, tumor proliferation and invasion, and inflammation regulation. At present, the research on the capsule mainly involves the regulation of tissue healing and fibrosis under the influence of inflammation. Because PGRN has a regulatory role in these processes, we believe that the study of both can provide a new theoretical basis and intervention sites for monitoring and inhibiting the development of the capsule.

Methods

In this experiment, the effects of different surgical operations on the content of PGRN in the surgical site and plasma of rats were detected. Sprague-Dawley (SD) rat dermal fibroblasts were co-cultured by recombinant PGRN. The effects of r-PGRN on fibroblasts were detected by 5-ethynyl-2’-deoxyuridine (EdU) assay, wound healing assay and Western blot assay. Finally, the effect of PGRN on capsule formation and contracture was studied by changing the content of PGRN in the prosthesis in rats after operation.

Results

Surgical trauma and silicone implant increased plasma and local PGRN levels in SD rats. PGRN can activate the TGF-β/SMAD signaling pathway in a dose-dependent manner, thereby promoting fibroblast proliferation, differentiation and migration and inhibiting apoptosis and enhancing cell function, thereby promoting capsule formation and contracture.

Conclusion

PGRN promotes the formation and contracture of the silicone implant capsule in SD rats by activating the TGF-β/SMAD signaling pathway. This discovery may provide new therapeutic targets and detection indicators.

Asiaticoside Combined With Carbon Ion Implantation to Improve the Biocompatibility of Silicone Rubber and to Reduce the Risk of Capsule Contracture

Capsular contracture caused by silicone rubber is a critical issue in plastic surgery that urgently needs to be solved. Studies have shown that carbon ion implant in silicone rubber (carbon silicone rubber, C-SR) can significantly improve the capsular structure, but the effect of this improvement only appear 2months or later. In this study, asiaticoside combined with carbon silicone rubber was used to explore the changes in the capsule to provide a reference for the treatment of capsule contracture. Human fibroblasts (HFF-1) were used for in vitro experiments. The combined effect of asiaticoside and carbon silicone rubber on cell proliferation was determined by the CCK8 method, cell migration changes were measured by Transwell assays, cell cycle changes were measured by flow cytometry, and the expression levels of fibroblast transformation markers (vimentin and α-SMA), collagen (Col-1A1) and TGF-β/Smad signaling pathway-related proteins (TGF-β1, TβRI, TβRII and Smad2/3) were detected by immunofluorescence. In vivo experiments were carried out by subcutaneous implantation of the material in SD rats, and asiaticoside was oral administered simultaneously. WB and ELISA were used to detect changes in the expression of TGF-β/Smad signaling pathway-related proteins. TGF-β/Smad signaling pathway proteins were then detected and confirmed by HE, Masson and immunohistochemical staining. The results shown that asiaticoside combined with carbon ion implantation inhibited the viability, proliferation and migration of fibroblasts on silicone rubber. In vitro immunofluorescence showed that the secretion levels of α-SMA and Col-1A1 were significantly decreased, the transformation of fibroblasts into myofibroblasts was weakened, and the TGF-β/Smad signaling pathway was inhibited. In vivo experimental results showed that asiaticoside combined with carbon silicone rubber inhibited TGF-β1 secretion and inhibited the TGF-β/Smad signaling pathway, reducing the thickness of the capsule and collagen deposition. These results imply that carbon silicone rubber combined with asiaticoside can regulate the viability, proliferation and migration of fibroblasts by inhibiting the TGF-β/Smad signaling pathway and reduce capsule thickness and collagen deposition, which greatly reduces the incidence of capsule contracture.

Perceptions and attitudes toward unusual complications following breast implant surgeries among Saudi female patients: How knowledgeable are our patients?

Background:

The number of breast implant-related procedures has rapidly increased. Given the current increase in social media coverage and its influence on the decision to undergo breast implant surgeries, it is critical to identify patients’ misinformation about unusual complications related to breast implants. Therefore, the present study aimed to assess the perceptions and attitudes toward unusual complications related to breast implants among patients who underwent breast implant surgeries.

Methods:

In the present cross-sectional study, a questionnaire was distributed between April 2021 and May 2021 among patients who had undergone breast implant surgeries between 2016 and 2021 at King Saud University Medical City in Riyadh, Saudi Arabia. The 26-item questionnaire was distributed online to assess the participants’ perceptions about breast implant illness (BII), capsular contracture, and breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL). Data were analyzed using Statistical Package for the Social Sciences (SPSS), version 23.0.

Results:

In total, 106 patients who underwent breast implant surgeries were included in the present study (response rate: 73.6%). Their mean age was 43.68 ± 10.69 years. The reason for undergoing breast implant surgery was cosmetic in 41.5% of the participants and reconstructive in 58.5%. Moreover, 22.6%, 23.6%, and 24.5% of the participants had knowledge about BIA-ALCL, BII, and capsular contracture, respectively.

Conclusions:

The present findings indicate that it is important for plastic surgeons to discuss unusual complications related to breast implants with patients on a regular basis. Despite the obscurity of these complications, such discussions are important to provide best available information to patients.

Peri-prosthetic Fat Grafting Decreases Collagen Content, Density, and Fiber Alignment of Implant Capsules

Background:

Lower capsular contracture rates have been observed with peri-prosthetic fat grafting. We investigated the effect of fat grafting on capsular characteristics and peri-prosthetic collagen density, content, and fiber alignment.

Methods:

Forty miniature tissue expanders were placed on the backs of 20 rats. After four weeks, both inguinal fat pads were harvested, homogenized, and injected into peri-prosthetic tissue of the right tissue expander (fat graft) while the left served as control. The animals were killed at three (10 rats) and 12 weeks (10 rats), and full thickness peri-prosthetic samples were histologically processed for morphology (H&E) and collagen type and content (picrosirius red).

Results:

An 8.1% increase in adipose peri-prosthetic thickness was associated with a 10% decrease in collagen content at any time point (P = 0.004). Fat-grafted capsules displayed a 59% reduction in % total collagen when compared with controls (P < 0.001). There were no differences in capsular thickness. Fat-grafted samples were 54 times more likely to have a higher inflammation score and 69 times more likely to have a lower capsular density score than their nongrafted counterparts (P < 0.001 and P = 0.001, respectively). The extent of inflammation decreased over time in all samples (P = 0.002). Additionally, fat-grafted samples were 67 times more likely to have a lower fiber alignment score than the controls (P < 0.001).

Conclusions:

Enhancement of peri-prosthetic tissue with fat grafting decreases collagen content, density, and fiber alignment of implant capsules. These findings support clinical application of fat grafting in prosthetic breast surgery to potentially decrease capsular contracture.

Implant Replacement or Removal: What Happens after Capsular Contracture? A German Study Examining Breast Implant Revision Surgery and Patient Choices in 946 Cases

Introduction

Capsular contracture most often leads to implant revision surgery for aesthetic or reconstructive purposes. However, little is known about which operation is chosen when revision surgery has to be performed. We performed analysis of revision indications and performed revision surgery considering implant removal or replacement and additional surgical procedures. To our knowledge, this study presents the largest German single-center analysis regarding implant revision surgery after the onset of complications.

Methods

Retrospective 10-year data analysis of a single-center population undergoing breast implant revision surgery.

Results

Capsular contracture was the most frequent finding before reoperation, both removal and replacement (p < 0.05). It was linked to longer duration of in situ implant placement (p < 0.05) and more frequently in reconstructive patients (p < 0.05). Implant replacement was performed more often before definite implant removal for reconstructive patients (p < 0.05). Mean duration of in situ implant placement before definite removal was lower for reconstructive patients (p = 0.005). Overall reconstructive patients were older than aesthetic patients (p < 0.05). After implant removal, 61.7% of aesthetic patients chose to undergo mastopexy, 54.7% of reconstructive patients opted for autologous breast reconstruction, and 25.4% did not choose an additional surgical procedure after implant removal.

Conclusion

Significant differences are observed for reconstructive and aesthetic patients regarding indication leading to revision surgery, time of revision surgery, and the type of performed revision surgery itself. After implant removal, more than 60% of aesthetic patients undergo mastopexy, more than half of reconstructive patients choose autologous breast reconstruction, and over a quarter of patients choose no additional surgical procedures.

Ultrastructural features of the double capsulated connective tissue around silicone prostheses

The implantation of breast prostheses for both aesthetic and reconstructive purposes has been growing exponentially in the last 20 years. Safety and prosthesis lifespan are majorly debated issues in relation to the correlated long-term complications. Mainly the periprosthetic capsule that develops around the implant is often the cause of complications and particularly for macrotextured silicone breast implants. Some reports have tried to elucidate the mechanism by which macrotextured silicone implants undergo damage and cause double capsule formation. In this study, we investigated the morphological characteristics of double capsule of macrotextured implants surgically removed from patients. With the use of microscopy techniques, this work analyzed the newly formed tissue observed in the interaction between synthetic and biological surfaces.

T regulatory cells and TGF-β1: Predictors of the host response in mesh complications

Polypropylene mesh is frequently used in urogynecology procedures; however, pain and mesh exposure into the vagina occur in ~10% of cases. Mesh-induced pain, which occurs with or without exposure, persists after removal in 50% of cases. Chronic pain history predicts poor response to mesh removal but only a fraction have this diagnosis. We hypothesize that mesh induced pain is correlated with fibrosis and failure to improve with a heightened inflammatory and fibrotic host response. Women undergoing mesh removal were offered participation in a mesh biorepository. Standardized questionnaires including visual analog scale (VAS) pelvic pain scores were completed at enrollment and 6 months after removal. Responders were considered those with ≥13 mm VAS improvement. 30 mesh-tissue explants were randomly selected for analysis. Samples were labeled for CD8, CD4 (T_h) and FoxP3 (T_regs). Peri-fiber collagen deposition (fibrosis) was measured using a customized semi-quantitative assay. Concentrations of TGF-b1, bFGF, MCP-1, PDGF-BB, and IGFBP-1 in tissue were determined by immunoassay and compared to vaginal control biopsies with pathway analysis. VAS pain scores were correlated with degree of histologic fibrosis. Responders had more T_regs (7.8 vs 0.3 per mm², p = 0.036) and patients were 1.6 times as likely to be a responder for every additional T_reg/mm² (p = 0.05). Pro-fibrotic TGF-β1 was doubled in nonresponders (p = 0.032). On pathway analysis, decreased bFGF and increased PDGF-BB provide a possible mechanism for upregulation of TGF-β1. In conclusion, fibrosis is a plausible mechanism of pain complications and the adaptive immune response likely contributes to mitigation/prevention of complications and recovery in affected patients. STATEMENT OF SIGNIFICANCE: Polypropylene mesh improves anatomical outcomes in urogynecologic procedures, but is associated with complications, including pain and exposure through the vaginal epithelium. Mesh-induced pain is difficult to treat, and it is unclear why only half of women experience pain improvement after mesh removal. In this study, patient pain correlated with the presence of fibrosis and women with more T regulatory cells and lower TGF-β1 were more likely to have pain improvement following mesh removal. These findings implicate fibrosis as a mechanism of pain complications and suggest that the adaptive immune response may be responsible for prevention of complication and recovery. This improved understanding of how mesh can lead to pain moves us closer to the ultimate goal of preventing mesh complications.

Interactions at engineered graft-tissue interfaces: A review

The interactions at the graft-tissue interfaces are critical for the results of engraftments post-implantation. To improve the success rate of the implantations, as well as the quality of the patients' life, understanding the possible reactions between artificial materials and the host tissues is helpful in designing new generations of material-based grafts aiming at inducing specific responses from surrounding tissues for their own reparation and regeneration. To help researchers understand the complicated interactions that occur after implantations and to promote the development of better-designed grafts with improved biocompatibility and patient responses, in this review, the topics will be discussed from the basic reactions that occur chronologically at the graft-tissue interfaces after implantations to the existing and potential applications of the mechanisms of such reactions in designing of grafts. It offers a chance to bring up-to-date advances in the field and new strategies of controlling the graft-tissue interfaces.

Covalently Grafted 2-Methacryloyloxyethyl Phosphorylcholine Networks Inhibit Fibrous Capsule Formation around Silicone Breast Implants in a Porcine Model

The surface of human silicone breast implants is covalently grafted at a high density with a 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer. Addition of cross-linkers is essential for enhancing the density and mechanical durability of the MPC graft. The MPC graft strongly inhibits not only adsorption but also the conformational deformation of fibrinogen, resulting in the exposure of a buried amino acid sequence, γ377-395, which is recognized by inflammatory cells. Furthermore, the numbers of adhered macrophages and the amounts of released cytokines (MIP-1α, MIP-1β, IL-8, TNFα, IL-1α, IL-1β, and IL-10) are dramatically decreased when the MPC network is introduced at a high density on the silicone surface (cross-linked PMPC-silicone). We insert the MPC-grafted human silicone breast implants into Yorkshire pigs to analyze the in vivo effect of the MPC graft on the capsular formation around the implants. After 6 month implantation, marked reductions of inflammatory cell recruitment, inflammatory-related proteins (TGF-β and myeloperoxidase), a myoblast marker (α-smooth muscle actin), vascularity-related factors (blood vessels and VEGF), and, most importantly, capsular thickness are observed on the cross-linked PMPC-silicone. We propose a mechanism of the MPC grafting effect on fibrous capsular formation around silicone implants on the basis of the in vitro and in vivo results.

Establishment and Characterization of Bacterial Infection of Breast Implants in a Murine Model

BACKGROUND

Staphylococcus epidermidis and Pseudomonas aeruginosa are the most common causes of Gram-positive and Gram-negative breast implant-associated infection. Little is known about how these bacteria infect breast implants as a function of implant surface characteristics and timing of infection.

OBJECTIVES

The aim of this work was to establish a mouse model for studying the impact of various conditions on breast implant infection.

METHODS

Ninety-one mice were implanted with 273 breast implant shells and infected with S. epidermidis or P. aeruginosa. Smooth, microtextured, and macrotextured breast implant shells were implanted in each mouse. Bacterial inoculation occurred during implantation or 1 day later. Implants were retrieved 1 or 7 days later. Explanted breast implant shells were sonicated, cultured, and colony-forming units determined or analyzed with scanning electron microscopy.

RESULTS

P. aeruginosa could be detected on all device surfaces at 1- and 7- days post infection (dpi), when mice were implanted and infected concurrently or when they were infected 1- day after implantation. However, P. aeruginosa infection was more robust on implant shells retrieved at 7 dpi and particularly on the macrotextured devices that were infected 1 day post implantation. S. epidermidis was mostly cleared from implants when mice were infected and implanted concurrently. Other the other hand, S. epidermidis could be detected on all device surfaces at 1 dpi and 2 days post implantation. However, S. epidermdis infection was suppressed by 7 dpi and 8 days post implantation.

CONCLUSIONS

S. epidermidis required higher inoculating doses to cause infection and was cleared within 7 days. P. aeruginosa infected at lower inoculating doses, with robust biofilms noted 7 days later.

Smooth Prosthesis: Our Experience and Current State of Art in the Use of Smooth Sub-muscular Silicone Gel Breast Implants

BACKGROUND

The objective of this clinical review is to provide an overview of the use of silicone gel-filled breast implants placed in the sub-muscular position, with a focus on complication rates reported for both smooth and textured implants. Furthermore, our experience in this field is also reviewed.

METHODS

MEDLINE, EMBASE, Web of Science, Scopus, the Cochrane Central and Google Scholar databases were reviewed to identify the literature related to smooth breast implants. Each article was reviewed by two independent reviewers to ensure all relevant publications were identified. The literature search identified 98 applicable articles. Of these, just a few articles were found to have a therapeutic level of evidence. The reference lists in each relevant paper were screened manually to include relevant papers not found through the initial search.

RESULTS

Eight articles report the risk of capsular contracture when the breast implants were placed in the sub-muscular position. Six of these articles report a similar rate of capsular contracture in smooth and textured implants. Local complications such as wrinkling, late seroma and double capsules were found to be associated with the use of textured breast implants (4 articles). All articles concerning BIA-ALCL reported a total absence occurring in smooth breast implants. All cases have been associated with textured mammary prostheses.

CONCLUSION

With our expertise in the field and the results of this up-to-date literature review, it can be concluded that there are no significant advantages of using one type of implant surface over the other when placed in the sub-pectoral position.

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.

Smooth Muscle Alpha Actin Immunoexpression (α-Sma) and CD-117 Antibody (C-Kit) in Capsules Formed by Polyurethane Foam-Coated Silicone Implants and with Textured Surface: A Study on Rats

BACKGROUND

One of the undesirable complications that might occur after breast augmentation with silicone implants is capsular contracture. In its etiology, the relations between mast cells and myofibroblasts play an important role in collagen synthesis. Mast cells are able to activate fibroblasts into myofibroblasts, through paracrine secretions, inducing collagen production. The objectives of this study were to analyze the myofibroblast concentration through the α-SMA immunomarker and evaluate the intensity of mast cell expression against the C-Kit immunomarker.

MATERIAL AND METHOD

Sixty-four Wistar rats were used, divided into two groups (polyurethane foam and textured surface) with 32 animals in each. The animals received silicone implants on the back, below the panniculus carnosus, and after the determined period, they were killed and the capsules formed around the implants were studied. The capsules were analyzed employing the immunohistochemical technique, with the α-SMA and C-Kit immunomarkers in subgroups of 30, 50, 70 and 90 days.

RESULTS

The myofibroblast concentration was higher in the polyurethane group when compared to the textured group (30 days p = 0.105; 50 days p = 0.247; 70 days p = 0.014 and 90 days p = 0.536). The intensity of mast cell expression was more pronounced in the polyurethane group when compared to the textured group (30 days p = 0.798; 50 days p = 0.537; 70 days p = 0.094 and 90 days p = 0.536).

CONCLUSIONS

Polyurethane-coated implants induced higher concentrations of myofibroblasts and higher expression of mast cells, when compared to the textured surface implants.

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 .

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.

The Role of Periostin in Capsule Formation on Silicone Implants

Although silicone implants are widely used in breast and other reconstructive surgeries, the limited biocompatibility of these materials leads to severe complications, including capsular contracture. Here, we aimed to clarify the relationship between periostin and the process of capsule formation after in vivo implantation. Seven-week-old wild-type (WT) C57BL/6 mice and periostin-deficient mice were used. Round silicone implants were inserted into a subcutaneous pocket on the dorsum of the mice. After 8 weeks, the fibrous capsule around the implant was harvested and histologically examined to estimate capsular thickness and the number of inflammatory cells. Additionally, immunohistochemical analysis (periostin, α-SMA, and collagen type I) and western blotting (CTGF, TGF-β, VEGF, and MPO) were performed for a more detailed analysis of capsule formation. The capsules in periostin-knockout mice (PN-KO) were significantly thinner than those in WT mice. PN-KO mice showed significantly lower numbers of inflammatory cells than WT mice. Fibrous tissue formation markers (α-SMA, periostin, collagen type I, and CTGF) were significantly reduced in PN-KO mice. We also confirmed that inflammatory reaction and angiogenesis indicators (TGF-β, MPO, and VEGF) had lower expression in PN-KO mice. Inhibition of periostin could be important for suppressing capsule formation on silicone implants after in vivo implantation.