Characterization of the Capsule Surrounding Smooth and Textured Tissue Expanders and Correlation with Contracture

The cellular and molecular properties of capsule surrounding silicone implants in humans vary uniquely according to the tissue type adjacent to the implant

The foreign body reaction (FBR) to biomaterials results in fibrous encapsulation. Excessive capsule fibrosis (capsular contracture) is a major challenge to the long-term stability of implants. Clinical data suggests that the tissue type in contact with silicone breast implants alters susceptibility to developing capsular contracture; however, the tissue-specific inflammatory and fibrotic characteristics of capsule have not been well characterized at the cellular and molecular level. In this study, 60 breast implant capsule samples are collected from patients and stratified by the adjacent tissue type including subcutaneous tissue, glandular breast tissue, or muscle tissue. Capsule thickness, collagen organization, immune and fibrotic cellular populations, and expression of inflammatory and fibrotic markers is quantified with histological staining, immunohistochemistry, and real-time PCR. The findings suggest there are significant differences in M1-like macrophages, CD4+ T cells, CD26+ fibroblasts, and expression of IL-1β, IL-6, TGF-β, and collagen type 1 depending on the tissue type abutting the implant. Subglandular breast implant capsule displays a significant increase in inflammatory and fibrotic markers. These findings suggest that the tissue microenvironment contributes uniquely to the FBR. This data could provide new avenues for research and clinical applications to improve the site-specific biocompatibility and longevity of implantable devices.

Cervicofacial Pediatric Tissue Expansion: Aesthetic Unit-Based Algorithm

BACKGROUND

Tissue expansion is a powerful tool in reconstruction of pediatric soft-tissue pathologies, but complication rates in children have been reported to be as high as 40%. Infection and implant extrusion lead to premature removal and delays in reconstruction. Expanding the head and neck is uniquely challenging because the confluence of facial aesthetic units must be respected. These challenges prompted the senior author (R.J.R.) to create an aesthetic unit-based algorithm.

METHODS

A retrospective study of pediatric patients who underwent cervicofacial tissue expander placement over a 17-year period was performed by the senior author. Predictor variables included age, sex, race, indication, number of expanders placed at each operation, serial expansion, expander type, expander size, home versus clinic inflation, and prophylactic antibiotics. Univariate and multivariate analyses were performed to identify risk factors for complications.

RESULTS

An aesthetic unit-based reconstructive algorithm is proposed. Forty-eight pediatric patients had 111 cervicofacial tissue expanders placed. Twenty expanders were associated with complications (18%) for surgical site infection (12.6%), extrusion (4.5%), or expander deflation (6.3%). Expanders placed for congenital nevi ( P = 0.042) and use of textured expanders ( P = 0.027) were significantly associated with decreased complication levels. When controlling for covariates, serial expansion of the same site was associated with increased rate of readmission ( P = 0.027) after having just 1 previous expander. Iatrogenic ectropion occurred in 13.5% of the study population; expanders with at least 1 complication during tissue expansion were significantly associated with incidence of iatrogenic ectropion ( P = 0.026).

CONCLUSION

By using an aesthetic unit-based algorithm, reconstructive outcomes can be optimized for pediatric cervicofacial tissue expansion.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Smooth Operator: Nanotextured Breast Tissue Expanders Are Associated with Lower Rates of Capsular Contracture

Background: Continuous research on breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) has introduced a focus on surface texturizations and a shift towards smooth breast devices, yet outcomes comparing the complication profiles of differently textured tissue expanders (TEs) remain conflicting. The study aim was to compare the complication profile of a new nanotextured and MRI-compatible TE to micro- and macrotextured TEs and to identify possible predictors for complications. Methods: A retrospective analysis of women undergoing expander-based breast reconstruction after mastectomy between January 2016 and March 2022 was conducted. The primary endpoint was the development of capsular contracture. Possible predictors were analyzed in a mixed-effects model using the least absolute shrinkage and selection operator (LASSO). Moreover, a comparison of complications and an evaluation of predictors were carried out. Results: A total of 147 breasts, encompassing 82 nanotextured, 43 microtextured and 22 macrotextured TEs, were analyzed. Breasts with nanotextured TEs were less likely to develop capsular contracture overall (OR, 0.12; 95%CI 0.05-0.28, p < 0.001). Post-mastectomy radiotherapy (PMRT) was identified as a predictor for capsular contracture (OR, 4.67; 95%CI 1.86-11.71, p < 0.001). Breasts with nanotextured TEs showed a higher rate of seroma, but lower rates of malposition and pain. Predictors for developing postoperative complications included higher mastectomy weight (p = 0.008). Conclusions: Breasts with nanotextured TEs exhibited the lowest rate of capsular contracture compared to micro- and macrotextured TEs. Together with its MRI-compatibility and improved oncologic follow-up, the nanotextured TE seems to be a favorable device for expander-based breast reconstruction.

Impact of Tissue Expander Surface Texture on Two-Stage Breast Reconstruction Outcomes: A Combined Analysis

BACKGROUND

With ongoing investigations of the impact of device texturing on breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL), studies have begun comparing complication profiles of tissue expanders. However, there is a paucity of timing and severity data of complications. The aim of this study was to provide a comparative survival analysis of postoperative complications between smooth (STEs) and textured tissue expanders (TTEs) in breast reconstruction.

METHODS

A single-institution experience with tissue expander breast reconstruction was reviewed for complications up to 1 year after second-stage reconstruction from 2014 to 2020. Demographics, comorbidities, operation-related variables, and complications were evaluated. Kaplan-Meier curves, Cox proportional hazard models, and a consensus-based ordinal logistic regression model were used to compare complication profiles.

RESULTS

Of 919 total patients, 600 (65.3%) received TTEs and 319 (34.7%) received STEs. There was increased risk of infection ( P < 0.0001), seroma ( P = 0.046), expander malposition ( P < 0.0001), and wound dehiscence ( P = 0.019) in STEs compared with TTEs. However, there was also a decreased risk of capsular contracture ( P = 0.005) in STEs compared with TTEs. Failure of breast reconstruction ( P < 0.001) and wound dehiscence ( P = 0.018) occurred significantly earlier in STEs compared with TTEs. Predictors for significantly higher severity complications included the following: smooth tissue expander use ( P = 0.007), shorter time to complication ( P < 0.0001), higher body mass index ( P = 0.005), smoking history ( P = 0.025), and nipple-sparing mastectomy ( P = 0.012).

CONCLUSIONS

Differences in the timing and severity of complications contribute to the safety profiles of tissue expanders. STEs are associated with increased odds of higher severity and earlier complications. Therefore, tissue expander selection may depend on underlying risk factors and severity predictors.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Altered Foreign Body Response at the Posterior Surface Compared to the Anterior Surface of Human Silicone Breast Implants

Soft implantable devices are crucial to optimizing form and function for many patients. However, periprosthetic capsule fibrosis is one of the major challenges limiting the use of implants. Currently, little is understood about how spatial and temporal factors influence capsule physiology and how the local capsule environment affects the implant structure. In this work, we analyzed breast implant capsule specimens with staining, immunohistochemistry, and real-time polymerase chain reaction to investigate spatiotemporal differences in inflammation and fibrosis. We demonstrated that in comparison to the anterior capsule against the convex surface of breast implants, the posterior capsule against the flat surface of the breast implant displays several features of a dysregulated foreign body reaction including increased capsule thickness, abnormal extracellular remodeling, and infiltration of macrophages. Furthermore, the expression of pro-inflammatory cytokines increased in the posterior capsule across the lifespan of the device, but not in the anterior capsule. We also analyzed the surface oxidation of breast explant samples with XPS analysis. No significant differences in surface oxidation were identified either spatially or temporally. Collectively, our results support spatiotemporal heterogeneity in inflammation and fibrosis within the breast implant capsule. These findings presented here provide a more detailed picture of the complexity of the foreign body reaction surrounding implants destined for human use and could lead to key research avenues and clinical applications to treat periprosthetic fibrosis and improve device longevity.

Complication Profiles of Smooth vs Textured Tissue Expanders in Breast Reconstruction: A Systematic Review and Meta-Analysis

BACKGROUND

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a type of non-Hodgkin lymphoma first linked with breast implants in 2011. The correlation between BIA-ALCL and textured devices has led to increased use of smooth devices. However, much of the data surrounding smooth and textured devices investigates breast implants specifically and not tissue expanders.

OBJECTIVES

We performed a systematic review and a meta-analysis to compare surgical outcomes for smooth tissue expanders (STEs) and textured tissue expanders (TTEs).

METHODS

A search was performed on PubMed, including articles from 2016 to 2023 (n = 419). Studies comparing TTEs and STEs and reported complications were included. A random-effects model was utilized for meta-analysis.

RESULTS

A total of 5 articles met inclusion criteria, representing 1709 patients in the STE cohort and 1716 patients in the TTE cohort. The mean duration of tissue expansion with STEs was 221.25 days, while TTEs had a mean time of tissue expansion of 220.43 days.Our meta-analysis found no differences in all surgical outcomes except for explantation risk. STE use was associated with increased odds of explantation by over 50% compared to TTE use (odds ratio = 1.53; 95% CI = 1.15 to 2.02; P = .003).

CONCLUSIONS

Overall, STEs and TTEs had similar complication profiles. However, STEs had 1.5 times higher odds of explantation. The incidence of BIA-ALCL is low, and only a single case of BIA-ALCL has been reported with TTEs. This indicates that TTEs are safe and may lower the risk of early complications requiring explantation. Further studies are warranted to further define the relationship between tissue expanders and BIA-ALCL.

LEVEL OF EVIDENCE: 4

Implant-based breast surgery and capsular formation: when, how and why?-a narrative review

Background and Objective

Implant-based breast surgery is a common procedure for both reconstructive and aesthetic purposes. Breast implants, like any foreign object, trigger the formation of a capsule around them. While generally harmless, the capsule can undergo fibrotic changes leading to capsular contracture, which can negatively impact surgical outcomes and patient well-being. Additionally, rare but serious complications, such as breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) and capsule-associated squamous cell carcinoma, have been reported. This paper aims to review the physiology of capsular formation, identify factors contributing to capsule-related pathologies, and discuss their clinical implications.

Methods

A review of relevant literature was conducted by searching databases for articles published between inception and September 2022. The search included but not limited to terms such as "capsular formation" and "capsular contracture". Selected articles were critically analyzed to address the objectives of this review.

Key Content and Findings

Capsular formation involves interactions between the implant surface, surrounding tissues, and the immune system. Factors influencing pathological changes in the capsule include genetic predisposition, bacterial contamination, implant characteristics, and surgical techniques. Capsular contracture, characterized by tissue hardening, pain, and implant distortion, remains the most common complication. Rare but life-threatening conditions, such as BIA-ALCL and capsule-associated squamous cell carcinoma, necessitate vigilant monitoring and early detection.

Conclusions

Understanding the physiology of capsular formation and its associated pathologies is crucial for healthcare providers involved in implant-based breast surgery. Efforts should focus on minimizing the risk of capsular contracture through improved implant materials, surgical techniques, and infection prevention. The emergence of BIA-ALCL and capsule-associated squamous cell carcinoma underscores the importance of long-term surveillance and prompt diagnosis. Further research is needed to uncover underlying mechanisms and develop preventive measures and treatments for these complications. Enhancing our knowledge and clinical management of capsular formation will lead to safer and more successful outcomes in implant-based breast surgery.

Histologic and Immunohistochemical Evaluation of Human Breast Capsules Formed around Five Different Expander Surfaces

BACKGROUND

Polyurethane (PU) coating and implant texturization were designed to reduce the incidence of capsular contracture (CC), even if the link between surface type and CC remains unclear. To date, the etiopathogenetic aspects have not been fully clarified. The aim of this study was to evaluate capsules formed around five different breast expanders.

METHODS

Thirty patients were divided into randomized groups implanted with five different expanders: smooth, coated with PU foam (poly), with a low-microtextured, high-microtextured, and macrotextured surface (L-micro, H-micro, macro). Specimens of the capsules were removed at implant reconstruction and evaluated for morphology and immunohistochemistry expression of α-smooth muscle actin (α-SMA), collagen type I and III, CD68, CD34, and CD3. Remodeling Combined Index was also evaluated.

RESULTS

Expression of α-SMA was significantly increased in smooth capsules versus poly, low-microtextured, and high-microtextured groups ( P = 0.007; P = 0.010; P = 0.028), whereas the prevalence of collagen type I in smooth capsules and collagen type III in poly capsules identified a stable versus an unstable tissue. Remodeling Combined Index and α-SMA showed an inverted correlation. CD68 and CD34 cellular expression increased significantly in poly capsules with respect to smooth ( P < 0.001; P < 0.001) and macrotextured groups ( P < 0.001; P < 0.001). CD3 showed no significant difference among the groups.

CONCLUSION

In this human study, the authors observed that increased tissue remodeling and reduced myofibroblast activation, along with the inflammatory infiltration and neoangiogenesis, especially in the poly and low-microtextured groups, might promote the formation of an unstable and less fibrotic capsule, lowering the risk of CC.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Risk of Breast Implant-Associated Anaplastic Large Cell Lymphoma in Patients with Textured Tissue Expanders

BACKGROUND

The association between textured implants and breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is well established, but the risk of BIA-ALCL in patients with transient exposure to a textured tissue expander (TE) is not as well documented. The aim of this study was to assess the incidence and risk of BIA-ALCL in patients with temporary exposure to a textured TE with subsequent smooth implant placement.

METHODS

This single-institution retrospective cohort study included all female patients who underwent two-stage breast reconstruction with placement of a textured TE from 1995 to 2016 with subsequent exchange to a smooth permanent implant. Primary outcome of interest was development of BIA-ALCL. Patients with exposure to textured implants were excluded. Follow-up was determined by last documented visit. The authors calculated summary statistics for exposure time and follow-up intervals.

RESULTS

Overall, 3310 patients had temporary exposure to a textured TE with exchange to a smooth implant, totaling 5201 textured TEs. Average textured TE exposure time was 6.7 months (median, 5.8 months). Average follow-up was 6.8 years (median, 6.3 years), ranging from 3.7 months to 18 years. No cases of BIA-ALCL were identified.

CONCLUSIONS

As no cases of BIA-ALCL were identified, the risk of BIA-ALCL with short exposure to textured TEs is likely lower than the risk from exposure to permanent textured implants. Although longer follow-up is needed, these results can help counsel patients with previous exposure to textured TEs who are concerned about their risk of BIA-ALCL and can contribute to discussions on potential continued utility of textured TEs.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, IV.

Advances on Capsular Contracture-Prevention and Management Strategies: A Narrative Review of the Literature

Capsular contracture (CC) is the most relevant complication of both aesthetic and reconstructive breast implant surgery. For many years, experimental and clinical trials have attempted to analyze CC risk factors, clinical features, and appropriate management strategies. It is commonly accepted that a multifactorial etiology promotes CC development. However, the heterogeneity in patients, implants and surgical techniques make it difficult to suitably compare or analyze specific factors. As a consequence, discordant data are present in literature, and a true systematic review is often limited in its conclusions. Hence, we decided to present a comprehensive review of current theories on prevention and management strategies, rather than a specific "solution" to this complication.

Methods

The PubMed database was searched for literature regarding CC prevention and management strategies. Pertinent articles in English, published before December 1, 2022, were compared with selection criteria and eventually included in this review.

Results

Through the initial search, 97 articles were identified, of which 38 were included in the final study. Several articles explored different medical and surgical preventive and therapeutic strategies, showing numerous controversies on appropriate CC management.

Conclusions

This review provides a clear overview of the complexity of CC. The wide variety of clinical situations in term of patients, implants, and surgical techniques prevent the standardization of CC management strategies. By contrast, a patient-customized approach should be preferred, and different strategies should be considered depending on the specific case. Further research is desirable to better ascertain evidence-based protocols with regard to CC prevention and treatment.

The Efficacy of Anterior Capsulotomy and Basal Capsulectomy Adherent to Expanded Scalp Flap During Alopecia Reconstruction in Pediatric Burned Patients

BACKGROUND

Scalp expansion is an optimal treatment for alopecia resulting from burn injuries, especially in the pediatric population through providing highly vascularized adjacent local tissues with optimal hair density, color matching, texture, and hair-bearing characteristics. The aim of this study was to evaluate the efficacy of anterior capsulotomy and basal capsulectomy adherent to expanded scalp flap during alopecia reconstruction with scalp expansion in pediatric burned patients.

METHODS

The study was conducted on 127 patients with an age range of 5 to 19 years who presented with postburn alopecia accompanied by hairline loss. The patients were divided into 2 groups: group I consisted of 58 patients who were operated on using conventional technique, and group II consisted of 69 patients who were operated using modified technique including basal capsulectomy on the skull side and anterior capsulotomy on the expanded scalp flap.

RESULTS

The Hairdex, a validated questionnaire of Hair-Specific Health-Related Quality of Life measures, showed that percentage of satisfaction concerning outcomes was 91.50%, psychological well-being was 95%, and self-confidence was 84.30% in group II, compared with 63%, 55.70%, and 66.20%, respectively, in group I. This significant values had a great positive effect on patient satisfaction, changing child's behavior and self-confidence.

CONCLUSION

Although physiological background of tissue expansion is the same, proper flap design with anterior capsulotomy on flap undersurface and basal capsulectomy on the skull side improve results of the traditional method significantly and minimize the complication rate. These surgical modifications provide maximum benefits from expanded tissue, with restoration of the hairline and a uniform hair direction.

LEVEL OF EVIDENCE

Level III, case-control study.

Reduced fibrous capsule elastic fibers from biologic ECM-enveloped CIEDs in minipigs, supported with a novel compression mechanics model

BACKGROUND

Fibrous capsules (Fb) in response to cardiovascular implantable electronic devices (CIEDs), including a pacemaker (P) system, can produce patient discomfort and difficulties in revision surgery due partially to their increased compressive strength, previously linked to elevated tissue fibers.

OBJECTIVE

A preliminary study to quantify structural proteins, determine if biologic extracellular matrix-enveloped CIEDs (PECM) caused differential Fb properties, and to implement a realistic mechanical model.

METHODS

Retrieved Fb (-P and -PECM) from minipigs were subjected to biomechanical (shear oscillation and uniaxial compression) and histological (collagen I and elastin) analyses.

RESULTS

Fb-PECM showed significant decreases compared to Fb-P in: low strain-loss modulus (390 vs. 541 Pa) across angular frequencies, high strain-compressive elastic modulus (1043 vs. 2042 kPa), and elastic fiber content (1.92 vs. 3.15 μg/mg tissue). Decreases in elastin were particularly noted closer to the implant's surface (Fb-PECM = 71% vs. Fb-P = 143% relative to dermal elastin at mid-tangential sections) and verified with a solid mechanics hyperelasticity with direction-dependent fiber viscoelasticity compression simulation (r2 ≥ 98.9%).

CONCLUSIONS

The biologic envelope composed of decellularized porcine small intestine submucosa ECM for CIEDs promoted fibrous tissues with less elastic fibers. Novel compression modeling analyses directly correlated this singular reduction to more desirable subcutaneous tissue mechanics.

Risk factors for capsular contracture after breast reconstruction with tissue expanders and silicone implants in nonirradiated patients: A retrospective observational cohort study

Breast reconstruction surgery with tissue expanders and silicone implants is widely performed; however, risk factors for late complications such as capsular contracture have not been fully investigated despite their high prevalence. We investigated the association between expander and implant positions and the development of capsular contracture in patients who underwent breast reconstruction surgery over 10 years previously. In this retrospective observational study, we analyzed 239 patients, among whom 69 (28.9%) had developed capsular contracture of Baker Classification grade II or higher. The position of the expander was classified into six categories based on the inferior margin of the healthy breast. The position of the implant was defined as an upward movement from the position of the expander and was classified into three categories based on the inferior margin of the breast at the time of expander insertion. Using multivariate logistic regression analysis, we assessed whether the misalignment of the expander and silicone implant positions affected capsular contracture development. Both expander and implant positions were significantly different between the groups. The odds ratios, adjusted for confounding variables, were 3.4 and 5.2 for an expander position of 1 and 2 lateral fingers upward, respectively, and 4.8 and 45.4 for a silicone implant position of 2 and 3 lateral fingers upward, respectively. We identified malposition of expanders and silicone implants as risk factors for developing capsular contracture. Correct insertion and adequate dilatation of the expander in the correct position could reduce the risk for capsular contracture.

Smooth versus textured tissue expanders in breast reconstruction - A retrospective review of post-operative surgical site infections

BACKGROUND

Textured tissue expanders (TTEs) were introduced to limit migration and reduce capsular contracture, which were inherent to smooth tissue expanders (STEs). Previous reports suggest that textured devices have increased rates of bacterial contamination and biofilm formation in comparison with smooth devices. Recently, the relative increased association of anaplastic large cell lymphoma (ALCL) with textured versus smooth devices has led to increased adoption of smooth devices. The aim of our study is to evaluate the post-operative surgical site infection (SSI) rates of STEs versus TTEs.

METHODS

A retrospective case series was conducted at a single academic teaching hospital from April 2016 to December 2019. The primary outcome variable was the development of a post-operative SSI.

RESULTS

One hundred seventy-seven breasts underwent reconstruction with TTEs and 109 breasts underwent reconstruction with STE. In total, 54 SSIs were recorded (n = 34 TTE; n = 20 STE), with the majority of infections occurring within the first 30 post-operative days (TTE 65%, STE 70%). There was no statistically significant difference in overall post-operative infection rates between TTE and STE groups when broken down into the following time points: <30 day, 30-60 days, and >90 days (p = 0.924). There was no statistically significant difference between infection type (superficial vs. deep, p = 0.932), infection management (medical, surgical, or both, p = 0.409) or salvage results (p = 0.078) seen in STE versus TTE cohort. On multivariate analysis, seroma history was associated with SSI development (OR 3.18, p = 0.041).

CONCLUSION

There was no significant difference in the rate of post-operative SSI following breast reconstruction with STE relative to TTE.

miR-491-5p Inhibits Emilin 1 to Promote Fibroblasts Proliferation and Fibrosis in Gluteal Muscle Contracture via TGF-β1/Smad2 Pathway

Gluteal muscle contracture (GMC) is a chronic fibrotic disease of gluteal muscles due to multiple etiologies. Emilin 1 plays a determinant role in fibers formation, but its role in the progression of GMC remains unclear. The present study was aimed to search for the predictive role and regulatory mechanism of Emilin 1 on GMC. Here, Protein and mRNA expression of Emilin 1 were decreased in GMC tissues compared to normal muscle tissues. Using the analysis of target prediction, Emilin 1 was observed to be a potential downstream sponge of miR-491-5p. In comparison to Emilin 1, miR-491-5p showed an aberrant elevation in GMC tissues, which was further proven to have a negative correlation with Emilin 1. The direct binding of miR-491-5p to Emilin 1 mRNA was confirmed by luciferase reporter gene assay, and miR-491-5p mimics inhibited, while miR-491-5p inhibitor promoted the protein expression and secretion of Emilin 1 in contraction bands (CB) fibroblasts. Additionally, miR-491-5p mimics promoted the expression of cyclin-dependent kinase 2 and cyclin D1 and the proliferation of CB fibroblasts, which could be reversed by Emilin 1 overexpression. Mechanistically, miR-491-5p mimics possibly activated transforming growth factor β1 (TGF-β1)/Smad3 signal cascade via binding to 3’-untranslated region of Emilin 1 mRNA, thereby promoting the progression of fibrosis of CB fibroblasts. Collectively, miR-491-5p inhibited Emilin 1 expression, and subsequently promoted CB fibroblasts proliferation and fibrosis via activating TGF-β1/Smad3 signal axis. MiR-491-5p might be a potentially effective biomarker for predicting GMC, providing a novel therapeutic strategy for GMC.

Reducing Capsular Contracture Formation in Breast Augmentation with Silicone Implants: Experimental Study on Rats

Silicone implants are frequently used for breast augmentation and reconstruction. However, late complication, such as capsular contracture, remain the most important side effect. In this study we compare different methods for reducing the inflammatory reaction around the silicone implant by introducing one microtextured breast implant in wistar rats. The rats were dividing in 4 groups: the first one was the control group that received untreated implant; in the second we used silicone implants impregnated with rifampin solution, the third one had implant combined with intramuscular dexamethasone injection and the last one had silicone implant associated with autologous centrifuged fat introduced in the implant pocket. The implants and the capsular tissue surrounding were removed after eight weeks. Capsule samples were submitted to histological evaluations. The present study demonstrated that fat grafting may have a role in reducing and preventing capsular contractures after breast augmentation with silicone implants by decreasing the inflammatory process.

Histological Analyses of Capsular Contracture and Associated Risk Factors: A Systematic Review

BACKGROUND

Capsular contracture is a severe complication to breast surgery with implants. Previous studies suggest multiple risk factors are associated with capsular contracture, but the etiology is still unknown. We performed a literature review to investigate existing studies on histological analyses of breast implant capsules and how clinical risk factors impact the capsule morphology.

METHODS

The literature search was conducted in PubMed. Studies that performed histological analyses of breast implant capsules were included. Animal studies or studies with a study population of less than five patients were excluded.

RESULTS

Fifty-two studies were included. The histological analyses showed that the breast implant capsules were organized in multiple layers with an inner layer of synovial-like metaplasia which was reported to diminish in capsules with capsular contracture. The remaining layers of the capsule mostly consisted of collagen. The alignment of the collagen fibers differed between contracted and non-contracted capsules, and capsules with higher Baker grade were generally thickest and contained more tissue inflammation. Studies investigating capsules affected by radiotherapy found a more pronounced inflammatory response and the capsules were generally thicker and fibrotic compared with nonirradiated capsules.

CONCLUSIONS

The included studies offer valuable insights into the histological changes caused by capsular contracture and their relation to clinical risk factors. Further studies with larger sample sizes and more strict inclusion criteria are needed to further investigate implant capsules and the role of the synovial-like metaplasia for the development of capsular contracture.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://www.springer.com/00266 .

Biocell-Initial patents versus user instructions guide: A discrepancy at the core of a crisis

PURPOSE

Our aim is to do a comparative qualitative analysis of patents and "User Manuals" of the Biocell textured implants in order to determine if red flags were omitted when marketing and using Biocell textured implants.

MATERIALS AND METHODS

We performed a systematic qualitative analysis using the NVivo software version 11 of the patents describing the Biocell textured implants prior to their approval by the FDA and of user guides published by the 3 companies owning the patents (McGhan, Inamed, Allergan). To guide our thematic analysis, we used a form of systems theory known as the complexity theory.

RESULTS

Four patents related to Biocell and 2 user manuals (McGhan- Inamed and Allergan) were analyzed. Four themes emerged from the patents: invention description, mechanism of action (Tissue ingrowth), the timing of the mechanism of action and hypothetical actions on capsular contractures prevention. Of all patent's content, 34% described the invention, 29% the mechanism of action (tissue ingrowth), 1% the timing of this mechanism of action and 34% a hypothetical action against capsular contracture. Solid evidence was found on the concept of anchoring and very little on capsular contracture. On the user guide side, the main themes were indications and contraindications, surgical techniques and long-term effects. The "directed" content analysis approach of the user guides regarding the patent's themes reflected that 94% of the user guides content related to the patent thematics was about the hypothetical role on capsular contracture while only 4% was about invention description and 1.5% about tissue ingrowth.

CONCLUSIONS

This analysis highlights the discrepancies between patents of Biocell textured implants and user guides for these implants. The indications of use of a treatment or device can evolve quicker than the study of its potential complications and side effects. The BIA-ALCL crisis should serve as a cautionary tale to the plastic surgery community which embraces new technologies eagerly, and sometimes precariously, in a mission to advance patient care.

Novel Histopathologic and Immunohistochemical Observations in Explanted Orbital Peri-implant Capsules

PURPOSE

To describe the histopathologic and immunohistochemical characteristics of peri-orbital implant capsule and correlate the observed changes with delayed implant extrusion.

MATERIALS AND METHODS

Prospective, ex-vivo, histopathologic, immunohistochemical study of peri-implant capsules excised from capsules surrounding a poly-methyl metha acrylate (PMMA) implant. Thirteen capsules were harvested and divided into two groups. Group 1 (implant extrusion group) consisted of capsules harvested from around exposed/extruded implants and Group 2 (implant non-extrusion group) from implants that were surgically exchanged for volume augmentation. Data collected included demography, clinical presentations, etiology of the explantation, age of the capsule in months, inflammatory cells noted/high power field (HPF), CD3, CD20, and CD68, percentage Masson's trichrome staining and mean capsular thickness.

RESULTS

Mean patient age at presentation was 33 ± 13 years. Of the 13 capsules included, 7 belonged to group 1and 6 to group 2. Mean age of the fibro-collagenous membranes were 33 ± 57 months (median 13 months). Median CD3, CD20, and CD68 positivity was 80%, 9%, and 7% denoting a predominant T-lymphocytic response. Mean capsular thickness was 733 ± 422µ (median 678µ). Age of the harvested capsule showed a linear correlation with inflammatory cells/HPF (r = 0.93, p < .0001, 95% C.I. 0.73 to 0.98), with CD3 positivity (r = 0.6, p = .04, 95% C.I. 0.02 to 0.9), with capillary proliferation/HPF (r = 0.85, p = .003, 95% C.I. 0.43 to 0.96) and with percentage of cells showing Masson's trichrome stain positivity (r = 0.71, p = .03, 95% C.I. 0.08 to 0.93). In the extrusion group, the capsules demonstrated high inflammation and low fibrosis.

CONCLUSIONS

PMMA orbital spherical implant incites a predominantly T-cell mediated inflammatory response which clinically presents as a peri-implant capsule. Increasing inflammation in the absence of significant fibrosis may be responsible for delayed PMMA implant exposure and extrusion.

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.

Comparison of inflammatory response and synovial metaplasia in immediate breast reconstruction with a synthetic and a biological mesh: a randomized controlled clinical trial

The aim of this study was to compare inflammatory response and synovial metaplasia in implant-based immediate breast reconstruction with a biological mesh (Veritas^®) with that of a synthetic mesh (TIGR^® Matrix Surgical Mesh). We hypothesize that the inflammatory response and formation of synovial metaplasia might be different and the rate of capsular contracture therefore different. The patients were recruited from the Gothenburg TIGR^®/Veritas^® Study (ClinicalTrials.Gov identifier NCT02985073). All referrals for bilateral immediate breast reconstruction were assessed for inclusions. During the operation, the patients were randomized to which sides the biological and the synthetic mesh were going to be applied. During the implant exchange biopsies were taken. Biopsies were taken from 30 breasts in 15 patients. There seem to be more myofibroblast and neovascularization in the biological meshes than in the synthetic and the collagen fibers seem to be aligned in an irregular pattern with both parallel and vertical fibers. In the synthetic meshes, there were more giant cells and foreign body reaction and the collagen fibers were loosely and well aligned, oriented parallel to the surface of the implant. Synovial metaplasia was seen in the majority of both the biological and the synthetic meshes. The histological patterns in early capsules from biological and synthetic meshes vary considerably. Nonetheless, it is unknown what role different cell types have in capsular formation in the long run and there was no difference in clinical capsular contracture at the clinical follow-up in this study.

The Effect of Postmastectomy Radiation Therapy on Breast Implants: Material Analysis on Silicone and Polyurethane Prosthesis

INTRODUCTION

The pathogenic mechanism underlying capsular contracture is still unknown. It is certainly a multifactorial process, resulting from human body reaction, biofilm activation, bacteremic seeding, or silicone exposure. The scope of the present article is to investigate the effect of hypofractionated radiotherapy protocol (2.66 Gy × 16 sessions) both on silicone and polyurethane breast implants.

METHODS

Silicone implants and polyurethane underwent irradiation according to a hypofractionated radiotherapy protocol for the treatment of breast cancer. After irradiation implant shells underwent mechanical, chemical, and microstructural evaluation by means of tensile testing, infrared spectra in attenuated total reflectance mode, nuclear magnetic resonance, and field emission scanning electron microscopy.

RESULTS

At superficial analysis, irradiated silicone samples show several visible secondary and tertiary blebs. Polyurethane implants showed an open cell structure, which closely resembles a sponge. Morphological observation of struts from treated polyurethane sample shows a more compact structure, with significantly shorter and thicker struts compared with untreated sample. The infrared spectra in attenuated total reflectance mode spectra of irradiated and control samples were compared either for silicon and polyurethane samples. In the case of silicone-based membranes, treated and control specimens showed similar bands, with little differences in the treated one. Nuclear magnetic resonance spectra on the fraction soluble in CDCl3 support these observations. Tensile tests on silicone samples showed a softer behavior of the treated ones. Tensile tests on Polyurethane samples showed no significant differences.

CONCLUSIONS

Polyurethane implants seem to be more resistant to radiotherapy damage, whereas silicone prosthesis showed more structural, mechanical, and chemical modifications.

Roxatidine inhibits fibrosis by inhibiting NF‑κB and MAPK signaling in macrophages sensing breast implant surface materials

Capsular contracture is an important complication after silicone mammary implant surgery. Fibroblasts and macrophages play critical roles in the pathogenesis of capsular contracture, making these two cell types therapeutic targets. It has been reported that inhibiting histamine receptors results attenuates fibrosis, but the role of roxatidine (a histamine receptor 2 inhibitor) in preventing fibrosis caused by breast implant materials remains unknown. The aim of the present study was to assess the hypothesis that roxatidine might have a prophylactic effect in capsular contracture induced by implant material. Inflammation induced by breast implant materials was mimicked by co-culturing macrophages or fibroblasts with these materials in vitro. Capsular contracture was modeled in mice by planting breast implant materials in a subcutaneous pocket. Roxatidine was added in the culture medium or administered to mice bearing breast implant materials. By co-culturing macrophages or fibroblasts with common breast implant materials (micro-textured or smooth breast implants), the present study demonstrated that macrophages respond to these materials by producing pro-inflammatory cytokines, a process that was abolished by addition of roxatidine to the culture medium. Although fibroblasts did not respond to implant surface materials in the same way as macrophages, the conditioned media of macrophages induced proliferation of fibroblasts. Mechanistically, administration of roxatidine inhibited activation of NF-κB and p38/mitogen-activated protein kinase (MAPK) signaling in macrophages. Furthermore, treatment with roxatidine in implant-bearing mice reduced serum concentrations of transforming growth factor-β and the abundance of fibroblasts around the implant. The present study concluded that roxatidine plays an important role in preventing fibrosis by inhibiting activation of NF-κB and p38/MAPK signaling in macrophages.