Étude au microscope électronique à balayage des surfaces des implants mammaires à texturation poreuse et de leurs capsules. Description de l'effet « velcro å des prothèses à texturation poreuse

Advances in surface modifications of the silicone breast implant and impact on its biocompatibility and biointegration

Silicone breast implants are commonly used for cosmetic and oncologic surgical indications owing to their inertness and being nontoxic. However, complications including capsular contracture and anaplastic large cell lymphoma have been associated with certain breast implant surfaces over time. Novel implant surfaces and modifications of existing ones can directly impact cell-surface interactions and enhance biocompatibility and integration. The extent of foreign body response induced by breast implants influence implant success and integration into the body. This review highlights recent advances in breast implant surface technologies including modifications of implant surface topography and chemistry and effects on protein adsorption, and cell adhesion. A comprehensive online literature search was performed for relevant articles using the following keywords silicone breast implants, foreign body response, cell adhesion, protein adsorption, and cell-surface interaction. Properties of silicone breast implants impacting cell-material interactions including surface roughness, wettability, and stiffness, are discussed. Recent studies highlighting both silicone implant surface activation strategies and modifications to enhance biocompatibility in order to prevent capsular contracture formation and development of anaplastic large cell lymphoma are presented. Overall, breast implant surface modifications are being extensively investigated in order to improve implant biocompatibility to cater for increased demand for both cosmetic and oncologic surgeries.

Defining Double Capsules: A Clinical and Histological Study

BACKGROUND

Macrotextured breast implants are associated with double capsules. There is little agreement as to what defines double capsules, how they present, and whether different degrees of double capsule exist.

OBJECTIVES

This study aimed to define double capsules and report an association between double-capsule type and degree of tissue adherence.

METHODS

Consecutive aesthetic patients undergoing explantation of Biocell (Allergan, Inc., Irvine, CA) implants between May 2018 and November 2018 were included if they were found to have double capsules intraoperatively. Patient demographics, implant characteristics, explantation reason, implant adherence, and intraoperative findings were recorded. Both adherent and double capsules were histologically examined. Data were analyzed by descriptive statistics.

RESULTS

Eleven patients had 22 Biocell implants explanted during the study period. The average explantation time was 8.0 years. Sixteen implants were found to have some degree of nonadherence, and all areas of nonadherence were associated with double-capsule formation. Double capsules were either partial or complete. The architecture of the inner layer of double capsules varied between an organized capsular layer and a thin area of nascent capsule. Histologically, all capsular specimens demonstrated an overall hypocellular fibrous capsule with scattered chronic inflammatory infiltrates. Synovial metaplasia was present in all capsule types and spaces/cracks in the capsule were disproportionately represented in partially adherent capsules.

CONCLUSIONS

This is the first study to identify a clinical and pathological correlation between double capsules and failed tissue adherence. Double capsules represent a spectrum of inner capsule formation ranging between nascent capsular tissue to a mature inner capsular layer.

LEVEL OF EVIDENCE: 4

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.

Implant Surface Options and Biofilm Mitigation Strategies

Two important topics in breast augmentation and reconstruction relate to device surface texture and practices to mitigate biofilm contamination of implants. Breast augmentation can be considered a manufacturing process where planning concepts of process engineering and quality can be used to produce great outcomes. This article reviews the options available for surgeons with regards to device surface texture selection and practices to mitigate biofilm contamination of implants at the time of surgery.

A Step Forward Toward the Understanding of the Long-Term Pathogenesis of Double Capsule Formation in Macrotextured Implants: A Prospective Histological Analysis

BACKGROUND

Although increasingly reported in the literature, most plastic surgeons cannot define the etiology of double capsules. Often an incidental finding at implant exchange, double capsules are frequently associated with macrotextured devices. Several mechanisms have been proposed, including at the forefront that shearing causes a delamination of the periprosthetic capsule into a double capsule.

OBJECTIVES

This study was designed to confirm the hypothesis that mechanical forces are involved in formation of double capsules by histological analysis.

METHODS

A prospective analysis of consecutive implants with double capsules removed over 2 years was performed. Data collected at the time of surgery included Baker classification, reason for explant, implant manufacturer and style, and any presence of a seroma associated with the capsule. Specimens were sent for analysis by histology utilizing hematoxylin and eosin and alpha-smooth muscle actin staining techniques.

RESULTS

Eight double capsules were collected for specimen analysis. All capsules demonstrated evidence of granulation tissue, alpha-smooth muscle actin positive myofibroblasts, and folds with embedded texture. Fibrosis surrounded weak areas with presence of layering and splitting, creating a potential space that is prone to separation. Tears and folds from granulomatous reaction are also present within the outer layer of the double capsule, which can only be explained by a mechanical shearing force as a pathogenic mechanism.

CONCLUSIONS

Understanding the pathogenesis of double capsules may allow plastic surgeons to refine their indications for macrotextured implants while providing guidance to patients on avoidance of activities that produce shear-forces. The findings support the hypothesis that shearing forces delaminate the capsule into 2 separate distinct capsules.

LEVEL OF EVIDENCE: 5

Low rate of capsular contracture in a series of 214 consecutive primary and revision breast augmentations using microtextured implants

Capsular contracture is the most common major complication after implant-based breast augmentation. The aetiology of capsular contracture is multifactorial. The author reports a retrospective personal series of patients managed over a seven-year period with a nearly unchanged surgical strategy implementing most of known measures for capsular contracture prevention. A microtextured silicone gel-filled implant from a single manufacturer was used in all cases.

There were 214 consecutive patients (126 primary augmentations and 88 revision augmentations) operated on over the study period. Mean age of the population was 40.0 years, and mean BMI was 22.0 kg/m². Of the patients in the revision cohort, 44.3% were reoperated on because of previous capsular contracture.

Average follow-up was 20.2 months. There was a 0% capsular contracture rate in the primary augmentation cohort and a 3.4% capsular contracture rate in the revision cohort. At last follow-up, 91.2% of breasts received a Baker I grading.

Although the follow-up was relatively short, this rate of capsular contracture would still be considered very low. Determining the reason for such a low rate of capsular contracture on Multivariate Analyses would be difficult due to the potential myriad of confounding variables. However, given the constancy of the technique and implant type employed by a single surgeon, the author is of the opinion that the microtexturing topography on the implant surfaceused in this series contributed to the low rate of capsular contracture formation. However, this would need to be tested in arandomized controlled trial comparing microtextured devices with implants that have macrotextured surfaces.

Do Bacteria and Biofilm Play a Role in Double-Capsule Formation around Macrotextured Implants?

BACKGROUND

The double capsule is a complication mostly described in aggressive macrotextured implants. Mechanical shear stress applied onto an immature periprosthetic capsule has been linked to their formation. The authors aim to demonstrate the role of bacterial phenotype and biofilm in the development of the double capsule.

METHODS

Seven double capsules formed at the interface of macrotextured breast expander implants were studied using scanning electron microscopy. Two samples for each surface of the inner capsule layer (the prosthesis interface and the intercapsular space) were analyzed for bacteria cell size, bacterial density, and biofilm deposition.

RESULTS

Although all routine bacterial cultures were negative, the prosthesis interface had both higher bacteria load and biofilm deposition compared with the intercapsular space (Mann-Whitney U test, p = 0.004 and p = 0.008, respectively). Moreover, bacteria cell sizes were significantly smaller at the prosthesis interface in six of seven samples. Comparison of bacteria density and biofilm dispersion showed an increase of biofilm extracellular matrix deposition over 2000 cells/mm (linear regression, p = 0.0025). These results indicate a common trend among bacteria species.

CONCLUSIONS

Bacterial expression between the different surfaces of the double capsule displays significant differences; bacteria at the prosthesis interface are mostly in a biofilm state, whereas they demonstrate a planktonic phenotype at the intercapsular space. When a sufficient amount of bacteria are present at a specific location, quorum sensing may trigger a biofilm phenotypic switch in planktonic bacteria cells. Biofilm formation may alter capsule formation through immune response, thereby weakening capsule strength and facilitating extracellular matrix delamination and double-capsule formation.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Is Rotation a Concern with Anatomical Breast Implants? A Statistical Analysis of Factors Predisposing to Rotation

BACKGROUND

Since their introduction in 1993, anatomical implants have provided a more natural appearance in breast augmentation, and many surgeons advocate their use and promote the good aesthetic results. However, the risk of implant rotation makes some of them reluctant to use these devices. The rotation rate varies among authors.

METHODS

The authors present a 6.5-year series of 531 patients who underwent primary breast augmentation with macrotextured anatomical implants in a Swedish facility performed by one consultant surgeon (P.M.). The authors examined the rotation rate and the correlation with possible predisposing factors such as preoperative breast cup size, childbirth, and body mass index.

RESULTS

A total of 20 implants (1.88 percent; 95 percent CI, 1.15 to 2.89 percent) in 19 patients (3.58 percent; 95 percent CI, 2.17 to 5.53 percent) were rotated. In one patient (0.22 percent), both implants rotated, whereas in the remaining patients, the rotation was unilateral. The authors were unable to establish a statistically significant correlation between implant rotation and previous childbirth or increased body mass index. However, there was a relation between rotation rate and preoperative breast cup size that showed an upward trend as the cup size increased from A to C.

CONCLUSION

The authors believe that if the implant is correctly selected and the operation is performed meticulously with proper pocket dissection, the rotation rate is minimal and it should not be considered a disadvantage for the use of anatomical implants.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Textured Breast Implants: A Closer Look at the Surface Debris Under the Microscope

BACKGROUND

Texturing of breast implants is done to decrease the risk of associated complications. Each manufacturer utilizes unique and at times proprietary techniques to texture the surface of their implants. Little is known about the integrity of this surface structure texturing or the propensity for the surfaces to shed particulate matter. This study aimed to determine the extent of surface particulate shedding from 3 textured implants approved by the US Food and Drug Administration (FDA), which are manufactured by Allergan, Mentor, and Sientra.

METHODS

Control images of each of the 3 textured breast implants were obtained with scanning electron microscopy (SEM). A liquid adhesive, ethylene vinyl acetate (EVA) copolymer was then applied to the external shell of the implants, allowed to cool, and peeled from the surface. Images of the EVA copolymer were taken with SEM to qualitatively analyze displacement of surface particulate debris. Scanning electron microscopy imaging of the implants was repeated for qualitative comparisons with the control images.

RESULTS

The peeled copolymer of the 3 implants exhibited surface shedding. Comparison of the 3 breast implants showed the shedding to be greatest for the Allergan implant.

CONCLUSIONS

This study highlights the dynamic surface material properties of the 3 FDA-approved breast implants. Shedding of particulate matter from the implant surfaces can be precipitated by moderate adhesion. Our qualitative examination of SEM findings showed more debris shed from the Allergan breast implants than from the Mentor or Sientra implants.

Breast-implant texturing associated with delamination of capsular layers: A histological analysis of the double capsule phenomenon

BACKGROUND

Macro-texturing of breast implants was developed with the double goal of improving implant stabilization within the breast cavity and decreasing the rate of capsular contractures. However, recent evidence suggests that double capsular formation, a potentially worrisome phenomenon associated with late seromas and biofilms, occurs with preponderance in macro-textured implants. Our objective was to analyze histologically different regions of double capsules to determine if they are more prone to mechanical movements.

METHODS

A prospective analysis including patients undergoing second-stage expander to definitive breast-implant reconstruction post-mastectomy was conducted after intraoperative identification of the double capsule phenomenon. Two samples were collected from each capsules around the implant, located centrally and laterally. The specimens were sent for histological analysis by the institution's pathologist.

RESULTS

In total, 10 patients were identified intraoperatively with partial double capsule phenomenon. Among samples retrieved from the lateral aspect of the breast implant, all were associated with delamination and fractures in the collagen matrix of the double capsules. This phenomenon was not observed in any sample from the dome of the breast.

CONCLUSIONS

Breast-implant macro-texturing plays an important role on delamination of capsules on lateral portions of the breast, which may have an etiologic role in double capsule formation. Manufacturing implants with macro-texturing on one side and smooth surface on the other could diminish mechanical shear forces responsible for these findings.

Long-term outcomes with the McGhan Style 153 dual-lumen breast implant: Implications for future implant design

BACKGROUND

A variety of saline and silicone implants have been introduced over the years to optimize the shape, aesthetic result and safety profile for use in breast surgery. The McGhan Style 153 dual-lumen silicone implant represented an early generation of anatomically shaped implants later removed from the market due to a high rate of rupture. This study reports long term outcomes and complications, including a revised rupture rate, and discusses potential mechanisms of implant failure and their implications for future implant design.

METHODS

A retrospective review was performed on 79 patients (134 implants). Demographics, operative details, outcomes, and complications were recorded. Rupture rate and location of rupture were included.

RESULTS

The revised implant rupture rate was 36.6% of implants. At least one rupture occurred in 49.4% of patients. Clinical exam was the most common method of detection (55.1% of ruptures). The most common location of rupture was the superior pole (30.6%), followed by a posterior location (24.5%). The capsular contracture rate (Baker grade III/IV) was 51.5%. The total implant removal rate (for rupture, contracture, size change, or asymmetry) was 77.6%. The average time to implant removal was 91.8 months, or 7.5 years (±47.3 months). Average follow up was 120.7 months or 10 years (±49.9 months).

DISCUSSION

The experiences with this anatomic gel implant highlight the importance of shell stability over time, suitable gel cohesiveness to support the asymmetric anatomic shape, avoidance of fold flaws due to wrinkling, and the prevention of distinct stress points on the shell that can result from dual lumen or multi-compartment designs.

LEVEL OF EVIDENCE

Level III, retrospective cohort, therapeutic study.

Characterization of Breast Implant Surfaces, Shapes, and Biomechanics: A Comparison of High Cohesive Anatomically Shaped Textured Silicone, Breast Implants from Three Different Manufacturers

Several companies offer anatomically shaped breast implants but differences among manufacturers are often misunderstood. The shell texture is a crucial parameter for anatomically shaped implants to prevent rotation and to decrease the risk of capsular contracture, even though concerns have recently been raised concerning the complications associated with textured breast implants. The aim of this study was to characterize differences in terms of texture, cell adhesion, shape, and stiffness between some commonly used anatomically shaped implants from three different manufacturers.

METHODS

Five commercially available anatomically shaped breast implants from 3 different manufacturers (Allergan, Mentor, and Sebbin) were used. Scanning electron microscopy, X-ray microtomography, and scanning mechanical microscopy were used to characterize the shell texture. Human fibroblast adhesion onto the shells was evaluated. 3D models of the implants were obtained using CT-scan acquisitions to analyze their shape. Implant stiffness was evaluated using a tractiometer.

RESULTS

Major differences were observed in the topography of the textures of the shells, but this was not conveyed by a statistically significant fibroblast adhesion difference. However, fibroblasts adhered better on anatomically shaped textured implants than on smooth implants (p < 0.01). Our work pointed out differences in the Biocell® texture in comparison with older studies. The 3D analysis showed significant shape differences between the anatomically shaped implants of the 3 companies, despite similar dimensions. Implant stiffness was comparable among the 3 brands.

CONCLUSIONS

Each texture had its specific topography, and this work is the first description of Sebbin anatomic breast implant texturation. Moreover, major discrepancies were found in the analysis of the Biocell® texture when comparing our results with previous reports. These differences may have clinical implications and are discussed. This study also highlighted major shape differences among breast implants from different manufacturers, which is quite counterintuitive. The clinical impact of these differences however needs further investigation.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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.

Prothèses mammaires de 1957 changées en 2005: un recul exceptionnel et historique de 48 ans

A 78-year-old woman underwent a breast implants removal on August 2005. The prosthetic breast augmentation was performed during 1957, in France. The photos of these polyethylene made breast implants are shown.

The Composition and Behavior of Capsules around Smooth and Textured Breast Implants in Pigs

BACKGROUND

The surface of the implant is one of the many factors often associated with the occurrence of capsular contracture, the etiopathogeny of which remains unclear. The purpose of this study was to analyze the behavior of capsular contracture by means of applanation tonometry and histology using a midsized animal model.

METHODS

Silicone breast implants were implanted into 33 pigs and observed at 30, 60, 180, and 270 postoperative days.

RESULTS

Capsular contracture in smooth implants showed significantly greater pressure values of tonometry, and the smooth implant capsule was significantly thicker than the textured implant capsule. Both pressure and thickness of the capsules increased at each period. The collagenous layer did not show any difference considering the periods of time in which the total thickness was analyzed; on the other hand, the increase in total capsular thickness occurred by thickening of the noncollagenous layer in both smooth and textured implants. Taking into consideration both kinds of implants, histomorphometric analysis showed that thin fibers were replaced by thick fibers in later postoperatives periods (180 and 270 days).

CONCLUSIONS

The greater incidence of capsular contracture in smooth implants was correlated with the progressive increase in total capsule thickness, due to a higher concentration of collagenous fibers, when compared with textured implants (p = 0.011; mean difference, 6.61), and a higher concentration of thick fibers (p = 0.034; average, >5.51 percentage points per field of thick fibers than the textured implants in all periods). Pigs are good animal models for studying the healing process after breast augmentation with implants.

Prothèses mammaires rondes ou anatomiques. Avantages et inconvénients respectifs

The authors report of their experience of mammary augmentation with anatomical implants from 10 years ago. The important proportion of rotation of those anatomical implants obliged them to stop the clinical serie. Sylvain Staub return to a "revisited" classical technique with round implants, smooth in a majority of cases and placed them most of the time in a retromuscular pocket. Eric Auclair, ceduced by the concept of anatomical implants, decided to continue in this direction with a personal concept of anti rotation system. He shows a strategie of mammary augmentation that favorise the premuscular position and define the respective place of round and anatomical implants.

Prothèses lisses ou texturées : que choisir ?

Envelope structure has evolved since the seventies. Indeed, low-bleed implants allow an important reduction of capsular contracture for silicone filled implants. Later, textured implants permit an additional reduction of capsular contracture, especially when positioned in a retroglandular pocket. Whereas many studies confirm these findings, the interest of textured implants in the retromuscular plane is not really clear, even if some authors recommend it. Due to the need of a tissular anchorage, anatomical implants are not manufactured with smooth envelopes.