Silicone breakdown and clinical implications of mammary and extramammary synovial metaplasia in periprosthetic capsules

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.

Synovial metaplasia, a specialized form of repair

Synovial metaplasia is a change seen most frequently in the tissues surrounding silicone breast prostheses and in healing tissue adjacent to joint prostheses. It has also been described in skin and soft tissues, most frequently in healing or healed traumatic or surgical wounds. We report a case of synovial metaplasia occurring in a hitherto unreported location, namely, adjacent to a silicone low-pressure voice prosthesis. A review of cases of synovial metaplasia reported in the literature revealed that in most cases, spaces that form adjacent to foreign material (most commonly silicone breast prostheses) and the smooth gliding surfaces of the foreign material that resist penetration by fibroblast processes are frequent associated findings that precede the occurrence of synovial metaplasia. Thus, synovial metaplasia might represent a specialized form of healing in cases that have this combination of physical features.

The influence of time on human breast capsule histology: smooth and textured silicone-surfaced implants

Although the histology of capsular tissue is well described in the literature, most studies in humans do not correlate histologic findings with implant age (number of years an implant was in place before sampling). As such, questions regarding the long-term histology in humans remain. The microanatomy of 93 human periprosthetic capsular tissues surrounding 22 textured and 71 smooth silicone-surfaced prostheses was studied. The implants were divided into two groups according to the time between implantation and capsulectomy: between 0 and 5 years or more than 5 years. Hematoxylin and eosin and Masson trichrome-stained sections were analyzed by light microscopy, with and without polarization. Eighteen of the textured implants contained silicone gel and four contained saline. Sixty of the smooth implants contained silicone gel, eight contained saline, and in three, the filler type was not known. For the majority of patients, surgery was performed for augmentation mammaplasty, and the implants were removed because of capsular contracture. The following histologic features were assessed: synovial-like metaplasia, villous hyperplasia, density of the collagenous capsule, alignment of collagen fibers within the capsule, and the presence of foreign material and of a foreign body reaction. The following trends were observed. In smooth implants, increasing implant duration was associated with a decrease in the presence of synovial-like metaplasia (p = 0.003) and villous hyperplasia; there was no significant difference in the presence of a dense collagenous capsule, the orientation of collagen fibers, or the presence of a foreign body reaction. An increase was observed in the presence of foreign material (p = 0.01). In textured implants, increasing implant duration was associated with a decrease in the presence of synovial-like metaplasia, villous hyperplasia (p = 0.003), dense collagenous architecture, and parallel orientation of collagen fibers (p = 0.017). An increase in the presence of a foreign body type reaction and foreign material (p = 0.024) was observed. In comparing textured and smooth-surfaced implants, synovial-like metaplasia was observed more often in the textured group, both at 0 to 5 years (p = 0.01) and at greater than 5 years (p < 0.01). Textured implants more often had villous hyperplasia at 0 to 5 years (p = 0.03) but not beyond 5 years. Smooth implants more often had a dense collagenous capsule than textured implants after 5 years. No significant difference was seen in the orientation of collagen fibers in capsules around smooth and textured implants at 0 to 5 years. After 5 years, the incidence of capsules with collagen fibers arranged parallel to the implant surface was significantly greater in the smooth group than in the textured group (p = 0.01). The presence of a foreign body type reaction was seen more often in the textured group between 0 and 5 years (p = 0.01) and at greater than 5 years (p < 0.01), and the presence of foreign material was more often seen in the textured group between 0 and 5 years (p = 0.06) and at greater than 5 years (p < 0.01). In summary, the cytologic changes around implants seem to be dynamic in nature, and implantation duration and shell type play a significant role. Synovial-like metaplasia, villous hyperplasia, and foreign material were more often observed in the textured group within the 0 to 5 year interval. Beyond 5 years, synovial-like metaplasia, a foreign body type reaction, and foreign material were more often observed in the textured group. Differences in the density of collagenous capsules were not significant at any time point, and collagen fibers oriented parallel to the implant surface were more often observed in the smooth group after 5 years. The significance of these findings awaits further investigation.

Pathological and biophysical findings associated with silicone breast implants: a study of capsular tissues from 86 cases

Breast implant capsular tissues from 86 cases were studied to characterize the relationship between capsular findings and the type of implant used. Tissues were examined by light microscopy, immunohistochemistry, scanning electron microscopy/energy dispersive x-ray analysis and Fourier transform infrared, and Raman microspectroscopy. Capsular pathology was influenced by the structure and composition of the implant. A pseudoepithelium at the inner capsular surface (synovial metaplasia) was noted with silicone gel-filled, saline-filled, and polyurethane-coated implants, and disproportionatelywith textured surface implants. Immunohistochemical studies of pseudoepithelium supported a macrophage/histiocyte cellular origin. Talc was identified intracellularly within macrophages in 42 cases. Capsular calcification was strongly associated with the presence of implant stabilization patch material. Infrared spectra were used to identify silicone, talc, Dacron, and two different types of polyurethane in capsular tissues. Micropapillary structures identified at the pseudoepithelial surface have, to the authors' knowledge, not been previously described.

Silicone breast implants: pathology

Questions as to the bioreactivity of silicone breast implants (SBIs) have recently been intensely scrutinized, most notably by the media and legal system. Pathologists must be aware of the controversy and treat each SBI and associated tissue as a potential lawsuit. Grossly, silicone is a clear, viscous substance that may be observed either within or extruding from a silastic bag. By light microscopy, silicone is a nonstainable, nonpolarizable, refractile substance. Thicker sections, especially when viewed by non-Köhler illumination, phase-contrast, and darkfield microscopy will enhance visualization. Ultrastructurally, silicone is an electron-dense, amorphous substance often located within phagocytic vacuoles or extracellularly within the stroma. Correlating electron probe microanalysis allows for reliable identification. In most cases, a fibrous capsule surrounds the SBI, with the interface lining varying from a virtually acellular to a synovial-like lining composed of phagocytic and secretory cells. Silicone can often be identified within the fibrous capsule and also in distant tissues biopsied for suspected autoimmune disorders, such as synovium, skin, and lymph nodes, often without ultrastructural evidence of cytologic effects. This study has demonstrated that silicone accumulates at distant tissue sites due to preexisting inflammation acting as a stimulus. Thus, silicone is not a primary inducer of inflammatory disease processes. These findings are supported by various large epidemiologic studies.