A Rabbit Model for Capsular Contracture: Development and Clinical Implications

Efficacy of Acellular Dermal Matrix Type in Treatment of Capsular Contracture in Breast Augmentation: A Systematic Review and Meta-Analysis

BACKGROUND

Capsular contracture is a known complication of breast augmentation and is among the top reasons for revisional breast augmentation procedures. The use of acellular dermal matrix (ADM) has been shown to reduce the rate of capsular contracture in breast reconstruction and augmentation, theorizing that it acts as a protective barrier between the implant capsule and inflammatory process responsible for capsular contracture. The role of ADM in treatment of capsular contracture has been investigated in numerous studies, with a variety of ADMs.

OBJECTIVES

The aim of this study was to perform a systematic review of existing literature on the use of ADM for treatment of capsular contracture in aesthetic breast augmentation patients to investigate differences in efficacy of ADM types.

METHODS

The PubMed, Embase, and CINAHL databases were systematically reviewed for articles pertaining to capsular contracture, acellular dermal matrices, and breast augmentation. Number of patients, type of ADM, Baker grade, follow-up time, complication rate, and capsular contracture rate were recorded from identified articles. Data was pooled from studies to calculate a capsular contracture rate for each ADM type, with a chi-squared test performed for analysis. Identified studies with a comparative group were included in a meta-analysis utilizing risk ratio (RR) to assess the efficacy of ADM.

RESULTS

Nine articles including ADM for treatment of capsular contracture in breast augmentation met criteria for inclusion, with a total of 481 breasts. Strattice was the most commonly utilized ADM (n = 391), followed by AlloDerm (n = 57). There was a statistically significant difference in efficacy of ADM among the studied ADM types (P < .001). AlloDerm, FlexHD, and DermaMatrix had the lowest capsular contracture rates (0%). NeoForm and SurgiMend had the highest capsular contracture rates (each 25%, but with n = 4 and n = 8, respectively). Strattice had a capsular contracture rate of 1.53% in the pooled data, and meta-analysis showed that Strattice reduced the risk of capsular contracture (RR 0.14 [95% CI 0.06, 0.31]) compared with conventional treatment.

CONCLUSIONS

Acellular dermal matrices appear to be effective at treating capsular contracture after breast augmentation while maintaining a low complication rate. Overall capsular contracture rates are low with the use of ADM. There is a statistically significant difference in efficacy among ADM types. Meta-analysis shows that Strattice is effective at reducing the risk of capsular contracture in breast augmentation patients when compared to conventional treatment. Future research, especially in the form of randomized controlled trials, is needed to further investigate the efficacy of various ADMs in the treatment of capsular contracture.

LEVEL OF EVIDENCE: 4

Impact on capsule formation for three different types of implant surface tomography

Although capsular contracture remains one of the major problems following silicone breast implantation, the associated mechanism has yet to be determined. This study thus aimed to investigate capsule formation and capsular contracture using three types of implants with different surface topographies in vivo. Three types of implants (i.e., smooth, macrotexture, and nanotexture) with different surface topographies were inserted in a total of 48 Wistar rats. After 4 and 12 weeks, the samples were analyzed via histological, immunohistochemical, and Western blot examination. To identify implant movement, the degree to which implant position changed was measured. And the surface topography was characterized using scanning electron microscopy. Hematoxylin–eosin staining showed that the nanotexture type implant promoted significant decreases in capsule thickness at 12 weeks (P < 0.05), while Masson trichrome staining showed decreased collagen fiber density with the same implant type. Immunohistochemical and Western blot examination revealed reduced fibrosis markers (myofibroblast, and transforming growth factor beta-1) in the nanotexture surface implant. Meanwhile, implant location evaluation found that the nanotexture and smooth surface implants had significantly increased movement (P < 0.05). The nanotexture surface implant had been found to reduce capsule formation given that it minimizes the effects of factors related to foreign body reaction.

Follistatin and the Breast Implant Capsule

Supplemental Digital Content is available in the text.

Background:

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

Methods:

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

Results:

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

Conclusions:

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

Effects of Medical Chitosan on Capsular Formation Following Silicone Implant Insertion in a Rabbit Model

BACKGROUND

Capsular contracture is a serious complication that occurs after breast implant surgery. This study was performed to confirm that medical chitosan (MC) affects capsule formation and elucidates a possible mechanism.

MATERIALS AND METHODS

In this study, we used 18 female adult New Zealand White rabbits. In each rabbit, two silicone implants were placed under the pectoralis muscle layer on both sides (one side was included in the experimental group and the other side was included in the control group). MC was applied around the silicone implant of the experiment group, while the control group received no treatment. The capsular thickness was calculated by Masson's trichrome stain. The expression of MMPs and TIMPs were determined by real-time PCR, Western blotting, and immunohistochemistry.

RESULTS

Compared to the control group, the capsular thickness of the MC group was significantly reduced at 4, 8, and 12 weeks after the operation (4 week: 229.3 ± 72.2 vs 76.1 ± 12.6 µm, p < 0.05; 8 week: 326.0 ± 53.8 vs 155.4 ± 61.7 µm, p < 0.0.5; 12 week: 151.2 ± 52.5 vs 60.0 ± 22.0 µm, p < 0.05). Compared to the control group, the MC group had significantly lower expressions of TIMP-1 and TIMP-2 (p < 0.05). However, compared to the control group, there was no statistically significant difference in the expressions of MMP-2 and MMP-9 in the experiment group (p > 0.05).

CONCLUSION

MC reduced the risk of developing capsular contracture around silicone implants, possibly by blocking the signaling pathway of TIMPs.

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.

Prevention of capsular contracture with Guardix-SG(®) after silicone implant insertion

BACKGROUND

Capsular contracture is the most common side effect of breast implant insertion and the problem that breast surgeons seek to avoid the most. Previous animal studies have proved that an antiadhesive barrier solution (AABS) prevents peri-implant capsule formation. In this study, the authors sought to explore the effect that Guardix-SG(®), an AABS that can encapsulate implants in the form of a gel, can have on capsular contracture.

METHOD

This study used 12 female New Zealand white rabbits weighing 2.5-3 kg. Implants were inserted into the subpanniculus carnosus plane through an incision in the bilateral midback area. Once the implant was inserted, 3 g of Guardix-SG(®) and normal saline were instilled into the left and right sides, respectively. The rabbits were killed 6 months after the procedure. The intracapsular pressure was measured using tonometry with a 38.2-g circular glass piece, and capsular thickness was measured by dyeing the biopsy specimen with hematoxylin and eosin and Masson's trichrome stain. The myofibroblasts were quantitatively analyzed through monoclonal anti-alpha smooth muscle actin antibody immunohistochemistry staining.

RESULTS

The intracapsular pressure in the control group (4.51 ± 0.98 mmHg) was significantly higher (p = 0.002) than in the study group (3.51 ± 0.4 mmHg). The average capsular thickness was significantly greater in the control group (0.33 ± 0.15 mm; p = 0.015). In the analysis, the interrelation between capsular thickness and intracapsular pressure was insignificant in both groups, as was the number of myofibroblasts in both groups (p = 0.582).

CONCLUSION

Through this study, the authors were able to demonstrate that capsular contracture can be suppressed in the rabbit model by instilling Guardix-SG(®) after insertion of cohesive gel implants in the subpanniculus carnosus plane.

LEVEL OF EVIDENCE IV

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