Histologic analysis of zafirlukast's effect on capsule formation around silicone implants

Comparison of Cromolyn Sodium, Montelukast, and Zafirlukast Prophylaxis for Capsular Contracture

BACKGROUND

Capsular contracture is the most common complication following breast augmentation. Recently, prophylaxis studies aiming to inhibit the release of profibrotic substances to prevent capsular contracture have gained in importance. This study investigated the effects of cromolyn sodium, montelukast, and zafirlukast on capsular contracture in a rat model.

METHODS

Thirty female Wistar albino rats were randomly divided into five groups: control, sham, cromolyn sodium, montelukast, and zafirlukast. Intraperitoneal injections were administered daily to the sham (1 ml per day), cromolyn sodium (10 mg/kg per day), montelukast (10 mg/kg per day), and zafirlukast (1.25 mg/kg per day) groups 1 month before surgery. Miniature breast implants were then placed on the backs of the rats in each group. Injections were continued for the next 3 months. The rats were subsequently killed, and the capsules were harvested and assessed histopathologically. The histopathologic outcomes were acute inflammation status, inflammation severity, synovial metaplasia, foreign body reaction, mast cell count, and capsular thickness.

RESULTS

The cromolyn sodium, montelukast, and zafirlukast groups had less acute inflammation and lower mean inflammation severity scores, foreign body reaction occurrence, mast cell counts, and capsular thickness than the control and sham groups ( p < 0.05). These parameters were better in the cromolyn sodium group than in the montelukast and zafirlukast groups ( p < 0.05).

CONCLUSIONS

Cromolyn sodium appears to inhibit capsular contracture more efficiently than montelukast and zafirlukast. This report may be a pioneer study for the prophylactic use of cromolyn sodium in capsular contracture.

CLINICAL RELEVANCE STATEMENT

The prophylactic administration of cromolyn sodium appears to reduce capsular contracture more efficiently than that of montelukast and zafirlukast. This report might constitute a pioneer study for the prophylactic use of cromolyn sodium in capsular contracture.

Pharmacological Approaches for the Prevention of Breast Implant Capsular Contracture

Capsular contracture is a common complication associated with breast implants following reconstructive or aesthetic surgery in which a tight or constricting scar tissue capsule forms around the implant, often distorting the breast shape and resulting in chronic pain. Capsulectomy (involving full removal of the capsule surrounding the implant) and capsulotomy (where the capsule is released and/or partly removed to create more space for the implant) are the most common surgical procedures used to treat capsular contracture. Various structural modifications of the implant device (including use of textured implants, submuscular placement of the implant, and the use of polyurethane-coated implants) and surgical strategies (including pre-operative skin washing and irrigation of the implant pocket with antibiotics) have been and/or are currently used to help reduce the incidence of capsular contracture. In this article, we review the pharmacological approaches-both commonly practiced in the clinic and experimental-reported in the scientific and clinical literature aimed at either preventing or treating capsular contracture, including (i) pre- and post-operative intravenous administration of drug substances, (ii) systemic (usually oral) administration of drugs before and after surgery, (iii) modification of the implant surface with grafted drug substances, (iv) irrigation of the implant or peri-implant tissue with drugs prior to implantation, and (v) incorporation of drugs into the implant shell or filler prior to surgery followed by drug release in situ after implantation.

Histopathological evaluation of the effect of hyperbaric oxygen therapy on capsule occurrence around silicone breast prosthesis: an experimental study

BACKGROUND

In general, capsular contracture is the underlying cause of complications such as pain, stiffening, breast asymmetry, and animation deformity that are seen in the late postoperative period due to the use of silicone breast prostheses. Considering the positive effects of HBO therapy on wound healing, the objective of this study was to investigate the effect of HBO therapy on capsule reaction occurring due to silicone implants.

MATERIAL AND METHODS

Rats were divided into four groups. 1 cm × 1 cm silicone implants with rough surface were inserted in subcutaneous plane on the m spinotrapezius muscle fascia at just right of the dorsal region midline in rats in Group 1, while implants with same properties were inserted beneath m spinotrapezius muscle in rats in Group 2.Implants with the same properties were inserted in the subcutaneous area on the m spinotrapezius muscle in rats in Group 3 and into the area under the muscle in rats in Group 4. Beginning from the first postoperative day, rats in Groups 3 and 4 received HBO therapy for 90 min under 2.5 ATM pressure as one session a day over 15 days.

RESULTS

The mean capsule thickness was statistically significantly lower in the groups treated with HBO compared to the control groups. Fibroblast, neutrophil and macrophage counts were statistically significantly lower in the groups treated with HBO compared to the control groups.

CONCLUSION

We believe that HBO therapy can be used as an adjuvant treatment options to decrease capsule contraction occurring after silicone implant application.

Efficacy of Acellular Dermal Matrix in Capsular Contracture of Implant-Based Breast Reconstruction: A Single-Arm Meta-analysis

BACKGROUND

A large number of clinical studies have suggested that acellular dermal matrix (ADM) can decrease the incidence of capsular contracture in implant-based breast reconstruction. Yet, there is currently no high-level epidemiological evidence to prove this. The goal of this meta-analysis was to clarify the efficacy of ADM in capsular contracture, and provide a reference value for plastic surgeons.

METHODS

We systematically performed a search on PubMed, EMBASE, and the Cochrane Library to identify eligible studies from inception up to October 1, 2019. A random-effects model was used to obtain a pooled incidence rate. We conducted subgroup analysis according to geographic region, type of ADM, body mass index (BMI), duration of follow-up, and proportion of participants who have received radiotherapy.

RESULTS

A total of 18 studies involving 2941 cases were included. Overall, the pooled incidence rate of capsular contracture was 2.4% (95% CI 1.2-3.9%). The results from subgroup analyses indicated an even lower incidence in North America (1.6%, 95% CI 0.5-3.3%) and in human-derived ADM (HADM) (1.2%, 95% CI 0.2-3.0%). In addition, the results showed that the patients with BMI < 24, or who have received radiotherapy, were more prone to capsular contracture.

CONCLUSION

The application of ADM can effectively reduce the incidence of capsular contracture in implant-based breast reconstruction. And we infer that it might also apply to breast augmentation. However, additional high-quality trials are warranted to corroborate the findings of this meta-analysis.

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 www.springer.com/00266.

Size matters-in vitro behaviour of human fibroblasts on textured silicone surfaces with different pore sizes

Capsular contracture remains a challenge in plastic surgery and represents one of the most common postoperative complications following alloplastic breast reconstruction. The impact of the surface structure of silicone implants on the foreign body reaction and the behaviour of connective tissue-producing cells has already been discussed. The aim of this study was to investigate different pore sizes of silicone surfaces and their influence on human fibroblasts in an in vitro model. Four different textures (no, fine, medium and coarse texture) produced with the salt-loss technique, have been assessed in an in vitro model. Human fibroblasts were seeded onto silicone sheets and evaluated after 1, 4 and 7 days microscopically, with viability assay and gene expression analysis. Comparing the growth behaviour and adhesion of the fibroblasts on the four different textures, a dense cell layer, good adhesion and bridge-building ability of the cells could be observed for the fine and medium texture. Cell number and viability of the cells were increasing during the time course of experiments on every texture. TGFß1 was lowest expressed on the fine and medium texture indicating a trend for decreased fibrotic activity. For silicone surfaces produced with the salt-loss technique, we were able to show an antifibrotic effect of smaller sized pores. These findings underline the hypothesis of a key role of the implant surface and the pore size and pore structure in preventing capsular contracture.

Elastic net of polyurethane strands for sustained delivery of triamcinolone around silicone implants of various sizes

We propose an elastic net made of a biocompatible polymer to wrap silicone implants of various sizes, which also allows for the sustained release of an anti-inflammatory drug, triamcinolone, to prevent fibrosis. For this, we first prepared a strand composed of a mixture of polyurethane and triamcinolone via electrospinning, which was then assembled to prepare the elastic drug-delivery net (DDN). The DDN was prepared to just fit for wrapping the small silicone implant sample herein, but was also able to wrap a sample 7 times as large at 72% strain due to the elastic property of polyurethane. The DDN exhibited sustained drug release for 4 weeks, the profile of which was not very different between the intact and strained DDNs. When implanted in a subcutaneous pocket in living rats, the DDN-wrapped silicone implant samples showed an obvious antifibrotic effect due to the sustained release of triamcinolone. Importantly, this effect was similar for the small and large silicone samples, both wrapped with the same DDN. Therefore, we conclude that this drug-loaded net made of an elastic, biocompatible polymer has high potential for sustained drug delivery around silicone implants manufactured in various sizes.

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 .

The aetiopathogenesis of capsular contracture: A systematic review of the literature

BACKGROUND

Capsular contracture is the most frequent complication after breast augmentation or reconstruction with breast implants. The immune system plays a prominent role in capsular contracture formation, albeit to an unknown extent. Bacterial contamination in situ has been hypothesized to be causative for capsular contracture. How this relates to the immunological processes involved is unknown. This article aims to provide an overview of immunological and bacterial factors involved in development of capsular contracture.

MATERIALS AND METHODS

We undertook a systematic literature review focused on immunological factors and microbiota in relation to capsular contraction around implants. This systematic review was performed in accordance with the PRISMA guidelines. PubMed, EMBASE, and the Cochrane databases were searched from inception up to October 2016. Included studies were assessed for the following variables: subject characteristics, number of capsules, primary indication for surgery, surgical procedure, follow-up or implant duration, study methods, type of antibiotics or medical therapies and outcomes related to microbiota and immunological factors.

RESULTS

Data on immunological factors and bacterial contamination were retrieved from 64 included studies. Notably the presence of macrophages and Staphylococcus epidermidis within capsules was often associated with capsular contracture.

CONCLUSION

This review provides a clear overview of the immunological factors associated with capsular contracture and provides a hypothetical immunological model for development of the disease. Furthermore, an overview of bacterial contamination and associations with capsular contracture has been provided. Follow-up research may result in clinical recommendations to prevent capsular contracture.

Acellular dermal matrix reduces capsule formation in two-stage breast reconstruction

Acellular dermal matrix (ADM) is commonly employed to create an inferior pocket for the tissue expander in two-stage breast reconstruction. The authors sought to determine whether placement of ADM during the first stage of reconstruction decreases the amount of capsule formation at implant exchange. Patients who underwent mastectomy and tissue expander reconstruction were included in this study. Two biopsies were obtained at the time of implant exchange, one from the pocket adjacent to the ADM and the other from the area adjacent to the pectoralis muscle. Pathology analysis was performed on each sample. Ten patients underwent immediate breast reconstruction with Alloderm during the 3-month study period. Capsule thickness was significantly greater in the areas where the expander was in direct contact with the pectoralis muscle (782 ± 194 µm) compared to those in contact with human acellular dermal matrix (hADM) (47·91 ± 110·82 µm; P < 0·05). Analysis of the sub-pectoral capsule demonstrated diffuse deposition of collagen, neutrophils, contractile myofibroblasts and synovia-like metaplasia, characteristic of a foreign body response. Conversely, within the inferior pocket where the hADM was in direct contact with the expander, we noted migration of host epithelial cells, fibroblasts, mesenchymal cells and angiogenesis, indicating host tissue regeneration. Acellular dermal matrix, when placed at the first stage of breast reconstruction, significantly reduces thickness and inflammatory character of the capsule in comparison to the patient's native tissue.

The Effect of Hyaluronic Acid Application on the Perisilicon Capsule Structure

BACKGROUND

Silicon implants constitute a major part of plastic surgery practice. Although materials with high biocompatibility have been used around the implants, capsule formation still develops and progressive nature of this process results in capsule contraction. The aim of this study is to evaluate the effects of hyaluronic acid injected around the silicon block on the capsule structure.

METHODS

Twenty Wistar albino rats were used in the study. Rats were divided into two main groups (group 1 and group 2) and two subgroups. Rats in group 1 were sacrificed in week 4 and rats in group 2 were sacrificed in week 8. A subcutaneous pouch was created in the dorsum of the rats and a silicon block was placed into the pouch in groups 1A and 2A. 0.2 ml of hyaluronic acid was injected around the silicon block in group 1B and group 2B. Rats were sacrificed and capsule structure and thickness were analyzed following macroscopic evaluation. Concentrations of transforming growth factor-β1 (TGF-β1) and heat shock protein-47 (HSP-47) were evaluated immunohistochemically, and statistical comparisons were made.

RESULT

Capsule structure consisted of three layers in all the groups. A more intense collagen structure was observed in the middle layer. The capsule was thinnest in group 1A and thickest in group 2B; the difference between the groups was statistically significant. TGF-β1 was most intense in group 2B and it was correlated with the amount of collagen. Involvement of HSP-47 was observed mainly in collagen and also in fibroblasts and vascular structures, and its concentration was found to be lower in groups 2A and 2B.

CONCLUSION

Exogenously added cross-linked hyaluronic acid increased the capsular thickness and may increase the risk of developing capsular contracture around silicone implants.

LEVEL OF EVIDENCE II

Evidence was obtained from the well-designed controlled trials without randomization.

Stealthy role of size-driven stresses in biomechanics of breast implants capsular contracture

Breast Capsular Contracture (BCC) is one of the adverse complications occurring with greater incidence in breast augmentation surgical procedures. Its formation can be interpreted as the conclusive result of the physiological process known as response to a foreign body. From a biochemical standpoint, the formation of the peri-prosthetic capsule is certainly a multifactorial process: many hypotheses concerning its etiology have been suggested in the literature and a number of related pharmacological protocols have been consequently proposed to clinically treat this pathology with the aim to prevent further complications and avoid future re-interventions. However, the vast majority of these theories seems to be only partially supported by clinical outcomes and thus a shared opinion on this matter is still absent among specialists. Within this framework, by starting from clinical observations which highlighted an unexpected correlation between histo-morphological features of fibrotic capsules and overall size of breast implants, the present study investigates the hypothesis that the biomechanical interaction between prosthesis and host tissue may play a crucial role in the biological processes governing the pathological phenomenon at hand. Therefore, to shed light on the underlying mechanisms which could trigger the breast capsular contracture, both simple analytical solutions, in which elasticity and growth are simultaneously taken into account, and more accurate geometrically faithful Finite Element-based numerical simulations have been exploited. The theoretical findings demonstrate that somehow counter-intuitive radial and hoop stress fields occur at the capsula-implant interface in a way such that their combined action, independently from other possible concurrent factors, results significantly amplified for small-size breast prostheses, localized stress peaks in these cases promoting detaching and rippling phenomena actually observed in BCC clinical complications.

Noninvasive Shock Wave Treatment for Capsular Contractures After Breast Augmentation: A Rabbit Study

BACKGROUND

Capsular contracture is the most common complication of breast augmentation. Although numerous procedures are intended to prevent capsular contracture, their efficacy does not satisfy surgeons or patients. In the present study, we used shock waves to develop innovative protocols to treat capsular contracture in rabbits.

METHODS

We used shock waves to treat capsular contracture in a rabbit model. Six clinical parameters were evaluated to determine the treatment efficacy of shock waves on the pathological histology of capsular contracture. Dual-flip-angle T1-mapping magnetic resonance imaging was used to confirm the pathological findings.

RESULTS

Among the parameters, myxoid change, vascular proliferation, and lymphoplasma cell infiltration around the capsule increased more after treatment than they did in a control group. Capsular thickness, inner thinner collagen layer, and capsule wall collagen deposition decreased after shock wave treatment; only the inner thinner collagen layer and capsule wall collagen deposition changed significantly. The MRI findings for both scar thickness and water content were consistent with pathological biology findings.

CONCLUSION

This was the first pilot study and trial to treat capsular contractures using shock waves. We found that shock waves can cause changes in the structure or the composition of capsular contracture. We conclude that the treatment could decrease water content, loosen structure, decrease collagen deposition, and might alleviate scar formation from capsular contracture. We believe that the treatment could be a viable remedy for capsular contractures.

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 .

Histologic, Molecular, and Clinical Evaluation of Explanted Breast Prostheses, Capsules, and Acellular Dermal Matrices for Bacteria

BACKGROUND

Subclinical infections, manifest as biofilms, are considered an important cause of capsular contracture. Acellular dermal matrices (ADMs) are frequently used in revision surgery to prevent recurrent capsular contractures.

OBJECTIVE

We sought to identify an association between capsular contracture and biofilm formation on breast prostheses, capsules, and ADMs in a tissue expander/implant (TE/I) exchange clinical paradigm.

METHODS

Biopsies of the prosthesis, capsule, and ADM from patients (N = 26) undergoing TE/I exchange for permanent breast implant were evaluated for subclinical infection. Capsular contracture was quantified with Baker Grade and intramammary pressure. Biofilm formation was evaluated with specialized cultures, rtPCR, bacterial taxonomy, live:dead staining, and scanning electron microscopy (SEM). Collagen distribution, capsular histology, and ADM remodeling were quantified following fluorescent and light microscopy.

RESULTS

Prosthetic devices were implanted from 91 to 1115 days. Intramammary pressure increased with Baker Grade. Of 26 patients evaluated, one patient had a positive culture and one patient demonstrated convincing evidence of biofilm morphology on SEM. Following PCR amplification 5 samples randomly selected for 16S rRNA gene sequencing demonstrated an abundance of suborder Micrococcineae, consistent with contamination.

CONCLUSIONS

Our data suggest that bacterial biofilms likely contribute to a proportion, but not all diagnosed capsular contractures. Biofilm formation does not appear to differ significantly between ADMs or capsules. While capsular contracture remains an incompletely understood but common problem in breast implant surgery, advances in imaging, diagnostic, and molecular techniques can now provide more sophisticated insights into the pathophysiology of capsular contracture.

LEVEL OF EVIDENCE

4 Therapeutic.

Biomedical implant capsule formation: lessons learned and the road ahead

Clinicians and investigators have been implanting biomedical devices into patients and experimental animals for centuries. There is a characteristic complex inflammatory response to the presence of the biomedical device with diverse cell signaling, followed by migration of fibroblasts to the implant surface and the eventual walling off of the implant in a collagen capsule. If the device is to interact with the surrounding tissues, the collagen envelope will eventually incapacitate the device or myofibroblasts can cause capsular contracture with resulting distortion, migration, or firmness. This review analyzes the various tactics used in the past to modify or control capsule formation with suggestions for future investigative approaches.

The preventive effect of topical zafirlukast instillation for peri-implant capsule formation in rabbits

Background

Capsular contracture is the most troublesome complication in breast implant surgery. Although capsule formation can be seen as a normal reaction to a foreign body, it can induce pain, hardness, deformity, and other pathologic problems. Surgical intervention is required in severe cases, but even surgery cannot guarantee a successful outcome without recurrence. This experimental study confirms that single topical administration of leukotriene antagonist zafirlukast (Accolate, Astrazeneca) reduces peri-implant capsule formation and prevents capsular contracture.

Methods

Twelve smooth-surfaced cohesive gel implants were implanted in New Zealand White rabbits. These miniature implants were designed to be identical to currently used products for breast augmentation. The rabbits were divided into 2 groups. In the experimental group (n=6), the implant and normal saline with zafirlukast were inserted in the submuscular pocket. In the control group (n=6), the implant and normal saline alone were used. Two months later, the implants with peri-implant capsule were excised. We evaluated capsule thickness and collagen pattern and performed immunohistochemical staining of myofibroblasts, transforming growth factor (TGF)-β1, 2.

Results

The thickness of the capsules in the experimental group was reduced in both dorsal and ventral directions. The collagen pattern showed parallel alignment with low density, and the number of myofibroblasts as well as the amounts of TGF-β1 and TGF-β2 were reduced in the experimental group.

Conclusions

We suggest that single topical administration of leukotriene antagonist zafirlukast can be helpful in reducing capsule formation and preventing capsular contracture via myofibroblast suppression, modulation of fibroblastic cytokines, and anti-inflammatory effect.

Effect of propranolol on capsular reaction around silicone implants in guinea pigs

PURPOSE

To evaluate the effect of propranolol on capsular architecture around silicone implants by measuring the inflammation, capsular thickness, and collagen fiber density, using a guinea pig experimental model.

METHODS

Thirty six adult male guinea pigs randomly divided into two groups (n=18) were used. Each one received a silicone implant with textured-surface. The capsular tissue around implants from untreated or treated animals with the beta-adrenoceptor antagonist propranolol (10 mg/kg, dissolved in daily water) were analyzed for inflammation by histological scoring, capsular thickness by computerized histometry, and collagen fibers type I and Type III density by picrosirius polarization at different time points (7, 14 or 21 days after silicone implantation).

RESULTS

Propranolol treatment reduced inflammation and impaired capsular thickness and delayed collagen maturation around the textured implant.

CONCLUSION

Propranolol reduces the risk of developing capsular contracture around silicone implants with textured surface.

Further evidence that human acellular dermal matrix decreases inflammatory markers of capsule formation in implant-based breast reconstruction

BACKGROUND

Human acellular dermal matrix (HADM; previously termed "acellular cadaveric dermis") may limit inflammatory changes believed to play a role in capsular contracture, a common complication of implant-based breast reconstruction.

OBJECTIVES

Differences between HADM and native breast capsule specimens were evaluated by immunohistochemical analysis of key inflammatory markers involved in capsule formation.

METHODS

Twenty consecutive patients underwent immediate, 2-stage, implant-based breast reconstruction with dual-plane HADM. During tissue expander-implant exchange, full-thickness biopsies of biointegrated HADM and native breast capsule (internal control) from the tissue-expander envelope were obtained. Immunohistochemical analysis was performed for endothelial cells (CD31), B cells (CD20), T cells (CD3), macrophages (CD68), collagen I and III, and myofibroblasts (α-smooth muscle actin). Observed levels of marker labeling were semiquantitatively scored from 0 (none) to 3 (severe) by a blinded histopathologist and were statistically analyzed with the Wilcoxon rank sum test.

RESULTS

A bilateral sample was obtained from 1 patient; all other samples were unilateral. Compared with capsule samples from native breast tissue, HADM samples had significantly lower levels of all inflammatory markers (P < .001).

CONCLUSIONS

These lower levels of inflammatory markers support previous evidence that HADM may inhibit inflammatory and profibrotic signaling characteristics of breast capsule development and decrease the risk of capsular contracture. Further investigation is needed to determine the mechanism by which HADM inhibits these inflammatory cells, whether HADM reduces the incidence of breast capsular contracture, and if so, the longevity of this effect.

Pulsed acoustic cellular expression (PACE) reduces capsule formation around silicone implants

Capsular contracture remains a major complication after reconstructive or aesthetic breast augmentation. Formation of capsular fibrosis is a multifactorial process. An initial inflammatory reaction appears to be key to the development of capsular contracture. Recent studies have shown that pulsed acoustic cellular expression (PACE) has significant antiinflammatory effects. Thus, this study aimed to determine the potential of PACE to prevent or attenuate capsular contracture around silicone implants in a rodent model. For this study, 36 Lewis rats were divided into two groups, and a textured silicone implant was placed in a dorsal submuscular pocket. One group received PACE treatment, whereas the other group served as the control group and received no treatment. Follow-up evaluations were performed after 10, 35, and 100 days. Capsule thickness, collagen density, myofibroblasts, vascular density, and a semiquantitative real-time polymerase chain reaction that addressed differential gene expression were assessed. The PACE treatment significantly reduced capsule thickness on days 10, 35, and 100 compared with the control group (day 10: 632.9 ± 164.5 vs 932.6 ± 160.8, p < 0.05; day 35: 709.5 ± 175 vs 825.9 ± 313.3, p < 0.0.5; day 100: 736.3 ± 198.1 vs 1,062.3 ± 151.9, p < 0.05). This was accompanied by a significant suppression of proinflammatory genes (cluster of differentiation 68, monocyte chemotactic protein-1, CCL4) and synergistic alterations of pro- and antifibrotic proteins (transforming growth factor-beta 1, matrix metalloproteinase-2). This study showed that the PACE application significantly reduces capsular contracture around silicone implants. A decrease in capsular thickness after PACE treatment seems to be associated with a downregulation of proinflammatory genes and proteins. The study identifies PACE technology as a potential low-cost technique that is easy to use for reduction of capsular contracture after augmentation using silicone implants.

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 http://www.springer.com/00266 .

An innovative procedure for the treatment of primary and recurrent capsular contracture (CC) following breast augmentation

BACKGROUND

Capsular contracture (CC) is the most frequently reported complication following alloplastic breast augmentation. At present, none of the available preventive measures are effective, and various treatment modalities have been advocated. Reduction of the inflammatory process is critical for successful treatment. Late intracapsular glucocorticosteroid (GC) injections have been somewhat effective for the treatment, but the fine balance between the effectiveness of therapeutic GC dosages and their potential serious side effects is of utmost importance.

OBJECTIVES

The authors investigate whether instillation of a rapid-acting water-soluble GC in the implant pocket during the early proliferative phase of wound healing is more effective than delayed instillation during the remodeling phase.

METHODS

Between 2003 and 2009, 33 consecutive patients presenting with CC (Baker grades III and IV) were managed by capsulectomy with implant replacement and corticosteroid therapy immediately as well as 2 to 3 days later through an indwelling catheter left in place for that period. This delayed but early administration is a novel technique for GC injection.

RESULTS

Complete correction of the contracture with no recurrence was achieved in all patients with a follow-up range of 2 to 10 years.

CONCLUSIONS

This GC administration technique avoids the potential complications of long-term, slow corticosteroid release. It has a targeted anti-inflammatory effect, probably at a critical stage of the healing process, and could effectively prevent CC following alloplastic breast augmentation.

Effects of zafirlukast on capsular contracture: long-term results

Capsular contracture is a distressing complication after breast augmentation for both the patient and surgeon. Although capsular contracture is a multifactorial process, one common denominator in the successful treatment of this complication is believed to be the abatement of inflammation. Leukotriene antagonists have recently emerged as effective prophylactic agents in reactive airway diseases. A prospective study was carried out on 60 female patients (120 prostheses implanted) with mild/severe capsular contracture in at least one breast. The hardness of capsular contracture was assessed by means of the mammary compliance method. Patients received zafirlukast (Accolate&#174;) for a 6-month period. Mammary compliance was assessed at the start of the study and thereafter monthly, during drug intake and for one year after drug withdrawal. The results show a significant decrease in breast compliance values in the first 6 months, followed by a significant increase one year after the end of drug intake. Indeed, zafirlukast-treated patients displayed a 6.93 percent reduction in mammary compliance after 1 month, 14.42 percent after 3 months, 22.05 percent after 6 months and 22.52 percent after 7 months (1 month after the withdrawal of the drug). Thereafter, mammary compliance values gradually increased. A 5.47 percent reduction in mammary compliance was observed 1 year after drug withdrawal. The present study suggests that zafirlukast may be effective in reducing breast capsule distortion in patients with long-standing contracture, though reduced capsular contracture values are strictly related to the duration of drug intake.

The impact of triamcinolone acetonide in early breast capsule formation in a rabbit model

BACKGROUND

The etiology and clinical treatment of capsular contracture remain unresolved as the causes may be multifactorial. Triamcinolone acetonide applied in the pocket during surgery was reported to be ineffective in prevention of capsular contracture. However, if injected 4-6 weeks after surgery or as a treatment for capsular contracture, decreased applanation tonometry measurements and pain were observed. It was assumed that intraoperative application of triamcinolone was not effective because its effect does not last long enough. However, betadine, antibiotics, and fibrin were found to be effective in preventing capsular contracture with intraoperative applications and are more effective in the early phases of wound healing than in later stages. The role of triamcinolone acetonide in capsule formation is unknown. The purpose of this study was to determine if triamcinolone acetonide modulates breast capsule formation or capsular contracture in the early phases of wound healing in a rabbit model.

METHODS

Rabbits (n=19) were implanted with one tissue expander and two breast implants and were killed at 4 weeks. Implant pocket groups were (1) Control (n=10) and (2) Triamcinolone (n=9). Pressure/volume curves and histological, immunological, and microbiological evaluations were performed. Operating room air samples and contact skin samples were collected for microbiological evaluation.

RESULTS

In the triamcinolone group, a decreased capsular thickness, mild and mononuclear inflammation, and negative or mild angiogenesis were observed. There were no significant differences in intracapsular pressure, fusiform cell density, connective tissue, organization of collagen fibers, and microbiological results between the groups. There was no significant difference in the dialysate levels of IL-8 and TNF-α, but correlation between IL-8 and TNF-α was observed.

CONCLUSION

Triamcinolone acetonide during breast implantation influences early capsule formation and may reduce 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 at www.springer.com/00266.

The effect of Zafirlukast on capsule formation in post-radiation silicone implants

Currently, breast cancer represents the most common indication for mastectomy with negative influence on personal perception, sexuality and partnership. Since the introduction of breast implants, silicone, and saline breast implantation have become one of the most common procedures performed by plastic surgeons, not only for aesthetic reasons but also for reconstructive purposes. These women will ultimately be faced with the prospect of capsular contracture. This is especially true in patients receiving radiation therapy, where irradiation increases the risk of complications, capsular contracture and may compromise a favorable aesthetic result. Despite the capsular contracture is the most common complication for both aesthetic and reconstructive breast surgery, the treatment have remained unsolved. Leukotriene antagonists (LTRAs) have emerged as effective prophylactic agents in the management of reactive airway diseases, and recently they have used as an off label prophylactic agent against the capsular contracture after breast augmentation. However up to now there is no any experimental research or clinical study in the medical literature about the effect of Zafirlukast on the capsular formation around irradiated silicone implants.

Effect of zafirlukast on capsular contracture around silicone implants in rats

PURPOSE: To evaluate the effect of zafirlukast on capsular contracture around silicone implants by measuring the pressure within the implant, using a rat experimental model. METHODS: Forty adult female Wistar rats were used. Each one received two silicone implants, one with smooth-surface and the other with textured-surface. They were randomly divided into four groups (n=10). The rats of control group I were sacrificed after the implants. The remaining animals were subjected to a daily regimen of intra-peritoneal injection for a period of 90 days and they were distributed as follows: control group II received 0.9% physiological saline solution; experimental group I received zafirlukast 1.25 mg/kg; and experimental group II received zafirlukast 5 mg/kg. The measurement of intra-implant pressure of control group I was determined on the surgery day and in other groups on the ninetieth day, after being sacrificed. RESULTS: In the evaluation of textured implants there was an increase of internal pressure in the control group II, and there was no increase in the experimental groups. Compared to the controls there were not significant differences in smooth implants. CONCLUSION: Zafirlukast reduced the risk of developing capsular contracture around silicone implants with textured surface.

The impact of Smad3 loss of function on TGF-β signaling and radiation-induced capsular contracture

BACKGROUND

Capsular contracture remains a major problem following prosthetic breast implantation, especially in patients undergoing irradiation. Recent studies suggest that such radiation injuries are a cascading process of cytokine activation, with transforming growth factor (TGF)-β acting as the "master switch." Because TGF-β signals through phosphorylation of Smad3, a plausible approach to abate TGF-β-induced capsular contracture would be to interrupt Smad3 signaling. To test this hypothesis, capsular contracture formation in wild-type and Smad3 knockout mice was compared using micro-computed tomographic and histologic examination.

METHODS

On day 0, 48 mice were implanted with bilateral silicone gel implants. Postoperatively, animals were imaged using live-scan micro-computed tomographic scanning. Animals in the radiation arm then received a 10-Gy directed radiation dose. On postoperative days 21, 28, 35, and 42, animals were imaged again. Histologic evaluation was performed at necropsy.

RESULTS

Irradiated implants in the wild-type mice demonstrated shape and contour deformation on micro-computed tomographic scanning beginning on postoperative day 21 and progressing through day 42. Conversely, micro-computed tomographic scanning of irradiated implants in knockout mice demonstrated few changes from day 0 through day 42. Corresponding histologic specimens from wild-type mice demonstrated irregular capsules composed of disorganized collagen that became thicker from day 21 to day 42. Irradiated knockout specimen maintained thin capsules from day 21 through day 42.

CONCLUSIONS

In this work, inhibiting TGF-β signaling led to a reduction in radiation-induced capsular contracture as measured by micro-computed tomographic and histologic evaluation. The results of this study suggest a promising target for the prevention of capsular contracture through the development of anti-Smad3/TGF-β-based therapies.

Silicone and autoimmunity

BACKGROUND

Since the 1960s, silicone implants have been successfully used for breast augmentation and reconstruction. However, safety issues regarding the use of silicone have led to a moratorium by the US Food and Drug Administration between 1992 and 2006.

DESIGN

To date, although the moratorium has been removed and women overwhelmingly prefer silicone over saline implants, local and systemic adverse effects still remain a concern.

RESULTS

Silicone-elicited inflammatory fibro-proliferative response and capsular contracture is irrefutable. Studies on silicone breast implants have not supported a relationship to carcinogenesis, whereas that to autoimmunity mainly to nondefined autoimmune phenomena seems very plausible. These silicone-related autoimmune adverse events termed 'siliconosis' are probably limited to a small minority of implanted patients.

CONCLUSIONS

Risk factors, such as characteristic environmental exposure and/or genetic predisposition, still require further elucidation. Similarly to antibacterial agents, texturized implants and Zafirlukast that were found to be beneficial in inhibiting fibro-proliferative response and capsular contracture, elucidating autoimmune-related risk factors might subsequently enable physicians to accurately predict long-term health status of silicone implant recipients.

Acellular cadaveric dermis decreases the inflammatory response in capsule formation in reconstructive breast surgery

BACKGROUND

Acellular cadaveric dermis in implant-based breast reconstruction provides an alternative to total submuscular placement. To date, there has been no detailed in vivo human analysis of the histopathologic sequelae of acellular cadaveric dermis in implant-based breast reconstruction. Based on clinical observations, we hypothesize that acellular cadaveric dermis decreases the inflammatory response and foreign body reaction normally seen around breast implants.

METHODS

Twenty patients underwent tissue expander reconstruction using the "dual-plane" acellular cadaveric dermis technique (AlloDerm). During implant exchange, intraoperative biopsy specimens were obtained of (1) biointegrated acellular cadaveric dermis and (2) native subpectoral capsule (internal control). Histopathologic analysis was performed. Masked biopsy specimens were scored semiquantitatively by an experienced histopathologist to reflect observed granulation tissue formation, vessel proliferation, chronic inflammatory changes, capsule fibrosis, fibroblast cellularity, and foreign body giant cell inflammatory reaction. Scores were analyzed statistically using the Wilcoxon signed rank test.

RESULTS

Acellular cadaveric dermis (AlloDerm) had statistically diminished levels for all parameters compared with corresponding native breast capsules (p<0.001).

CONCLUSIONS

This represents the first detailed histopathologic comparative analysis between biointegrated acellular cadaveric dermis and native capsules in implant-based breast reconstruction. These histopathologic findings suggest that certain properties intrinsic to acellular cadaveric dermis may limit capsule formation by diminishing inflammatory changes that initiate capsule formation. Further investigation is needed to determine whether acellular cadaveric dermis reduces the incidence of breast capsular contracture.

Efficacy of antiadhesion barrier solution on periimplant capsule formation in a white rat model

Antiadhesive barrier solution (AABS) has been proven to prevent intraabdominal adhesion by reducing inflammation and fibrosis formation. Because this mechanism can also be applied to capsule formation after the breast implant insertion, we hypothesize that AABS can reduce capsular contraction and evaluate the efficacy of AABS on perisilastic implant capsule formation after submuscular insertion. A silicone block was inserted beneath the panniculus carnosus muscle in 10 rats. The experiment group received 0.1 mL of AABS (Guardix, Hanmi Medical Co.) instilled into the pocket, whereas the control group received 0.1 mL saline solution. Periimplant capsules were excised after 4 weeks and were evaluated for inflammatory cell count, capsular thickness, collagen pattern, and amount of myofibroblast. The inflammatory cell count and the capsular thickness were lower in the experiment group than in the control group (P < 0.05). The collagen pattern was loose and parallel in the experiment group, and the amount of myofibroblast was much less compared with the control group. AABS reduced the amount of inflammatory cells, myofibroblast, and capsular thickness. It also made the collagen fibers in the capsule loose and parallel. Therefore, AABS seemed to be effective in reducing the periimplant capsule formation.

Local Delivery of Nicotine does not Mitigate Fibrosis but may Lead to Angiogenesis

As with most implanted biomaterials, the wound healing response following implantation of a silicone breast implant leads to the formation of a fibrotic capsule. This can result in capsular contracture, a painful complication that often necessitates the removal of implant. It is well established that nicotine and nicotinic agonists inhibit inflammatory signaling. Based on the link between the inflammatory response and capsule formation, we hypothesized that local delivery of nicotine from the implant may lead to the reduction in inflammation and capsule thickness, which may ultimately reduce the incidence of capsular contracture. Nicotine was loaded into PDMS membranes using a previously established method. The loaded materials were implanted into the submammary pockets between the third and fourth mammary glands of rats. To confirm that the nicotine was acting locally and not systemically, serum cotinine, the primary metabolite of nicotine, was measured by ELISA at 3 days. Thirty days post implantation, the animals were euthanized and the tissue samples were fixed for histological analysis. Blood vessel density was measured immunohistochemically, while the capsule thickness was evaluated microscopically. While the presence of the nicotine metabolite, cotinine, in the serum at the early time points demonstrated that the nicotine was released locally from the devices, there were no significant differences in the capsule thickness between the control and experimental implants. However, the results indicated that there were differences in angiogenesis with the local delivery of nicotine, which may have other implications for the development of biomaterials.

The use of acellular dermal matrix to prevent capsule formation around implants in a primate model

BACKGROUND

Implant-based breast reconstruction is a popular option after mastectomy, but capsular contracture may detract from long-term outcomes. The authors have observed that breast implants covered with acellular dermal matrix (AlloDerm) are less likely to develop a capsule in the area where the implant is in direct contact with the acellular matrix. The authors tested this observation experimentally by comparing capsular formation around implants in the presence and absence of AlloDerm in primates.

METHODS

Eight smooth-surfaced tissue expanders were implanted into eight African green monkeys. In four experimental animals, a sheet of AlloDerm was draped over the tissue expander so as to cover the implant. Four control animals underwent placement of a tissue expander only. Animals were killed after 10 weeks and specimens underwent histologic and immunohistochemical analysis.

RESULTS

Hematoxylin and eosin staining of control specimens revealed the presence of a distinct layer of wavy, parallel arrays of collagen fibers consistent with capsule formation. Immunostaining identified abundant myofibroblasts, a profibrotic cell found in breast capsules. In the AlloDerm-covered specimens, no capsule layer was visible, and specimens stained weakly for myofibroblasts. The difference in myofibroblast staining intensity was statistically significant.

CONCLUSIONS

The use of AlloDerm to partially enclose implants effectively prevented formation of a capsule in areas where AlloDerm contacted the implant at 10 weeks. Long-term studies will be required to determine whether this is a durable result that can be reproduced in humans.

Effects of Singulair (montelukast) treatment for capsular contracture

BACKGROUND

Capsular contracture (CC) is one of the most common complications of breast augmentation surgery. Leukotrienes are implicated in the inflammatory cascade and have been postulated to be involved in the formation of CC. Therefore, leukotriene antagonists Accolate and Singulair have been prescribed by plastic surgeons off-label to treat and prevent CC. To date, there are no studies investigating the efficacy of Singulair on CC.

OBJECTIVE

The authors retrospectively review a series of patients treated with Singulair to determine whether it improves CC after breast implant surgery.

METHODS

Nineteen patients treated with Singulair by the senior surgeon (NH) after implant placement from March 2006 to November 2009 were included in this study. Follow-up on Singulair efficacy was obtained by a combination of office chart review and standardized telephone questionnaire. Results were characterized as complete improvement, improvement, no change, or worse.

RESULTS

Seventeen patients presented with CC resulting from a variety of breast operations. Two patients who had a history of recurrent CC were prescribed Singulair prophylactically immediately after surgery. Twenty-one breasts with existing CC were included in the total. Two (11%) patients became worse, three (16%) patients had no change, five (26%) improved, seven (37%) completely improved, and two (11%) were prevented from having CC formation.

CONCLUSION

Our preliminary study shows that Singulair improves CC. Breasts with mild CC (Baker score < III) appeared to have better improvement with Singulair compared to those with more severe contracture (Baker score III and IV). Singulair is well tolerated with minimal side effects and can be administered to patients after breast implant surgery to improve CC.

Influence of leukotriene inhibitor montelukast on wound contraction and cutaneous healing process in rats

BACKGROUND

Wound contractures can cause severe deformities and disabilities. Recent studies have suggested that leukotriene receptor antagonists have an inhibitory effect on the healing contraction process. This study aimed to evaluate the influence of the leukotriene inhibitor montelukast on the cutaneous healing process and the wound contraction phenomenon in rats.

METHODS

For this study, 60 male rats were randomly divided into four groups (MK-7d, SF-7d, MK-14d, and SF-14d) according to the drug given through a rigid orogastric tube (MK group: montelukast 10 mg/kg/day; SF group: normal saline solution) and the day the animals were killed (7d: postoperative day 7; 14d: postoperative day 14). An excisional wound (2 x 2 cm) was created on the dorsum of each rat. The wounds were left open to heal spontaneously and documented by standard digital photographs on different postoperative days. Wound contraction rates were calculated with specific software, and specimens were histologically evaluated using picrosirius red stain. Results were analyzed using the Aspin-Welch, Mann-Whitney, and t tests, assuming a significance level of 5%.

RESULTS

The wound contraction rates were similar between the control and study groups (p > 0.05). On postoperative day 7, the wounds showed a marginally significant reduction in collagen maturation in the study group (40.1% +/- 6.88% vs 61.2% +/- 8.02%; p = 0.0607). On postoperative day 14, this reduction was statistically significant in the MK group (26% +/- 5.66% vs 68.3% +/- 7.76%; p = 0.0001).

CONCLUSIONS

Montelukast does not alter the contraction rate of excisional wounds in rats but has a significant and progressive inhibitory effect on collagen maturation.

Zafirlukast pocket delivery impairs the capsule healing around textured implants in rats

BACKGROUND

The aim of this study was to investigate the effects of zafirlukast on capsule thickness, collagen fiber density, and myofibroblast cell count of the healing tissue around silicone textured implants in rats.

METHODS

Thirty-six male Wistar rats were divided (n = 18) into two groups. In one group, two parallel incisions (1.5 cm long) were made into the right and left sides of the spine. Two pockets were then created in which shell-shaped textured implants were inserted. The left-side pocket was injected with 0.2 ml of saline solution (SSG) and the right-side pocket with a dose of 1.25 mg/kg of zafirlukast (ZLG). The other 18 rats (sham, SG) had only one pocket created, followed by the placement of an implant and injection of 0.2 ml of saline solution. The rats were euthanized on the 7th, 35th, or 90th days followed by careful dissection of the implant. The capsules and peri-implant tissues were prepared for histologic analysis. An ANOVA test and Tukey test were applied (p < 0.05).

RESULTS

ZL was effective in impairing the capsule thickness on the 35th and 90th days compared to the other two groups (sham and saline). Not only was it effective in impairing the collagen density on the 35th and 90th days, but it also showed the same effect in the SSG (systemic); fewer myofibroblasts were counted on the 90th day in the ZLG compared to the SG group; the number of myofibroblasts was significantly lower in the ZLG than in the SSG.

CONCLUSIONS

Pocket delivery of one dose of Zafirlukast was effective in impairing capsule formation around the textured implant.

Sentinel lymph node detection and evidence of axillary lymphatic integrity after transaxillary breast augmentation: a prospective study using lymphoscintography

BACKGROUND

The transaxillary breast augmentation (TBA) technique has gained popularity because of several advantages. However, the impact of the procedure on breast lymphatic drainage and sentinel node (SN) detection remains controversial. The objective of this study was to evaluate the lymphatic patterns and SN detection rates after TBA by using lymphoscintigraphy (LSG).

METHODS

Twenty patients (40 breasts) who underwent TBA were evaluated by LSG immediately after periareolar injections of phytate-99 mTc at three time points: before TBA (Pre-LSG) and approximately 30 days (Recent-Post-LSG) and 6 months after TBA (Late-Post-LSG). Statistical analysis considered p \ 0.05 significant, or p \ 0.017 when Bonferroni correction was applied.

RESULTS

All breasts drained primarily to the axillary SN. The binomial test did not show statistical differences in lymphatic drainage patterns between Pre-LSG and Recent-Post-LSG (p = 1), Pre-LSG and Late-Post-LSG (p = 0.625), and Recent-Post-LSG and Late-Post-LSG (p = 0.625). The average number of hot SN was 1.28 in Pre-LSG, 1.10 in Recent-Post-LSG, and 1.23 in Late-Post-LSG, without significant differences (p = 0.202). The average time of the first SN appearance was not significantly different (p = 0.186). Analysis of SN uptake percentage showed a significant difference between Pre-LSG and Recent-Post-LSG (p = 0.009), with a reduction of drainage magnitude in Recent-Post-LSG.

CONCLUSION

The preservation of axillary lymphatic drainage after TBA allowed for SN detection in all studied breasts. It seems that the applied surgical technique played an important role in axillary lymphatic integrity.

Reduction of capsular thickness around silicone breast implants by zafirlukast in rats

Capsular contracture is a very disappointing complication, with an overall incidence between 0.5 and 30% of breast implant operations and, if severe, requiring a further surgical procedure (capsulotomy or capsulectomy). Many frustrating attempts have been made to prevent the fibrotic reaction, mainly with steroids or antibiotics. More recently leukotriene antagonists clinically used in the asthma and lung diseases have been suggested to be potentially useful in counteracting the inflammatory pathway leading to a dense collagen membrane around the prosthesis and thus preventing contracture of the capsule. In this study we evaluated the effectiveness of zafirlukast with the following protocol. Disks of textured implant material were placed dorsally into each of the subcutaneous tissues of 40 rats that were subdivided in 2 groups: 20 rats treated with zafirlukast and 20 controls. At autopsy 77 days after, each implant with its surrounding collagenic tissue was excised, and the macroscopic measure of the membrane thickness was compared with the pathology reports, to definitely assess the foreign body reaction. The mean total thickness of the capsule around the implants was 161.97 microm in the zafirlukast-treated group compared with 345.98 microm in the control group (p < 0.001). Outstandingly, the collagen fibers and fibroblast layer were reduced in the zafirlukast-treated group compared to the controls. Our study confirms the effectiveness of this compound in preventing fibrosis and putatively also in reducing the extent of collagen reaction when a capsule has been formed.