The effectiveness of sodium 2-mercaptoethane sulfonate (mesna) in reducing capsular formation around implants in a rabbit model

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

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

Investigation of Autologous Fat Transfer in Capsule Formation around Silicone Implants in a Rat Model

BACKGROUND

In this experimental study, the authors investigated whether fat placement in the pocket during implant insertion affects capsule formation.

METHODS

Twenty albino Wistar rats, 400 g each, were used. The rats were divided into two groups, A and B, of 10 rats each. At the dorsum of each rat, four pockets (2 × 2 cm each) were dissected, two left and two right of the midline. In each pocket, a 1 × 1 × 1.5-cm silicone implant was inserted. In the two left pockets, only silicone implants were placed (control). In the two right pockets, 0.4 ml of fat was injected around the implant. Animals in group A were killed 2 months postoperatively, and those in group B were killed 4 months postoperatively. The implants were dissected with the capsule and sent for histopathologic examination.

RESULTS

The data of the fat transfer group was compared with control in groups A and B. Capsule thickness, neovascularization, myofibroblast layer thickness, and mast cell population demonstrated no statistically significant difference in either group A (p = 0.385, p = 0.862, p = 0.874, and p = 0.210, respectively) or group B (p = 0.338, p = 1.000, p = 0.288, and p = 0.344, respectively). Inflammation was statistically significantly less (p = 0.07) at 4 months (group B) in the fat transfer group compared to the control group. Likewise, cellularity was statistically significantly less (p = 0.019) at 4 months for the fat transfer group compared with the control group.

CONCLUSION

Fat injection in the pocket during implant placement may reduce inflammation and cellularity of capsules and predispose to faster capsule maturation.

CLINICAL RELEVANCE STATEMENT

PLEASE PROVIDE 1- TO 2-SENTENCE STATEMENT.

Topical Application of High-Dose Mesna Prevents Adhesion Formation: An Experimental Animal Study

BACKGROUND

Adhesion formation is a common complication of abdominal surgeries. Mesna is a drug with fibrinolytic properties which has been used in surgical field to facilitate tissue dissection. The aim of this experimental animal study was to investigate the effect of mesna on prevention of intra-abdominal adhesion in rats.

MATERIALS AND METHODS

Twenty-eight Wistar albino rats were used in the study. To create abdominal adhesion, cecum was abraded in all rats. No additional surgical procedure was performed other than adhesion in group 1 (only adhesion). In the other groups, rats were treated topically by administering 0.9% saline (group 2), 40 mg/kg mesna (group 3), and 400 mg/kg mesna (group 4). All rats were sacrificed on postoperative 21st day. Histopathological and macroscopic evaluations of adhesion formation were performed.

RESULTS

Quantity of adhesion scores (P = 0.022), severity of adhesion scores (P = 0.041), total adhesion scores (P = 0.023), and histopathological adhesion grading scores (P < 0.001) were reduced by 400 mg/kg mesna.

CONCLUSIONS

This is the first study for mesna on prevention of abdominal adhesion formation in rats. We concluded that dose-dependent reduction of adhesion was achieved by mesna. With future studies, topical administration of mesna during open abdominal surgeries may be used to prevent adhesion formation.

Sodium Mercaptoethane Sulfonate Reduces Collagenolytic Degradation and Synergistically Enhances Antimicrobial Durability in an Antibiotic-Loaded Biopolymer Film for Prevention of Surgical-Site Infections

Implant-associated surgical-site infections can have significant clinical consequences. Previously we reported a method for prophylactically disinfecting implant surfaces in surgical pockets, where an antibiotic solution containing minocycline (M) and rifampin (R) was applied as a solid film in a crosslinked biopolymer matrix that partially liquefied in situ to provide extended prophylaxis. Here we studied the effect of adding sodium 2-mercaptoethane sulfonate (MeSNA) on durability of prophylaxis in an in vitro model of implant-associated surgical-site infection. Adding MeSNA to the M/R biopolymer, antimicrobial film extended the duration for which biofilm formation by multidrug-resistant Pseudomonas aeruginosa (MDR-PA) was prevented on silicone surfaces in the model. M/R films with and without MeSNA were effective in preventing colonization by methicillin-resistant Staphylococcus aureus. Independent experiments revealed that MeSNA directly inhibited proteolytic digestion of the biopolymer film and synergistically enhanced antimicrobial potency of M/R against MDR-PA. Incubation of the MeSNA containing films with L929 fibroblasts revealed no impairment of cellular metabolic activity or viability.

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.

Effect of Antiadhesion Barrier Solution and Fibrin on Capsular Formation After Silicone Implant Insertion in a White Rat Model

INTRODUCTION

One of the most serious complications of breast reconstruction and augmentation using silicone implants is capsular contracture. Several preventive treatments, including vitamin E, steroids, antibiotics, and cysteinyl leukotriene inhibitors, have been studied, and their clinical effects have been reported. However, the problem of capsular contracture has not yet been completely resolved. This study was performed to compare anti-adhesion barrier solution (AABS) and fibrin in their ability to prevent fibrotic capsule formation and simultaneously evaluated their effect when used in combination by capsular thickness analysis and quantitative analysis of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and type I collagen within the fibrous capsule.

MATERIALS AND METHODS

This study used female six-week-old Sprague-Dawley rats. Eighty rats were equally subdivided into the four following groups: AABS-treated, fibrin-treated, AABS and fibrin combined-treated, and untreated control groups. Each rat received two silicone chips under the panniculus carnosus muscle layer. The test materials were applied around the silicon chips. Four weeks later, the implantation sites including the skin and muscle were excised to avoid the risk of losing the fibrous capsule around the implants. The capsular thickness was analyzed by Masson's trichrome stain. Quantitative analysis of type I collagen, MMPs, and TIMPs was performed by real-time PCR, Western blot, and zymography.

RESULTS

The mean capsular thickness was 668.10 ± 275.12 μm in the control group, 356.97 ± 112.11 μm in the AABS-treated group, 525.96 ± 130.97 μm in the fibrin-treated group, and 389.24 ± 130.51 μm in the AABS and fibrin combined-treated group. Capsular thickness was significantly decreased in all experimental groups (p < 0.05). Capsular thickness was greater in the fibrin-treated group than in the AABS-treated group (p < 0.05). There was no statistically significant difference in capsular thickness between the AABS and fibrin combined-treated group and the AABS- or fibrin-treated group (p > 0.05). Compared to the control group, the experimental groups had significantly lower expressions of type I collagen and MMP-1 (p < 0.05), but there was no statistically significant difference in expressions of type I collagen and MMP-1 between the AABS-, fibrin-, and AABS and fibrin combined-treated groups (p > 0.05). The expressions of MMP-2 and TIMP-2 were not significantly different between the control and the experimental groups (p > 0.05).

CONCLUSION

AABS is more effective in reducing capsular thickness compared with fibrin treatment in a white rat model.

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.

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 .

How smart do biomaterials need to be? A translational science and clinical point of view

Over the last 4 decades innovations in biomaterials and medical technology have had a sustainable impact on the development of biopolymers, titanium/stainless steel and ceramics utilized in medical devices and implants. This progress was primarily driven by issues of biocompatibility and demands for enhanced mechanical performance of permanent and non-permanent implants as well as medical devices and artificial organs. In the 21st century, the biomaterials community aims to develop advanced medical devices and implants, to establish techniques to meet these requirements, and to facilitate the treatment of older as well as younger patient cohorts. The major advances in the last 10 years from a cellular and molecular knowledge point of view provided the scientific foundation for the development of third-generation biomaterials. With the introduction of new concepts in molecular biology in the 2000s and specifically advances in genomics and proteomics, a differentiated understanding of biocompatibility slowly evolved. These cell biological discoveries significantly affected the way of biomaterials design and use. At the same time both clinical demands and patient expectations continued to grow. Therefore, the development of cutting-edge treatment strategies that alleviate or at least delay the need of implants could open up new vistas. This represents the main challenge for the biomaterials community in the 21st century. As a result, the present decade has seen the emergence of the fourth generation of biomaterials, the so-called smart or biomimetic materials. A key challenge in designing smart biomaterials is to capture the degree of complexity needed to mimic the extracellular matrix (ECM) of natural tissue. We are still a long way from recreating the molecular architecture of the ECM one to one and the dynamic mechanisms by which information is revealed in the ECM proteins in response to challenges within the host environment. This special issue on smart biomaterials lists a large number of excellent review articles which core is to present and discuss the basic sciences on the topic of smart biomaterials. On the other hand, the purpose of our review is to assess state of the art and future perspectives of the so called "smart biomaterials" from a translational science and specifically clinical point of view. Our aim is to filter out and discuss which biomedical advances and innovations help us to achieve the objective to translate smart biomaterials from bench to bedside. The authors predict that analyzing the field of smart biomaterials from a clinical point of view, looking back 50 years from now, it will show that this is our heritage in the 21st century.

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.

Can the use of hyaluronidase reduce capsule formation?

BACKGROUND

The purpose of this study was to find whether the use of hyaluronidase reduces capsule formation.

METHODS

Ten New Zealand White rabbits were used. Eight pockets were created using an aseptic technique, four on the right side and four on the left side, along the vertebral column of every animal. One piece of silicone from a silicone block was inserted inside every pocket. The dimensions of each piece were 3.5 × 2 × 1.5 cm. In every pocket on the right side of each animal we placed 0.5 ml of hyaluronidase solution. The animals were sacrificed 5 months postoperatively. Capsule formation in the each side of the animals was compared.

RESULTS

Two rabbits presented infection in two pockets and were excluded from the study. There was a statistically significant difference between groups concerning the capsule thickness variable using parametric (P = 0.003) and nonparametric (P = 0.001) analysis [capsule thickness on the right side: 256.46 ± 114.88 (mean ± SD) and on the left side: 369.10 ± 147.81 (mean ± SD); capsule thickness on the right side: 235.69 (104.72) [median (IQR)] and on the left side: 332.12 (188.68) median (IQR)].

CONCLUSION

The use of hyaluronidase may reduce capsule formation around implants.

Effects of coagulase-negative staphylococci and fibrin on breast capsule formation in a rabbit model

BACKGROUND

The etiology and ideal clinical treatment of capsular contracture (CC) remain unresolved. Bacteria, especially coagulase-negative staphylococci, have been previously shown to accelerate the onset of CC. The role of fibrin in capsule formation has also been controversial.

OBJECTIVE

The authors investigate whether fibrin and coagulase-negative staphylococci (CoNS) modulate the histological, microbiological, and clinical outcomes of breast implant capsule formation in a rabbit model and evaluate contamination during the surgical procedure.

METHODS

Thirty-one New Zealand white female rabbits were each implanted with one tissue expander and two breast implants. The rabbits received (1) untreated implants and expanders (control; n = 10), (2) two implants sprayed with 2 mL of fibrin and one expander sprayed with 0.5 mL of fibrin (fibrin; n = 11), or (3) two implants inoculated with 100 µL of a CoNS suspension (10(8)CFU/mL-0.5 density on the McFarland scale) and one expander inoculated with a CoNS suspension of 2.5 × 10(7) CFU/mL (CoNS; n = 10). Pressure/volume curves and histological and microbiological evaluations were performed. Operating room air samples and contact skin samples were collected for microbiological evaluation. The rabbits were euthanized at four weeks.

RESULTS

In the fibrin group, significantly decreased intracapsular pressures, thinner capsules, loose/dense (<25%) connective tissue, and negative/mild angiogenesis were observed. In the CoNS group, increased capsular thicknesses and polymorph-type inflammatory cells were the most common findings. Similar bacteria in capsules, implants, and skin were cultured from all the study groups. One Baker grade IV contracture was observed in an implant infected with Micrococcus spp.

CONCLUSIONS

Fibrin was associated with reduced capsule formation in this preclinical animal model, which makes fibrin an attractive potential therapeutic agent in women undergoing breast augmentation procedures. Clinical strategies for preventing bacterial contamination during surgery are crucial, as low pathogenic agents may promote CC.

Effects of fibrin, thrombin, and blood on breast capsule formation in a preclinical model

BACKGROUND

The root cause of capsular contracture (CC) associated with breast implants is unknown. Recent evidence points to the possible role of fibrin and bacteria in CC formation.

OBJECTIVES

The authors sought to determine whether fibrin, thrombin, and blood modulated the histological and microbiological outcomes of breast implant capsule formation in a rabbit model.

METHODS

The authors carried out a case-control study to assess the influence of fibrin, thrombin, and blood on capsule wound healing in a rabbit model. Eighteen New Zealand white rabbits received four tissue expanders. One expander acted as a control, whereas the other expander pockets received one of the following: fibrin glue, rabbit blood, or thrombin sealant. Intracapsular pressure/volume curves were compared among the groups, and histological and microbiological evaluations were performed (capsules, tissue expanders, rabbit skin, and air). The rabbits were euthanized at two or four weeks.

RESULTS

At four weeks, the fibrin and thrombin expanders demonstrated significantly decreased intracapsular pressure compared to the control group. In the control and fibrin groups, mixed inflammation correlated with decreased intracapsular pressure, whereas mononuclear inflammation correlated with increased intracapsular pressure. The predominant isolate in the capsules, tissue expanders, and rabbit skin was coagulase-negative staphylococci. For fibrin and thrombin, both cultures that showed an organism other than staphylococci and cultures that were negative were associated with decreased intracapsular pressure, whereas cultures positive for staphylococci were associated with increased intracapsular pressure.

CONCLUSIONS

Fibrin application during breast implantation may reduce rates of CC, but the presence of staphylococci is associated with increased capsule pressure even in the presence of fibrin, so care should be taken to avoid bacterial contamination.

Effect of the inhibitor peptide of the transforming growth factor beta (p144) in a new silicone pericapsular fibrotic model in pigs

BACKGROUND

Capsular contracture is the most common complication associated with silicone prostheses. It may take the form of anything from slight hardening to obvious deformity. The role of transforming growth factor beta (TGF-beta) in the scar physiopathology of any fibrotic process has been demonstrated. The effects of inhibition of TGF-beta have also been demonstrated in experimental models of fibrosis, which opens the way for new therapeutic alternatives in the treatment of capsular contracture. The aim of this study was to evaluate periprosthetic fibrosis with a newly synthesized TGF-beta peptide inhibitor (p144).

METHODS

Three experimental groups were formed: Group I, subcutaneous and submuscular textured silicone prostheses were left untreated; Group 2, the prostheses were left after being immersed in the vehicle; Group 3, the same protocol was followed as in Group 2, but the solution contained the vehicle with the inhibitor peptide of TGF-beta, p144 (15 mg/prosthesis). The animals were sacrificed 24 weeks after implantation, and the capsules were assessed both macroscopically and histologically.

RESULTS

The results obtained showed that the inhibition of capsular thickness and soluble collagen content in pericapsular fibrosis did not significantly decrease in the group of animals treated with the TGF-beta inhibitor peptide in comparison with control cases.

CONCLUSIONS

We detected no statistically significant reduction in fibrosis in the periprosthetic capsule after treating the implants with the inhibitor peptide p144, but we feel that the influence of trauma around the prosthesis is critical in impeding the antifibrotic activity of the inhibitor peptide.

The immunology of fibrosis: innate and adaptive responses

Fibrosis is an important health problem, and its pathogenetic principles are still largely unknown. It can develop either spontaneously, or, more frequently, as a consequence of various underlying diseases. Irrespective of the primary cause, however, fibrotic tissue is always infiltrated by mononuclear immune cells. In most instances the reason for the attraction of these cells to fibrotic tissue and their proliferation remains to be determined; however their cytokine profile shows clear-cut proinflammatory and profibrotic characteristics. In this review, we discuss the innate and adaptive immune reactions associated with the development of fibrosis and the molecular basis of the profibrotic mechanisms taking place in systemic sclerosis (scleroderma), arteriosclerosis and peri-silicone mammary implant fibrosis.

Flector tissugel used to treat capsular contracture after breast augmentation surgery

Capsular contracture constitutes the main postoperative complication after breast augmentation by implant placement. To date, no systemic treatment known allows for improvement that does not simultaneously put the patient at risk for secondary complications of a more general nature. Flector Tissugel is the sole locally active antiinflammatory patch. Its durable local antiinflammatory effect is associated only with a risk for rare and highly limited side effects. After approximately 3 weeks of treatment, a high frequency of change from capsular contracture Baker 2 or 3 to Baker 1 occurs, provided the application was started no later than 3 months after the onset of capsular contracture.

Pirfenidone prevents capsular contracture after mammary implantation

BACKGROUND

Pirfenidone (PFD), a new antifibrotic and antiinflammatory agent, prevents and resolves fibrous tissue. This study evaluated the effect of PFD on adverse events in mammary implants using an animal model. Mammary implantation, the most frequent aesthetic surgery, may present several complications after surgery such as swelling, capsule contracture, hardness, and pain.

METHODS

Wistar rats underwent submammary implantation with either smooth or textured silicone gel implants and were administrated 200 mg/kg of PFD daily. The control group received saline. The animals were killed at 8 weeks. The capsular tissue of both implants was removed for histologic and molecular analyses.

RESULTS

Typical postaugmentation periimplant capsules with opacity on adjacent tissues developed 8 weeks after silicone implantation. No significant differences were observed between the textured and smooth implants in any analyzed parameter. Clearly, PFD reduced capsule thickness around submmamary tissue, fibroblast-like cell proliferation, and recruitment of inflammatory cells. The total cell numbers per field were reduced as well. In contrast, the control group presented abundant mononuclear cell infiltration and fibroblast-like cell proliferation. The total content of collagen in the PFD group was 50% less than in the control group. Fibroblast cells displayed 45% less activated phenotype in the PFD group than in the control group, as determined by immunohistochemistry techniques. In the PFD animals, transforming growth factor-beta (TGF-beta) decreased 85% and collagen 1 gene expression 60%, compared with the control group.

CONCLUSION

The findings show a positive effect of PFD on mammary contracture in 10 rats. Despite the small number of animals, the differences found in 10 control rats encourage the authors to propose a larger study later and to suggest PFD as a potential preventive strategy in human mammary implantation surgery.

Influence of rifampin on capsule formation around silicone implants in a rat model

This study investigated the effect of rifampin on the thickness of capsules around silicone implants by bactericidal activity against Stapylococcus epidermidis. Silicone blocks (1 x 1 cm) were placed into pockets created for each of the 40 rats included in the study. In group 1, the operation was performed under aseptic conditions. In group 2, standard S. epidermidis was inoculated into the pocket, whereas rifampin and S. epidermidis were applied in group 3. In group 4, only rifampin was applied topically on implants. After 12 weeks, the peri-implant capsules were removed and examined under a photomicroscope and a scanning electron microscope. The mean thickness of the capsules was 63.307 microm in group 1, 111.538 microm in group 2, 43.076 microm in group 3, and 30.384 mum in group 4. The differences between groups 2 and 3 and groups 2 and 4 were found to be statistically significant (p < 0.001). Rifampin appears to be an agent for preventing peri-implant capsule formation.

Capsular Contracture of the Breast

BACKGROUND

Breast reconstruction and augmentation have become a standard surgical treatment worldwide as advancements in medicine and technology enable safer and simpler procedures. A variety of implants is used to mimic a natural breast both in appearance and texture. The most common complication of such procedures is capsular contracture encircling the implant, occurring in approximately 10%. As to date, the contracture is mainly estimated by a physical examination of the breast, which is standardized according to the Baker score.

METHODS

In a cross-sectional study, we compared the clinical assessment of capsular contractures to a radiologic thickness of the capsule, as evaluated by ultrasound (US) and magnetic resonance imaging (MRI). A total of 20 patients, with 27 implants, were evaluated in the study. All patients were examined by a single senior plastic surgeon and divided into 4 groups according to their clinical Baker score estimation. Following, a US imaging of the implant with emphasis on capsular evaluation was performed. The MRI results, recently done prior to the study, were reevaluated in relation to capsular findings.

RESULTS

Thirteen breasts had a clinical capsular contraction with a Baker score of I, 8 breasts with a Baker score of II, and 6 breasts with a Baker score of III-IV. The US and MRI images of breasts graded III-IV revealed a thickened capsule (mean of 2.39 mm by US and 2.62 mm by MRI) compared with the capsular imaging of the breasts with the lower clinical Baker scores (mean of 1.14 mm by US and 1.39 mm by MRI). These differences were statistically significant according to the Kruskal-Wallis test, with P values of 0.002 and 0.017, respectively. Both MRI and US studies revealed distinct appearance of the thickened capsule.

CONCLUSION

It seems the capsular thickness as portrayed by US and MRI correlates well with the Baker scoring system and at the same time provides the physician with an objective and consistent evaluation. However, since clinical assessment can be difficult to interpret at times, objective-imaging modalities can be effectively used to assess capsular thickening in women with a clinical suspicion of capsular contraction. A revised classification of capsular contracture, taking into account the imaging of the capsule, is suggested.

Use of the Transforming Growth Factor-??1 Inhibitor Peptide in Periprosthetic Capsular Fibrosis: Experimental Model with Tetraglycerol Dipalmitate

BACKGROUND

Capsular contracture is the most common specific complication associated with silicone prostheses. It is thought to be caused by the gradual retraction of the fibrous scar tissue that forms around the prosthesis. Molecular biology has made it possible to determine the role of transforming growth factor beta (TGF-beta) in the scar physiopathology of any fibrotic process, including periprosthetic capsular fibrosis. The effects on the inhibition of TGF-beta have also been demonstrated in experimental models of scar formation and fibrosis, which opens the way for new therapeutic alternatives in the treatment of capsular contracture.

METHODS

Three experimental groups of 10 rats each were formed to evaluate periprosthetic fibrosis after its modulation with a newly synthesized TGF-beta1 peptide inhibitor in a tetraglycerol dipalmitate matrix. In the first group, subcutaneously and submuscularly placed, smooth, solid silicone prostheses were left untreated; in the second group, the prostheses were left after being immersed in a solution of tetraglycerol dipalmitate; and in the third group, following the same protocol as in the second group, the solution contained tetra-glycerol dipalmitate mixed with the inhibitor peptide of TGF-beta1. The animals were euthanized 8 weeks after implantation, and the capsules were assessed both macroscopically and histologically.

RESULTS

Inhibition of capsular thickness and cellularity was significantly more effective in the group of animals treated with the inhibitor peptide of TGF-beta1.

CONCLUSIONS

The TGF-beta1 inhibitor peptide applied in a matrix with tetraglycerol dipalmitate is significantly effective in achieving a reduction in periprosthetic fibrosis after placement of silicone implants, either subcutaneously or submuscularly. This result suggests new therapeutic approaches.

Effect of amniotic fluid on peri-implant capsular formation

Although commonly used biomaterials are physically and chemically stable, nonimmunogenic, and nontoxic, implanted and blood-contact biomaterials trigger a wide variety of unwanted responses, including inflammation, thrombosis, infection, and fibrosis. Peri-implant fibrosis is the response most commonly seen by plastic surgeons. In this study, the authors hypothesized that as hyaluronic acid (HA) reduces scar formation by inhibiting the activity of mononuclear phagocytes and lymphocytes, human amniotic fluid (HAF), which contains high concentrations of HA, HA-stimulating activator (HASA), and other factors, might prevent the formation of fibrous capsules and capsule contracture when applied intraluminally. Two 1 x 1-cm silicone blocks were placed dorsally into separate surgically created pockets underneath the panniculus carnosus muscle, distant from the incisions, in each of the 10 rats in the study. At the time of implant insertion, 2 ml of HAF was instilled into the cranially located pockets in group 1, whereas 2 ml of saline solution was instilled into the caudally located pockets in group 2. After 6 months, intracapsular static and dynamic pressure measurements were made, and then all the peri-implant capsules were excised and fixed in 10% neutral buffered formaldehyde. The thicknesses of the capsules were measured in three different areas of each section, and a mean was calculated. Capsular firmness, according to the static and dynamic pressure readings, was significantly greater in the control group, which had saline solution introduced into the pocket, than in the treatment group, which had HAF used in the same manner. The mean total thickness of the capsules surrounding the implants was 876.7 microm in the control group, as comparied with 466.8 microm in the HAF-treated group. This difference was statistically significant (p < 0.001). Because of its ability to reduce capsular thickness and firmness and also because it can be stored in a freezer if it is prepared in a cell-free manner, HAF would appear to be a useful adjunct in the prevention of capsular contracture formation.