Smooth Silicone Implants Research Articles

Prediction model for intraoperative implant volume using the 3D surface imaging system (VECTRA XT 3D) in direct-to-implant breast reconstructions.

In direct-to-implant breast reconstruction, accurate preoperative breast volume estimation is crucial for surgeons to select the appropriate implant volume, considering the cosmetic outcomes during surgery. We proposed the prediction model for intraoperative implant volume based on the preoperative estimated volume of the contralateral breast obtained through a three-dimensional surface imaging system (3DSI) as surgeons usually choose the implant volume on the breast which should be reconstructed considering symmetricity with the contralateral breast. We enrolled 97 patients from our single institution who underwent unilateral mastectomy with immediate breast reconstruction using smooth silicone implants between October 2021 and January 2023. Preoperatively, plastic surgeons measured the volume of the contralateral breast using the VECTRA XT 3D imaging system. Data on implant volume and the types of acellular dermal matrix used during surgery, determined by a single surgeon to ensure symmetry, were also collected. Linear regression analysis was utilized to construct the predictive model. In the multiple linear regression analysis with preoperative contralateral breast volume, age, and body mass index as variables, the coefficient of determination of the model expressed as R squared (R2) was 0.554, and except for age, the other variables were statistically significant. When replaced by mastectomy volume instead of age, R2 increased to 0.723 and all variables were significant. 3DSI can be helpful for preoperative surgical planning and postoperative outcome simulation. With our multiple linear regression model, we can predict the intraoperative implant volume using preoperative contralateral breast volume measured by the 3D scans.

Reducing Peri-implant Capsule Thickness in Submuscular Rodent Model of Breast Reconstruction With Delayed Radiotherapy

IntroductionCapsular contracture remains the most common complication following device-based breast reconstruction, occurring in up to 50% of women who also undergo adjuvant radiotherapy either before or after device-based reconstruction. While certain risk factors for capsular contracture have been identified, there remains no clinically effective method of prevention. The purpose of the present study is to determine the effect of coating the implant with the novel small molecule Met-Z2-Y12, with and without delayed, targeted radiotherapy, on capsule thickness and morphologic change around smooth silicone implants placed under the latissimus dorsi in a rodent model. MethodsTwenty-four female Sprague Dawley rats each had 2 mL smooth round silicone breast implants implanted bilaterally under the latissimus dorsi muscle. Twelve received uncoated implants and twelve received implants coated with Met-Z2-Y12. Half of the animals from each group received targeted radiotherapy (20 Gray) on postoperative day ten. At three and 6 months after implantation, the tissue surrounding the implants was harvested for analysis of capsular histology including capsule thickness. Additionally, microCT scans were qualitatively analyzed for morphologic change. ResultsCapsules surrounding Met-Z2-Y12-coated implants were significantly thinner (P = 0.006). The greatest difference in capsule thickness was seen in the irradiated 6-month groups, where mean capsule thickness was 79.1 ± 27.3 μm for uncoated versus 50.9 ± 9.6 μm for Met-Z2-Y12-coated implants (P = 0.038). At the time of explant, there were no capsular morphologic differences between the groups either grossly or per microCT. ConclusionsMet-Z2-Y12 coating of smooth silicone breast implants significantly reduces capsule thickness in a rodent model of submuscular breast reconstruction with delayed radiotherapy.

Differential Gene Expression in Capsules Derived From Smooth and Textured Silicone Implants

PURPOSE: Capsular contracture is the most common complication of implant-based breast surgery in the United States, leading to abnormal breast contour, increased firmness, and pain to touch. It is well established that smooth implants have higher rates of capsular contracture than textured implants. Assessing the effect of implant texture on contracture pathogenesis may help identify therapeutic targets for this disease process. The purpose of this study is to elucidate the pathogenesis of capsular contracture by examining RNA expression in a rat model of capsular formation around textured and smooth silicone implants, with pathologic correlation. METHODS: A small animal model of capsular contracture was developed using Fischer rats. Ten animals underwent miniature smooth or textured silicone implant insertion in the submammary gland position. Six weeks postoperatively, implant capsules were harvested for histologic and molecular analysis. RNA sequencing was performed to identify target genes expressed in extracted capsules. Selected gene expression levels were confirmed with quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry (IHC). Additionally, implant capsules collected from patients with and without capsular contracture were analyzed and correlated with results from our animal model. RESULTS: RNA sequencing data were subjected to the Probability of Positive Log Ratio (PPLR) algorithm. Transcripts were identified for further characterization using cutoff values of PPLR ≥0.975 (2-fold increase) or a PPLR ≤0.025 (2-fold decrease). We identified 18,555 transcripts that met PPLR inclusion criteria. Quantitative reverse transcriptase polymerase chain reaction was performed for matrix metalloproteinase-3 (MMP-3), troponin T3 (TNNT-3), and neuregulin-1 (NRG-1). Expression of MMP-3 and TNNT-3 was upregulated in textured implant capsules compared to smooth implant capsules with a mean relative fold change of 8.79 (P = 0.0059) and 4.81 (P = 0.0056), respectively. Expression of NRG-1 was downregulated in textured implant capsules with a mean relative fold change of 0.40 (P < 0.0001) compared to smooth implant capsules. IHC staining of capsules extracted from our animal model was consistent with differential expression patterns, with smooth implant capsules expressing less MMP-3 and TNNT-3, and more NRG-1 than textured implant capsules. Similarly, IHC staining of human specimens revealed that contracted capsules had lower expression of MMP-3 and TNNT-3 and greater expression of NRG-1 compared to healthy capsules. CONCLUSION: We demonstrated that capsules around smooth and textured implants have different histologic appearances and different patterns of gene expression. Importantly, pathologic correlation reveals that contracted capsules have expression patterns for MMP-3, TNNT-3, and NRG-1 that are consistent with capsules derived from smooth implants, which are known to have higher contracture rates. These results may help elucidate the mechanism of capsular contracture and identify potential genes for the development of future therapeutic targets for this condition.

Periprosthetic Capsule Formation and Contracture in a Rodent Model of Implant-Based Breast Reconstruction With Delayed Radiotherapy.

Capsular contracture (CC) is the most common complication of breast implantation, with an incidence of nearly 50% in patients undergoing breast reconstruction with subsequent radiotherapy. Although the move toward submuscular (SM) device placement led to a decreased incidence of CC, subcutaneous (SQ) implantation has seen a resurgence. The purpose of this study was to use a rodent model of breast reconstruction with smooth silicone implants and delayed radiotherapy to assess the occurrence of CC in SQ versus SM implantation. Custom 2 mL smooth round silicone implants were placed bilaterally into 12 female Sprague Dawley rats that were randomized into 4 groups of 3, with each group differing by implantation plane (SQ vs SM) and irradiation status (irradiated vs nonirradiated). Rats from the SQ group received implants bilaterally underlying the skin on the flank. Rats in the SM groups received implants bilaterally under the latissimus dorsi muscle. Irradiated rats received 20 Gy localized to each implant on postoperative day 10. One rat from each group was imaged with a micro-computed tomography scanner at baseline and at explant 3 months later, whereupon capsules from all rats were examined histologically. Rats in the SQ group showed evidence of contracture on gross examination and greater evidence of morphologic disruption per micro-computed tomography scan. There was no evidence of contracture or morphologic disruption in either SM group. Mean ± SD capsule thickness was 39.0 ± 9.0 μm in the SQ versus 37.6 ± 9.8 μm in the SM nonirradiated groups and 43.9 ± 14.9 μm in the SQ versus 34.3 ± 8.3 μm in the SM irradiated groups (all P > 0.05). In a rodent model of smooth silicone breast implantation and delayed radiotherapy, although there did not appear to be differences in capsule thickness regardless of device placement plane, SQ implants demonstrated gross evidence of CC. These data indicate that capsule thickness is only part of a larger pathogenetic picture, which should take into consideration the contribution from all peri-implant tissue.

A murine model of radiation-induced capsule-tissue reactions around smooth silicone implants

As the availability of breast reconstruction using implants is becoming widespread and many implant recipients undergo radiation therapy, there is an increasing interest in understanding the potential complications associated with capsule-tissue interactions in response to irradiation. Accordingly, our medical institution designed an animal experiment to investigate the effects of irradiation on capsular contracture. A total of 40 mice (C57BL6) were divided into four groups according to whether or not they received irradiation and the time from implantation to irradiation. After each mouse received a specially-fabricated, 1.5 cm semi-spherical silicone implant inserted into the area below the panniculus carnosus, half of the mice were irradiated using singe administration of a 10 Gy dose of radiation (6 MeV). Subsequently, data from gross inspection, histological analysis and immunohistochemical analysis were obtained at one and three months postoperatively and analyzed. Changes that occurred near the capsule led to the phenomenon of contracture subsequent to encapsulation. Our findings suggest that the inflammation reaction occurring near the implant becomes aggravated by ‘radiation toxicity’ and creates an environment conducive to capsular contracture. The present study demonstrated the process by which the complication of capsular contracture may occur during the treatment of human breast cancer via radiotherapy. These findings may serve as the basis for research and development of future treatments of capsular contracture.

Different types of implants for reconstructive breast surgery.

Different types of implants for reconstructive breast surgery.

Current Trends and Controversies in Breast Augmentation.

A survey was conducted to study current attitudes and common practices in breast augmentation. A 35-item electronic questionnaire was sent to the entire active American Society of Plastic Surgeons membership. It was divided into current controversies, new technologies, common practices, secondary procedures, and member demographics. There were 1067 respondents. Fifty percent of surgeons never use anatomically shaped implants and another 42 percent do so less than half the time. Autologous fat is used infrequently as a primary technique but more often as a supplemental technique. Approximately 7 percent report a case of anaplastic large cell lymphoma. Eighty-five percent do not use preoperative three-dimensional imaging. More than half of surgeons use acellular dermal matrix in secondary procedures. Approximately half do not use insertion funnels. Preoperative sizing with silicone implants, inframammary incisions, partial submuscular pockets, and smooth silicone implants larger than 300 cc are dominant practice preferences. Postoperative massage is still popular with over half of respondents. Just over half do not use pharmacologic agents for capsular contracture. Capsular contracture and size change were the most frequent reasons for reoperation. Capsular contracture is typically treated with anterior capsulectomy the first time, and either total capsulectomy or anterior capsulectomy with acellular dermal matrix use when recurrent. Almost half of respondents perform fewer than 50 breast augmentations yearly. There is an established most common approach to breast augmentation among respondents. Most surgeons are slow to embrace controversial practices and to adopt new technologies, although acellular dermal matrix use is becoming more popular. The 7 percent incidence of anaplastic large cell lymphoma was noteworthy.

Titanium-coated polypropylene mesh (TiLoop Bra®)—an effective prevention for capsular contracture?

Background Silicone implants have been used in breast augmentation for more than 45 years. Complications, in particular, capsular contracture, still occur with a high incidence. Titanium-coated polypropylene mesh (TCPM; TiLoop Bra®, pfm medical, Cologne, Germany) provides new opportunities for implant-based breast reconstruction. We investigated the influence of the surface of silicone implants on the formation of capsular contracture by comparing textured silicone with TCPM-covered smooth silicone implants.

Antibiotic Selection for the Treatment of Infectious Complications of Implant-Based Breast Reconstruction

Infection requiring explantation remains the most devastating complication associated with implant-based breast reconstruction. There are many treatment algorithms to prevent reconstructive failure in face of infection using both oral and intravenous antibiotics. In the absence of patient-specific culture data, antibiotic selection is generally directed toward broad-spectrum coverage based on historical data. We hypothesize that reviewing our institution's microbiology data obtained from explanted implant-based breast reconstructions would provide a rational basis for antibiotic selection in the future. A retrospective review of 902 consecutive immediate implant-based breast reconstructions at a single institution from November 2007 to May 2011 was conducted. Implant reconstructions requiring explantation or drainage by interventional radiology were identified. Patient demographics, implant characteristics, presence of skin necrosis, microbiological data, and outcomes were reviewed. Forty-three (4.76%) implant reconstructions requiring explantation or drainage by interventional radiology met the inclusion criteria for this study. Five patients (11.6%) had round, smooth silicone implants, and 36 (88.4%) had textured tissue expanders. Twenty-six implants were explanted because of infection; 3, because of exposure from skin necrosis; and 11, because of the combination of flap necrosis and infection; and 1, secondarily because of cancer invasion into the skin. Reconstruction was salvaged in 21 breasts (51.2%): 12 (57.1%) by implant reconstruction, 5 (23.8%) by pedicled latissimus dorsi flaps, and 4 (19.1%) with a microvascular free flap. Thirty explants had microbiology data available. The most common organism isolated was Staphylococcus epidermidis (10), followed by methicillin-sensitive Staphylococcus aureus (5), Serratia marcescens (5), Pseudomonas aeruginosa (4), enterococcus (3), Escherichia coli (2), Enterobacter (2), group B streptococcus (1), and Morganella morganii (1). Forty percent of the organisms were resistant to cefazolin; however, 86% were sensitive to gentamicin, 80% were sensitive to Levaquin, and 63% were sensitive to ciprofloxacin. Infection associated with implant-based breast reconstructions continues to threaten explantation and reconstructive failure. Based on our microbiological data, initial cellulitis amenable to oral antibiotics should be treated with oral fluoroquinolones as a first-line treatment. If this regimen fails, intravenous imipenem or gentamicin and vancomycin should be initiated. Obviously, clinical judgment regarding specific patient risk factors and compliance should play a role in decision making, but these data provide an evidence-based rationale for first-line oral antibiotic selection.

Effect of Tissue Inhibitors of Metalloproteinases and Matrix Metalloproteinases on Capsular Formation Around Smooth and Textured Silicone Gel Implants

Capsular contracture is one of the most distressing complications after cosmetic breast augmentation. Evidence suggests that matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) may play a key role in the onset or progression of several fibrotic disorders. In this study we used quantitative reverse-transcription PCR methodology to profile the expression of TIMP-1, TIMP-2, MMP-2, and MMP-9 in the tissue of patients with capsular contracture after breast augmentation with smooth and textured silicone breast implants. The study included 20 female patients (average age = 37 +/- 15 years) with capsular contracture after bilateral subglandular cosmetic breast augmentation with smooth silicone implants. Ten patients developed grade II capsule contracture, 8 grade III contracture, and 1 grade IV contracture. Twenty other female patients (average age = 41 +/- 9 years) with capsular contracture after breast augmentation with textured silicone implants were also included (Baker grade II = 10 patients, grade III = 8, grade IV = 2). Expression of mRNA in capsular tissue was calculated using a relative quantification method (Pfaffl). Statistical analysis was performed using the Mann-Whitney test. The level of significance was considered to be p < 0.05. The expression of MMP-2 was significantly increased in tissue of patients with textured implants and capsular contracture grades II and III/IV in comparison to grade I (p < 0.05). In comparison to grade I, the capsular tissue from patients with Baker II and III/IV fibrosis showed a significant increase for TIMP-1 and TIMP-2 (p < 0.05) in both smooth and textured silicone implants. The expression was significantly higher in tissue from patients with severe contracture (Baker III/IV) and smooth silicone implants compared with that in tissue from patients with textured implants (p < 0.05). The decrease in MMP-to-TIMP expression can cause increased synthesis and deposition of collagen surrounding alloplastic breast implants, leading to a profibrotic state. The higher expression of TIMPs in capsular tissue of patients with smooth silicone gel implants might be a reason for the observed higher rates of capsular contracture. In the future, a nonoperative treatment that decreases TIMPs but increases the activity of MMPs may be an appropriate therapy for patients with capsular contracture.

Tissue reaction to rough and smooth silicone implants. (A comparative and analytical experimental study in rats.) (English-Portuguese)

Tissue reaction to rough and smooth silicone implants. (A comparative and analytical experimental study in rats.) (English-Portuguese)

Quality of the capsule in reconstructions with textured or smooth silicone implants after mastectomy.

Many women desire some kind of reconstruction after mastectomy for breast cancer to improve the cosmetic result. Since the introduction of silicone breast implants, capsular contracture has been the most common complication of breast augmentation or reconstruction. The aim of the present study was to evaluate the capsule quality in patients with breast cancer who had undergone reconstructions with either textured (rough) or smooth silicone implants after simple or modified radical mastectomy. Forty-three consecutive patients had reconstructions with textured silicone implants (49 implants) and were evaluated 32 months post-operatively in a prospective clinical trial. The last 43 consecutive patients who had reconstructions with bilumen smooth silicone implants (49 implants) acted as controls. The results were graded by Baker's classification. Among the patients with textured implants only 9% (4/47) was graded as having moderate or severe capsular contracture in contrast to 24% (11/46) in patients with bilumen smooth-surface implants (p < 0.05). These results confirm previous reports that favour textured silicone implants in breast augmentation and reconstruction.

The Biophysical and Histologic Properties of Capsules Formed by Smooth and Textured Silicone Implants in the Rabbit

Capsular contracture remains the major complication of reconstructive and aesthetic breast surgery. The purpose of this investigation was to determine if a silicone implant with a textured surface will form a capsule of significantly different biophysical and histologic properties than conventional smooth silicone. Thirty smooth and 30 textured silicone tissue expanders were implanted under the panniculus carnosus of rabbits. After 3 months, measurements related to contracture were performed on anesthetized animals in an investigator-blinded, controlled manner. Intraexpander pressures were measured as saline was injected over time. We found a significant correlation between intraexpander pressures, applanation tonometry, and Baker class. Histology revealed a thicker, more adherent, and inflammatory capsule around the textured silicone implants as compared with the smooth silicone implants. Dynamic pressures were plotted against volume of saline within the two types of implants. Statistical analysis revealed that the textured implants form a tighter and thicker capsule than the smooth implants after 3 months of observation (p less than 0.005).