Transumbilical Silicone Breast Augmentation: A 13-Year Experience and 5-Year Analysis.

BACKGROUND: Transumbilical breast augmentation (TUBA) with saline implants has been considered a safe and efficient technique for decades. However, because silicone implants are more popular than saline ones, TUBA with saline implants is not widely performed. In 2014, we published a report on transumbilical breast augmentation using silicone cohesive gel implants. As we have performed transumbilical silicone breast augmentation (TUSBA) for 13 years with slight modifications, this study aimed to describe this novel technique and present accompanying patient outcomes over 5 years. METHODS: We enrolled patients desiring breast augmentation at a single center. The preoperative design was initially determined with the patients in standing positions before they underwent surgery under general anesthesia in a supine position. RESULTS: Between January 2018 and December 2022, 69 women and one man underwent TUSBA at a single center. All patients underwent cohesive gel silicone implantation in the subpectoral pocket. The implant size varied from 225 to 300 mL (average 272 mL) because two patients underwent surgery with implants of different sizes due to breast asymmetry. All patients were satisfied with the surgery outcome except one who was dissatisfied because of abdominal bulging. CONCLUSIONS: TUSBA offers advantages such as minimal scarring and unrestricted arm movement; thus, it can be an alternative option for patients seeking breast augmentation. 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 https://www.springer.com/00266 .

Silicone breast implants and connective tissue diseases: How does current evidence add to the no-association consensus? Systematic review and meta-analysis.

To evaluate the current state of the evidence regarding the association of silicone breast implantation with the onset of connective tissue diseases, constitutional symptoms, and rheumatic serological profile in adult women. A comprehensive search was carried out using MEDLINE, Embase, Web of Science and Scopus, from inception to September 2, 2020. Cohort studies assessing the clinical and serological profile of women with cosmetic breast implants were included. Meta-analyses were conducted using risk ratios. A total of 10 cohorts with overall moderate quality of evidence were included in this systematic review. Exposure to silicone breast implants was slightly associated with the development of rheumatoid arthritis [RR: 1.35; (95% CI 1.08 to 1.68); P = .008; I2 = 0%]. However, no significant differences were exhibited between the breast implant-exposed population and controls regarding the rest of the outcomes. In adult women, exposure to silicone breast implantation is not associated with the onset of constitutional symptoms and most connective tissue diseases. A marginal association with rheumatoid arthritis was exhibited, but the certainty of this result is jeopardized by the significant amount of self-reported data for this outcome. Further research is required to adequately explore the clinical significance of these results.

[Breasts and congenital chest-wall deformities: Surgical strategy with 3D implants]. / Le sein et les malformations thoraciques : stratégie chirurgicale et implants.

Computer-aided design and manufacturing of custom-made elastomer implants leads from a CT scan to fill in with precision, a congenital chest wall congenital deformity, both bone (pectus excavatum) and muscle (Poland Syndrome), resulting in a natural repositioning of the breasts. We report our 25 years' experience in 301 women (234 Pectus+64 Poland). Parietal correction must always be done in first intention. It is common to have to carry out a second stage in women with an additional mammaplasty especially in the presence of insufficient glandular volume or a fairly frequently associated tuberous breast.

Barbie Doll Forehead: CAD Design from Silicon Block.

The forehead is an important determinant of masculine or feminine look of the face. There are many methods described to achieve forehead augmentation for a more feminine face, and they include fillers, autologous fat grafting, silicone implant or methyl methacrylate. We present a case of a "Barbie doll forehead," which is an interesting trend in Asian countries. Availability of silicone implants of various sizes are not uniform and currently unavailable in India. Alternatively, we devised carved silicone block using computer-aided design (CAD). We also discuss the various methods described for forehead augmentation with their advantages and disadvantages.

Breast Implants Follow-up: Results of a Cross-Sectional Study on Patients Submitted to MRI Breast Examinations.

INTRODUCTION: Breast implants follow-up with any type of examination is often neglected; this may cause an error or delay in the diagnosis of complications prosthesis-related such as BIA-ALCL. This study aims to better understand adequate follow-up criteria. METHOD: All female patients undergoing aesthetic breast augmentation and breast MRI in its follow-up conducted from April 2006 to December 2019 were included in this study. The variables analyzed were age, breast implant surgery date, time with the implant, reason for the examination, and the final examination report. A logistic regression analysis was conducted to search for the predictors of positive findings in MRI. A Cox Regression analysis and cumulative risk curves, controlled by age, was performed to investigate the relationship between time with implants and the risk of positive findings in MRI. RESULTS: The patients submitted to MRI had complaints in 29.6% of cases, with pain being the most common, 13.9% of cases. In logistic regression analysis, time with the implant was associated with a higher risk of positive findings in univariate analysis (OR = 1.07, p = 0.036), but not in multivariate analysis. Both pain and breast form changes were independent predictors for positive findings in MRI, OR = 2.79, p = 0.04, and OR = 16.98, p < 0.001, respectively. The cumulative risk of positive findings in MRI increased considerably only after 10 years of implantation. CONCLUSIONS: Time with breast implants may be associated with a higher risk of changes in breast MRI examinations, although this relationship was not significant in multivariate logistic regression analysis. The cumulative risk for positive findings seems to increase considerably only after 10 years of implantation. This study draws attention to the paramount importance of follow-up with a clinical breast examination. Despite time with implants or patients' age, both pain and breast form changes were the most important predictors for MRI alterations. 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 .

The Treatment of Capsular Contracture Around Breast Implants Induced by Fractionated Irradiation: The Collagenase of the Bacterium Clostridium Histolyticum as a Novel Therapeutic Approach.

BACKGROUND: Irradiation therapy limits the utilization of silicone implants for breast reconstruction due to a significant risk for capsular contracture. The injection of the collagenase of the bacterium Clostridium histolyticum (CCH) might trivialize this risk by providing a minimal-invasive treatment option by capsular contracture degradation. However, efficacy in degrading breast implant capsules induced by fractionated irradiation remains unclear. METHODS: Twenty-four rats in three groups received miniature silicone implants in a submuscular pocket. After 3D dose calculation and treatment field definition, rats of two groups underwent fractionated radiotherapy (6 × 8 Gy) using a linear accelerator. A third group served as control. On day 120, one irradiated group received injections of 0.3 mg/ml collagenase. Administration of plain solvent solution served as control in the two other groups. Outcome parameters included CT-imaging, histology, vessel wall analysis, immunohistochemistry, chemical collagen quantification and gene expression analysis. RESULTS: Fractioned irradiation leads to a significant increase in collagen deposition around silicone implants with higher capsule thickness and collagen density when comparing all groups. Additionally, significant alterations of collagen fiber deposition were evident. Vessel wall thickness was significantly increased after radiotherapy. The injection of collagenase led to a significant reduction of capsule thickness, collagen density and content. However, the collagenase application induced a significant overexpression of TGFß1. No side effects were monitored. CONCLUSIONS: The CCH proved to be a safe and effective approach to degrade capsule tissue induced by fractionated irradiation in an animal model. This may pave its way for clinical application in implant-based breast reconstruction patients. LEVEL OF EVIDENCE: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Clinical and MRI Evaluation of Silicone Gel Implants with RFID-M Traceability System: A Prospective Controlled Cohort Study Related to Safety and Image Quality in MRI Follow-Up.

BACKGROUND: SmoothSilk implants (SSI) are the first generation of implants to incorporate a radio-frequency identification device (RFID-M), a non-invasive traceability system. Although the RFID-M is considered compatible with magnetic resonance imaging (MRI), the size of the artifact and its influence on breast tissue vary. This prospective study assessed safety and MRI issues in a cohort of breast reconstruction patients. METHODS: Forty-four SSI were used for breast reconstruction in patients undergoing treatment for breast cancer. All patients were evaluated for magnetic field interactions, MRI-related heating and artifacts in a 1.5-T MRI unit using standard T1/T2-weighted sequences utilized in clinical assessment of breast tissue/implants. RESULTS: Mean patient age was 41.5 years (27-53ys) and body mass index was 28+-6.44 kg/m2. In 18/22 patients (81.8%), mastectomies were unilateral. No patients reported local heat/discomfort. All implants showed RFID-M-related artifacts with an estimated mean volume in T1 of 42.9cm3 (26.2-63.6cm3; SD±8.6 and 95% CI, 40.37-45.45) and in T2 of 60.5cm3 (35.4-97.2cm3; SD±14.7 and 95% CI, 56.29-65.01). Artifact volume was smaller in T1 than in T2, to a statistically significant degree (p <0.001). There were no statistically significant differences in artifact volume according to surgical indication, breast side or implant volume. There were 4/44 (9%) cases of minor rotation (<45°). In all cases, adequate analysis of the breast tissue was performed. CONCLUSIONS: The results demonstrate that SSI with RFID-M technology presented an artifact volume of 42.9cm3 and 60.5cm3 in T1 and T2 images, respectively. Our findings provide detailed information on the quality and location of MRI artifacts in a reconstructed cohort which can help guide clinical decision-making for patients. To our knowledge, this is the first time RFID-M breast implants have been prospectively evaluated for clinical and MRI issues in a cohort of reconstructive patients. 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 .

Breast implant-associated anaplastic large cell lymphoma: A rare case report of lymphoma in the form of a pericapsular solid formation.

Breast cancer is the most frequently diagnosed cancer in women in the western world and a major cause of premature death. Consequently, breast implants are widely used for breast reconstruction. Despite this, the prevalence of implant complications is low. Given widespread use of breast implants, there is an increased awareness of the risk for developing a breast implant associated- anaplastic large cell Lymphoma (BI-ALCL) although rare. Clinical presentation is variable and may include a palpable mass in the breast or axilla, generalized breast pain, or breast firmness. The estimated incidence of BI-ALCL is <3 per 1 million person years, approximately 0.1-0.3 per 100 000 women with prostheses per year. Since the publication by Keech and Creech in 1997, which reported the first case of BI-ALCL, an increasing number of BI-ALCL have appeared, in patients with both aesthetic and reconstructive indications. In this paper, we describe a patient who was diagnosed with invasive BIA-ALCL seventeen years after placement of silicone breast implants and was treated with only surgery.

Study on the Effects of Estradiol in Staphylococcus epidermidis Device-Related Capsule Formation.

BACKGROUND: Capsular contracture, mainly caused by Staphylococcus epidermidis (S. epidermidis) biofilm formation, is a complex problem for breast cancer patients who undergo surgical prosthetic breast reconstruction. Estradiol has been reported to be involved in the formation of bacterial biofilms. Thus, the underlying mechanism of estradiol in capsular contracture needs to be investigated. METHODS: Biofilm-related gene expressions were measured by qRT-PCR after sterilizing the silicone with bacterial suspension and E2 treatment in vitro. Rat models were established with bilateral ovariectomy operations and estradiol subcutaneous injections. The effects of estradiol on capsular contracture were detected by monitoring serum estradiol levels, bacterial infection rate in organs, biofilm formation and capsular contracture in vivo; inflammatory factors in vivo were examined as well. Biofilm on the silicone implants was observed under a scanning electron microscope. RESULTS: Both positive regulatory genes and negative regulatory genes were increased by the high concentration of estradiol, suggesting that estradiol can promote the formation of biofilm by not only positive but also negative regulations. High estradiol levels increased bacterial infection rate in organs, biofilm formation and capsular contracture. Further, high estradiol caused a large number of inflammatory cells to infiltrate and caused serious inflammatory reactions that aggravate the immune imbalances of the host. CONCLUSION: High estradiol levels contribute to increasing capsular contracture caused by S. epidermidis biofilm formation. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The Collagenase of the Bacterium Clostridium histolyticum in the Treatment of Irradiation-Induced Capsular Contracture.

BACKGROUND: Irradiation therapy is an important pillar in the treatment of breast cancer. However, it can trigger capsular fibrosis, the most significant complication of implant-based breast reconstruction. As collagen is the main component of fibrotic capsules, the collagenase of the bacterium Clostridium histolyticum poses a potential treatment option for this pathological condition. METHODS: Thirty-six rats received miniature silicone implants on their backs. On day 1, the implant sites of two groups were irradiated with 10 Gy. On day 120, one irradiated group received collagenase injections into the implant pockets (n = 12). Non-irradiated (n = 12) and irradiated capsules (n = 12) were injected with plain solvent solution serving as controls. Data were analyzed by means of in vivo imaging, histology, immunohistochemistry and gene expression analysis. RESULTS: Compared with both controls, the injection of collagenase led to significantly thinner capsules. This was verified by in vivo imaging and histology. Although irradiation provoked alterations in capsule collagen structure and vessel wall thickness, the application of collagenase resulted in a significant reduction of collagen density. This was accompanied by an up-regulation of VEGF-A gene expression. Of note, hematoma formation inside the implant pocket occurred in two cases after collagenase injection. CONCLUSIONS: The collagenase of the bacterium Clostridium histolyticum is effective in degrading irradiation-induced capsular fibrosis around silicone implants. Hematoma formation occurred most likely because of irradiation-induced alterations in vessel wall architecture and capsule vascularization. Further studies need to be performed to address the clinical safety of this novel treatment option.

[The pectus excavatum: Secondary surgery with implants]. / Le pectus excavatum : chirurgie secondaire par implants.

The pectus excavatum affects about one in 500 people. It is the most common malformation of the thorax. Several surgical or medical techniques have been proposed. Some are followed by complications or insufficient results. Secondary surgery with a deep customized 3D implant, may be an elegant and effective solution; it allows to obtain a good aesthetic result expected by patients in the absence of any respiratory or cardiovascular functional context.

Structural interaction between bone and implants due to arthroplasty of the first metatarsophalangeal joint.

BACKGROUND: Currently, the metatarsophalangeal joint replacement through a restorative arthroplasty, where implants are used, is a viable invasive surgical medical procedure in the treatment of severe cases of osteoarthritis in this joint, better known as hallux rigidus. However, few things are known about the postoperative complications that implants can cause on the joint, like Swanson and Tornier implants.Research in this field can provide a valuable information that would help the specialist surgeon in the decision-making during the selection of the more suitable joint implant in each patient, as well as the redesign of the devices, to make them more efficient, durable and biocompatible with the human body. METHODS: The aim of this work is to perform a structural biomechanical analysis of a restorative arthroplasty of the first metatarsophalangeal joint, and to analyze the interaction between bone and medical grade silicone implants. For that, a simulation of a foot with Swanson and Tornier joint implants were performed to evaluate the stress/strain distribution during a critical stage (toe-off). RESULTS AND CONCLUSIONS: Principal stresses obtained for the first metatarsal with both implants suggest that failure is induced in this bone because, values exceed (up to 136.84% for Swanson model) the tensile strength reported for phalange trabecular bone, which may be related to osteolysis. Stress and strain values obtained in this work suggest that arthroplasty surgery with Swanson implant is more likely to cause postoperative complications versus Tornier implant.

Reverse-Muscle Sling Reduces Complications in Revisional Mastopexy-Augmentation.

BACKGROUND: Simultaneous augmentation-mastopexy is a particularly tricky operation with a considerable reoperation rate. The pectoralis muscle sling has proven to be a suitable alternative technique for long-term results in breast parenchyma suspension without silicone implants. This study aims to propose a promising approach to simultaneous augmentation-mastopexy revisional surgery using an inverted dual-plane technique acting as a muscular sling. METHODS: A 10-year historic cohort was conducted to obtain the following variables from our preexisting database: age, preoperative measurements, operative technicalities, implant details, time from procedure to revision, complications, and outcomes. RESULTS: Twenty-six patients assessed after the initial postoperative year were analyzed. Review of this series of patients revealed a revision rate of 3.8% and overall rate of morbidity of 11.5%. CONCLUSION: Simultaneous augmentation-mastopexy using an inverted dual-plane technique acting as a muscular sling is a reliable and safe procedure. Review of this series of patients revealed low rates of morbidity and reoperation need. 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 .

Long-Term Effects of the Collagenase of the Bacterium Clostridium histolyticum for the Treatment of Capsular Fibrosis After Silicone Implants.

BACKGROUND: Capsular contracture remains the most frequent long-term complication after augmentation mammoplasty with silicone implants. Thereby, the main part of the fibrotic capsule is collagen. The collagenase of the bacterium Clostridium histolyticum is approved for the treatment of fibrotic diseases and has been demonstrated to be effective for capsular fibrosis treatment in the short term. However, long-term effectiveness is currently unknown but mandatory for clinical utilization. MATERIALS AND METHODS: Forty-eight rats received miniature silicone implants and an injection with either collagenase (treatment group) or plain solvent solution (control group) 120 days post insertion. Ten and 60 days after the injections, the rats underwent 7-Tesla magnetic resonance imaging (MRI) and high-resolution ultrasound (HR-US). Capsule tissue was harvested, and capsule thickness and collagen density were evaluated through histology. Furthermore, the expression levels of inflammatory (CD68, IL4, IL10, IL12, IL13), pro-, and anti-fibrotic (TGFb1, TGFb3, Smad3, Col1-4) genes were analyzed using qRT-PCR. RESULTS: On days 10 and 60 after injection of collagenase, histology showed that capsule thickness was significantly reduced in the treatment group when compared with the control (p < 0.05). Thickness measurements were verified by MRI and HR-US analysis. Skin perforation occurred in two cases after collagenase injection. The initial up-regulation of pro-fibrotic and inflammatory genes 10 days after collagenase injection did not persist in the long term. Contrarily, on day 60, a slight trend towards lower expression levels with a significant down-regulation of TGFb3 was detected in the treatment group. CONCLUSION: The collagenase of the bacterium C. histolyticum effectively degrades capsular fibrosis around silicone implants with stable outcomes throughout 60 days post injection. Skin perforation and adequate and uniform drug distribution within the implant pocket are issues that need to be addressed. Further studies are warranted to clarify whether collagenase injections have the potential to become a viable treatment option for capsular contracture. NO LEVEL ASSIGNED: This journal requires that authors 46 assign a level of evidence to each article. For a full 47 description of these Evidence-Based Medicine ratings, 48 please refer to the Table of Contents or the online 49 Instructions to Authors. www.springer.com/00266 .

Calf Augmentation and Restoration: Long-Term Results and the Review of the Reported Complications.

BACKGROUND: Augmentation or reconstruction of the calves is indicated in patients with thin legs, for bodybuilders, or when there is a defect after an injury or illness. The principle of placing implants under the investing crural fascia was worked out in the 1980s. The senior author (I.N.) introduced many technical modifications and improvements for this operation, among them the new instrument, an inserter for the calf implants. Presented patient material is unique in that the more challenging reconstructive cases almost equal the numbers of the aesthetic cases. METHODS: During the years 1991 through 2016, 50 patients underwent 60 calf contour corrections. Indications were aesthetic in 23 patients, six were bodybuilders, and 21 underwent lower leg reconstruction because of deformity caused by illness. RESULTS: According to evaluation by the surgeon, excellent-to-good results were obtained in 30 out of 37 followed patients. Patients rated their results as very good (18), good (10), acceptable (7) and bad (2). One 28-year-old professional bodybuilder sustained acute anterior compartment syndrome in one leg. Implants were removed 16 h after surgery, but he developed ischaemia in the anterior compartment leading to the necrosis of muscles. After several surgical operations, including microsurgical transfer of the innervated central caput of the quadriceps femoris muscle, he could resume his bodybuilding activities. Other complications were minor and manageable. CONCLUSION: Calf augmentation, performed properly, has evolved to be a safe, efficient and aesthetically pleasing operation. The possibility of acute compartment syndrome should be kept in mind. 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 .

Mid-term outcomes of first metatarsophalangeal arthroplasty using the Primus FGT double-stemmed silicone implants.

BACKGROUND: Silicone implants for first metatarsophalangeal (MTP-1) arthroplasty are regaining popularity, though most studies have long inclusion periods, or short follow-up. The authors aimed to report mid-term outcomes of a cohort that received a third-generation MTP-1 implant at minimum follow-up of 5 years. METHODS: The authors evaluated 70 MTP-1 arthroplasties performed in 64 patients using the Primus™ Flexible Great Toe implant. The indications were hallux rigidus of grade II (10%) and grade III (87.1%) or revision surgery (2.9%). RESULTS: All patients completed clinical and radiographic assessments at 83.5 months (range, 62-114). There were no revisions or reoperations and the AOFAS-HMI score was 88.9±9.1 (median, 90; range, 67-100). Metatarsalgia was 'absent' in 47.1%, 'mild' in 41.1%, 'moderate' in 7.1% and 'severe' in 1.4%. CONCLUSION: This study reported excellent mid-term clinical outcomes and survival rates of a third generation MTP-1 arthroplasty design and confirmed findings of recent studies regarding efficacy of silicone double-stemmed implants. LEVEL OF EVIDENCE: Level IV case series.

[Breast implant-associated anaplastic large-cell lymphoma: A case report and a review of literature]. / Assotsiirovannaia s implantatom anaplasticheskaia krupnokletochnaia limfoma molochnoi zhelezy: opisanie klinicheskogo sluchaia i obzor literatury.

Breast implant-associated anaplastic large-cell lymphoma will be identified as a separate nosological entity in the 2017 adapted WHO classification due to differences in its clinical presentations, pathogenesis, and prognosis with those of nodal and cutaneous anaplastic large-cell lymphomas. The paper gives a review of the literature and describes the authors' own clinical case of common breast implant-associated anaplastic large-cell lymphoma involving breast tissue, axillary lymph nodes, anterior chest muscles, and bone marrow. The treatment policy chosen by the authors could achieve complete remission.

Removing silicone artifacts in diffusion-weighted breast MRI by means of shift-resolved spatiotemporally encoding.

PURPOSE: Evaluate the usefulness of diffusion-weighted spatiotemporally encoded (SPEN) methods to obtain apparent diffusion coefficient (ADC) maps of fibroglandular human breast tissue, in the presence of silicone implants. METHODS: Seven healthy volunteers with breast augmentation were scanned at 3 Tesla (T) using customized SPEN sequences yielding separate silicone and water (1) H images in one scan, together with their corresponding diffusion-weightings. RESULTS: SPEN's ability to deliver multiple spectrally resolved images in a single scan, coupled to the method's substantial robustness to magnetic field heterogeneities, served to acquire ADC maps that could be freed from contributions that did not belong to fibroglandular tissue. CONCLUSION: SPEN-based sequences incorporating spectral discrimination and diffusion-weighting enable the acquisition of reliable ADC maps despite the presence of dominant signals from silicone implants, thereby opening new screening possibilities for the identification of malignancies in breast augmented patients.

Effects of Different Concentrations of Injectable Collagenase Enzyme on Capsular Tissue Around Silicone Implants: A Preliminary Experimental Study for the Development of a New Treatment Strategy.

OBJECTIVES: In recent studies, collagen organization was blamed for the formation of capsular contracture which is still a challenging problem after silicone implant-based breast operations. In this study, effects of different concentrations of collagenase enzyme derived from Clostridium histolyticum on the capsular tissue formation around the silicone implants were investigated. The injectable form of collagenase has a routine clinical use in the treatment of both Dupuytren's and Peyronie's diseases. MATERIALS AND METHODS: Thirty-two Wistar albino rats were randomized into four groups. A 2 × 1 × 0.3-cm-sized silicone block was inserted inside a dorsal subcutaneous pocket in all groups. After 2 months of insertion, capsule thicknesses around the implants were detected under ultrasonography. This was followed by injection of isotonic saline, 150, 300, and 600 IU in Gr-1, 2, 3, and 4, respectively. All the animals were sacrificed at the end of the first week for histologic sampling to determine fibroblast proliferation, vessel density of the tissue, necrosis, edema, inflammation, and capsule thickness. All the data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests and compared for significance of the results. RESULTS: There was no significant difference in terms of capsule thinning between the 300 and 600 IU groups but in both groups thinning was significantly higher than the sham group. In the 150 IU group there was no significant thinning as compared to the sham group (p > 0.05). However, complications such as skin necrosis, infection, and seroma formation were seen only in the 600 IU injection group. The optimal safe and effective dose of the enzyme was accepted as 300 IU. The 300 IU injection provided up to 89 % thinning in the capsule tissue. There was thinning of the collagen bundles parallel to capsule thickness. In the 600 IU group, micro-pores were encountered at the thinnest points. CONCLUSION: However, the late results and recurrence rates of capsular contracture were not included in this study; collagenase seemed effective for the reduction of capsular tissue around the 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 www.springer.com/00266.