Polyurethane-covered Implants Research Articles

Fat Grafting and Prepectoral Prosthetic Reconstruction with Polyurethane-Covered Implants: Protective Role against Adjuvant Radiotherapy.

Background/Objectives: Breast cancer treatment increasingly incorporates immediate prepectoral prosthetic reconstruction after conservative mastectomy, including nipple-sparing (NSMs) and skin-sparing mastectomies (SSMs). Although recent data from the literature show that postmastectomy radiotherapy (PMRT) after prepectoral reconstruction presents good clinical results, with reduction in capsular contracture and implant migration, compared to the traditional submuscular technique, these patients have higher rates of long-term complications when compared with nonradiated patients. This study evaluates the protective effects of autologous fat grafting to reduce long-term radiotherapy-induced complications in breast cancer patients submitted for prepectoral reconstruction with polyurethane-covered (PU) implants. Methods: A pilot study with two parallel cohorts of patients undergoing an NSM or SSM followed by PMRT was conducted. Patients were randomly assigned to either of the two groups to ensure homogeneity. One cohort underwent autologous fat grafting sessions, individually tailored based on periodic evaluations by the principal investigator (PI), M. Salgarello, at least six months after PMRT. The control group received standard clinical follow-ups without fat grafting. Inclusion criteria ensured participants were disease-free, non-smokers, and had a LENT-SOMA score within 2. Results: Preliminary findings indicate significant differences between the groups, with improved outcomes observed in patients undergoing tailored lipofilling. Specifically, these patients experienced a notable reduction in capsular contracture severity and reported higher satisfaction with the aesthetic results compared to the control group. Conclusions: Autologous fat grafting, customized per patient by the PI based on ongoing evaluations, appears to mitigate some adverse effects of radiotherapy in prepectoral breast reconstruction, suggesting a viable option for enhancing surgical outcomes in irradiated patients. Further research is needed to substantiate these findings and evaluate long-term benefits.

When to Consider Prepectoral Implant Conversion After Subpectoral Implant Breast Reconstruction and How to Plan It.

Many deformities occur after subpectoral implant-based breast reconstruction. Today, immediate prepectoral reconstruction with implants shows a significant increase in popularity as it has many advantages over subpectoral positioning: absence of muscle deficit, breast animation, reduced implant dislocation, less postoperative pain and easy recovery. As such, implant pocket conversion from the submuscular to prepectoral plane has become our preferred strategy for solving most problems related to the submuscular implant position. The authors performed a retrospective review (from June 2018 to December 2022) of patients who underwent prepectoral implant conversion for the correction of animation deformity, dysfunctional chronic pain, and to ameliorate poor cosmetic results. The use of acellular dermal matrix (ADM) was done in the first 7 cases, in the remaining 56 were used polyurethane-covered implants. Resolution of animation deformity, chronic pain was evaluated in addition to cosmetic results and the onset of postoperative complications. Sixty-three patients (87 breasts) underwent prepectoral implant conversion with complete resolution of animation deformity, chronic pain and improved cosmetic results. Preventive lipofilling was done in 18 patients. Complication rate included 3 periprosthetic seroma in ADMs group. All were solved after US-guided aspiration. Rippling was noted in 3 patients and edge visibility was documented in 1 patient. There are no incidences of grade III and IV capsular contracture. The prepectoral implant conversion improves functional and aesthetic results, reaching excellent outcomes. The preparation for this surgery with fat graft is considered a complementary procedure that increases the indications for prepectoral implant conversion.

Types of Errors Made During Breast Augmentation with Polyurethane Implants: A Systematic Review.

Implementation of polyurethane-covered (PU) implants into practice requires a reassessment of the experience and a learning curve period. Occasional publications describe a few difficulties in this regard. However, there are no publications covering the spectrum of errors. The absence of definite information and contradictory findings makes the learning curve longer leading to many unsatisfactory results. The systematization is based on the 12years of experience with over 1000 patients and previously published data. A literature review was conducted using PUBMED with the following keywords: polyurethane or foam or sponge and breast and implant. A total of 285 articles were found (last accessed 08/13/2019). All articles concerning polyurethane implants were studied along with any articles found describing the surgical techniques applied to them. Additional references found in the above-mentioned articles were also included in the study. All errors can be divided into planning errors, errors in pocket development and surface-dependent errors, for which the polyurethane surface is the main reason. Surface-dependent errors include the errors connected to positioning and biointegration. The possible causes of late seroma with PU implants are discussed. The polyurethane surface should not be considered textured in the clinical point of view. Previous experience with non-PU implants cannot be transferred to PU implants. The learning curve is unavoidable. The systematization of errors with PU implants facilitates a decision-making process during the primary and secondary surgery and lowers the risk of the unsatisfactory results. 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 Table of Contents or online Instructions to Authors www.springer.com/00266.

One-step breast reconstruction with polyurethane-covered implants after skin-sparing mastectomy

Skin-sparing mastectomy (SSM) and immediate one-step breast reconstruction with implants has become an increasingly popular, effective treatment for selected patients with breast carcinoma. However, it is associated with high complication rates. Breast augmentation with polyurethane-covered implants (PCIs) has consistently had optimal short-term and long-term results with low rates of capsular contracture. The aim of this study was to evaluate the clinical and aesthetic outcomes of immediate one-step breast reconstruction with PCI after SSM in early breast cancer patients at a single institution. We reviewed the records of 221 consecutive breast cancer patients who underwent one-stage immediate reconstruction with PCI after SSM from 1995 through 2005. Patient and tumour characteristics, type of reconstruction, postoperative complications, aesthetic results and recurrence rate were analysed. The mean age of the patients was 52±11 years (range, 30-76; standard deviation (SD), 11). The American Joint Committee on Cancer (AJCC) pathologic stages were 0 (10%), I (63.3%) and II (26.7%). Thirty-nine (17.65%; confidence interval (CI)=13.04-23.1) of the 221 patients had complications; seven had prosthesis extrusion requiring an implant (five due to skin necrosis, one due to infection and one due to late haematoma). In six of these seven cases, the procedure was indicated for local recurrence after conservative breast surgery with adjunctive radiation therapy (rescue procedure). Thirty-two (14.4%) patients had minor complications: 12 had cutaneous rash, four had malpositioned implants and 16 had inadequate implant projection. At long-term follow-up, four (1.8%) patients had developed grade IV capsular contracture associated with postoperative radiation therapy. At a median follow-up of 98 months (range, 36-156), 14 (6.3%) patients had tumour recurrence and 12.2% had distant metastasis. Nineteen patients had died of cancer, and 192 (86.8%) remained disease free. One-stage immediate breast reconstruction with PCI after SSM appears to be oncologically safe and provides a high level of patient satisfaction.

Textured-Surface Saline-Filled Silicone Breast Implants for Augmentation Mammaplasty

The earliest silicone breast implants were smooth-surface, silicone rubber devices filled with either silicone gel or saline. Because of persistent problems with capsular contracture, polyurethane-covered silicone implants were developed as an alternative. Particularly in the short run, these alternatives proved highly successful at reducing the incidence of capsular contracture. By 1990, polyurethane-covered implants were rapidly becoming the preferred implant choice of many plastic surgeons, but for legal, regulatory, financial, and safety reasons they were withdrawn from the market by Bristol-Myers in 1991. Meanwhile, during the late 1980s, surface texturing and improved materials became available on other silicone breast implants and expanders. Most studies suggest that textured-surface silicone gel-filled implants, saline-filled implants, and tissue expanders have less frequent capsular contracture than their smooth-surface counterparts.

Analysis of risk factors associated with rupture of silicone gel breast implants.

Despite many recent studies on breast implant rupture, there is no general consensus on causation or incidence. Existing studies have not reported a multivariate analysis of risk factors associated with breast implant rupture. Most studies lack adequate sample size to study the effect of implant type, manufacturer, and other patient-related factors that might affect rupture. This study addresses all of these shortcomings. Patients undergoing implant removal by a single surgeon between 1990 and 1996 were examined for rupture and for 16 potential risk factors. The association between rupture and various factors was analyzed by univariate and multivariate analyses. A total of 842 patients underwent removal of 1619 implants. Increasing age of implant [p < 0.0001; adjusted odds ratio (OR), 1.20; 95% confidence interval (CI), 1.15 to 1.23], retroglandular location (p = 0.0002; OR, 1.93; CI, 1.37 to 2.71), Baker contracture grades III and IV (p = 0.005; OR, 1.52; CI, 1.14 to 2.03), and presence of local symptoms (p = 0.05; OR, 1.37; CI, 1.00 to 1.89) were associated with rupture. When different implant types were compared with smooth gel implants, after adjustment, double-lumen (p < 0.0001; OR, 0.33; CI, 0.22 to 0.50) and polyurethane-covered implants (p < 0.0002; OR, 0.33; CI, 0.20 to 0.57) had significantly lower rupture rates. When various manufacturers were compared with Dow Corning after adjusting for other factors, rupture rates were significantly lower for McGhan (p < 0.0001; OR, 0.41; CI, 0.26 to 0.65), whereas higher for Surgitek (p < 0.019; OR, 1.52; CI, 1.05 to 2.18). Significant risk factors for breast implant rupture were identified: older implants, retroglandular implant location, implant contracture, local symptoms, certain implant type, and certain manufacturer. Although the results of this study are based on a nonrandomized explant population from a single surgeon's practice, knowledge of these risk factors will permit better interpretation of future data on rupture. The knowledge will enable the medical community to better advise their breast implant population regarding durability and appropriate time for removal or replacement.

The fate of breast implants: a critical analysis of complications and outcomes.

Complications and outcomes were monitored following the implantation of 1655 breast implants over a 15-year period. Smooth, polyurethane, and textured implants were used in a variety of clinical settings. The time course of capsular contracture was analyzed by the Kaplan-Meier method. Regardless of implant type or indication for surgery, the probability of contracture increased with time. Polyurethane-covered implants were associated with a significant reduction in the risk of contracture for at least 7 years following implantation. Smooth and textured silicone implants had contracture rates similar to each other, and the particular type of surface texturing (Biocel versus Siltex) was of no consequence. Contracture was more common following breast reconstruction and implant replacement than after augmentation mammaplasty and was not affected by filler material or implant size. Implant position did not alter the risk of contracture after augmentation; tissue expansion did not affect the risk of contracture after breast reconstruction. Infections were unusual but most common after reconstruction and unrelated to surface texture or filler material. Skin wrinkling was more frequent with saline implants and in the presence of surface texturing. Implant rupture was rare, with an incidence of 1 per 760 implant-years. Implant-associated connective-tissue disease was noted in only one individual, an incidence of 1 per 3801 implant-years.

Biodegradation of the Polyurethane Foam Covering of Breast Implants

Although it is generally accepted that polyurethane-covered breast implants have decreased the incidence of clinical capsular contracture, there remain many unanswered questions regarding the physical and chemical degradation of the polyurethane foam covering itself. We have systematically studied the fibrous capsule and polyurethane foam recovered from human breast "explants" in an effort to characterize more precisely the biodegradation of polyurethane foam in the human body. Seventy-five freshly retrieved polyurethane-covered implants and surrounding capsule from 47 patients have been analyzed. Capsular tissue from several sampling sites around the surface of the implants was digested in a collagenase solution until foam was recovered or all tissue was digested. Additional samples were fixed in 10% formalin. Scanning electron microscopy was used to look for structural changes in the recovered intact foam and to determine the foam strut widths. Fourier transform IR spectroscopy and x-ray photoelectron spectroscopy were used to analyze the chemical composition of the polyurethane. The formalin-preserved capsule samples were examined histologically for further evidence of foam degradation. Of the 75 prostheses analyzed, 36 (48 percent) were removed because of capsular contracture and 10 (13 percent) because of infection or exposure of the prosthesis. The remaining 29 (39 percent) implants were removed for various other reasons. Visibly intact foam was recovered from 36 (48 percent) prostheses after enzymatic digestion of capsule tissue. There was a progressive decline in the ability to recover intact foam as the total implantation time increased. Scanning electron microscopy revealed fractures and fissures in the foam structure and thinning of the polyurethane struts. The mean strut width of control, unimplanted foam was 49 +/- 1.5 microns (+/- SEM). Retrieved foam from implants which developed capsular contracture and the infected implants had strut widths of 30 +/- 3.1 and 32 +/- 3.1 microns, respectively. In implants removed for other reasons, the polyurethane foam strut width was 41.2 +/- 2.3 microns. Despite an inability to recover visibly intact foam from 39 specimens, standard light microscopy of 37 of these same specimens showed residual polyurethane still present in the capsule. Various degrees of scalloping and fracturing of the foam were seen in the histologic sections. There is convincing evidence by scanning electron microscopy and histology that polyurethane is degrading. It was not possible to quantitate accurately the rate of degradation, but factors such as capsular contracture, infection, and time appear to have a role in the biodegradation of polyurethane in the human body. These relationships require further study.

Polyurethane-covered mammary implants: a 12-year experience.

Polyurethane-covered mammary implants are the implants of choice in aesthetic and reconstructive mammary surgery. These implants give very good results in regard to breast contour and consistency, and have a very low complication rate. We present our 12-year experience using polyurethane-covered prostheses. We place the implant mostly in the subglandular or subcutaneous site, and their capsular contracture rate is extremely low (3.3%). Based on our experience, we also review the other complications and side effects occurring with polyurethane prostheses and discuss them in detail.

Breast Reconstruction Utilizing Subcutaneous Tissue Expansion Followed by Polyurethane-Covered Silicone Implants

Breast Reconstruction Utilizing Subcutaneous Tissue Expansion Followed by Polyurethane-Covered Silicone Implants

Use of Stacked Polyurethane-Covered Mammary Implants in Aesthetic and Reconstructive Breast Surgery

The use of stacked polyurethane-covered mammary implants has proven useful in improving results in the correction of deficiencies of mammary form and projection that can occur in certain cases of congenital and acquired breast deformity. The method has been used in 57 patients (102 breasts). The rate of significant complications, including seroma, rash, infection, hematoma, and capsular contracture, has been low (1 to 6 percent). Polyurethane-covered implants will maintain their position when used in a stacked system because of their unique biophysical characteristics, which include tissue bonding and a high friction coefficient between the implant surfaces.

Comparative Experience with Smooth and Polyurethane Breast Implants Using the Kaplan-Meier Method of Survival Analysis

Smooth-walled silicone implants have been widely used in breast surgery. Capsular contracture, causing undesirable firmness and spherical deformity, has been a common problem. Recent studies suggest that polyurethane-covered breast implants are associated with a lower incidence of capsular contracture. The statistical methodology employed in some of these studies, however, may be subject to criticism. Between July of 1984 and June of 1990 (72 months), 427 polyurethane breast implants were used in 279 patients and 439 smooth prostheses were used in 250 patients for a variety of aesthetic and reconstructive procedures. The occurrence of capsular contracture was carefully monitored and then analyzed using the Kaplan-Meier method of survival analysis. This method is particularly well suited to analysis of these types of clinical data because it allows for the fact that contractures occur at varying intervals after surgery and that follow-up of patients is incomplete. The probability of capsular contracture with smooth-walled prostheses was found to be significantly greater than with polyurethane-covered implants in each group of patients studied (p less than 0.05). Other complications occurred at a similar rate regardless of prosthesis type. This study supports the belief that polyurethane breast implants have a lower contracture rate; furthermore, it introduces the Kaplan-Meier method for analyzing the outcome of alternative plastic surgical therapies.

Long-Term Complications of Polyurethane-Covered Breast Implants

The authors's personal experience using an earlier manufactured polyurethane-covered gel prosthesis is presented. Very long-term follow-up did not validate the author's initial enthusiasm. It is to be hoped that the newer polyurethane-covered implants will give more satisfactory long-term results.

Treatment of Breast Contractures with Open Capsulotomy and Replacement of Gel Prostheses with Polyurethane-Covered Implants

Capsular contracture around gel and gel-saline implants is the most common complication following breast augmentation and reconstruction. Thirty-one patients with postaugmentation gel-implant contractures were treated with open capsulotomy and replacement with polyurethane-covered implants. Eighty-seven percent remain soft after a minimum follow-up of 14 months. Results of replacement after subcutaneous mastectomy and reconstruction are more varied and less successful. Results in 14 patients are presented.

Surgical Correction of Breast Deformities Following Long-lasting Complications of Polyurethane-covered Implants

Breast deformities following long-lasting complications associated with the use of polyurethane prostheses are encountered with increasing frequency in our practice. Patients with this problem often feel frustrated after a long period of unsuccessful treatment and multiple operations. The anatomopathological bases of the deformity in such patients can be summarized as follows: volumetric mammary defect, soft tissue deficiency, and distortion and fibrosis of residual breast tissues. The reconstructive procedure should provide adequate aesthetic results with permanent or long-lasting symmetry, possibly in a single operative stage. The procedures employed in 12 patients are reviewed, and 3 representative cases are described in detail. The best aesthetic results in difficult cases have been achieved with either a latissimus dorsi muscular flap raised through minimal posterior incisions and transposed anteriorly to cover a permanent, expandable implant, or a suitably tailored, partly deepithelialized transverse rectus abdominis musculocutaneous flap.

Polyurethane Implants

The author reviews 6 years of experience and 416 patients in whom polyurethane implants were used for augmentation and reconstruction of the breast. As with many other plastic surgeons, early use was confined to "salvage cases." Owing to the impressive results, use was extended to routine augmentation. Polyurethane implants are now used exclusively for aesthetic breast surgery. Results are evaluated for replacement of gel capsules and simple and radical mastectomy reconstruction. Gel capsules (Baker stages III to IV), in which prostheses were removed and replaced with polyurethane-covered implants, improved in 29 of 32 patients (87 percent). For reconstruction, placement of polyurethane implants in unscarred situations gives far superior results than following repeated procedures. The incidence of infection is no higher than with gel implants. Removal without capsulectomy was not a problem in most instances. However, on two recent occasions capsulectomy was extremely difficult.