Polyurethane-coated breast implants revisited: a 30-year follow-up

Polyurethanes and Their Biomedical Applications

The tunable mechanical properties of polyurethanes (PUs), due to their extensive structural diversity and biocompatibility, have made them promising materials for biomedical applications. Scientists can address PUs' issues with platelet absorption and thrombus formation owing to their modifiable surface. In recent years, PUs have been extensively utilized in biomedical applications because of their chemical stability, biocompatibility, and minimal cytotoxicity. Moreover, addressing challenges related to degradation and recycling has led to a growing focus on the development of biobased polyurethanes as a current focal point. PUs are widely implemented in cardiovascular fields and as implantable materials for internal organs due to their favorable biocompatibility and physicochemical properties. Additionally, they show great potential in bone tissue engineering as injectable grafts or implantable scaffolds. This paper reviews the synthesis methods, physicochemical properties, and degradation pathways of PUs and summarizes recent progress in applying different types of polyurethanes in various biomedical applications, from wound repair to hip replacement. Finally, we discuss the challenges and future directions for the translation of novel polyurethane materials into biomedical applications.

Secondary Breast Augmentation: The Six Winning Moves

BACKGROUND

Breast augmentation in 2019 was the first among the top five cosmetic surgical procedures performed worldwide, according to the International Society of Aesthetic Plastic Surgery. It is not only the most commonly performed cosmetic surgery, but also the aesthetic procedure with the highest reoperation rate.

METHODS

A retrospective observational study of 306 female patients who underwent secondary breast surgery, with a follow-up of at least 1 year after surgery, from 2010 to 2020 is presented. For patients'selection, we decided to include all patients who performed a secondary breast surgery for aesthetic reasons; only patients with history of previous radiotherapy were excluded.

RESULTS

Patients were divided into different groups according to the performed procedure (the six winning moves) and associated postoperative outcomes are shown.

CONCLUSIONS

The aim of this paper, based on authors' own experience, is to present a personalized approach to secondary breast reshaping, describing the six "winning" moves to apply, which, differently combined among each other, intend to address each specific cause of reintervention with a dedicated surgical procedure.

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 .

Additive manufacturing of TPU devices for genital herpes treatment with sustained acyclovir release

The treatment of recurrent genital herpes typically involves daily doses of acyclovir for extended periods. Additive manufacturing is an intriguing technique for creating personalised drug delivery systems, which can enhance the effectiveness of treatments for various diseases. The vaginal route offers a viable alternative for the systemic administration of drugs with low oral bioavailability. In this study, we produced different grades of thermoplastic polyurethane (TPU) filaments through hot-melt extrusion, with acyclovir concentrations of 0%, 10%, and 20% by weight. We used fused filament fabrication to manufacture matrix-based devices, including intrauterine devices and intravaginal rings. Our results, obtained through SEM, FTIR, and DSC analyses, confirm the successful incorporation of acyclovir into the matrix. Thermal analysis reveals that the manufacturing process alters the organization of the TPU chains, resulting in a slight reduction in crystallinity. In our in-vitro tests, we observed an initial burst release on the first day, followed by sustained release at reduced rates for up to 145 days, demonstrating their potential for long-term applications. Additionally, cytotoxicity analysis suggests the excellent biocompatibility of the printed devices, and biological assays show a remarkable 99% reduction in HSV-1 replication. In summary, TPU printed devices offer a promising alternative for long-term genital herpes treatment, with the results obtained potentially contributing to the advancement of pharmaceutical manufacturing.

Long-term Insights: Histopathological Assessment of Polyurethane Implant Capsules Over 24 Years

BACKGROUND

Polyurethane (PU)-coated breast implants are known for their strong integration into breast tissue and the formation of capsules around them. However, capsular contracture can pose both aesthetic and clinical challenges.

OBJECTIVES

The objectives of this study were to analyze the biological and morphological characteristics of the capsular tissue surrounding PU-coated implants, irrespective of their contracture status, and to assess their potential suitability as a flap in revisional breast surgery for capsular contracture.

METHODS

A total of 23 tissue samples were harvested from the capsules surrounding PU-coated breast implants in 12 female patients during replacement or revisional surgery. We evaluated collagen abundance, cellular and vascular density, inflammation, collagen band types and alignment, synovial metaplasia, capsule thickness, and the expression of inflammatory biomarkers and myofibroblasts with immunohistochemical techniques. Scanning electron microscopy was employed to assess implant surface characteristics over time.

RESULTS

We found a significant association of capsule contraction with longer implantation durations and greater implant surface roughness (P = .018 and P = .033, respectively). Synovial metaplasia was significantly more frequent in noncontracted capsules (P = .0049). Both capsule types consisted of paucicellular, type I collagen-rich compact fibrous tissue with low vascularization. There was a marked reduction in inflammatory cells within the foreign body granuloma. The expression of inflammatory biomarkers in the capsular tissue was negligible.

CONCLUSIONS

Given the reduced levels of inflammatory and vascular components within the dense, fibrous capsular tissue, we consider them to be viable alternatives for capsular flaps in revisional surgery. This strategy has the potential to mimic the reconstruction achieved with acellular dermal matrix.

LEVEL OF EVIDENCE: 4

Capsular contracture in breast reconstruction: A systematic review and meta-analysis

BACKGROUND

Capsular contracture after implant-based breast reconstruction is not an uncommon problem and affects reconstruction outcomes. It can be influenced by various factors, such as the plane of implant placement, implant surface and implant type. This systematic review and meta-analysis aimed to evaluate how the abovementioned risk factors can affect capsular contracture rates.

METHODS

A systematic review and meta-analysis was performed. PubMed MEDLINE, EMBASE (OvidSP) and Cochrane Library were searched. Comparison groups included subpectoral versus prepectoral implant placement, smooth versus textured implants and saline versus silicone implants. Odds ratios (ORs) were calculated for capsular contracture for each group. The level of evidence was evaluated using the Oxford Centre for Evidence-Based Medicine.

RESULTS

Twenty-three studies met the inclusion criteria. Sixteen studies compared subpectoral versus prepectoral implant placement, with no statistically significant differences in capsular contracture rates [OR, 1.21; 95% confidence interval (95% CI), 0.75-1.95; P = 0.44]. Five studies compared smooth versus textured implants, with no statistically significant differences in capsular contracture rates (OR, 0.99; 95% CI, 0.50-1.93; P = 0.97). Two studies compared saline versus silicone implants for capsular contracture. Patients receiving saline implants had significantly lower capsular contracture rates than silicone implants (OR, 0.19; 95% CI, 0.08-0.43; P < 0.0001).

CONCLUSIONS

Implant-based breast reconstruction using saline implants demonstrated reduced capsular contracture rates compared to silicone implants. However, no significant differences were observed in capsular contracture rates between subpectoral versus prepectoral implant placement and smooth versus textured implants.

Immediate Breast Reconstruction in Skin-Reducing Mastectomy with Prepectoral Polyuretane (Pu) Implant Covered with an Autologous Dermo-Adipose Flap

BACKGROUND

The aim of this study was to present our new technique of immediate breast reconstruction with prepectoral Polyuretane (PU) Implants, covered with an autologous dermo-adipose flap, in skin-reducing mastectomy both for risk-reducing (prophylactic mastectomy) and therapeutic cases.

METHODS

We performed a single-center, retrospective review of 21 patients (mean age 47 years), undergone skin-reducing mastectomy and immediate breast reconstruction with prepectoral Polyuretane (PU) Implants, covered with an autologous dermo-adipose flap, un the period January 2018-June 2021. All procedures were performed by the same surgeon.

RESULTS

A total of 36 skin-reducing mastectomies (6 curative, 15 prophylactic) with one-stage prepectoral PU foam-coated implant and autologous dermo-adipose flap reconstruction were performed. All postoperative complications were collected. Quality of life (QoL) and satisfaction with reconstruction were evaluated through the BREAST-Q questionnaire, administered preoperatively and at 12 months after surgery. Independent Student's t tests were used to compare means of continuous variables and Chi-square test was used for ordinal variables. A p-value ≤0.05 was considered statistically significant. Uni- and multiple linear regression analyses were used to confirm all results. Out of 21 patients, we observed one small wound dehiscence and one partial Nipple-Areola Complex (NAC) necrosis. All cases of minor complications were managed conservatively and did not affect the quality of the final outcome. No implant loss was observed. No significant severe capsular contracture (grade III or IV) was detected at follow-up. Overall satisfaction with breasts, psychosocial, physical and sexual well-being all significantly increased, analyzing BRAST-Q data. Statistical analysis showed a significant influence of diabetes on the risk of complications.

CONCLUSIONS

Our experience suggests that the procedure described is effective, feasible and cost-effective. It is easier to perform compared to similar and more demanding procedure, reduces operative time, and minimizes complications related to manipulation of the pectoralis major muscle, while also contributing to the containment of costs. Moreover, it appears to be oncologically safe, provides good esthetic results with low postoperative complication rate and leads to high level of patients' satisfaction.

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 .

In Vivo Comparison of the Efficacy and Duration of Local Antibiotics on Smooth, Textured and Polyurethane Implant Surfaces

BACKGROUND

Capsular contracture is one of the most common complications after breast surgery involving silicone implants. The most likely cause of this condition is biofilm formation. In this study, the efficacy of local antibiotherapy against biofilm formation on implant surfaces was investigated.

METHODS

Thirty-six rats were divided into six groups. Three pockets were created on the dorsum of each rat, and 1 × 2 cm implant surface samples from smooth, polyurethane and textured implants were randomly placed into pockets. All samples were inoculated with staphylococcus epidermidis. In groups 1-2-3, inoculated samples were placed into the pockets and removed after 1, 6 and 24 h, respectively. In groups 4-5-6, inoculated samples immersed with rifamycin were placed and removed after 1, 6 and 24 h, respectively. Bacterial load was measured with plate count method.

RESULTS

Bacterial load was lower in groups 4-5-6 than in groups 1-2-3 (p < 0.05). In groups 4-5-6, bacterial load was lower for polyurethane than for textured surfaces at all time points (1, 6 and 24 h; p < 0.05). Again, in groups 4-5-6, bacterial load was lower for smooth than for textured surfaces at 24 h (p < 0.05). In groups 4-5-6, bacterial load was lower for polyurethane than for smooth surfaces at all time points, but difference was not statistically significant (1, 6 and 24 h; p < 0.05).

CONCLUSION

The results suggest that local antibiotic therapy was effective in reducing the bacterial load on all surfaces. The effectiveness of local rifamycin on the polyurethane surface was higher, and the duration of activity was longer than other surfaces.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of contents or the online Instructions to Authors www.springer.com/00266 .

Technical Refinements and Outcomes Assessment in Prepectoral Pocket Conversion After Postmastectomy Radiotherapy

BACKGROUND

Several studies show how submuscular breast reconstruction is linked to animation deformity, shoulder dysfunction, and increased postoperative chest pain, when compared to prepectoral breast reconstruction. In solving all these life-impairing side effects, prepectoral implant pocket conversion has shown encouraging results.

OBJECTIVES

The aim of this study was to propose a refinement of the prepectoral implant pocket conversion applied to previously irradiated patients.

METHODS

We conducted a retrospective study on 42 patients who underwent previous nipple- or skin-sparing mastectomy and immediate submuscular reconstruction, followed by radiotherapy. We performed fat grafting sessions as regenerative pretreatment. Six months after the last fat graft, we performed the conversion, with prepectoral placement of micropolyurethane foam-coated implants. We investigated the preconversion and postconversion differences in upper limb range of motion, Upper Extremity Functional Index, and patient satisfaction with the breast and physical well-being of the chest.

RESULTS

We reported a resolution of animation deformity in 100% of cases. The range of motion and the Upper Extremity Functional Index scores were statistically improved after prepectoral implant pocket conversion. BREAST-Q scores for satisfaction with the breast and physical well-being of the chest were also improved.

CONCLUSIONS

The refined prepectoral implant pocket conversion is a reliable technique for solving animation deformity and improving quality of life in patients previously treated with submuscular reconstruction and radiotherapy.

LEVEL OF EVIDENCE: 3

Polyurethane Implants in Revisional Breast Augmentation: A Prospective 5-Year Study

BACKGROUND

Revisional surgery for aesthetic breast augmentation remains a challenging procedure. Polyurethane (PU) implants have been found to avoid capsular contracture recurrence as well as to prevent implant displacement by bio-integrating with the pocket.

OBJECTIVES

Our study aimed to assess the use of PU implants in breast revisional surgery and to provide an algorithm.

METHODS

Over a 5-year period, a prospective study was conducted involving consecutive patients undergoing implant revision. Patient demographics, previous breast procedures, and specific surgical details were documented. Postoperative outcomes were followed up.

RESULTS

Out of 92 patients (184 breasts), 78 (156 breasts) were included in the analysis. The average age was 47.5, with a BMI of 22.3 and a mean follow-up of 5 years. A majority (63%) represented secondary revisional cases, while 37% were tertiary cases. Implant size averaged 296 cc, with 53% placed in retropectoral position and 47% prepectoral. Significantly more implants in secondary cases were changed from prepectoral to retropectoral (P = .005), and in tertiary changed from retropectoral to prepectoral (P = .002). Complete capsulectomy was performed in 61.5% and partial in 25.6%. Additional lipofilling was performed in 32%, and concurrent mastopexy in 40%. Revisional surgery in our series had a 1.9% acute complication rate, 4.5% longer-term reoperation rate for corrections, 0.6% implant exchange rate, and no recurrent capsular contracture.

CONCLUSIONS

This is the first study to provide data on outcomes of revisional breast augmentation surgery with PU implants. It shows that polyurethane implants offer consistent stability and have low rates of recurrent capsular contracture in revisional surgery.

LEVEL OF EVIDENCE: 3

Impact of polyurethane versus acellular dermal matrix coating on prepectoral reconstruction outcomes: Interface does matter

BACKGROUND

Interfaces continue to be used in prepectoral breast reconstruction to refine breast appearance, but more clinical data are required to assess their effectiveness. This study compares the rates of capsular contracture, breast esthetics, and patient satisfaction between two commonly used interface materials, acellular dermal matrix (ADM) and polyurethane (PU) foam.

METHODS

A cross-sectional assessment was conducted on all patients who underwent prepectoral direct-to-implant reconstruction with an interface material between June 2018 and June 2022. We compared capsular contracture rates (assessed in-person), esthetic outcomes (evaluated by a three-member panel using a specially designed scale), and patient satisfaction (measured using the Breast-Q questionnaire) among the members of the interface groups.

RESULTS

Among the 79 reconstructed breasts (20 bilateral cases), 35 were reconstructed using ADM and 44 using PU implants. The ADM group had a significantly higher frequency of Baker III/IV capsular contracture compared with the PU group (14.3% vs. 0%, p = 0.014) and lower ratings from the panel in terms of capsular contracture (median 3.7 vs. 4.0, p < 0.001). PU reconstructions scored worse in implant visibility (median 2.3 vs. 3.3, p < 0.001) and rippling (median 3.0 vs. 3.7, p < 0.001). However, after appropriate adjustment for confounders, no significant differences in overall appearance and patient satisfaction were found.

CONCLUSIONS

ADM reconstructions are prone to capsular contracture with all their related esthetic issues, but PU implants have certain cosmetic flaws, such as implant visibility and malposition. Since each technique has its own limitations, neither the experienced surgeons nor patients exhibited a clear preference for either approach.

Nonadherence of Polyurethane Implants: A Retrospective Cohort Study

Background  Biointegration of polyurethane (PU) implants providing their stable position years after surgery ensures predictable results of breast augmentation and reconstruction almost eliminating implant factor as a cause of complications. However, in rare cases PU implants appear to be not connected to the surrounding tissues. The aim of the study was to determine the incidence of PU implant nonadherence after primary breast augmentations and augmentation mastopexies with dual plane implant position, to analyze possible causes, and to propose preventive measures and treatment possibilities of this complication. Methods  The results of primary aesthetic surgeries in 333 patients with dual plane PU implant placement were analyzed. Patients were evaluated clinically, and pictures and videos taken in different periods after the surgery were compared. Particular attention was given to the changes in implant position and the appearance of asymmetries over time. Results  PU implant nonadherence was found in seven patients. It can be divided into primary and secondary and may be complete or partial. Primary nonadherence was found in two cases (0.6%), and secondary in five (1.5%) cases. Possible influencing factors could have been traumatic surgical technique, seroma, hematoma, or physical trauma. The average follow-up was 33 months (1 month-15 years). Conclusion  Biointegration is mandatory for the long-term predictable results with PU implants. PU implant nonadherence leads to implant malposition and may cause typical complications connected to non-PU implants. Improvements in surgical maneuvers, manufacturing process, and weight reduction of the implant may be beneficial for the stability of the results. Level of Evidence  V.

Silicone Shell Breast Implants in Patients Undergoing Risk-Reducing Mastectomy With a History of Breast-Conserving Surgery and Adjuvant Radiotherapy: A Long-term Study

BACKGROUND

Indications for breast-conserving surgery and adjuvant radiotherapy (BCSAR) in patients with breast carcinoma are increasing, as are indications for risk-reducing mastectomy (RRM) in healthy subjects. Most of these cases are reconstructed with silicone shell breast implants (SSBIs).

OBJECTIVES

The aim of this work was to study complications of SSBIs in breast reconstruction in patients undergoing RRM with previous BCSAR.

METHODS

A prospective cohort study was designed. The study group included cases of RRM reconstructed with SSBI in patients who had previously undergone BCSAR in the same breast. The control group consisted of patients with high-risk breast cancer who had undergone RRM and immediate SSBI reconstruction without previous BCSAR.

RESULTS

There was a history of BCSAR in 15.8% of cases. The first SSBI used in immediate reconstruction after RRM was replaced in 51.5% of cases with a mean [standard deviation] survival of 24.04 [28.48] months. BCSAR was significantly associated with pathological capsular contracture (P = .00) with this first SSBI (37.5% vs 5.9%). Of the cases requiring the replacement of the first SSBI, 44.23% suffered failure of the second SSBI, with a mean survival of 27.95 [26.53] months. No significant association was found between the consecutive development of capsular contracture in the second SSBI and a previous history of BCSAR (P = .10).

CONCLUSIONS

BCSAR prior to RRM reconstructed with an SSBI is associated with a significant increase in pathological capsular contracture. Patients should be warned of the high rate of SSBI complications and reconstruction failure. Polyurethane-coated implants may provide an alternative in cases in which alloplastic reconstruction is considered in patients with previous BCSAR.

LEVEL OF EVIDENCE: 3

It Is Time to Resolve the Dilemma and Move Away From Using Drains in Primary Breast Augmentation

Background

Breast augmentation is one of the most commonly performed aesthetic surgical procedures, yet there has been no consensus on the use of drains. While some surgeons believe in using them due to fear of complications or because they were taught in a conventional manner, the authors present their experience of performing breast surgery without the use of drains.

Objectives

To study whether performing breast augmentation without the use of drains is safe.

Methods

Anthropometric details and complications of all the consecutive primary breast augmentation patients performed by a single surgeon from 2009 to 2022 were collected and analyzed. In none of these patients, drains were used.

Results

A total of 429 (21%) patients were lost to follow-up and only those 1617 patients with a minimum follow-up of 6 months were included in this study. The mean age of the study group was 29.8 years with a mean BMI of 24.68. Mean follow-up was 16.24 months. Hematoma occurred in 15 patients (0.92%), seroma in 12 (0.74%), explantation due to infection in 3 patients (0.18%), and capsular contracture in 44 patients (2.72%). All these complications were in the lower range of complications of breast augmentation reported in the literature.

Conclusions

Unwarranted use of drains in breast augmentation should be avoided as it does not seemingly prevent the complications of breast augmentation surgery. Instead, it may increase the chances of infection, pain, and discomfort, and prolong the antibiotic coverage, and hence put an additional overall financial burden on the patient.

Level of Evidence 4

A multi-targeting bionanomatrix coating to reduce capsular contracture development on silicone implants

BACKGROUND

Capsular contracture is a critical complication of silicone implantation caused by fibrotic tissue formation from excessive foreign body responses. Various approaches have been applied, but targeting the mechanisms of capsule formation has not been completely solved. Myofibroblast differentiation through the transforming growth factor beta (TGF-β)/p-SMADs signaling is one of the key factors for capsular contracture development. In addition, biofilm formation on implants may result chronic inflammation promoting capsular fibrosis formation with subsequent contraction. To date, there have been no approaches targeting multi-facted mechanisms of capsular contracture development.

METHODS

In this study, we developed a multi-targeting nitric oxide (NO) releasing bionanomatrix coating to reduce capsular contracture formation by targeting myofibroblast differentiation, inflammatory responses, and infections. First, we characterized the bionanomatrix coating on silicon implants by conducting rheology test, scanning electron microcsopy analysis, nanoindentation analysis, and NO release kinetics evaluation. In addition, differentiated monocyte adhesion and S. epidermidis biofilm formation on bionanomatrix coated silicone implants were evaluated in vitro. Bionanomatrix coated silicone and uncoated silicone groups were subcutaneously implanted into a mouse model for evaluation of capsular contracture development for a month. Fibrosis formation, capsule thickness, TGF-β/SMAD 2/3 signaling cascade, NO production, and inflammatory cytokine production were evaluated using histology, immunofluorescent imaging analysis, and gene and protein expression assays.

RESULTS

The bionanomatrix coating maintained a uniform and smooth surface on the silicone even after mechanical stress conditions. In addition, the bionanomatrix coating showed sustained NO release for at least one month and reduction of differentiated monocyte adhesion and S. epidermidis biofilm formation on the silicone implants in vitro. In in vivo implantation studies, the bionanomatrix coated groups demonstrated significant reduction of capsule thickness surrounding the implants. This result was due to a decrease of myofibroblast differentiation and fibrous extracellular matrix production through inhibition of the TGF-β/p-SMADs signaling. Also, the bionanomatrix coated groups reduced gene expression of M1 macrophage markers and promoted M2 macrophage markers which indicated the bionanomatrix could reduce inflammation but promote healing process.

CONCLUSIONS

In conclusion, the bionanomatrix coating significantly reduced capsular contracture formation and promoted healing process on silicone implants by reducing myfibroblast differentiation, fibrotic tissue formation, and inflammation. A multi-targeting nitric oxide releasing bionanomatrix coating for silicone implant can reduce capsular contracture and improve healing process. The bionanomatrix coating reduces capsule thickness, α-smooth muscle actin and collagen synthesis, and myofibroblast differentiation through inhibition of TGF-β/SMADs signaling cascades in the subcutaneous mouse models for a month.

Comparing Polyurethane and Acellular Dermal Matrix Implant Cover in Prepectoral Breast Reconstruction: Short-term Complications

Implant covering with an interface material is the standard in prepectoral breast reconstruction. Acellular dermal matrix (ADM) is frequently used, but it is expensive and associated with complications. Alternatively, we have been using integrated devices consisting of a silicone implant coated with polyurethane (PU) foam. We aimed to compare both techniques in terms of acute complications.

Methods

The authors retrospectively reviewed patients undergoing prepectoral direct-to-implant reconstruction from June 2018 to January 2022. Two cohorts were defined based on the interface material used: ADM versus PU. Total drainage volume, time to drain removal, and acute complications (hematoma, seroma, infection, and explantation) were analyzed.

Results

Forty-four breast reconstructions were performed in 35 patients (10 bilateral); implants were covered with ADM in 23 cases and with PU foam in 21. Median total drainage volume (500 versus 515 cc for ADM and PU, respectively) and time to drain removal (9 versus 8 days) were not affected by the interface material used, but seromas and infections occurred exclusively in the ADM cohort (seromas in four of 23 of cases, P = 0.109; infections in three of 23 cases, P = 0.234). Overall complications occurred more often in cases reconstructed with ADM, but the difference was nonsignificant (P = 0.245).

Conclusions

The use of interface materials is generally considered a prerequisite for state-of-the-art prepectoral breast reconstruction for a variety of reasons, including the prevention of capsular contracture. In this study, PU coating tended to be associated with fewer short-term complications than ADM, including seroma and infection.

Improving Decision-making in Prepectoral Direct-to-implant Reconstruction After Nipple Sparing Mastectomy: The Key Role of Flap Thickness Ratio

We report our experience in direct-to-implant breast reconstruction with prepectoral polyurethane implants, with a focus on intraoperative mastectomy flap thickness compared to preoperative data (flap thickness ratio) as a reliable predictive variable of ischemic complications and reconstructive outcomes (satisfaction with breast).

BACKGROUND

The optimization of nipple sparing mastectomy and implant-based reconstruction techniques led to an increase in the popularity of prepectoral reconstruction. The aim of this study is to explore the ratio between the intraoperative and preoperative breast tissue coverage assessment as reliable tool in order to predict the risk of ischemic complications in prepectoral reconstruction.

METHODS

We analyzed 124 preoperative digital mammograms of 100 patients who underwent prepectoral implant-based reconstruction. We applied a Rancati modified score for breast tissue coverage classification, adding 4 measurements on the craniocaudal view. The intraoperative mastectomy flap thickness was measured using an intraoperative ultrasound assessment. We investigated the differences between the groups with and without ischemic complications related to the preoperative, intraoperative, and flap thickness ratio data.

RESULTS

The flap thickness ratio was lower in ischemic complication group compared to no ischemic complication group (0.4 vs. 0.8) with statistically significant differences for all ischemic complication subgroups: major mastectomy flap necrosis (P = .000), minor mastectomy flap necrosis (P = .005), partial nipple areola complex necrosis (P = .007), and implant exposure (P = .001).

Advances in surface modifications of the silicone breast implant and impact on its biocompatibility and biointegration

Silicone breast implants are commonly used for cosmetic and oncologic surgical indications owing to their inertness and being nontoxic. However, complications including capsular contracture and anaplastic large cell lymphoma have been associated with certain breast implant surfaces over time. Novel implant surfaces and modifications of existing ones can directly impact cell-surface interactions and enhance biocompatibility and integration. The extent of foreign body response induced by breast implants influence implant success and integration into the body. This review highlights recent advances in breast implant surface technologies including modifications of implant surface topography and chemistry and effects on protein adsorption, and cell adhesion. A comprehensive online literature search was performed for relevant articles using the following keywords silicone breast implants, foreign body response, cell adhesion, protein adsorption, and cell-surface interaction. Properties of silicone breast implants impacting cell-material interactions including surface roughness, wettability, and stiffness, are discussed. Recent studies highlighting both silicone implant surface activation strategies and modifications to enhance biocompatibility in order to prevent capsular contracture formation and development of anaplastic large cell lymphoma are presented. Overall, breast implant surface modifications are being extensively investigated in order to improve implant biocompatibility to cater for increased demand for both cosmetic and oncologic surgeries.

Wound Healing Response After Bleb-Forming Glaucoma Surgery With a SIBS Microshunt in Rabbits

Purpose

The PreserFlo MicroShunt is an innovative implant for the surgical treatment of glaucoma. Although usually effective, surgeries can still fail due to fibrosis. This study was conducted to gain insight into the histological aspects of the fibrotic response and find potential targets to reduce postoperative fibrosis.

Methods

Fifteen New Zealand White rabbits were implanted with a microshunt and followed up for 40 days. Animals were euthanized at postoperative days (PODs) 1, 5, and 40 to collect eyes for histological evaluation. Bleb formation and ocular health were assessed by slit-lamp (SL) biomicroscopy and optical coherence tomography (OCT). Intraocular pressure (IOP) was measured using rebound tonometry.

Results

Blebs failed after approximately 2 weeks based on bleb survival and IOP measurements. No severe complications were observed with OCT and SL. Histology revealed a wide variety of cells, in the bleb and around the microshunt, including polymorphonuclear leucocytes (PMNs), myofibroblasts, and foreign body giant cells, at different PODs.

Conclusions

Implantation of a poly(styrene-b-isobutylene-b-styrene) microshunt in rabbits resulted in the occurrence of a wide variety of cells during the wound-healing response. Future research should further elucidate the potential of these (earlier often overlooked) cells to target the fibrotic response in vivo—for example, by developing novel antifibrotic drugs, methods for sustained delivery of medications, or augmenting material properties.

Translational Relevance

Current antifibrotic therapies aim to inhibit myofibroblasts; however, a wide variety of cells are involved in the fibrotic response. Future research focusing on these cells could offer novel methods for reducing the fibrotic response after glaucoma surgery.

Challenges in delivering therapeutic peptides and proteins: A silk-based solution

Peptide- and protein-based therapeutics have drawn significant attention over the past few decades for the treatment of infectious diseases, genetic disorders, oncology, and many other clinical needs. Yet, protecting peptide- and protein-based drugs from degradation and denaturation during processing, storage and delivery remain significant challenges. In this review, we introduce the properties of peptide- and protein-based drugs and the challenges associated with their stability and delivery. Then, we discuss delivery strategies using synthetic polymers and their advantages and limitations. This is followed by a focus on silk protein-based materials for peptide/protein drug processing, storage, and delivery, as a path to overcome stability and delivery challenges with current systems.

HISTORY OF BREAST IMPLANTS: BACK TO THE FUTURE

Modern breast implants are a staple of plastic surgery, finding uses in esthetic and reconstructive procedures. Their history began in the 1960s, with the first generation of smooth devices with thick silicone elastomer, thick silicone gel, and Dacron patches on the back. They presented hard consistency, high capsular contracture rates and the patches increased the risk of rupture. In the same decade, polyurethane coating of implants was implemented. A second generation was introduced in the 1970s with a thinner shell, less viscous gel filler and no patches, but increased silicone bleed-through and rupture rates. The third generation, in the early 1980s, featured implants with a thicker multilayered elastomer shell reinforced with silica to reduce rupture risk and prevent silicone bleed-through. A fourth generation from the late 1980s combined thick outer elastomer shells, more cohesive gel filler, and implemented for the first-time outer shell texturing. In the early 1990s, the fifth generation of devices pioneered an anatomical shape with highly cohesive form-stable gel filler and a rough outer shell surface. Surface texturing was hampered by the discovery of Breast Implant Associated-Anaplastic Large Cell Lymphoma and its link with textured devices. From the 2010s, we have the era of the sixth generation of implants, featuring innovations regarding the surface, with biomimetic surfaces, more resistant shells and variations in gel consistency. The road to innovation comprises setbacks such as the FDA moratorium in 1992, the PIP scandal, the Silimed CE mark temporary suspension and the FDA-requested voluntary recall of the Allergan BIOCELL implants.

A Shakespearean Dilemma in Breast Augmentation: to Use Drains or not? a Systematic Review : Drains in Breast Augmentation

BACKGROUND

Breast augmentation is one of the most commonly requested and performed plastic surgery procedures. In order to prevent early postoperative complications such as seroma or hematoma, surgical drains could be useful. The aim is to perform a systematic review of the literature on the use of surgical drains in primary breast augmentation.

METHODS

This review was performed following the PRISMA guidelines. PubMed, SCOPUS, Web of Science and Cochrane Library databases were queried in search of clinical studies describing the use of surgical drains in women undergoing primary breast augmentation with implants and documenting seroma and/or hematoma formation rate and/or infection rate.

RESULTS

Initial search identified 2596 studies, and 162 were found relevant. Full-text review and application of our inclusion criteria to all retrieved papers produced 38 articles that met inclusion criteria. Among the included studies, 16 papers reported the use of surgical drains in breast augmentation, while in the remaining 22 articles drains were not used. Only 5 studies specifically investigated the role and effectiveness of surgical drains in augmentation mammaplasty and its possible relationship with complication rate such as seroma, hematoma or infection.

CONCLUSIONS

Despite similar complication rates emerged from the analyzed articles, because of the heterogeneity of the studies, we were not able to demonstrate specifically whether drain use affects the rate of early postoperative complications such as seroma, hematoma and infection. Additional randomized controlled trials are strongly advocated in order to provide the necessary scientific evidence.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The surface topography of silicone breast implants mediates the foreign body response in mice, rabbits and humans

Silicone is widely used in chronic implants and is generally perceived to be safe. However, textured breast implants have been associated with immune-related complications, including malignancies. Here, by examining for up to one year the foreign body response and capsular fibrosis triggered by miniaturized or full-scale clinically approved breast implants with different surface topography (average roughness, 0-90 μm) placed in the mammary fat pads of mice or rabbits, respectively, we show that surface topography mediates immune responses to the implants. We also show that the surface surrounding human breast implants collected during revision surgeries also differentially alters the individual's immune responses to the implant. Moreover, miniaturized implants with an average roughness of 4 μm can largely suppress the foreign body response and fibrosis (but not in T-cell-deficient mice), and that tissue surrounding these implants displayed higher levels of immunosuppressive FOXP3⁺ regulatory T cells. Our findings suggest that, amongst the topographies investigated, implants with an average roughness of 4 μm provoke the least amount of inflammation and foreign body response.

Additive Manufacturing of Multi-Scale Porous Soft Tissue Implants That Encourage Vascularization and Tissue Ingrowth

Medical devices, such as silicone-based prostheses designed for soft tissue implantation, often induce a suboptimal foreign-body response which results in a hardened avascular fibrotic capsule around the device, often leading to patient discomfort or implant failure. Here, it is proposed that additive manufacturing techniques can be used to deposit durable coatings with multiscale porosity on soft tissue implant surfaces to promote optimal tissue integration. Specifically, the "liquid rope coil effect", is exploited via direct ink writing, to create a controlled macro open-pore architecture, including over highly curved surfaces, while adapting atomizing spray deposition of a silicone ink to create a microporous texture. The potential to tailor the degree of tissue integration and vascularization using these fabrication techniques is demonstrated through subdermal and submuscular implantation studies in rodent and porcine models respectively, illustrating the implant coating's potential applications in both traditional soft tissue prosthetics and active drug-eluting devices.

Evaluating the Necessity of Capsulectomy in Cases of Textured Breast Implant Replacement

BACKGROUND

Capsulectomy has traditionally been recommended as a treatment for capsular contracture after breast augmentation. With the advent of breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL), and the Food and Drug Administration's decision to ban Biocell textured devices, this operation has taken on new importance. This review was undertaken to better inform clinical recommendations for women with textured devices.

METHODS

An electronic search was performed using PubMed to identify all the available literature on the subject of capsulectomy and open capsulotomy (the alternative treatment).

RESULTS

Fifty-seven articles on this topic were identified. Capsulectomy was widely recommended for treatment of capsular contracture, although many authors recommended leaving thin capsular tissue behind in the absence of symptoms. En bloc resection was recommended only for women with a diagnosis of BIA-ALCL. No information supported a prophylactic role for capsulectomy in asymptomatic women with textured breast implants who are concerned regarding their future risk of BIA-ALCL. Routine pathologic examination in asymptomatic patients was not supported.

DISCUSSION

Capsulectomy adds substantially to the surgical risk, discomfort, recovery time, and expense. Implant removal or replacement without a simultaneous capsulectomy is atraumatic and poses negligible risk.

CONCLUSIONS

Capsulectomy introduces additional morbidity and is not mandatory for asymptomatic patients. Implant removal or exchange for smooth implants without a capsulectomy may be an acceptable choice for many women who do not demonstrate capsular pathology. However, any symptoms or surgical findings suggesting pathology warrant a capsulectomy. En bloc resections are reserved for patients diagnosed with BIA-ALCL.

Direct to Implant Breast Reconstruction With Prepectoral Micropolyurethane Foam-Coated Implant: Analysis of Patient Satisfaction

BACKGROUND

Immediate implant reconstruction after mastectomy with submuscular implant placement is widely used in order to avoid implant exposure, capsular contracture and poor aesthetic result. Postoperative complications can be reduced by maintain mastectomy flap thickness and asses flap vascularity with near infrared imaging. The prepectoral reconstruction with polyurethane implants has been utilized with encouraging results. Postoperative patient satisfaction was assessed with the BREAST-Q scores in patients who underwent prepectoral reconstruction with polyurethane implants. Additionally the impact of mastectomy flap thickness on breast reconstruction was investigated.

MATERIALS AND METHODS

The Breast Q-scores of satisfaction with the breast, the postoperative outcome and physical well-being of the chest in 70 patients underwent immediate implant breast reconstructions with prepectoral polyurethane implant were retrospectively reviewed. The correlation between mastectomy flap thickness and satisfaction with breast was analyzed.

RESULTS

At 12-month follow-up the mean Q-score for satisfaction with breast was 71.73 (standard deviation: 13.31), and for physical well-being chest was 70.73 (standard deviation: 7.94). A positive linear correlation between mastectomy flap thickness and satisfaction with the breast was identified.

CONCLUSIONS

The postoperative Q-scores are encouraging in the use of polyurethane prepectoral implants in immediate breast reconstruction, especially in patients with "thick" mastectomy flaps.

Current status of breast implant-associated anaplastic large cell lymphoma in South Korea

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a unique type of lymphoma caused by breast implants. Concerns about BIA-ALCL have increased worldwide, and three domestic cases have been reported in South Korea. However, the incidence of the disease is not clear, and the risk probability has been reported to be up to 1/3,000. The most important factor in BIA-ALCL is the texturing of the implanted devices. Since the type of texturing is heterogeneous among products and companies, it is important for physicians to be aware of the spectrum of products and their implied risk. The pathophysiology of BIA-ALCL is presumed to be a combination of chronic inflammation related to the microenvironment and genetic predisposition. Further studies will allow accurate diagnosis and prognosis of the disease. The prognosis of BIA-ALCL is favorable if patients with late seroma or pericapsular masses are diagnosed early and complete surgical removal is achieved. Accurate diagnosis includes cytology or pathology with immunohistochemistry, including the CD30 protein and anaplastic lymphoma kinase. An essential factor in surgical success is radical excision with total capsulectomy. However, there is no evidence for prophylactic removal of a textured implant without symptoms. Careful examination and consultation should precede the implant removal, which can lead to deformity or complications. Domestic collaboration among healthcare providers for diagnosis and treatment is needed along with active reporting and registration of suspected patients. Finally, worldwide cooperation and improved awareness leading to regular surveillance are crucial in the era of BIA-ALCL.

Immediate Breast Reconstruction after mastectomy with polyurethane implants versus textured implants: A retrospective study with focus on capsular contracture

BACKGROUND

Capsular contracture (CC) is the most common complication following Immediate Breast Reconstruction (IBR) with breast implants. Different implant surfaces were developed aiming to reduce the incidence of CC. We evaluated the incidence and degree of CC after Direct-to-Implant (DTI) IBR with insertion of textured (TE) or polyurethane (PU) covered implants.

METHODS

A retrospective review of consecutive patients treated at our Institution with mastectomy and one-stage IBR and implant reconstruction between 2013 and 2018, with or without post mastectomy radiation therapy (PMRT), was conducted. Immediate breast reconstruction was performed by implanting 186 PU covered implants and 172 TE implants.

RESULTS

Three-hundred-twelve women underwent 358 DTI IBR with PU or TE implants, were analyzed with a median follow-up time of 2.3 years (range 1.0-3.0). The overall rate of CC Baker grade III and IV was 11.8% (95%CI: 8.4-16.3), while, after PU and TE implant placement it was 8.1% (95% CI: 4.1-15.7) and 15.8% (95% CI: 4.1-15.7) [p = 0.009]), respectively. Irradiated breasts developed CC more frequently rather than non-irradiated breasts (HR = 12.5, p < 0.001), and the relative risk was higher in the TE group compared with the PU group (HR = 0.3, p = 0.003).

CONCLUSIONS

After mastectomy and one-stage IBR, the use of PU covered implants is associated with a lower incidence of CC compared to TE implants. This advantage is amplified several folds for patients who necessitate PMRT. Footnote: Capsular contracture (CC); Immediate Breast Reconstruction (IBR); Directto- Implant (DTI); Textured (TE); Polyurethane (PU); Post mastectomy radiation therapy (PMRT); Nipple Sparing mastectomy (NSM).

Outcome of complete acellular dermal matrix wrap with polyurethane implant in immediate prepectoral breast reconstruction

Background

Polyurethane implants have been used on and off in breast reconstruction since 1991 while prepectoral breast reconstruction has gained popularity in recent times. In this study, we present our outcomes from the use of acellular dermal matrix (ADM) complete wrap with polyurethane implants in prepectoral breast reconstruction.

Methods

This is a retrospective review of prospectively maintained database from 41 patients receiving complete ADM wrap with prepectoral polyurethane implants over a 3-year period. Selection criteria were adapted from a previous study (4135 Trust Clinical Audit Database) evaluating prepectoral reconstruction with Braxon matrices. Patient demographics, operative data, surgical complications, and outcomes were collected and analyzed.

Results

A total of 52 implant reconstructions were performed in 41 patients with a mean follow-up of 14.3 months (range, 6–36 months). The overall reported complication rates including early (less than 6 weeks) and late complications. Early complications included two patients (4.9%) with wound dehiscence. One of which had an implant loss that was salvageable. Another patient (2%) developed red-breast syndrome and two women (4.9%) developed with seroma treated conservatively. Late complications included one patient (2%) with grade II capsular contraction, 12 patients with grade I-II rippling and two patients (4.9%) with grade III rippling.

Conclusions

We present our experience of prepectoral polyurethane implant using complete ADM wrap. This is one of the few papers to report on the outcome of the prepectoral use of polyurethane in immediate implant-based breast reconstruction. Our early observational series show satisfactory outcome and long-term results are warranted by a large multicenter study.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) in Poland: analysis of patient series and practical guidelines for breast surgeons

Introduction

Although breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is infrequent, with less than 1000 noted cases worldwide, patients consenting for breast implant surgery should be aware of its risk. We describe the first Polish multicenter case-series data on BIA-ALCL patients and present diagnostic and treatment recommendation for breast surgeons.

Material and methods

In cooperation with the Polish Society of Surgical Oncology and Polish Lymphoma Research Group, we collected BIA-ALCL cases in Poland.

Results

We retrospectively reviewed clinical data of seven BIA-ALCL patients, diagnosed between July 2013 and November 2019. The median time from implant placement to the first BIA-ALCL symptoms was 65 months (range: 33-96 months). All the patients were exposed to textured implants at presentation. Capsulectomy with implant removal was performed in all the patients with immediate reimplantation in 2 cases. In a median follow-up of 19 months (range 5-81 months), there was no recurrence and all the patients stayed alive. Between 2013 and 2019, the incidence of BIA-ALCL in Polish female population age 30 and above ranged from 0 to 0.021/100 000/year.

Conclusions

BIA-ALCL is scarce in the Polish population. In a short-term follow-up, patients' prognosis remains excellent. Due to the withdrawal of roughly textured implants from the market and the exclusion of likely the most potent etiologic factor, it might be expected that the incidence of BIA-ALCL will become even rarer.

Systematic Investigation of Polyurethane Biomaterial Surface Roughness on Human Immune Responses in vitro

It has been widely shown that biomaterial surface topography can modulate host immune response, but a fundamental understanding of how different topographies contribute to pro-inflammatory or anti-inflammatory responses is still lacking. To investigate the impact of surface topography on immune response, we undertook a systematic approach by analyzing immune response to eight grades of medical grade polyurethane of increasing surface roughness in three in vitro models of the human immune system. Polyurethane specimens were produced with defined roughness values by injection molding according to the VDI 3400 industrial standard. Specimens ranged from 0.1 μm to 18 μm in average roughness (Ra), which was confirmed by confocal scanning microscopy. Immunological responses were assessed with THP-1-derived macrophages, human peripheral blood mononuclear cells (PBMCs), and whole blood following culture on polyurethane specimens. As shown by the release of pro-inflammatory and anti-inflammatory cytokines in all three models, a mild immune response to polyurethane was observed, however, this was not associated with the degree of surface roughness. Likewise, the cell morphology (cell spreading, circularity, and elongation) in THP-1-derived macrophages and the expression of CD molecules in the PBMC model on T cells (HLA-DR and CD16), NK cells (HLA-DR), and monocytes (HLA-DR, CD16, CD86, and CD163) showed no influence of surface roughness. In summary, this study shows that modifying surface roughness in the micrometer range on polyurethane has no impact on the pro-inflammatory immune response. Therefore, we propose that such modifications do not affect the immunocompatibility of polyurethane, thereby supporting the notion of polyurethane as a biocompatible material.

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

BACKGROUND

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.

MATERIALS AND METHODS

The systematization is based on the 12 years 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.

RESULTS

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.

CONCLUSIONS

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.

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 Table of Contents or online Instructions to Authors www.springer.com/00266.

Implant Surface Options and Biofilm Mitigation Strategies

Two important topics in breast augmentation and reconstruction relate to device surface texture and practices to mitigate biofilm contamination of implants. Breast augmentation can be considered a manufacturing process where planning concepts of process engineering and quality can be used to produce great outcomes. This article reviews the options available for surgeons with regards to device surface texture selection and practices to mitigate biofilm contamination of implants at the time of surgery.

The Epidemiology of Breast Implant-Associated Anaplastic Large Cell Lymphoma in Australia and New Zealand Confirms the Highest Risk for Grade 4 Surface Breast Implants

BACKGROUND

The epidemiology and implant-specific risk for breast implant-associated (BIA) anaplastic large cell lymphoma (ALCL) has been previously reported for Australia and New Zealand. The authors now present updated data and risk assessment since their last report.

METHODS

New cases in Australia and New Zealand were identified and analyzed. Updated sales data from three leading breast implant manufacturers (i.e., Mentor, Allergan, and Silimed) were secured to estimate implant-specific risk.

RESULTS

A total of 26 new cases of BIA-ALCL were diagnosed between January of 2017 and April of 2018, increasing the total number of confirmed cases in Australia and New Zealand to 81. This represents a 47 percent increase in the number of reported cases over this period. The mean age and time to development remain unchanged. The implant-specific risk has increased for Silimed polyurethane (23.4 times higher) compared with Biocell, which has remained relatively static (16.5 times higher) compared with Siltex implants.

CONCLUSIONS

The number of confirmed cases of BIA-ALCL in Australia and New Zealand continues to rise. The implant-specific risk has now changed to reflect a strong link to implant surface area/roughness as a major association with this cancer.

Microtexture and the Cell/Biomaterial Interface: A Systematic Review and Meta-Analysis of Capsular Contracture and Prosthetic Breast Implants

BACKGROUND

The use of textured breast implants over smooth implants has been widely shown to have a lower incidence of capsular contracture. However, the impact of micropatterning techniques on the incidence of postoperative patient morbidity has not been comprehensively investigated.

OBJECTIVES

The authors sought to examine the incidence of capsular contracture, seroma, and implant rippling among the 3 major micropatterning techniques applied in the manufacturing of textured breast implants.

METHODS

Literature searches of PubMed/Medline and Embase between 1995 and 2017 were performed, and 19 studies were selected for analysis. Data from each study were extracted into a form including mean age, study design, population size, mean follow-up, number of capsular contracture cases, number of seroma cases, and number of rippling cases. Meta-analysis was performed separately for studies that included capsular contracture rates for foam textured implants, imprinted textured implants, and salt-loss textured implants.

RESULTS

The pooled rate of capsular contracture rates in primary augmentation patients was 3.80% (95% CI, 2.19-5.40) for imprinted textured implants, 4.90% (95% CI, 3.16-6.64) for foam textured implants, 5.27% (95% CI, 3.22-7.31) for salt-loss textured implants, and 15.56% (95% CI, 13.31-18.16) for smooth implants. The results of each meta-analysis were summarized on a forest plot depicting the distribution of capsular contracture rates from each study.

CONCLUSIONS

Micropatterning of prosthetic implants could drastically reduce postoperative patient morbidity given the advent of recent technologies that allow for more detailed texturing of implant surfaces.

LEVEL OF EVIDENCE: 4

Cosmetic reconstruction in breast cancer patients: Opportunities for nanocomposite materials

The most common malignancy in women, breast cancer remains a major medical challenge that affects the life of thousands of patients every year. With recognized benefits to body image and self-esteem, the use of synthetic mammary implants for elective cosmetic augmentation and post-mastectomy reconstruction continues to increase. Higher breast implant use leads to an increased occurrence of implant-related complications associated with implant leakage and rupture, capsular contracture, necrosis and infections, which include delayed healing, pain, poor aesthetic outcomes and the need for revision surgeries. Along with the health status of the implant recipient and the skill of the surgeon, the properties of the implant determine the likelihood of implant-related complications and, in doing so, specific patient outcomes. This paper will review the challenges associated with the use of silicone, saline and "gummy bear" implants in view of their application in patients recovering from breast cancer-related mastectomy, and investigate the opportunities presented by advanced functional nanomaterials in meeting these challenges and potentially opening new dimensions for breast reconstruction. STATEMENT OF SIGNIFICANCE: Breast cancer is a significant cause of morbidity and mortality in women worldwide, which is difficult to prevent or predict, and its treatment carries long-term physiological and psychological consequences. Post-mastectomy breast reconstruction addresses the cosmetic aspect of cancer treatment. Yet, drawbacks of current implants contribute to the development of implant-associated complications, which may lead to prolonged patient care, pain and loss of function. Nanomaterials can help resolve the intrinsic biomechanical mismatch between implant and tissues, enhance mechanical properties of soft implantable materials, and provide an alternative avenue for controlled drug delivery. Here, we explore advances in the use of functionalized nanomaterials to enhance the properties of breast implants, with representative examples that highlight the utility of nanomaterials in addressing key challenges associated with breast reconstruction.

Removal of Polyurethane Implants

Polyurethane (PU) implants are associated with great difficulties in extraction if secondary surgery is needed. The published data are contradictory, often misleading, making the decision for the secondary surgery complicated, the time period and the procedure itself not optimal, thus negatively influencing the final result.

MATERIALS AND METHODS

Typical videos of PU implant removal in different periods after primary surgeries with polyurethane implants were selected for the study. The videos show the strength and extent of the tissue ingrowth and the manipulations needed for implant extraction in different periods from the initial procedure. Classifications of the types of adhesion and adhesion patterns are introduced.

CONCLUSIONS

The data provided in this article facilitate the decision-making process if secondary surgery is indicated. Secondary surgery should be performed in the first 30 days after the initial surgery or in the period after 6 months. The optimal layer for removal of the PU implant depends on the time after the primary surgery. The polyurethane implant should be exchanged after 1 month if the properties of the polyurethane foam are expected to be used.

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, refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Association Between Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL) Risk and Polyurethane Breast Implants: Clinical Evidence and European Perspective

This article aims to present an overview on the use of polyurethane (PU) breast implants and the possible association with the risk of developing breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), with a special look at the current situation in Europe. It is well known that the real cause of BIA-ALCL remains unknown. Although this is a rare disease, many interesting theories surrounding its development have been advanced; however, none of these theories has been able to demonstrate with statistical significance, as required by the criteria of evidence-based medicine, definitive clinical proof as to why BIA-ALCL develops. It is widely assumed that the implant surface plays a crucial role. Most BIA-ALCL cases are associated with macro-textured implants, but from a strictly scientific point of view, this link is not supported by any clear clinical evidence. A deeper discussion of the various implant surfaces indicates that adding further categories to the existing surface classification (smooth, micro-, and macro-textured) should be avoided. Moreover, one of the most common misunderstandings should be clarified: PU breast implants cannot be classified as macro-textured implants. The PU foam that covers breast implants provides a completely different surface, and the mechanisms of action related to tissue adhesion, as well as to fibrous capsule formation, differ substantially from those of smooth or textured implants.

Breast Reconstruction Actualized in Nipple-sparing Mastectomy and Direct-to-implant, Prepectoral Polyurethane Positioning: Early Experience and Preliminary Results

BACKGROUND

Implant-based breast reconstruction after nipple-sparing mastectomy has been the most common breast reconstruction procedure performed, for both breast cancer treatment and prophylactically. Subpectoral implant placement with partial detachment of the pectoralis major muscle has been the procedure of choice for staged reconstruction and direct-to-implantation. Prepectoral implant placement has recently increased in popularity among plastic surgeons owing to the high rates of animation deformity, loss of muscle function, and chronic pain observed with submuscular implant placement. Acellular dermal matrices or synthetic meshes have been used for implant coverage and support to avoid capsular contracture and implant visibility. In the present study, we have introduced breast reconstruction actualized in nipple-sparing mastectomy and direct-to-implant with prepectoral polyurethane positioning (BRAND4P).

PATIENTS AND METHODS

A total of 34 nipple-sparing mastectomies and immediate direct-to-implant breast reconstructions with prepectoral polyurethane-coated implant placement were performed in 21 patients (13 bilateral and 8 unilateral). The implant was placed subcutaneously in the exact place of the excised breast parenchyma with no further coverage.

RESULTS

After a mean follow-up of 4 months, no major complications had been observed. No patient presented with animation deformity or grade III-IV capsular contracture. Patient satisfaction, assessed using the BREAST-Q, was excellent.

CONCLUSIONS

The BRAND4P method represents a novel prepectoral approach and a feasible alternative to subpectoral implant placement among the available implant-based breast reconstruction techniques.

Hydrogels in adipose tissue engineering-Potential application in post-mastectomy breast regeneration

Current methods of breast reconstruction are associated with significant shortcomings, including capsular contracture, infection, rupture, the need for reoperation in implant-based reconstruction, and donor site morbidity in autologous reconstruction. These limitations result in severe physical and psychological issues for breast cancer patients. Recently, research has moved into the field of adipose tissue engineering to overcome these limitations. A wide range of regenerative strategies has been devised utilising various scaffold designs and biomaterials. A scaffold capable of providing appropriate biochemical and biomechanical cues for adipogenesis is required. Hydrogels have been widely studied for their suitability for adipose tissue regeneration and are advantageous secondary to their ability to accurately imitate the native extracellular matrix. The aim of this review was to analyse the use of hydrogel scaffolds in the field of adipose tissue engineering.

Polyurethane Microparticles for Stimuli Response and Reduced Oxidative Degradation in Highly Porous Shape Memory Polymers

Shape memory polymers (SMPs) have been found to be promising biomaterials for a variety of medical applications; however, the clinical translation of such technology is dependent on tailorable properties such as gravimetric changes in degradation environments. For SMPs synthesized from amino-alcohols, oxidation resulting in rapid mass loss may be problematic in terms of loss of material functionality as well as toxicity and cytocompatibility concerns. Control of gravimetric changes was achieved through the incorporation of small molecule antioxidants, either directly into the polymer matrix or included in microparticles to form a SMP composite material. With direct incorporation of small molecule phenolic antioxidant 2,2'-methylenebis(6- tert-butyl)-methylphenol (Methyl), SMPs displayed reduce strain recovery by more than 50% (Methyl) and increase elastic modulus from approximately 1.4 to 2.3 MPa, at the expense of the strain to failure being reduced from 45% to 32%. Importantly, such changes could not ensure retention of the antioxidants and therefore did not increase oxidative stability beyond 15 days in accelerated oxidative conditions (equivalent to approximately 800 days in porcine aneurysms) in all cases except for the inclusion of a hindered amine that capped network growth, which also resulted in shape memory reduction (only 80% recoverable strain achieved). However, the inclusion of antioxidants in microparticles was found to produce materials with similar thermomechanical ( T_g migration below 1.0 °C) and shape recovery of 100%, while increasing oxidative resistance compared to controls (oxidation onset was delayed by 3 days and material lifespan increased to approximately 20-22 days in accelerated oxidative solution or beyond 1000 days in the porcine aneurysm). The microparticle composite SMPs also act as a platform for environmental sensing, such as pH-dependent fluorescence shifts and payload release, as demonstrated by fluorescent dye studies using phloxine B and nile blue chloride and the release of antioxidants over a 3 week period. The use of polyurethane-urea microparticles in porous SMPs is demonstrated to increase biostability of the materials, by approximately 25%, and ultimately extend their lifespan for use in aneurysm occlusion as determined through calculated in vivo degradation rates corresponding to a porcine aneurysm environment.

Nanoporous 3D-Printed Scaffolds for Local Doxorubicin Delivery in Bone Metastases Secondary to Prostate Cancer

The spine is the most common site of bone metastasis, often originating from prostate, lung, and breast cancers. High systemic doses of chemotherapeutics such as doxorubicin (DOX), cisplatin, or paclitaxel often have severe side effects. Surgical removal of spine metastases also leaves large defects which cannot spontaneously heal and require bone grafting. To circumvent these issues, we designed an approach for local chemotherapeutic delivery within 3D-printed scaffolds which could also potentially serve as a bone substitute. Direct treatment of prostate cancer cell line LAPC4 and patient derived spine metastases cells with 0.01 µM DOX significantly reduced metabolic activity, proliferation, migration, and spheroid growth. We then assessed uptake and release of DOX in a series of porous 3D-printed scaffolds on LAPC4 cells as well as patient-derived spine metastases cells. Over seven days, 60–75% of DOX loaded onto scaffolds could be released, which significantly reduced metabolic activity and proliferation of both LAPC4 and patient derived cells, while unloaded scaffolds had no effect. Porous 3D-printed scaffolds may provide a novel and inexpensive approach to locally deliver chemotherapeutics in a patient-specific manner at tumor resection sites. With a composite design to enhance strength and promote sustained drug release, the scaffolds could reduce systemic negative effects, enhance bone repair, and improve patient outcomes.

Risk factors for developing capsular contracture in women after breast implant surgery: A systematic review of the literature

BACKGROUND

Capsular contracture is the most frequent complication in breast augmentation or reconstruction with breast implants. The exact mechanism for this complication is not completely understood. Yet, it is most likely to be a multifactorial condition. Several patient-, surgery-, and implant-specific risk factors have been related to cause capsular contracture. This review aims to provide a clear overview of all risk factors for capsular contracture.

METHODS

A systematic literature review was performed focusing on patient-, surgery-, and/or implant-related factors related to capsular contracture in breast implants. PubMed, Embase, and Wiley/Cochrane Library databases were searched for relevant articles published from inception up to October 20, 2016. The included studies were assessed for the following main variables: study characteristics, patient characteristics, indication for surgery, type of surgery, implant characteristics, and other characteristics.

RESULTS

Data on the risk factors for the development of capsular contracture were retrieved from 40 studies. A presumptive increased risk in the development of capsular contracture is shown for the following variables: longer duration of follow-up, breast reconstructive surgery in patients with a history of breast cancer, subglandular implant placement, postoperative hematoma, and a textured implant surface. There is little, weak, or no evidence for the association of other factors with capsular contracture. This review also shows a large heterogeneity between studies and within the definition of capsular contracture.

CONCLUSION

This review provides an overview of the relationship between patient-, surgery-, and implant-specific risk factors in the development of capsular contracture.