High-throughput assay for bacterial adhesion on acellular dermal matrices and synthetic surgical materials

Research Progress on Extracellular Matrix-Based Composite Materials in Antibacterial Field

Due to their exceptional cell compatibility, biodegradability, and capacity to trigger tissue regeneration, extracellular matrix (ECM) materials have drawn considerable attention in tissue healing and regenerative medicine. Interestingly, these materials undergo continuous degradation and release antimicrobial peptides (AMPs) while simultaneously promoting tissue regeneration, thereby exerting a potent antibacterial effect. On this basis, a variety of basic properties of ECM materials, such as porous adsorption, hydrophilic adsorption, group crosslinking, and electrostatic crosslinking, can be used to facilitate the integration of ECM materials and antibacterial agents through physical and chemical approaches in order to enhance the antibacterial efficacy. This article reviews the recent advancements in the study of ECM antibacterial materials, including the antibacterial function and antibacterial mechanism of free-standing ECM materials and ECM-based composite materials. In addition, the urgent challenges and future research prospects of ECM materials in the anti-infection industry are discussed.

Surgical and Patient-Reported Outcomes After Mastectomy and Implant-Based Prepectoral Reconstruction Using TIGR® Synthetic Mesh

Background Single-stage direct-to-implant (DTI) breast reconstruction after mastectomy has gained popularity over the last decade, thanks to the wide use of biological matrices and synthetic meshes. Despite their high cost, there is no evidence of superior outcome from the biological matrices compared to the synthetic meshes. In this study, we aimed to evaluate our experience with TIGR, a synthetic, long-term absorbable mesh, in mastectomy and immediate breast reconstruction (MIBR) with a focus on patient-reported outcomes (PROMs). Methods This was a single-trust prospective quality improvement study conducted between 2017 and 2019. The main objectives were complication rates including infection, implant loss, and other surgical complications in patients undergoing TIGR mesh-assisted MIBR in the prepectoral plane for either cancer or risk reduction. PROMs were measured using the validated European Organisation for Research and Treatment of Cancer (EORTC) breast questionnaire module. Clinical evaluations were conducted at one week, three weeks, and 12 months postoperatively. All patients provided written consent, and the audit was registered with the Quality Improvement Department of the organization. Results One hundred and twelve meshes were used in 93 patients with a mean age of 49 (24-75) years and a body mass index (BMI) of 23.4 (19.1-29.6). During the follow-up period, complications occurred in 26 patients (28%), including infection in four (4.3%), complete skin flap necrosis in one (1%), partial flap necrosis in three (3.2%), and implant loss in four (4.3%) patients. PROM data from 41 individuals indicated a moderate overall quality of life (82.7%), with high functional domain scores with relatively lower emotional functioning scores. Symptom domains generally scored poorly except for body image and sexual functioning. Conclusion Mastectomy and immediate prepectoral breast reconstruction using TIGR mesh is safe with low major complication rates. It is associated with high functional and quality of life scores but low scores in symptom domains which could be multifactorial. However, limitations due to study type and follow-up duration suggest caution in generalizing findings.

Comparing the Outcomes and Complication Rates of Biologic vs Synthetic Meshes in Implant-Based Breast Reconstruction: A Systematic Review

OBJECTIVE

This systematic review evaluates all published studies comparing biologic and synthetic meshes in implant-based breast reconstruction (IBBR), to determine which category of mesh produces the most favorable outcomes.

SUMMARY BACKGROUND DATA

Breast cancer is the most common cancer in women globally. Implant-based breast reconstruction is currently the most popular method of postmastectomy reconstruction, and recently, the use of surgical mesh in IBBR has become commonplace. Although there is a long-standing belief among surgeons that biologic mesh is superior to synthetic mesh in terms of surgical complications and patient outcomes, few studies exist to support this claim.

METHODS

A systematic search of the EMBASE, PubMed, and Cochrane databases was performed in January 2022. Primary literature studies comparing biologic and synthetic meshes within the same experimental framework were included. Study quality and bias were assessed using the validated Methodological Index for Non-Randomized Studies criteria.

RESULTS

After duplicate removal, 109 publications were reviewed, with 12 meeting the predetermined inclusion criteria. Outcomes included common surgical complications, histological analysis, interactions with oncologic therapies, quality of life measures, and esthetic outcomes. Across all 12 studies, synthetic meshes were rated as at least equivalent to biologic meshes for every reported outcome. On average, the studies in this review tended to have moderate Methodological Index for Non-Randomized Studies scores.

CONCLUSION

This systematic review offers the first comprehensive evaluation of all publications comparing biologic and synthetic meshes in IBBR. The consistent finding that synthetic meshes are at least equivalent to biologic meshes across a range of clinical outcomes offers a compelling argument in favor of prioritizing the use of synthetic meshes in IBBR.

Comparing Complications of Biologic and Synthetic Mesh in Breast Reconstruction: A Systematic Review and Network Meta-Analysis

Background  In breast reconstruction, synthetic meshes are frequently used to replace acellular dermal matrix (ADM), since ADM is expensive and often leads to complications. However, there is limited evidence that compares the types of substitutes. This study aimed to compare complications between materials via a network meta-analysis. Methods  We systematically reviewed studies reporting any type of complication from 2010 to 2021. The primary outcomes were the proportion of infection, seroma, major complications, or contracture. We classified the intervention into four categories: ADM, absorbable mesh, nonabsorbable mesh, and nothing used. We then performed a network meta-analysis between these categories and estimated the odds ratio with random-effect models. Results  Of 603 searched studies through the PubMed, MEDLINE, and Embase databases, following their review by two independent reviewers, 61 studies were included for full-text reading, of which 17 studies were finally included. There was a low risk of bias in the included studies, but only an indirect comparison between absorbable and non-absorbable mesh was possible. Infection was more frequent in ADM but not in the two synthetic mesh groups, namely the absorbable or nonabsorbable types, compared with the nonmesh group. The proportion of seroma in the synthetic mesh group was lower (odds ratio was 0.2 for the absorbable and 0.1 for the nonabsorbable mesh group) than in the ADM group. Proportions of major complications and contractures did not significantly differ between groups. Conclusion  Compared with ADM, synthetic meshes have low infection and seroma rates. However, more studies concerning aesthetic outcomes and direct comparisons are needed.

Acellular cadaveric dermal matrix grafts for orbital wall reconstruction in patients with sinonasal malignancies

PURPOSE

To describe the utilization of acellular cadaveric dermal matrix (ACDM) in patients undergoing orbital wall reconstruction after orbital preservation surgery for sinonasal malignancy.

METHODS

Retrospective case series of seven patients with sinonasal malignancy who had orbital reconstruction with ACDM implants from January 2012 to August 2020. Orbital preservation was performed in all patients with tumor extension up to and including periorbital. The main outcome measures were implant exposure, orbital infection, diplopia in primary gaze, enophthalmos, and eyelid malposition.

RESULTS

Patients ranged 37-78 years old (median: 66 years) and included 4 females and 3 males. The median follow-up time was 9 months (range 6-43 months) from the date of surgery. Squamous cell carcinoma comprised the majority of tumors with all patients needing medial wall reconstruction. Three patients received postoperative radiation therapy. No patients had any implant exposure, orbital infection, enophthalmos, or eyelid malposition.

CONCLUSIONS

ACDM grafts can be used safely in orbital wall reconstruction in patients with sinonasal malignancies.

"Oncologic Safety of Staged Pre-Pectoral Implant Reconstruction Following Nipple-Sparing Mastectomy: a Mean 9-Year Follow-Up."

BACKGROUND

Prepectoral reconstruction following nipple-sparing mastectomy has recently gained popularity as an alternative to total or partial submuscular reconstruction. In the absence of long-term follow-up, concerns have been raised over the oncologic safety of using mastectomy flaps that preserve the entire thickness of the subcutaneous fat and its circulation. In this article we present our average 9-year oncologic follow-up of patients who underwent nipple-sparing mastectomy and 2-stage prepectoral implant reconstruction without acellular dermal matrix.

METHODS

In this retrospective study, a group of previously reported 151 consecutive breast cancer patients [246 breasts, (160 therapeutic, 86 preventative)] who underwent nipple-sparing mastectomy and staged prepectoral implant reconstruction between 2005 and 2015 were followed up for an average of 109 months (range, 14 to 192 months). Tumor related data, oncologic markers, staging, neoadjuvant/adjuvant therapy, and radiation therapy were evaluated to determine local recurrence, overall survival, and disease-free survival rates.

RESULTS

Local recurrence rate in 151 patients was 2.6 percent. Eleven patients (7.3 percent) died from metastatic disease and 3 patients from unrelated causes. The average 109-month overall survival rate was 92.9 percent and disease-free survival rate was 87.8 percent. Over the same period nine patients (6 percent) were alive with distant disease.

CONCLUSION

Our 9-year two-stage prepectoral reconstruction study of nipple-sparing mastectomy shows that the procedure is oncologically safe, having comparable recurrence, overall survival, and disease-free survival rates as total mastectomy.

"Never Trust the Skin": A Rationale for Using Polydioxanone Internal Support Matrix to Minimize Scarring in Primary Mastopexy-Augmentation-An Observational Study

Background

The process of scar formation is complex and multi-factorial. Basic plastic surgery tenets focus on tension-free techniques to optimize aesthetic outcomes and minimize scarring.

Objectives

Prophylactic use of a polydioxanone (PDO) internal support matrix in cosmetic mastopexy-augmentation to decrease scar burden has never before been described.

Methods

A high volume (n = 41) single-surgeon mastopexy-augmentation experience (S.S.K.) followed scar quality in consecutive cases from June 2020 to July 2021. A minimum of 6 months of postoperative evaluation was required to assess scar quality. Fitzpatrick scores were also evaluated and compared. All surgeries in this study were performed in the dual plane using silicone gel implants, a superior or superomedial dermal pedicle blood supply, and a wise-pattern or vertical scar. Scar quality was evaluated by photography and scored according to an internally developed scar quality scale.

Results

There have been no cases of hypertrophic or keloid scarring. All patients receiving mastopexy-augmentation with prophylactic PDO mesh have a favorable appearance with fine line scars, and the mean scar quality scale score across the cohort was 4.341/5. The mean Fitzpatrick scale score across the cohort was 2.97, and, of the patients who scored a 5 on the scar quality index, the mean Fitzpatrick scale score was 3.545.

Conclusions

Prophylactic use of PDO internal support matrix in silicone gel mastopexy-augmentation offers further protection against poor scarring in patients across the Fitzpatrick scale, with varying degrees of skin quality, and across medium to high-volume implant augmentations. Patients who received PDO prophylaxis demonstrated a better-than-average scar appearance.

Level of Evidence 4

Polydioxanone Internal Support Matrix: A Rationale for Prophylactic Internal Bra Support in Breast Augmentation

Background

Textured breast implants have been used in aesthetic breast surgery to decrease the rates of implant malposition. A recent analysis of a large-volume single-surgeon experience found statistically similar rates of malposition in smooth vs micro-textured breast implants.

Objectives

Prophylactic use of a polydioxanone (PDO) internal support matrix in breast augmentation was hypothesized to prevent scar malposition and increase pocket control.

Methods

In total, 200 patients received silicone gel primary augmentations performed by a single surgeon from January 2018 to December 2020; 84 patients received smooth implants alone; 49 patients received micro-textured implants; and 67 patients received smooth implants plus PDO internal support matrix. All surgeries were performed in the dual plane using an inframammary incision. Implant-related complications and scar malposition were recorded and compared.

Results

No significant difference in implant-related complication rates was found between shell types (3.57% for smooth devices alone and 2.04% for textured devices [P = 0.62; 95% CI −0.06 to 0.01]). There were zero complications in the smooth plus mesh study arm. A comparison of scar malposition rates between the smooth alone and textured groups revealed no significant difference (15.4% for smooth devices and 8.16% for textured devices [P = 0.23; 95% CI −0.12 to 0.01]). The smooth implant group with the prophylactic placement of PDO mesh had the lowest scar malposition rate of 4.48%, a significant difference compared with the smooth devices alone (P = 0.03; 95% CI −0.21 to −0.01).

Conclusions

Micro-textured devices show a trend toward decreased scar malposition, although not significant. Prophylactic use of PDO internal support matrix in silicone gel breast augmentation is safe and has the lowest incidence of scar malposition.

Level of Evidence: 3

[Reconstruction of oncological defects of the perianal region]

In addition to the progressive development of surgical oncological techniques for malignant tumors of the rectum, anal canal and vulva, reconstructive procedures after oncological interventions in the perianal region represent a cornerstone in the postoperative quality of life of patients. Modern treatment modalities for rectal cancer with neoadjuvant chemoradiotherapy increase the survival rate and simultaneously reduce the risk of local recurrence to 5-10%, especially by cylindrical extralevatory extirpation of the rectum. The price for increased surgical radicality and improved oncological safety is the acceptance of larger tissue defects. Simple suture closure of perineal wounds often does not primarily heal, resulting in wound dehiscence, surgical site infections and formation of chronic fistulas and sinuses. The interdisciplinary one-stage or two-stage reconstruction of the perianal region with well-vascularized tissue has proven to be a reliable procedure to prevent or control such complications.

Prophylactic antibiotic use in acellular dermal matrix-assisted implant-based breast reconstruction

BACKGROUND

Prophylactic antibiotics are used in acellular dermal matrix-assisted implant-based breast reconstructions. However, there are no universally accepted guidelines regarding the best regimen. This retrospective, multicentre study was designed to compare the different prophylactic antibiotic regimens in these patients in three hospitals across two NHS trusts over a five-year period.

METHODS

Case notes and electronic records were reviewed for all patients undergoing acellular dermal matrix-assisted implant-based breast reconstructions between January 2010 and December 2014. Prophylactic antibiotic regimens, duration of use, wound infection, implant loss, seroma and therapeutic antibiotic use was recorded. Patients were divided into groups based on prophylactic antibiotic regimen and actual duration of use. Intergroup analysis was performed using Stata 13.0. Implant loss due to infection was the primary outcome measure.

RESULTS

A total of 105 patients had 122 breast reconstructions performed over the study period. Four prophylactic antibiotic regimens were identified: single dose (n = 20), three doses (n = 17), antibiotics for five-seven days (n = 51) and antibiotics until drains removed (n = 32). There was no statistically significant difference (p > 0.05) between the various regimens in implant loss, wound infection, therapeutic antibiotic prescription or seroma rates. Based on the actual duration of prophylactic antibiotics usage, three groups were identified: prophylactic antibiotics given for one day (n = 26), antibiotics for up to one week (n = 76) and for more than one week (n = 13). Again, no statistically significant difference was observed in the groups for any outcome measure.

CONCLUSION

The study demonstrated no difference in outcomes between different prophylactic antibiotic regimens in acellular dermal matrix-assisted implant-based breast reconstructions.

Comparison of subpectoral versus dual-plane implant based immediate breast reconstruction after nipple-areola sparing mastectomy

BACKGROUND

Selection of implant pocket and size is a dilemma for surgeons especially if radiation therapy is envisaged after implant based immediate breast reconstruction (IBR). The aim of this study is to compare complication rates between subpectoral and the dual plane polyglactin mesh supported IBR after nipple-areola sparing mastectomy.

PATIENTS AND METHOD

Reconstructive analysis of 208 breasts of 190 patients with breast cancer undergoing implant based IBR at a single university hospital were evaluated. The patients were reconstructed with either dual-plane polyglactin mesh supported (n=91) or subpectoral (n=117) implant based IBR after nipple-areola sparing mastectomy. Demographic data, and postoperative complications were compared.

RESULTS

The mean age was 43.3 years. Early complications encountered in 12% (n=25) and late complications occurred in 18% (n=37) of breasts. Both early (13,7% vs 9.9%, P=0.406) and late complications (24.8% vs 8.8%, P=0.003) were more common in subpectoral group, but only late complication occurrence rate was statistically significant. Capsular contracture (P=0.000), inframammary fold problems (P=0.010), bottoming-out (P=0.370), mechanical shift (P=0.036) and animation deformity (P=0.007) were all more common in subpectoral group. Only rippling deformity (P=0.011) was more common in dual plane group.

CONCLUSIONS

Dual plane IBR has acceptable complication rates compared to subpectoral IBR. It is associated with less capsular contracture, fewer animation and bottoming-out deformity and better inframammary fold appearance.

The application possibility of acellular dermal matrix decorated with nano-silver in the reconstruction of contaminated abdominal wall

Acellular dermal matrix (ADM) is a biomaterial, which commonly used for repair of tissue defects; however, infection is the main factor underlying the failure of treatments involving ADM. To enhance the anti-infection ability of ADM, we constructed a new form of ADM that was decorated with nano-silver ('NS-ADM'). The introduction of nano-silver did not destroy the decellularized structure of ADM, and no significant difference was detected with regards to the maximum tensile force when compared between NS-ADM and ADM (P = 0.351). NS-ADM was not cytotoxic to cell growth when the concentration of nano-silver solution ≤ 25 ppm and exhibited strong antibacterial activity in vitro. Besides, when rats were inoculated with 10⁴ CFU/mL, there were significantly lower bacterial counts in the NS-ADM group than in the ADM group when assessed seven days after surgery (P = 0.047); no significant differences were detected on days 14 and 28. Although there were no significant differences in bacterial counts on days 7, 14, or 21 between the two groups (rats were inoculated with 10⁶ CFU/mL), the number of rats showing reduced bacterial counts or clearing was higher in the NS-ADM group than in the ADM group. Rats that were inoculated with 10⁸ CFU/mL showed repair failure. Overall, NS-ADM is a promising antibacterial biomaterial for repairing contaminated soft-tissue defects, in which antibacterial properties are superior to ADM. The antibacterial activity of NS-ADM was limited for severe infections, and further in vivo studies are needed to evaluate its efficacy and biosafety.

Preliminary Results Supporting the Bacterial Hypothesis in Red Breast Syndrome following Postmastectomy Acellular Dermal Matrix- and Implant-Based Reconstructions

Acellular dermal matrices have become a mandatory tool in reconstructive breast surgery. Since their introduction, they have been considered to be nonreactive and nonimmunogenic scaffolds. However, some patients who undergo implant-based breast reconstruction with acellular dermal matrices develop postoperative cutaneous erythema overlying their matrices, a condition commonly referred to as red breast syndrome. The aim of this study was to gain a better understanding of this phenomenon. An analysis was conducted on consecutive patients who underwent acellular dermal matrix- and implant-based breast reconstructions and developed red breast syndrome that was treated surgically between April of 2017 and June of 2018 at the authors' institution. During surgery, 1-cm specimens of acellular dermal matrix were sampled and analyzed by scanning electron microscopy. Observations were charted to score and record the presence and thickness of biofilm, and for identification of bacteria. These measurements were performed using Adobe Photoshop CS6 Extended software. Six postmastectomy breast reconstruction patients were included, all with AlloDerm Ready-to-Use-based reconstructions. All specimens were colonized by various bacteria ranging from Gram-negative bacilli to Gram-positive microorganisms. Biofilm was present in all studied specimens. The cause of skin erythema overlying acellular dermal matrix grafts, and the so-called red breast syndrome, may be related to contamination with various bacteria. Although contamination was omnipresent in analyzed samples, its clinical significance is variable. Even if acellular dermal matrix-based reconstructions are salvaged, this could come at the price of chronic local inflammation.

[Acellular dermal matrix and synthetic mesh in implant-based immediate breast reconstruction: Current concepts]

The use of acellular dermal matrices and synthetic meshes is gaining popularity in direct-to-implant breast reconstruction, allowing the complete coverage of the prosthesis with greater pocket control and improved cosmesis. In this concise review, we present the advantages of acellular dermal matrices and resorbable or nonresorbable synthetic meshes in implant-based breast reconstruction, we discuss the risk of postoperative complications, and we raise their contribution in the growing interest of prepectoral breast reconstruction.

Yeasts from skin colonization are able to cross the acellular dermal matrix

In recent decades, the prognosis for burn patients has improved considerably with the development of specialized care. The acellular dermal matrix (ADM) is a totally artificial acellular device that functions to control water loss, prevent penetration by bacteria and allow migration of endothelial cells and fibroblasts from patient tissues. However, little is known about its effectiveness against yeasts. The present study evaluated the capacity of colonization and migration of some human commensal yeasts. Three clinical isolates from skin scales, identified as Candida parapsilosis, Candida glabrata and Rhodotorula mucilaginosa, were used. Their ability to cross the ADM was evaluated. After three days, all isolates had crossed the ADM. C. parapsilosis showed the lowest growth, while R. mucilaginosa showed intermediate and C. glabrata the highest growth. In the plates incubated for seven days, the growth of C. parapsilosis and C. glabrata increased by 1 log over the third day. All isolates have the capacity to colonize and migrate through the matrix, increasing the potential risk to burn patients, who can develop severe and even fatal infections by invasive fungi.

Pedicle screw augmentation with bone cement enforced Vicryl mesh

Achieving sufficient mechanical purchase of pedicle screws in osteoporotic or previously instrumented bone is technically and biologically challenging. Techniques using different kinds of pedicle screws or methods of cement augmentation have been used to address this challenge, but are associated with difficult revisions and complications. The purpose of this biomechanical trial was to investigate the use of biocompatible textile materials in combination with bone cement to augment pullout strength of pedicle screws while reducing the risk of cement extrusion. Pedicle screws (6/40 mm) were either augmented with standard bone-cement (Palacos LV + G) in one group (BC, n = 13) or with bone-cement enforced by Vicryl mesh in another group (BCVM, n = 13) in osteoporosis-like saw bone blocks. Pullout testing was subsequently performed. In a second experimental phase, similar experiments were performed using human cadaveric lumbar vertebrae (n = 10). In osteoporosis-like saw bone blocks, a mean screw pullout force of 350 N (±125) was significantly higher with the Bone cement (BC) compared to bone-cement enforced by Vicryl mesh (BCVM) technique with 240 N (±64) (p = 0.030). In human cadaveric lumbar vertebrae the mean screw pullout force was 784 ± 366 N with BC and not statistically different to BCVM with 757 ± 303 N (p = 0.836). Importantly, cement extrusion was only observed in the BC group (40%) and never with the BCVM technique. In vitro textile reinforcement of bone cement for pedicle screw augmentation successfully reduced cement extrusion compared to conventionally delivered bone cement. The mechanical strength of textile delivered cement constructs was more reproducible than standard cementing. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:212-216, 2018.

Pros and cons of immediate Vicryl mesh insertion after lumpectomy

BACKGROUND

Lumpectomy is a standard surgery for breast cancer; however, it results in breast deformity, especially after radiation therapy. Wider surgical margin correlates lower local recurrence rate. However, bigger defect brings worse cosmetic outcome. The use of a simple filler for the defect is expected. We aimed to improve the cosmetic outcome by using an absorbable Vicryl mesh for breast reconstruction immediately post-lumpectomy.

METHODS

One sheet of Vicryl woven mesh was prepared for insertion, washed the cavity with natural saline, and placed into the space. The cosmetic outcome was scored for the size, shape, scar, and softness of the breast. The size, shape, color, and position of the nipple-areola complex were also scored. Adverse events were collected retrospectively.

RESULTS

From April 2008 to October 2014, 24 female patients received immediate Vicryl mesh insertion. A lumpectomy only group was recruited for cosmetic analysis. All patients received postsurgical radiotherapy. The mean cosmetic assessment score was 8.0 and 9.1 of 12 for the Vicryl mesh group and lumpectomy only group, respectively (P = 0.17). Sixteen patients had adverse events such as erythema at approximately 2 weeks post-surgery. No significant differences were shown except adverse events between two groups. No patient has had local recurrence thus far.

CONCLUSION

Immediate Vicryl mesh insertion leads to significantly increased incidence of postoperative complications and delay in commencement of adjuvant radiotherapy. Furthermore, the cosmetic outcomes are not superior to that of no reconstruction. The development of superior biomaterials is anticipated for breast reconstruction after lumpectomy.

Biological and synthetic mesh use in breast reconstructive surgery: a literature review

Mesh use in surgical breast reconstruction is becoming increasingly common; however, there is still no consensus on whether synthetic matrices or biological matrices produce the best outcomes. This review analyses these outcomes, namely the differences in aesthetic outcomes, cost, and the rates of the most commonly reported complications.

The results indicate that breast reconstruction with a synthetic matrix produces comparable aesthetic outcomes to a biological matrix, with lower costs and complication rates. The individual results for complication rates show that biological matrixes are associated with lower infection rates and slightly lower capsular contracture, but higher haematoma rates, and slightly higher rates of skin necrosis and explantation—although many had post-op radiotherapy.

The majority of the studies evaluated used biological matrices, and there are no randomised controlled trials directly comparing the two types of meshes; definite conclusions cannot be drawn from the available evidence. The authors suggest that a randomised controlled trial comparing these outcomes in synthetic and biological matrix use is needed.

Alloplastic adjuncts in breast reconstruction

BACKGROUND

There has been an increasing role of acellular dermal matrices (ADMs) and synthetic meshes in both single- and two-stage implant/expander breast reconstruction. Numerous alloplastic adjuncts exist, and these vary in material type, processing, storage, surgical preparation, level of sterility, available sizes and cost. However, there is little published data on most, posing a significant challenge to the reconstructive surgeon trying to compare and select the most suitable product. The aims of this systematic review were to identify, summarize and evaluate the outcomes of studies describing the use of alloplastic adjuncts for post-mastectomy breast reconstruction. The secondary aims were to determine their cost-effectiveness and analyze outcomes in patients who also underwent radiotherapy.

METHODS

Using the PRSIMA 2009 statement, a systematic review was conducted to find articles reporting on the outcomes on the use of alloplastic adjuncts in post-mastectomy breast reconstruction. Multiple databases were searched independently by three authors (Cabalag MS, Miller GS and Chae MP), including: Ovid MEDLINE (1950 to present), Embase (1980 to 2015), PubMed and Cochrane Database of Systematic Reviews.

RESULTS

Current published literature on available alloplastic adjuncts are predominantly centered on ADMs, both allogeneic and xenogeneic, with few outcome studies available for synthetic meshes. Outcomes on the 89 articles, which met the inclusion criteria, were summarized and analyzed. The reported outcomes on alloplastic adjunct-assisted breast reconstruction were varied, with most data available on the use of ADMs, particularly AlloDerm(®) (LifeCell, Branchburg, New Jersey, USA). The use of ADMs in single-stage direct-to-implant breast reconstruction resulted in lower complication rates (infection, seroma, implant loss and late revision), and was more cost effective when compared to non-ADM, two-stage reconstruction. The majority of studies demonstrated inferior outcomes in ADM assisted, two-stage expander-to-implant reconstruction compared to non-ADM use. Multiple studies suggest that the use of ADMs results in a reduction of capsular contracture rates. Additionally, the reported beneficial effects of ADM use in irradiated tissue were varied.

CONCLUSIONS

ADM assisted two-stage breast reconstruction was associated with inferior outcomes when compared to non-ADM use. However, alloplastic adjuncts may have a role in single stage, direct-to-implant breast reconstruction. Published evidence comparing the long-term outcomes between the different types of adjuncts is lacking, and further level one studies are required to identify the ideal product.

Use of Acellular Dermal Matrix in Postmastectomy Breast Reconstruction: Are All Acellular Dermal Matrices Created Equal?

BACKGROUND

AlloDerm and FlexHD are two types of acellular dermal matrices commonly used in implant-based reconstruction. Although the use of acellular dermal matrix has revolutionized immediate breast reconstruction in the setting of breast cancer, it remains unclear which type of acellular dermal matrix is best. The purpose of this retrospective cohort study was to compare postoperative complication rates between these two types of acellular dermal matrix.

METHODS

The authors reviewed the records of all patients who underwent implant-based breast reconstruction at their institution between 1998 and 2013. Dependent variables of seroma, hematoma, infection, delayed wound healing, implant exposure, and return to the operating room for management of complications were recorded.

RESULTS

A total of 309 consecutive patients were identified. Of these, AlloDerm was used in 123 patients (39.8 percent) and FlexHD was used in 186 patients (60.2 percent). Most patients in the authors' cohort underwent immediate reconstruction [n = 288 (93.2 percent)], with a mean follow-up of 20.0 months. Patients receiving AlloDerm were half as likely to have major infections compared with patients receiving FlexHD (OR, 0.50; 95 percent CI, 0.16 to 1.00; p < 0.05). The rates of other complications were similar between the two groups.

CONCLUSION

There are significantly increased odds of a major infection in patients who undergo implant-based breast reconstruction using FlexHD compared with AlloDerm.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Mesh Infection and Hernia Repair: A Review

BACKGROUND

The use of a prosthetic mesh to repair a tissue defect may produce a series of post-operative complications, among which infection is the most feared and one of the most devastating. When occurring, bacterial adherence and biofilm formation on the mesh surface affect the implant's tissue integration and host tissue regeneration, making preventive measures to control prosthetic infection a major goal of prosthetic mesh improvement.

METHODS

This article reviews the literature on the infection of prosthetic meshes used in hernia repair to describe the in vitro and in vivo models used to examine bacterial adherence and biofilm formation on the surface of different biomaterials. Also discussed are the prophylactic measures used to control implant infection ranging from meshes soaked in antibiotics to mesh coatings that release antimicrobial agents in a controlled manner.

RESULTS

Prosthetic architecture has a direct effect on bacterial adherence and biofilm formation. Absorbable synthetic materials are more prone to bacterial colonization than non-absorbable materials. The reported behavior of collagen biomeshes, also called xenografts, in a contaminated environment has been contradictory, and their use in this setting needs further clinical investigation. New prophylactic mesh designs include surface modifications with an anti-adhesive substance or pre-treatment with antibacterial agents or metal coatings.

CONCLUSIONS

The use of polymer coatings that slowly release non-antibiotic drugs seems to be a good strategy to prevent implant contamination and reduce the onset of resistant bacterial strains. Even though the prophylactic designs described in this review are mainly focused on hernia repair meshes, these strategies can be extrapolated to other implantable devices, regardless of their design, shape or dimension.

Bacterial adhesion to biological versus polymer prosthetic materials used in abdominal wall defect repair: do these meshes show any differences in vitro?

PURPOSE

Although clinical data suggest the similar performance of collagen-based biological prosthetic materials to some polymer materials, the use of a biomesh for abdominal hernia repair in a setting of infection is controversial. This in vitro study compares the adhesion of two Staphylococcus strains to polymer and biological meshes.

METHODS

Sterile fragments of Optilene(®) (Op), Surgipro™ (Surg), Preclude(®) (Precl), TIGR(®) (TIGR), Bio-A(®) (BioA), Permacol™ (Perm), Surgisis(®) (SIS), and Tutomesh(®) (Tuto) were inoculated with 10(6) CFU of S. aureus (Sa) or S. epidermidis (Se) (n = 18 per strain per mesh). The first five meshes are polymer materials while Perm, SIS and Tuto are biomeshes. After 24/48 h of incubation, bacterial adhesion was examined by sonication, scanning electron microscopy (SEM) and light microscopy.

RESULTS

Sa and Se showed a high affinity for the absorbable meshes (TIGR, BioA, Perm, SIS, Tuto) (p < 0.001). Precl yielded the lowest bacterial loads (p < 0.001). Surg, Precl and BioA underwent no substantial change over time, while Op (p < 0.001) and TIGR (p < 0.05) showed decreasing bacterial loads during incubation. The Sa-contaminated biomeshes behaved similarly while biomeshes inoculated with Se returned higher bacterial yields at 48 h, especially SIS (p < 0.001). SEM and light microscopy observations revealed planktonic bacteria and biofilms on the polymer surface and bacterial niches in biomesh pores.

CONCLUSIONS

Within 48 h of contamination, the absorbable polymer and biological meshes exhibited high bacterial loads. Given their lower affinity for both bacterial strains, the conventional non-absorbable polymer materials could be better candidates for use in contaminated surgical fields.

Bacteria repelling poly(methylmethacrylate-co-dimethylacrylamide) coatings for biomedical devices†Electronic supplementary information (ESI) available: Polymer microarray screening, including analysis of bacterial adhesion by fluorescence microscopy and SEM, and chemical composition of bacteria repelling polymers identified in the screen; polymer synthesis and characterisation; preparation of catheter pieces and solvent studies, and details for confocal imaging/analysis. See DOI: 10.1039/c4tb01129eClick here for additional data file

Nosocomial infections due to bacteria have serious implications on the health and recovery of patients in a variety of medical scenarios. Since bacterial contamination on medical devices contributes to the majority of nosocomical infections, there is a need for redesigning the surfaces of medical devices, such as catheters and tracheal tubes, to resist the binding of bacteria. In this work, polyurethanes and polyacrylates/acrylamides, which resist binding by the major bacterial pathogens underpinning implant-associated infections, were identified using high-throughput polymer microarrays. Subsequently, two 'hit' polymers, PA13 (poly(methylmethacrylate-co-dimethylacrylamide)) and PA515 (poly(methoxyethylmethacrylate-co-diethylaminoethylacrylate-co-methylmethacrylate)), were used to coat catheters and substantially shown to decrease binding of a variety of bacteria (including isolates from infected endotracheal tubes and heart valves from intensive care unit patients). Catheters coated with polymer PA13 showed up to 96% reduction in bacteria binding in comparison to uncoated catheters.

An in vitro study assessing the effect of mesh morphology and suture fixation on bacterial adherence

PURPOSE

Prosthetic infections, although relatively uncommon in hernia surgery, are a source of considerable morbidity and cost. The aims of this experimental study were to assess the influence of the morphological properties of the mesh on bacterial adherence in vitro. The morphological properties assessed were the polymer type, filament type, filament diameter, mesh weight, mean pore size, and the addition of silver chlorhexidine and titanium coatings. In addition, the study assessed the effect on bacterial adherence of adding a commonly used suture to the mesh and compared adherence rates to self-gripping mesh that does not require suture fixation.

METHODS

Eight commercially sourced flat hernia meshes with different material characteristics were included in the study. These were Prolene(®) (Ethicon(®)), DualMesh(®) (Gore(®)), DualMesh(®) Plus (Gore(®)), Parietex™ ProGrip (Covidien™), TiMesh(®) Light (GfE Medical), Bard(®) Soft Mesh (Bard(®)), Vypro(®) (Ethicon(®)), and Omyra(®) (Braun(®)). Individual meshes were inoculated with Staphylococcus epidermidis and Staphylococcus aureus with a bacterial inoculum of 10(2) bacteria. To assess the effect of suture material on bacterial adhesion, a sterile piece of commonly used monofilament suture material (2.0 Prolene(®), ZB370 Ethicon(®)) was sutured to selected meshes (chosen to represent different commonly used polymers and/or the presence of an antibacterial coating). Inoculated meshes were incubated for 18 h in tryptone soy broth and then analysed using scanning electron microscopy. A previously validated method for enumeration of bacteria using automated stage movement electron microscopy was used for direct bacterial counting. The final fraction of the bacteria adherent to the mesh was compared between the meshes and for each morphological variable. One-way analysis of variance (ANOVA) was performed on the bacterial counts. Tukey's test was used to determine the difference between the different biomaterials in the event the ANOVA was significant.

RESULTS

Properties that significantly increased the mean bacterial adherence were the expanded polytetrafluoroethylene polymer (P < 0.001); multifilament meshes (P < 0.001); increased filament diameter (P < 0.001); increased mesh weight (P < 0.001); and smaller mean pore size (P < 0.001). In contrast, mesh coating with antibacterial silver chlorhexidine significantly reduced bacterial adhesion (S. epidermidis mean bacterial count 140.7 ± 19.1 SE with DualMesh(®) vs. 2.3 ± 1.2 SE with DualMesh(®) Plus, P < 0.001; S. aureus mean bacterial count 371.7 ± 22.7 SE with DualMesh(®) vs. 19.3 ± 4.7 SE with DualMesh(®) Plus, P = 0.002). The addition of 2.0 Prolene suture material significantly increased the mean number of adherent bacteria independent of the mesh polymer or mesh coating (P = 0.04 to <0.001).

CONCLUSION

The present study demonstrates the significant influence of the prosthetic load on bacterial adherence. In patients at increased risk of infection, low prosthetic load materials, i.e., lightweight meshes with large pores, may be beneficial. Furthermore self-fixing meshes, which avoid increasing the prosthetic load and antibacterial impregnated meshes, may have an advantage in this setting.