Multilayer reconstruction of abdominal wall defects with acellular dermal allograft (AlloDerm) and component separation

Recent Advancements in Hydrogel Biomedical Research in Italy

Hydrogels have emerged as versatile biomaterials with remarkable applications in biomedicine and tissue engineering. Here, we present an overview of recent and ongoing research in Italy, focusing on extracellular matrix-derived, natural, and synthetic hydrogels specifically applied to biomedicine and tissue engineering. The analyzed studies highlight the versatile nature and wide range of applicability of hydrogel-based studies. Attention is also given to the integration of hydrogels within bioreactor systems, specialized devices used in biological studies to culture cells under controlled conditions, enhancing their potential for regenerative medicine, drug discovery, and drug delivery. Despite the abundance of literature on this subject, a comprehensive overview of Italian contributions to the field of hydrogels-based biomedical research is still missing and is thus our focus for this review. Consolidating a diverse range of studies, the Italian scientific community presents a complete landscape for hydrogel use, shaping the future directions of biomaterials research. This review aspires to serve as a guide and map for Italian researchers interested in the development and use of hydrogels in biomedicine.

Biological importance of human amniotic membrane in tissue engineering and regenerative medicine

The human amniotic membrane (hAM) is the innermost layer of the placenta. Its distinctive structure and the biological and physical characteristics make it a highly biocompatible material in a variety of regenerative medicine applications. It also acts as a supply of bioactive factors and cells, which indicate the advantages over other tissues. In this review, we firstly discussed the biological properties of hAM-derived cells in vivo or in vitro, along with their stemness of markers, pointing out a promising source of stem cells for regenerative medicine. Then, we systematically summarized current knowledge on the collection, preparation, preservation, and decellularization of hAM, as well as their characteristics helping to improve the understanding of applications in tissue engineering. Finally, we highlighted the recent advances in which hAM has undergone additional modifications to achieve an adequate perspective of regenerative medicine applications. More investigations are required in utilizing appropriate modifications to enhance the therapeutic effectiveness of hAM in the future.

Peritoneal Bridging Versus Nonclosure in Laparoscopic Ventral Hernia Repair: A Randomized Controlled Trial

Introduction

Postoperative seroma and pain are common problems following laparoscopic intraperitoneal onlay mesh (IPOM) repair of ventral hernias. These adverse outcomes may be avoided by dissecting and using the peritoneum in the hernial sac to bridge the hernia defect.

Methods

This was a patient- and outcome assessor-blinded, parallel-design, randomized controlled trial comparing nonclosure and peritoneal bridging approaches in patients scheduled for elective midline ventral hernia repair. The primary endpoint was seroma volume on ultrasonography. The secondary endpoints were postoperative pain, recurrence, and complications.

Results

Between November 2018 and December 2020, 112 patients were randomized, of whom 60 were in the nonclosure group and 52 were in the peritoneal bridging group. The seroma volume in the nonclosure and peritoneal bridging groups were 17 cm3 (6-53 cm3) versus 0 cm3 (0-26 cm3) at 1-month follow-up (P = 0.013). The median volume was zero at the 3-, 6-, and 12-month follow-ups in both groups. No significant differences were observed in early postoperative pain (P = 0.447) and in recurrence rate (P = 0.684). There were 4 (7%) and 1 (2%) perioperative complications that lead to reoperations in simple IPOM (sIPOM) and IPOM with peritoneal bridging (IPOM-pb), respectively.

Conclusions

Seroma was less prevalent after IPOM-pb at 1-month follow-up compared with sIPOM, with similar postoperative pain 1 week after index surgery in both groups. At subsequent follow-ups, the differences in seroma were not statistically significant. Further studies are required to confirm these results. Trial registration (NCT04229940).

Erratum: Addendum: Abdominal Wall Reconstruction: An Integrated Approach

[This corrects the article DOI: 10.1055/s-0038-1667062.].

A novel tool to evaluate bias in literature on use of biologic mesh in abdominal wall hernia repair

PURPOSE

Biologic meshes are being increasingly used for abdominal hernia repair in high-risk patients or patients with a previous history of wound infection, due to their infection-resistant properties. Several studies have been carried out to assess whether biologic mesh is superior to synthetic mesh, as well as to establish guidelines for their use. Unfortunately, most of these studies were not rigorously designed and were vulnerable to different types of bias. The systematic reviews that have been published so far on this topic contain the same biases and limitations of the primary articles that are analyzed. The lack of a literature review on the bias on the use of biological mesh prompted us to conduct the literature search, assessment and plan this article.

METHODS

We performed a literature search in PubMed, Embase and Cochrane databases of systematic reviews on biologic mesh for ventral hernia repair. The literature review was conducted using the Population, Intervention, Comparisons, Outcomes and Design approach. We identified 40 studies that matched the stringent criteria we had set. We then created a 13-point instrument to assess for bias and applied it on the primary studies that we intended to analyze.

RESULTS

Most primary studies are case series or case reports of patients undergoing abdominal hernia repair with biologic mesh, without any comparison group, and the inclusion of cases was only specified to be consecutive in 6 out of 40 cases. In terms of assessing outcomes, in none of the 40 articles were the outcome assessors blinded to the intervention or exposure status of participants.

CONCLUSION

The instrument that we created could allow to assess the risk of bias in different kind of studies. Our assessment of the studies based on the criteria that we had set up in the instrument clearly identified that further research needs to be done due to the lack of unbiased studies regarding the use of biologic meshes for abdominal hernia repair.

Xenogeneic acellular nerve scaffolds supplemented with autologous bone marrow-derived stem cells promote axonal outgrowth and remyelination but not nerve function

Autologous nerves, artificial scaffolds or acellular nerve scaffolds are commonly used in bridging treatment for peripheral nerve defects. Xenogeneic acellular nerve scaffolds and allogeneic cellular nerve scaffolds have the same structural characteristics. Due to the wider source of raw materials, these latter scaffolds have high-potential value for applications. However, whether their heterogeneity will affect nerve regeneration is unknown. The current study evaluated the efficiency of xenogeneic acellular nerve scaffolds (XANs) combined with 5-ethynyl-2'-deoxyuridine (EdU)-labeling of autologous bone marrow-derived stem cells (BMSCs) for repair of a 1.5 cm gap in rat sciatic nerves. XANs from rabbit tibial nerves were prepared, the structure and components of the scaffolds were evaluated after completely removing the cellular components. Animals were divided into four groups based on graft: the simple XAN group, the XAN + BMSC group, the XAN + Media (from BMSC culture) group, and the autograft group. Serological immune tests showed that XANs induce an immune response in the first 2 weeks after transplantation. Moreover, cell tracking revealed that the proportion of EdU+ cells decreased over time, as shown by the measures at 2 days (70%), 4 days (20%), and 8 days (even <3%) postoperatively. Nerve functional analyses revealed that in contrast to the autograft group results, the XAN-BMSC, XAN + Media, and XAN groups did not exhibit good restoration of the sciatic functional index (SFI) or electrophysiological results (the peak action potential amplitudes) 12 weeks, postoperatively. However, the XAN-BMSC and autograft groups demonstrated greater remyelination and increased axon numbers and myelin thickness than the XAN + Media and XAN groups 12 weeks, postoperatively (p < .05). In conclusion, in the early stage of transplantation, XANs induce a certain degree of inflammation. Although the combination of XANs with autologous BMSCs enhanced the number of regenerated axons and the remyelination, the combination did not effectively improve the recovery of nervous motor function. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3065-3078, 2018.

Effect of ascorbic and chondrogenic derived decellularized extracellular matrix from mesenchymal stem cells on their proliferation, viability and differentiation

BACKGROUND

The development and application of biomaterials to promote stem cell proliferation and differentiation has undergone major expansion over the last few years. Decellularized stem cell matrix (DSCMs) represent bioactive and biocompatible materials which achieve similar characteristics of native extracellular matrix. DSCMs have given promising outcomes in generating novel cell culture substrates mimicking specific niche microenvironments in tissue engineering.

AIMS

This research aims at producing two different DSCMs obtained from adipose derived mesenchymal stem cells and bone marrow mesenchymal stem cells, characterize them and evaluate the DSCMs bioactivity on mesenchymal stem cells.

METHODS

DSCMs were produced using ascorbic or chondrogenic medium, which were then used as a scaffold for adipose derived mesenchymal stem cells and bone marrow mesenchymal stem cells, respectively. The biological characteristics of both types of DSCMs, including cell attachment, morphology, proliferation, viability, and chondrogenic and osteogenic differentiation were evaluated and compared.

RESULTS

Differences between ascorbic derived-DSCMs and chondrogenic derived DSCMs were found. Chondrogenic derived-DSCMs remained compact and stronger during extraction and this made their handling easier. Ascorbic derived-DSCMs showed a different protein composition to chondrogenic-DSCMs. Bioactive characteristics analyzed were different depending on the cellular origin of DSCM and the method used to produce them.

CONCLUSIONS

The DSCMs obtained in this work constitutes favorable structure- and growth factors providing a microenvironment which is very similar to that of native ECM, which results in enhanced biological potential of the MSCs and responsiveness to the induction of differentiation. We found differences between ascorbic derived-DSCMs and chondrogenic derived DSCMs. Our results suggest that the cell source used to produce DSCMs is highly related to the bioactive characteristics of DSCMs.

A Meta-analysis of Outcomes Using Acellular Dermal Matrix in Breast and Abdominal Wall Reconstructions: Event Rates and Risk Factors Predictive of Complications

BACKGROUND

The use of acellular dermal matrix (ADM) has gained acceptance in breast and abdominal wall reconstructions. Despite its extensive use, there is currently a wide variation of reported outcomes in the literature. This study definitively elucidates the outcome rates associated with ADM use in breast and abdominal wall surgeries and identifies risk factors predisposing to the development of complications.

METHODS

A literature search was conducted using the Medline database (PubMed, US National Library of Medicine) and the Cochrane Library. A total of 464 articles were identified, of which 53 were eligible for meta-analysis. The endpoints of interest were the incidences of seroma, cellulitis, infection, wound dehiscence, implant failure, and hernia. The effects of various risk factors such as smoking, radiation, chemotherapy, and diabetes on the development of complications were also evaluated.

RESULTS

A majority of the studies were retrospective (68.6%) with a mean follow-up of 16.8 months (SD ± 10.1 months) in the breast group and 14.2 months (SD ± 7.8 months) in the abdominal wall reconstructive group. The overall risks and complications were as follows: cellulitis, 5.1%; implant failure, 5.9%; seroma formation, 8%; wound dehiscence, 8.1%; wound infection, 16.1%; hernia, 27.6%; and abdominal bulging, 28.1%. Complication rates were further stratified separately for the breast and abdominal cohorts, and the data were reported. This provides additional information on the associated abdominal wall morbidity in patients undergoing autologous breast reconstruction in which mesh reinforcement was considered as closure of the abdominal wall donor site. Radiation resulted in a significant increase in the rates of cellulitis (P = 0.021), and chemotherapy was associated with a higher incidence of seroma (P = 0.014).

CONCLUSION

This study evaluates the overall complication rates associated with ADM use by conducting a meta-analysis of published data. This will offer physicians a single comprehensive source of information during informed consent discussions as well as an awareness of the risk factors predictive of complications.

Comparison of Synthetic and Biologic Mesh in Ventral Hernia Repair Using Components Separation Technique

Ventral hernia repair (VHR) for large abdominal wall defects is challenging. Prior research established that the use of mesh is superior to suture closure alone and that component separation is an effective technique to combat loss of abdominal domain. Studies comparing component separation technique (CST) outcomes utilizing synthetic versus biologic mesh are limited. A retrospective review was conducted of 72 consecutive patients who underwent VHR with CST between 2006 and 2010 at our institution. Surgeon preference and the presence of contamination guided whether synthetic mesh (27 patients) or biologic mesh (45 patients) was used. Mean follow-up interval for all comers was 13.9 months and similar in both groups (P > 0.05). Degree of contamination and severity of premorbid medical conditions were significantly higher in the biologic mesh group, as reflected in the higher Ventral Hernia Working Group (VHWG) score (2.04 versus 2.86). Clinical outcomes, as measured by both minor and major complication rates and recurrence rates, were not significantly different. Minor complication rates were 26% in the synthetic group and 37% in the biologic group and major complication rates 15% in the synthetic group and 22% in the biologic group. There was 1 recurrence (4%) in the synthetic mesh group versus 5 (11%) in the biologic mesh group. Multivariable analysis for major complications revealed no significant difference for either synthetic or biologic mesh while controlling for other variables. Subset analysis of uncontaminated cases revealed recurrence rates of 4% in the synthetic mesh group and 6% in the biologic mesh group. VHR using CST and either synthetic mesh or biologic mesh resulted in low recurrence rates with similar overall complication profiles, despite the higher average VHWG grading score in the biologic mesh group. Our results support the VHWG recommendation for biologic mesh utilization in higher VHWG grade patients. In VHWG grade 2 patients, our clinical outcomes were similar, supporting the use of either type of mesh.

Synthetic mesh repair of an anterior perineal hernia following robotic radical urethrocystectomy

Introduction:

Perineal hernia is a protrusion of intra-abdominal viscera through a defect in the pelvic floor and is a rare but challenging complication after extensive abdominoperineal surgery. There have been small series published after colorectal exenteration, but no cases have been reported after radical cystectomy and urethrectomy.

Case Presentation:

A 68 years old woman developed an anterior perineal hernia, with no vaginal prolapse, after an anterior exenteration for bladder cancer. A perineal approach with the use of a synthetic polypropylene mesh was chosen to resolve the condition. After 6 months of follow-up, the patient has no symptoms or recurrence of the anterior perineal hernia.

Conclusion:

To our knowledge, this case is the first report of perineal hernia after radical urethrocystectomy. Although being a case report, this article describes a potential and challenging complication after extensive anterior pelvic surgery, that could increase its incidence in the future. Literature review shows that whether perineal, abdominal or combined approach is chosen, surgery must respect hernia repair principles.

Abdominal Wall Reconstruction After Temporary Abdominal Closure: A Ten-Year Review

Abdominal wall reconstruction (AWR) is often required for hernias created after temporary abdominal closure (TAC). Demographic and clinical data from patients undergoing TAC and AWR between January 1, 1992, and December 31, 2002, were collected and univariate analysis performed. Temporary abdominal closure and AWR were performed in 21 patients. Complications developed in 12 patients (57.1%) after TAC; associated risk factors were mesh placement ( P = .04) and skin grafting ( P = .04). Successful AWR included mesh (n = 6), component separation (n = 6), primary repair (n = 4), and 3 combination techniques. Six patients (28.6%) developed intraoperative complications, and 14 (66.7%) developed postoperative complications. Intraoperative complications were increased in patients with tissue expanders ( P = .01). Postoperative complications ( P = .04) were less likely with component separation. The complication rate with TAC and AWR is high. Tissue expanders are associated with an increased risk of intraoperative complications with AWR, whereas component separation is associated with a reduction in postoperative complications.

Outcomes following placement of non-cross-linked porcine-derived acellular dermal matrix in complex ventral hernia repair

Repair of complex ventral hernias frequently results in postoperative complications. This study assessed postoperative outcomes in a consecutive cohort of patients with ventral hernias who underwent herniorrhaphy using components separation techniques and reinforcement with non–cross-linked intact porcine-derived acellular dermal matrix (PADM) performed by a single surgeon between 2008 and 2012. Postoperative outcomes of interest included incidence of seroma, wound infection, deep-vein thrombosis, bleeding, and hernia recurrence determined via clinical examination. Of the 47 patients included in the study, 25% were classified as having Ventral Hernia Working Group grade 1 risk, 62% as grade 2, 2% as grade 3, and 11% as grade 4; 49% had undergone previous ventral hernia repair. During a mean follow-up of 31 months, 3 patients experienced hernia recurrence, and 9 experienced other postoperative complications: 4 (9%) experienced deep-vein thrombosis; 3 (6%), seroma; 2 (4%), wound infection; and 2 (4%), bleeding. The use of PADM reinforcement following components separation resulted in low rates of postoperative complications and hernia recurrence in this cohort of patients undergoing ventral hernia repair.

Outcomes of Laparoscopic versus Open Fascial Component Separation for Complex Ventral Hernia Repair

Ventral hernia recurrence rates have improved with advancements in technique. Open and laparoscopic fascial component separation techniques improve recurrence rates by allowing a tension free closure. This study examines laparoscopic component separation (LCS) and open component separation (OCS) techniques in the repair of complex ventral hernias and compares factors affecting patient outcomes. A retrospective chart review of patients who underwent ventral hernia repair with LCS and OCS was conducted between 2009 and 2013. Patient characteristics and outcomes were documented. Hernia recurrence was determined using physical exam and computed tomography if physical exam was equivocal. Univariate and multivariate analyses were performed. Ten patients underwent LCS and 38 underwent OCS. The rate of wound infection in the LCS group was 20 per cent versus 50 per cent in the OCS group. The overall rate of recurrence after LCS was 20 per cent, and 26 per cent in the OCS group. For body mass index > 30, the recurrence rate was 20 per cent in the LCS group and 29 per cent ( P = 0.5) in the open group. The use of LCS demonstrates a trend in the reduction of hernia recurrence and wound infection overall and in patients with body mass index > 30 compared with OCS.

In vivo Quantification of the Effects of Radiation and Presence of Hair Follicle Pores on the Proliferation of Fibroblasts in an Acellular Human Dermis in a Dorsal Skinfold Chamber: Relevance for Tissue Reconstruction following Neoadjuvant Therapy

INTRODUCTION

In neoadjuvant therapy, irradiation has a deleterious effect on neoangiogenesis. The aim of this study was to examine the post-implantation effects of neoadjuvant irradiation on the survival and proliferation of autologous cells seeded onto an acellular human dermis (hAD; Epiflex). Additionally, we examined the influence of dermal hair follicle pores on viability and proliferation. We used dorsal skinfold chambers implanted in rats and in-situ microscopy to quantify cell numbers over 9 days.

METHODS

24 rats received a skinfold chamber and were divided into 2 main groups; irradiated and unirradiated. In the irradiated groups 20Gy were applied epicutaneously at the dorsum. Epiflex pieces were cut to size 5x5mm such that each piece had either one or more visible hair follicle pores, or no such visible pores. Fibroblasts were transduced lentiviral with a fluorescent protein for cell tracking. Matrices were seeded statically with 2.5x104 fluorescent fibroblasts and implanted into the chambers. In each of the two main groups, half of the rats received Epiflex with hair follicle pores and half received Epiflex without pores. Scaffolds were examined in-situ at 0, 3, 6 and 9 days after transplantation. Visible cells on the surface were quantified using ImageJ.

RESULTS

In all groups cell numbers were decreased on day 3. A treatment-dependent increase in cell numbers was observed at subsequent time points. Irradiation had an adverse effect on cell survival and proliferation. The number of cells detected in both irradiated and non-irradiated subjects was increased in those subjects that received transplants with hair follicle pores.

DISCUSSION

This in-vivo study confirms that radiation negatively affects the survival and proliferation of fibroblasts seeded onto a human dermis transplant. The presence of hair follicle pores in the dermis transplants is shown to have a positive effect on cell survival and proliferation even in irradiated subjects.

A systematic review of outcomes following repair of complex ventral incisional hernias with biologic mesh

Repair of contaminated/infected ventral incisional hernias is marked by high rates of recurrence, complications, and/or explantation of synthetic mesh. Biologic mesh products are recommended for repair to permit reconstruction and reduce complications. A systematic review of PubMed, EMBASE, and Cochrane databases identified English-language articles reporting postoperative outcomes (e.g., hernia recurrence, infection, mesh explantation) in patients undergoing contaminated/infected ventral incisional herniorrhaphy. Eleven studies met inclusion criteria and contained quantitative outcome data. All were retrospective chart reviews of biologic mesh use (mostly human acellular dermal matrix). Hernia recurrence and wound infection rates were highly variable and inconsistently reported across studies. Mesh explantation was rarely reported. Outcome variability is likely owing to heterogenous patient populations, surgical technique variations, and follow-up duration. Biologic mesh use in contaminated/infected herniorrhaphy was marked by low reported rates of secondary surgeries for infected mesh removal. Data from large, well-controlled, prospective trials with biologic mesh products are needed.

Critical analysis of Strattice performance in complex abdominal wall reconstruction: intermediate-risk patients and early complications

The purpose of this study was to analyze the performance of a porcine-derived acellular dermal matrix (Strattice Reconstructive Tissue Matrix) in patients at increased risk for perioperative complications. We reviewed medical records for patients with complex abdominal wall reconstruction (AWR) and Strattice underlay from 2007 to 2010. Intermediate-risk patients were defined as having multiple comorbidities without abdominal infection. Forty-one patients met the inclusion criteria (mean age, 60 years; mean body mass index, 35.5 kg/m(2)). Comorbidities included coronary artery disease (63.4%), diabetes mellitus (36.6%), and chronic obstructive pulmonary disease (17.1%). Fascial closure was achieved in 40 patients (97.6%). Average hospitalization was 6.4 days (range, 1-24 days). Complications included seroma (7.3%), wound dehiscence with Strattice exposure (4.9%), cellulitis (2.4%), and hematoma (2.4%). All patients achieved abdominal wall closure with no recurrent hernias or need for Strattice removal. Patients with multiple comorbidities at intermediate risk of postoperative complications can achieve successful, safe AWR with Strattice.

Acellular dermal matrix allograft: An effective adjunct to oronasal fistula repair in patients with cleft palate

Context:

Oronasal fistula (ONF) following cleft palate (CP) repair are a challenging problem associated with high recurrent rates. Acellular dermal matrix allograft is an available tissue substitute.

Aims:

The aim of this study was to evaluate the effectiveness of acellular dermal matrix in the repair of ONF associated with CP that is recurrent or larger than 15 mm in any dimension.

Settings and Design:

This is a prospective study where 12 patients with repaired CP suffering from ONF of the hard palate >15 mm in diameter were included.

Materials and Methods:

Age ranged from 12 to 25 years. Acellular dermal matrix was firmly secured between repaired oral and nasal mucosal layers. Patients were clinically followed-up for 6 months postoperatively to assess total time for complete healing, dehiscence and/or refistulaization.

Statistical Analysis Used:

Fisher's exact test.

Results:

Acellular dermal matrix was integrated with successful fistula closure in all except 1 patient where failure of graft integration was noticed early postoperatively. In 6 patients, the oral mucosal layer showed dehiscence, through which the graft was exposed. Graft integration extended from 4 to 12 weeks postoperatively during which patients were instructed to follow a soft diet and meticulous oral hygiene measures.

Conclusions:

Acellular dermal matrix allografts are safe and effective adjuncts for use in closure of ONF in the hard palate that is recurrent or larger than 15 mm in any dimension.

Study of insertion force and deformation for suturing with precurved NiTi guidewire

This research presents an experimental study evaluating stomach suturing using a precurved nickel-titanium (NiTi) guidewire for an endoscopic minimally invasive obesity treatment. Precise path planning is critical for accurate and effective suturing. A position measurement system utilizing a hand-held magnetic sensor was used to measure the shape of a precurved guidewire and to determine the radius of curvature before and after suturing. Ex vivo stomach suturing experiments using four different guidewire tip designs varying the radius of curvature and bevel angles were conducted. The changes in radius of curvature and suturing force during suturing were measured. A model was developed to predict the guidewire radius of curvature based on the measured suturing force. Results show that a small bevel angle and a large radius of curvature reduce the suturing force and the combination of small bevel angle and small radius of curvature can maintain the shape of guidewire for accurate suturing.

Method for perfusion decellularization of porcine whole liver and kidney for use as a scaffold for clinical-scale bioengineering engrafts

BACKGROUND

Whole-organ engineering provides a new alternative source of donor organs for xenotransplantation. Utilization of decellularized whole-organ scaffolds, which can be created by detergent perfusion, is a strategy for tissue engineering. In this article, our aim is to scale up the decellularization process to human-sized liver and kidney to generate a decellularized matrix with optimal and stable characteristics on a clinically relevant scale.

METHODS

Whole porcine liver and kidney were decellularized by perfusion using different detergents (1% SDS, 1% Triton X-100, 1% peracetic acid (PAA), and 1% NaDOC) via the portal vein and renal artery of the liver and kidney, respectively. After rinsing with PBS to remove the detergents, the obtained liver and kidney extracellular matrix (ECM) were processed for histology, residual cellular content analysis, and ECM components evaluation to investigate decellularization efficiency, xenoantigens removal, and ECM preservation.

RESULTS

The resulting liver and kidney scaffolds in the SDS-treated group showed the most efficient clearance of cellular components and xenoantigens, including DNA and protein, and preservation of the extracellular matrix composition. In comparison, cell debris was observed in the other decellularized groups that were generated using Triton X-100, PAA, and NaDOC. Special staining and immunochemistry of the porcine liver and kidney ECMs further confirmed the disrupted three-dimension ultrastructure of the ECM in the Triton X-100 and NaDOC groups. Additionally, Triton X-100 effectively eliminated the residual SDS in the SDS-treated group, which ensured the scaffolds were not cytotoxic to cells. Thus, we have developed an optimal method that can be scaled up for use with other solid whole organs.

CONCLUSIONS

Our SDS-perfusion protocol can be used for porcine liver and kidney decellularization to obtain organ scaffolds cleared of cellular material, xenoimmunogens, and preserved vital ECM components.

Histologic characterization of acellular dermal matrices in a porcine model of tissue expander breast reconstruction

BACKGROUND

Acellular dermal matrices (ADMs) have been commonly used in expander-based breast reconstruction to provide inferolateral prosthesis coverage. Although the clinical performance of these biologic scaffold materials varies depending on a number of factors, an in-depth systematic characterization of the host response is yet to be performed. The present study evaluates the biochemical composition and structure of two ADMs, AlloDerm(®) Regenerative Tissue Matrix and AlloMax™ Surgical Graft, and provides a comprehensive spatiotemporal characterization in a porcine model of tissue expander breast reconstruction.

METHODS

Each ADM was characterized with regard to thickness, permeability, donor nucleic acid content, (residual double-stranded DNA [dsDNA]), and growth factors (basic fibroblast growth factor [bFGF], vascular endothelial growth factor [VEGF], and transforming growth factor-beta 1 [TGF-β1]). Cytocompatibility was evaluated by in vitro cell culture on the ADMs. The host response was evaluated at 4 and 12 weeks at various locations within the ADMs using established metrics of the inflammatory and tissue remodeling response: cell infiltration, multinucleate giant cell formation, extent of ADM remodeling, and neovascularization.

RESULTS

AlloMax incorporated more readily with surrounding host tissue as measured by earlier and greater cell infiltration, fewer foreign body giant cells, and faster remodeling of ADM. These findings correlated with the in vitro composition and cytocompatibility analysis, which showed AlloMax to more readily support in vitro cell growth.

CONCLUSIONS

AlloMax and AlloDerm demonstrated distinct remodeling characteristics in a porcine model of tissue expander breast reconstruction.

Biologic versus nonbiologic mesh in ventral hernia repair: a systematic review and meta-analysis

BACKGROUND

The current standard of treatment for most ventral hernias is a mesh-based repair. Little is known about the safety and efficacy of biologic versus nonbiologic grafts. A meta-analysis was performed to examine two primary outcomes: recurrence and wound complication rates.

METHODS

Electronic databases and reference lists of relevant articles were systematically searched for all clinical trials and cohort studies published between January 1990 and January 2012. A total of eight retrospective studies, with 1,229 patients, were included in the final analysis.

RESULTS

Biologic grafts had significantly fewer infectious wound complications (p < 0.00001). However, the recurrence rates of biologic and nonbiologic mesh were not different. In subgroup analysis, there was no difference in recurrence rates and wound complications between human-derived and porcine-derived biologic grafts.

CONCLUSIONS

Use of biologic mesh for ventral hernia repair results in less infectious wound complications but similar recurrence rates compared to nonbiologic mesh. This supports the application of biologic mesh for ventral hernia repair in high-risk patients or patients with a previous history of wound infection only when the significant additional cost of these materials can be justified and synthetic mesh is considered inappropriate.

Abdominal wall dynamics after component separation hernia repair

BACKGROUND

The component separation technique (CST) is an important technique now used frequently in complex ventral hernia repair (VHR). Although this technique has demonstrated superior success rates, there is a paucity of research describing how release of the external obliques coupled with rectus myofascial advancement alters the morphology of the abdominal architecture. In this study, we apply the new concept of analytic morphomics to describe the immediate changes in morphology of the abdomen that take place after VHR by CST.

METHODS

We identified 21 patients who underwent VHR by CST and received both preoperative and postoperative computed tomography scans between 2004 and 2009 in our clinical database. The surgical technique involved incisional release of the external oblique muscle lateral to the linea semilunaris with rectus abdominis myofascial advancement in all patients. Using semiautomated morphomic analysis, we measured the pre- and post-operative dimensions of the abdominal wall including the anterior-posterior distance from the anterior vertebra-to-skin and fascia along with the circumferential area of the skin and fascial compartments. Paired Student t-tests were used to compare pre- and post-operative values.

RESULTS

After hernia repair, there was a decrease in the anterior vertebra-to-skin distance (16.6 cm-15.8 cm, P = 0.007). There were also decreases in total body area (968.0 cm(2)-928.6 cm(2), P = 0.017) and total body circumference (113.6 cm-111.4 cm, P = 0.016). The distance from fascia to skin decreased as well, almost to the point of statistical significance (3.3 cm-2.9 cm, P = 0.0505). Interestingly, fascia area and circumference did not decrease significantly after the operation (578.2 cm(2)-572.5 cm(2), P = 0.519, and 89.1 cm-88.6 cm, P = 0.394, respectively).

CONCLUSIONS

Morphomic analysis can be used to compare and pre- and post-operative changes in patients undergoing abdominal surgery. Our study demonstrates that component separation affects the dimensions of the entire abdomen, but leaves the fascia area and circumference relatively unchanged. These changes in the abdominal wall may help explain the muscular changes observed as a result of this operation and demonstrate that this is a functional operation that restores fascial area. By better defining the effects of this procedure, we can better understand the reason for its clinical success.

Endoscopic versus open component separation: systematic review and meta-analysis

BACKGROUND

The component separation technique (CST) was developed to improve the integrity of abdominal wall reconstruction for large, complex hernias. Open CST necessitates large subcutaneous skin flaps and, therefore, is associated with significant ischemic wound complications. The minimally invasive or endoscopic component separation technique (MICST) has been suggested in preliminary studies to reduce wound complication rates post-operatively. In this study, we systematically reviewed the literature comparing open versus endoscopic component separation and performed a meta-analysis of controlled studies.

METHODS

A comprehensive search of electronic databases was completed. All English, randomized controlled trials, non-randomized comparison study, and case series were included. All comparison studies included in the meta-analysis were assessed independently by two reviewers for methodological quality using the Cochrane Risk of Bias tools.

RESULTS

63 primary studies (3,055 patients) were identified; 7 controlled studies and 56 case series. The total wound complication rate was lower for MICST (20.6 %) compared to Open CST (34.6 %). MICST compared to open CST was shown to have lower rates of superficial infections (3.5 vs 8.9 %), skin dehiscence (5.3 vs 8.2 %), necrosis (2.1 vs 6.8 %), hematoma/seroma formation (4.6 vs 7.4 %), fistula tract formation (0.4 vs 1.0 %), fascial dehiscence (0.0 vs 0.4 %), and mortality (0.4 vs 0.6 %.) The open component CST did have lower rates of intra-abdominal abscess formation (3.8 vs 4.6 %) and recurrence rates (11.1 vs 15.1 %). The meta-analysis included 7 non-randomized controlled studies (387 patients). A similar suggestive overall trend was found favoring MICST, although most types of wound complications did not show to significance. MICST was associated with a significantly decreased rate of fascial dehiscence and was shown to be significantly shorter procedure.

CONCLUSION

This systematic review and meta-analysis comparing MICST to open CST suggests MICST is associated with decreased overall post-operative wound complication rates. Further prospective studies are needed to verify these findings.

Hernia emergencies

Hernia emergencies are commonly encountered by the acute care surgeon. Although the location and contents may vary, the basic principles are constant: address the life-threatening problem first, then perform the safest and most durable hernia repair possible. Mesh reinforcement provides the most durable long-term results. Underlay positioning is associated with the best outcomes. Components separation is a useful technique to achieve tension-free primary fascial reapproximation. The choice of mesh is dictated by the degree of contamination. Internal herniation is rare, and preoperative diagnosis remains difficult. In all hernia emergencies, morbidity is high, and postoperative wound complications should be anticipated.

Repair of giant ventral hernias

Repair of huge ventral hernias is technically challenging for the surgeon and a major operation for the patient and should be performed by experienced surgeons in centers that are used to caring for patients who are commonly massively obese with significant comorbidities. Preoperative medical optimization of patients is an important part in the overall management of these large hernias. Conventional component separation with retromuscular mesh repair is the workhorse operation, which successfully deals with many giant ventral hernias, but multiple alternative strategies must be available to address situations in which myofascial elements are completely deficient or there is significant loss of domain The complexity of this surgery is reflected by recurrence rates ranging from 10% to 30% and wound complication rates as high as 40% to 50% in experienced centers.

Chemical decellularization: a promising approach for preparation of extracellular matrix

BACKGROUND

A biological scaffold from extracellular matrix can be produced by a variety of decellularization methods whose caveat consists in efficiently eliminating cells from the treated tissue. This scaffold can be used in diverse applications for tissue engineering and organ regeneration. Preservation of the extracellular matrix ultrastructure is highly desirable because of its unique architecture, contained growth factors and decreased immunological response. All of these properties provide attachment sites and adequate environment for cells colonizing this scaffold, reconstituting the decellularized organ. This review briefly describes chemical decellularization methods, evaluation of these protocols and the role of ECM in tissue engineering.

CONCLUSION

Chemical decellularization is an often used method for scaffold preparation and makes possible a well-preserved three dimensional structure of extracellular matrix.

Comparison study of acellular dermal matrices in complicated hernia surgery

BACKGROUND

Damage control surgery and management of the open abdomen has led to a significant improvement in survival in trauma and emergency surgical patients. However, subsequent abdominal reconstruction has become a significant challenge. The objective of this study was to compare 2 different acellular dermal matrices in regard to hernia recurrence and complications in patients who present with a large complicated ventral hernia as a result of trauma or emergency surgery.

STUDY DESIGN

A prospective quasi-experimental time-interrupted series design was used to evaluate the incidence of hernia recurrence in trauma/emergency surgery patients who had a ventral hernia repair with a biologic matrix. From January 2005 to December 2007, 55 patients with a complicated ventral hernia were repaired with AlloDerm (Life Cell Corporation). Beginning in February 2008 to January 2010, 40 patients with the same criteria were repaired with FlexHD (Musculoskeletal Transplant Foundation) and followed prospectively over the following year. The primary outcome for this study was hernia recurrence (functional or real) at 1 year. Other outcomes variables included abdominal laxity, seroma formation, and wound or intra-abdominal infection.

RESULTS

There was no significant difference in age, sex, and body mass index between the groups. In addition, there was no significant difference in the mean hernia size and size of the acellular dermis that was inserted. At 1 year postsurgery, all of the AlloDerm patients were diagnosed with recurrence requiring a second formal repair. Eleven patients (31%) whose hernias were repaired with FlexHD were diagnosed with a recurrence requiring a second formal repair.

CONCLUSIONS

FlexHD appears to have reduced the recurrence and laxity rates while maintaining a similar complication profile compared with AlloDerm in trauma/emergency surgery patients with large complicated ventral hernias.

A modified approach to component separation using biologic graft as a load-sharing onlay reinforcement for the repair of complex ventral hernia

BACKGROUND

Components separation has been proposed as a means to close large ventral hernia without undue tension. We report a modification on open components separation that allows for the incorporation of onlaid noncrosslinked porcine acellular dermal matrix (Strattice, LifeCell Corp, Branchburg, NJ) as a load-sharing structure.

METHODS

This was a retrospective case series including all cases using Strattice from July 2008 through December 2009. Data evaluated included patient demographics, comorbidities associated with risk of recurrence, hernia grade, and postoperative complications. The primary outcomes were hernia recurrence and surgical site occurrences.

RESULTS

There were 58 patients; 60.8% presented with a recurrent incisional hernia. Average length of follow-up was 384 days. There were 4 hernia recurrences (7.9%). Complications included surgical site infection (20.7%), seroma (15.5%), and hematoma (5%) requiring intervention. Four deaths occurred in the series due to causes unrelated to the hernia repair, only 1 within 30 days of operation.

CONCLUSIONS

This series demonstrates that components separation reinforced with noncrosslinked porcine acellular dermal matrix onlay is an efficacious, single-stage repair with a low rate of recurrence and surgical site occurrences.

Effect of static seeding methods on the distribution of fibroblasts within human acellular dermis

INTRODUCTION

When developing tissue engineered solutions for existing clinical problems, cell seeding strategies should be optimized for desired cell distribution within matrices. The purpose of this investigation was to compare the effects of different static cell seeding methods and subsequent static cell culture for up to 12 days with regard to seeding efficiency and resulting cellular distribution in acellular dermis.

MATERIALS AND METHODS

The seeding methods tested were surface seeding of both unmodified and mechanically incised dermis, syringe injection of cell suspension, application of low-pressure and use of an ultrasonic bath to remove trapped air. The effect of "platelet derived growth factor" (PDGF) on surface seeding and low pressure seeding was also investigated. Scaffolds were incubated for up to 12 days and were histologically examined at days 0, 4, 8 and 12 for cell distribution and infiltration depth. The metabolic activity of the cells was quantified with the MTT assay at the same time points.

RESULTS

The 50 ml syringe degassing procedure produced the best results in terms of seeding efficiency, cell distribution, penetration depth and metabolic activity within the measured time frame. The injection and ultrasonic bath methods produced the lowest seeding efficiency. The incision method and the 20 ml syringe degassing procedure produced results that were not significantly different to those obtained with a standard static seeding method.

CONCLUSION

We postulate that air in the pores of the human acellular dermis (hAD) hinders cell seeding and subsequent infiltration. We achieved the highest seeding efficiency, homogeneity, infiltration depth and cell growth within the 12 day static culturing period by degassing the dermis using low- pressure created by a 50 ml syringe. We conclude that this method to eliminate trapped air provides the most effective method to seed cells and to allow cell proliferation in a natural scaffold.

Update: Innovation in cardiology (IV). Cardiac tissue engineering and the bioartificial heart

Heart failure is the end-stage of many cardiovascular diseases-such as acute myocardial infarction-and remains one of the most appealing challenges for regenerative medicine because of its high incidence and prevalence. Over the last 20 years, cardiomyoplasty, based on the isolated administration of cells with regenerative capacity, has been the focal point of most studies aimed at regenerating the heart. Although this therapy has proved feasible in the clinical setting, the degree of infarcted myocardium regenerated and of improved cardiac function are at best modest. Hence, tissue engineering has emerged as a novel technology using cells with regenerative capacity, biological and/or synthetic materials, growth, proangiogenic and differentiation factors, and online registry systems, to induce the regeneration of whole organs or locally damaged tissue. The next step, seen recently in pioneering animal studies, is de novo generation of bioartificial hearts by decellularization and preservation of supporting structures for their subsequent repopulation with new contractile, vascular muscle tissue. Ultimately, this new approach would entail transplantation of the "rebuilt" heart, reestablishing cardiac function in the recipient.

A critical review of biologic mesh use in ventral hernia repairs under contaminated conditions

PURPOSE

We used an evidence-based approach to determine whether the promotions and claims of superiority of biologic mesh over synthetic mesh use in ventral hernia repairs (VHRs) under contaminated conditions were sound and valid.

METHODS

We searched the Medline database to specifically identify review articles relating to biologic mesh and VHR and critically reviewed these studies using an evidence-based approach.

RESULTS

For the past 45 years, four clinical reviews and one systematic review have included biologic meshes as part of a larger discussion on available prosthetics for VHR. All reviews supported biologic mesh use, especially in the setting of contaminated fields. Yet, the primary literature included in these reviews and served as the basis for these conclusions consisted entirely of case series and case reports, which have the lowest level of evidence in determining scientific validity. Furthermore, the FDA has neither cleared nor approved this particular use.

CONCLUSIONS

The cumulative data regarding biologic mesh use in VHRs under contaminated conditions does not support the claim that it is better than synthetic mesh used under the same conditions. The highly promoted and at least moderately utilized practice of placing biologic mesh in contamination is being done outside of the original intended use, and a re-evaluation of or possible moratorium on biologic mesh use in hernia surgery is seriously warranted. Alternatively, an industry-sponsored national registry of patients in whom ventral hernia repairs involved biologic mesh would substantively add to our understanding regarding how these intriguing biomaterials are being used and their overall clinical efficacy.

The role of biologic mesh in abdominal wall reconstruction: a systematic review of the current literature

BACKGROUND

Biologic mesh in the form of allograft or xenograft products have been used in complicated abdominal hernia repair, but few comparative studies exist.

METHODS

A systematic review of original incisional hernia studies was conducted to include 2 primary end points: hernia recurrence and surgical site occurrence. Analysis of variance and a Satterthwaite t test compared the devices.

RESULTS

Twenty-nine studies were included in this analysis, which included 1,257 patients. The total number of studies and the total subjects for each device include the following: Permacol (Tissue Science Laboratories, Hampshire, UK) (4/64), Surgisis (Cook Medical, Bloomington, IN) (3/87), and Alloderm (LifeCell, Corp, Branchburg, NJ) (23/1,106). Device-specific recurrence rates and surgical site occurrence rates, respectively, were as follows: Alloderm (20.8%, 31.4%), Permacol (10.9%, 25%), and Surgisis (8.0%, 40.2%). A Satterthwaite t test comparison revealed significantly higher numbers of hernia recurrence (P = .006) and surgical site occurrence (P = .04) when comparing Alloderm with Permacol.

CONCLUSIONS

Biologic mesh does play a beneficial role in abdominal wall reconstruction although allograft acellular dermal matrix does have a higher recurrence rate as compared with xenograft products, which limits its current role in hernia repair.

Biologic grafts for ventral hernia repair: a systematic review

BACKGROUND

Biologic grafts hold promise of a durable repair for ventral hernias with the potential for fewer complications than synthetic mesh. This systematic review was performed to evaluate the effectiveness and safety of biologic grafts for ventral hernia repair.

METHODS

MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched for studies on biologic grafts for the repair of ventral hernias. Outcomes are presented as weighted pooled proportions.

RESULTS

Twenty-five retrospective studies were included. Recurrence depended on wound class, with an overall rate of 13.8% (95% confidence interval [CI], 7.6-21.3). The recurrence rate in contaminated/dirty repairs was 23.1% (95% CI, 11.3-37.6). Abdominal wall laxity occurred in 10.5% (95% CI, 3.7-20.3) of patients. The surgical morbidity rate was 46.3% (95% CI, 33.3-59.6). Infection occurred in 15.9% (95% CI, 9.8-23.2) of patients but only led to graft removal in 4.9% of cases.

CONCLUSIONS

No randomized trials are available to properly evaluate biologic grafts for ventral hernia repair. The current evidence suggests that biologic grafts perform similarly to other surgical options. Biologic grafts are associated with a high salvage rate when faced with infection.

The use of porcine acellular dermal matrix in a bridge technique for complex abdominal wall reconstruction: an outcome analysis

BACKGROUND

Outcomes using the porcine acellular dermal matrix (PADM) in abdominal wall reconstruction (AWR) have been reported when used for midline reinforcement; however, there have been no reports focused on outcomes when used as a bridging mesh.

METHODS

A retrospective review was conducted of all patients who underwent AWR with a non-cross-linked PADM as a bridged repair without midline fascial approximation.

RESULTS

Nine patients were identified with an average follow-up of 546 days. The average preoperative hernia defect diameter was 22.4 cm. After PADM placement, the average defect diameter was 9.8 cm. Complications occurred in 55.6% of patients, with PADM exposure occurring in all of these patients. No PADM was explanted, and all patients eventually healed. Abdominal wall eventration and/or recurrence occurred in 8 of 9 (88.9%) patients.

CONCLUSIONS

When fascial approximation cannot be achieved, PADM bridging may be the best option to avoid complications associated with synthetic mesh. However, there is a high potential for abdominal wall eventration and/or recurrence.

Confocal laser scanning microscopy evaluation of an acellular dermis tissue transplant (Epiflex®)

The structure of a biological scaffold is a major determinant of its biological characteristics and its interaction with cells. An acellular dermis tissue transplant must undergo a series of processing steps, to remove cells and genetic material and provide the sterility required for surgical use. During manufacturing and sterilization the structure and composition of tissue transplants may change.

The composition of the human cell-free dermis transplant Epiflex® was investigated with specific attention paid to its structure, matrix composition, cellular content and biomechanics.

We demonstrated that after processing, the structure of Epiflex remains almost unchanged with an intact collagen network and extracellular matrix (ECM) protein composition providing natural cell interactions. Although the ready to use transplant does contain some cellular and DNA debris, the processing procedure results in a total destruction of cells and active DNA which is a requirement for an immunologically inert and biologically safe substrate. Its biomechanical parameters do not change significantly during the processing.

Suppressed wound healing in a patient with rheumatoid arthritis taking leflunomide (arava)

Although patients with rheumatoid arthritis taking disease-modifying antirheumatic drugs (DMARDs) are monitored for various medication adverse events, DMARDs, and leflunomide in particular, have effects that are not observed clinically, specifically adverse effects on wound healing.

Repair of incisional hernias with biological prosthesis: a systematic review of current evidence

BACKGROUND

No consensus has been reached on the use of bioprosthetics to repair abdominal wall defects. The purpose of this systematic review was to summarize the outcomes from studies describing this use of various bioprosthetics for incisional hernia repair.

METHODS

Studies published by October 2011 were identified through literature searches using EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials.

RESULTS

A total of 491 articles were scanned, 60 met eligibility criteria. Most studies were retrospective case studies. The studies ranged considerably in methodologic quality, with a modified Methodological Index of Nonrandomized Studies score from 5 to 12. Many repairs were performed in contaminated surgical sites (47.9%). At least one complication was seen in 87% of repairs. Major complications noted were wound infections (16.9%) and seroma (12.0%). With a mean follow-up period of 13.6 months the hernia recurrence rate was 15.2%.

CONCLUSIONS

There is an insufficient level of high-quality evidence in the literature on the value of bioprosthetics for incisional hernia repair. Randomized controlled trials that use standardized reporting comparing bioprosthetics with synthetic mesh for incisional hernia repair are needed.

Mechanical evaluation of decellularized porcine thoracic aorta

BACKGROUND

Decellularized tissues are expected to have major cellular immunogenic components removed and in the meantime maintain similar mechanical strength and extracellular matrix (ECM) structure. However, the decellularization processes likely cause alterations of the ECM structure and thus influence the mechanical properties. In the present study, the effects of different decellularization protocols on the (passive) mechanical properties of the resulted porcine aortic ECM were evaluated.

METHODS

Decellularization methods using anionic detergent (sodium dodecyl sulfate), enzymatic detergent (Trypsin), and non-ionic detergent [tert-octylphenylpolyoxyethylen (Triton X-100)] were adopted to obtain decellularized porcine aortic ECM. Histologic studies and scanning electron microscopy were performed to confirm the removal of cells and to examine the structure of ECM. Biaxial tensile testing was used to characterize both the elastic and viscoelastic mechanical behaviors of decellularized ECM.

RESULTS

All three decellularization protocols remove the cells effectively. The major ECM structure is preserved under sodium dodecyle sulfate (SDS) and Triton X-100 treatments. However, the structure of Trypsin treated ECM is severely disrupted. SDS and Triton X-100 decellularized ECM exhibits similar elastic properties as intact aorta tissues. Decellularized ECM shows less stress relaxation than intact aorta due to the removal of cells. Creep behavior is negligible for both decellularized ECM and intact aortas.

CONCLUSION

SDS and Triton X-100 decellularized ECM tissue appeared to maintain the critical mechanical and structural properties and might work as a potential material for further vascular tissue engineering.

Bioprosthetic mesh use for the problematic thoracoabdominal wall: outcomes in relation to contamination and infection

BACKGROUND

Limited controlled data exist regarding the role of bioprosthetic meshes for hernia repair. Often the only option available in contaminated cases, their high cost calls for an evaluation of their utility and indications for use.

METHODS

A retrospective review of cases in which human acellular dermal matrix (HADM) was used to reconstruct a thoracoabdominal wall defect at the Foothills Medical Centre of Calgary was conducted. Attention was placed to identify the need for surgical reintervention postoperatively.

RESULTS

Over 2 years, 13 patients required the use of HADM for reconstruction of their thoracoabdominal wall; 69.2% of the cases were contaminated or infected. Three patients (23.1%) presented postoperative infectious complications; only 1 required reoperation. No patients required removal of their prosthesis. Two patients presented recurrences (median follow-up = 126 days).

CONCLUSIONS

The use of HADM for complex thoracoabdominal wall defects in contaminated or infected settings is a reliable option available for surgeons.

Biological meshes: a review of their use in abdominal wall hernia repairs

PURPOSE

Biological meshes are mostly used in infected fields within complex abdominal wall hernia repairs. There is no consensus, however, on the most appropriate material to be used in a given situation.

METHODS

A literature review of published articles reporting the utilization of biological meshes in ventral/incisional hernia repair was conducted. Data were analyzed to compare the recurrence rates obtained with biological meshes.

MAIN FINDINGS

Only a few prospective comparative studies were identified. Most publications relate to AlloDerm®, Permacol™ and Surgisis™ with data from other meshes insufficient to draw conclusions. AlloDerm has a 0-100% recurrence rate among studies. It compares poorly with Surgisis and results in an unfavorable outcome when used as a 'bridge prosthesis'. Permacol has consistent recurrence rates of 0-15%, whatever the patients' profiles or the context of infected fields, when considering the most relevant studies. The Surgisis results are more conflicting: the mesh exhibits low recurrence rates in clean fields, but in infected fields the recurrence rate is up to 39%.

CONCLUSION

Taken together, these studies suggest that the cross-linked mesh, Permacol has the lowest failure rate and the longest time to failure, particularly in contaminated or infected fields. However, this data should be confirmed by large prospective randomized studies.