Comparison of Permacol™ and Strattice™ for the repair of abdominal wall defects

Platelet-Rich Therapies in Hernia Repair: A Comprehensive Review of the Impact of Platelet Concentrates on Mesh Integration in Hernia Management

Mesh-augmented hernia repair is the gold standard in abdominal wall and hiatal/diaphragmatic hernia management and ranks among the most common procedures performed by general surgeons. However, it is associated with a series of drawbacks, including recurrence, mesh infection, and adhesion formation. To address these weaknesses, numerous biomaterials have been investigated for mesh coating. Platelet-rich plasma (PRP) is an autologous agent that promotes tissue healing through numerous cytokines and growth factors. In addition, many reports highlight its contribution to better integration of different types of coated meshes, compared to conventional uncoated meshes. The use of PRP-coated meshes for hernia repair has been reported in the literature, but a review of technical aspects and outcomes is missing. The aim of this comprehensive review is to report the experimental studies investigating the synergistic use of PRP and mesh implants in hernia animal models. A comprehensive literature search was conducted across PubMed/Medline, Web of Science, and Scopus without chronological constraints. In total, fourteen experimental and three clinical studies have been included. Among experimental trials, synthetic, biologic, and composite meshes were used in four, nine, and one study, respectively. In synthetic meshes, PRP-coating leads to increased antioxidant levels and collaged deposition, reduced oxidative stress, and improved inflammatory response, while studies on biological meshes revealed increased neovascularization and tissue integration, reduced inflammation, adhesion severity, and mechanical failure rates. Finally, PRP-coating of composite meshes results in reduced adhesions and improved mechanical strength. Despite the abundance of preclinical data, there is a scarcity of clinical studies, mainly due to the absence of an established protocol regarding PRP preparation and application. To this point in time, PRP has been used as a coating agent for the repair of abdominal and diaphragmatic hernias, as well as for mesh fixation. Clinical application of conclusions drawn from experimental studies may lead to improved results in hernia repair.

Ibuprofen-loaded bilayer electrospun mesh modulates host response toward promoting full-thickness abdominal wall defect repair

Pro-inflammatory response impairs the constructive repair of abdominal wall defects after mesh implantation. Electrospinning-aid functionalization has the potential to improve the highly orchestrated response by attenuating the over-activation of foreign body reactions. Herein, we combined poly(L-lactic acid-co-caprolactone) (PLLA-CL) with gelatin proportionally via electrospinning, with Ibuprofen (IBU) incorporation to fabricate a bilayer mesh for the repair improvement. The PLLA-CL/gelatin/IBU (PGI) mesh was characterized in vitro and implanted into the rat model with a full-thickness defect for a comprehensive evaluation in comparison to the PLLA-CL/gelatin (PG) and off-the-shelf small intestinal submucosa (SIS) meshes. The bilayer PGI mesh presented a sustained release of IBU over 21 days with degradation in vitro and developed less-intensive intraperitoneal adhesion along with a histologically weaker inflammatory response than the PG mesh after 28 days. It elicited an M2 macrophage-dominant foreign body reaction within the process, leading to a pro-remodeling response similar to the biological SIS mesh, which was superior to the PG mesh. The PGI mesh provided preponderant mechanical supports over the SIS mesh and the native abdominal wall with similar compliance. Collectively, the newly developed mesh advances the intraperitoneal applicability of electrospun meshes by guiding a pro-remodeling response and offers a feasible functionalization approach upon immunomodulation.

Comparative proteomic analysis of regenerative acellular matrices: The effects of tissue source and processing method

Acellular tissue matrices are used in regenerative medicine from weak tissue re-enforcement to cosmetic augmentation. However, proteomic signatures leading to different clinical outcomes among matrices are not well understood. In an attempt to investigate the effects of tissue source and processing method, we examined by liquid chromatography tandem mass spectrometry (LC-MS/MS) the proteomic profiles of 12 regulatory agency-approved acellular matrices (AlloMax, AlloDerm, CollaMend, Heal-All, JayyaLife, ReGen, Renov, Strattice, SurgiMend, Surgisis, UniTrump and Vidasis). The compositions of acellular matrices varied greatly with the number of identified proteins ranging from 7 to 106. The content of individual proteins was between 0.0001% and 95.8% according to their abundances measured by the M/Z signal intensities. Most acellular matrices still contained numerous cellular proteins. AlloMax, AlloDerm, ReGen, Strattice, SurgiMend and Surgisis retained necessary structural and functional proteins to form the extracellular protein-protein interaction networks for cell adhesion, proliferation and tissue regeneration, whereas CollaMend, Heal-All, JayyaLife, Renov, UniTrump and Vidasis had only retained certain structural collagens. Principal component analysis showed that proteomic variations among acellular matrices were largely attributed to tissue source and processing method. Differences in proteomic profiles among acellular matrices offers insights into molecular interpretation for different clinical outcomes, and can serve as useful references for rational design of regenerative bio-scaffolds.

Abdominal wall hernia repair: from prosthetic meshes to smart materials

Hernia reconstruction is one of the most frequently practiced surgical procedures worldwide. Plastic surgery plays a pivotal role in reestablishing desired abdominal wall structure and function without the drawbacks traditionally associated with general surgery as excessive tension, postoperative pain, poor repair outcomes, and frequent recurrence. Surgical meshes have been the preferential choice for abdominal wall hernia repair to achieve the physical integrity and equivalent components of musculofascial layers. Despite the relevant progress in recent years, there are still unsolved challenges in surgical mesh design and complication settlement. This review provides a systemic summary of the hernia surgical mesh development deeply related to abdominal wall hernia pathology and classification. Commercial meshes, the first-generation prosthetic materials, and the most commonly used repair materials in the clinic are described in detail, addressing constrain side effects and rational strategies to establish characteristics of ideal hernia repair meshes. The engineered prosthetics are defined as a transit to the biomimetic smart hernia repair scaffolds with specific advantages and disadvantages, including hydrogel scaffolds, electrospinning membranes, and three-dimensional patches. Lastly, this review critically outlines the future research direction for successful hernia repair solutions by combing state-of-the-art techniques and materials.

Development of a full-thickness acellular dermal graft from human skin: Case report of first patient rotator cuff patch augmentation repair

The processing and initial testing of a new human tissue preparation is described. Full-thickness Acellular Dermal Matrix (ftADM) is the extracellular matrix (ECM) obtained by decellularization of full-thickness human skin from cadaveric donors. The safety, stability and usability of the graft are discussed with respect to the results of the residual cellular content, maintenance of ECM components, and biomechanical properties. Quantitative and qualitative analysis of the ECM demonstrated the absence of cell debris, while the native structure of human dermis was maintained. Biomechanical testing showed stiffness values comparable to other commercial products used for tendon reinforcement, suggesting that our ftADM could be successfully used not only in soft tissue regeneration surgeries, but also in tendon reinforcement. First case of ftADM in rotator cuff augmentation is described. Technical management of the patch during surgery and clinical outcomes are discussed.

Braxon®-assisted prepectoral breast reconstruction: A decade later

We are sitting on the cusp of the bioengineered breast era, in which implant-based breast reconstruction is seeing a growing trend and biotechnology research progressively empowers clinical practice. As never before, the choice of biomaterials has acquired great importance for achieving reconstructive outcomes, and the increase in the use of acellular dermal matrices (ADMs) in the field of senology tells us a story of profound upheaval and progress. With the advent of prepectoral breast reconstruction (PPBR), plenty of devices have been proposed to wrap the silicone prosthesis, either completely or partially. However, this has caused a great deal of confusion and dissent with regard to the adoption of feasible reconstructive strategies as well as the original scientific rationale underlying the prepectoral approach. Braxon^® is the very first device that made prepectoral implant positioning possible, wrapping around the prosthesis and exerting the proven ADM regenerative potential at the implant–tissue interface, taking advantage of the body's physiological healing mechanisms. To date, the Braxon^® method is among the most studied and practiced worldwide, and more than 50 publications confirm the superior performance of the device in the most varied clinical scenarios. However, a comprehensive record of the working of this pioneering device is still missing. Therefore, our aim with this review is to lay a structured knowledge of surgery with BRAXON^® and to provide a decision-making tool in the field of PPBR through a complete understanding on the very first device for prepectoral, one decade after its introduction.

Antimicrobial Meshes for Hernia Repair: Current Progress and Perspectives

Recent advances in the development of biomaterials have given rise to new options for surgery. New-generation medical devices can control chemical breakdown and resorption, prevent post-operative adhesion, and stimulate tissue regeneration. For the fabrication of medical devices, numerous biomaterials can be employed, including non-degradable biomaterials (silicone, polypropylene, expanded polytetrafluoroethylene) or biodegradable polymers, including implants and three-dimensional scaffolds for tissue engineering, which require particular physicochemical and biological properties. Based on the combination of new generation technologies and cell-based therapies, the biocompatible and bioactive properties of some of these medical products can lead to progress in the repair of injured or harmed tissue and in tissue regeneration. An important aspect in the use of these prosthetic devices is the associated infection risk, due to the medical complications and socio-economic impact. This paper provides the latest achievements in the field of antimicrobial surgical meshes for hernia repair and discusses the perspectives in the development of these innovative biomaterials.

Tailoring electrospun mesh for a compliant remodeling in the repair of full-thickness abdominal wall defect - The role of decellularized human amniotic membrane and silk fibroin

Tailored electrospun meshes have been increasingly explored for abdominal wall defect repair in preclinical and clinical studies. However, the fabrication of a bioengineered mesh adapts to the intraperitoneal repair for a compliant remodeling remains a great challenge. In this study, we fabricated a functional mesh by combining polycaprolactone (PCL) with silk fibroin (SF) and decellularized human amniotic membrane (HAM) proportionally via electrospinning. SF was integrated with PCL (40:60 w/w) to regulate the structural flexibility. Micronized HAM was incorporated to PCL/SF (10:90 w/w) to provide a biocompatible milieu with functions being conferred to facilitate intraperitoneal repair. After the blend electrospinning, the PCL/SF/HAM mesh was characterized in vitro and implanted into the rat model with a full-thickness defect for a comprehensive evaluation in comparison to the PCL and PCL/SF meshes. The results demonstrated that electrospinning fabricated PCL stabilized the mechanical elongation toward approximating the native counterparts after integrating with SF. After integrating with HAM, which is coupled with diverse biomolecular compositions, the developed PCL/SF/HAM mesh provided a better microenvironment for cell proliferation and vasculogenic network over other meshes without HAM addition and possessed the functions capable of inhibiting transforming growth factor β1 (TGF-β1) expression and collagen secretion under inflammatory conditions. Moreover, the functional mesh developed less-intensive adhesion along with histologically weaker inflammatory response and foreign body reaction than the PCL and PCL/SF meshes after 90 days in vivo. During the remodeling process, the bioactive structure induced more pronounced neovascularization and remarkable incorporation of collagen and elastin fibers and contractile filaments for a mechanically sufficient and physiologically stiffness-matched healing. This tailor-made mesh expands the intraperitoneal applicability of conventional electrospun meshes for a compliant remodeling in the repair of abdominal wall defects.

The use of Permacol® biological mesh for complex abdominal wall repair

BACKGROUND

Complex abdominal wall repair (CAWR) remains challenging, especially in contaminated fields where the use of a synthetic mesh is associated with prohibitively complication rates. Consequently, biological mesh has been proposed as an alternative. The aim of our study was to evaluate the safety and efficacy of using Permacol® in patients who had CAWR.

METHODS

We retrospectively reviewed the files of patients who had CAWR using the Permacol® mesh. Analysis included patients' preoperative characteristics, procedural parameters, and early and late post-operative complications including mainly recurrence. A multivariate regression model was performed to determine factors that influence 24-months recurrence rate.

RESULTS

Between January 2009 and December 2018, 75 patients. The most common indication was hernia in a contaminated field (48.0%) and abdominal wall defect greater than 10 cm in diameter (36%). Overall, 44% of our patients were Centers for Disease Control (CDC) class II or III and 81.3% fall into category II or III according to the Ventral Hernia Working Group (VHWG) classification. Recurrence rate of our series was 9.3%. Complete fascial closure was achieved in 60 patients (80%). Upon univariate analysis complete fascial closure, posterior component separation, seroma drainage, BMI >30 kg/m2 and age >65 years, VHWD grade >2, DINDO CLAVIEN class > 2 affected the recurrence rate at 2 years follow up. When subcutaneous drains are placed prophylactically, recurrence rates drop from 38.7% (5/14) to 3.3% (2/61 patients) when drains are placed at the time of operation (p=0.02). Only fascial closure affected the 24-months recurrence rate on multivariate analysis (p<0.001).

CONCLUSIONS

Permacol® surgical implant use for CAWR is safe with a relatively low rate of hernia recurrence at 2 years. Prophylactic subcutaneous drain placement may reduce the risk of hernia recurrence. The presence of contaminated fields does not appear to influence hernia recurrence when Permacol® is used, in fact, the only factor that affects recurrence rate at 24-months on multivariate analysis is completeness of the fascial closure.

Functionalized Strategies and Mechanisms of the Emerging Mesh for Abdominal Wall Repair and Regeneration

Meshes have been the overwhelmingly popular choice for the repair of abdominal wall defects to retrieve the bodily integrity of musculofascial layer. Broadly, they are classified into synthetic, biological and composite mesh based on their mechanical and biocompatible features. With the development of anatomical repair techniques and the increasing requirements of constructive remodeling, however, none of these options satisfactorily manages the conditional repair. In both preclinical and clinical studies, materials/agents equipped with distinct functions have been characterized and applied to improve mesh-aided repair, with the importance of mesh functionalization being highlighted. However, limited information exists on systemic comparisons of the underlying mechanisms with respect to functionalized strategies, which are fundamental throughout repair and regeneration. Herein, we address this topic and summarize the current literature by subdividing common functions of the mesh into biomechanics-matched, macrophage-mediated, integration-enhanced, anti-infective and antiadhesive characteristics for a comprehensive overview. In particular, we elaborate their effects separately with respect to host response and integration and discuss their respective advances, challenges and future directions toward a clinical alternative. From the vastly different approaches, we provide insight into the mechanisms involved and offer suggestions for personalized modifications of these emerging meshes.

The Role of Mesh Implants in Surgical Treatment of Parastomal Hernia

A parastomal hernia is a common complication following stoma surgery. Due to the large number of hernial relapses and other complications, such as infections, adhesion to the intestines, or the formation of adhesions, the treatment of hernias is still a surgical challenge. The current standard for the preventive and causal treatment of parastomal hernias is to perform a procedure with the use of a mesh implant. Researchers are currently focusing on the analysis of many relevant options, including the type of mesh (synthetic, composite, or biological), the available surgical techniques (Sugarbaker’s, “keyhole”, or “sandwich”), the surgical approach used (open or laparoscopic), and the implant position (onlay, sublay, or intraperitoneal onlay mesh). Current surface modification methods and combinations of different materials are actively explored areas for the creation of biocompatible mesh implants with different properties on the visceral and parietal peritoneal side. It has been shown that placing the implant in the sublay and intraperitoneal onlay mesh positions and the use of a specially developed implant with a 3D structure are associated with a lower frequency of recurrences. It has been shown that the prophylactic use of a mesh during stoma formation significantly reduces the incidence of parastomal hernias and is becoming a standard method in medical practice.

Long term comparative evaluation of two types of absorbable meshes in partial abdominal wall defects: an experimental study in rabbits

PURPOSE

Synthetic prosthetic materials that are fully absorbable seek to reduce the host foreign body reaction and promote host tissue regeneration. This preclinical trial was designed to analyse, in the long term, the behaviour of two prosthetic meshes, one synthetic and one composed of porcine collagen, in abdominal wall reconstruction.

METHODS

Partial defects were created in the abdominal walls of New Zealand rabbits and repaired using a synthetic absorbable mesh (Phasix™) or a non-crosslinked collagen bioprosthesis (Protexa™). After 3, 6, 12 and 18 months, specimens were recovered for light microscopy and collagen expression analysis to examine new host tissue incorporation, macrophage response and biomechanical strength.

RESULTS

Both materials showed good host tissue incorporation in line with their spatial structure. At 18 months postimplant, Protexa™ was highly reabsorbed while the biodegradation of Phasix™ was still incomplete. Collagenization of both materials was good. Macrophage counts steadily decreased over time in response to Phasix™, yet persisted in the collagen meshes. At 18 months, zones of loose tissue were observed at the implant site in the absence of herniation in both implant types. The stress-stretch behaviour of Phasix™ implants decreased over time, being more pronounced during the period of 12-18 months. Nevertheless, the abdominal wall repaired with Protexa™ became stiffer over time.

CONCLUSION

Eighteen months after the implant both materials showed good compatibility but the biodegradation of Phasix™ and Protexa™ was incomplete. No signs of hernia were observed at 18 months with the stress-stretch relations being similar for both implants, regardless of the more compliant abdominal wall repaired with Protexa™ at short term.

Regulation of Peritoneal Inflammatory Response to Implant Material Using an Ex Vivo Model System

BACKGROUND

Implants used in abdominal wall reconstruction are associated with intra-abdominal inflammation that can cause complications such as adhesions, fistulae, or failure of the implant. This study analyzed the inflammatory response of human peritoneum explants when exposed to different implant materials including synthetic and biological (cross-linked and non-cross-linked).

MATERIALS AND METHODS

Human peritoneum explants (parietal and visceral) were incubated in culture with implants used for abdominal wall reconstruction. Implants included Permacol (biological implant with chemical cross-linking); Biodesign and Strattice (biological implants without chemical cross-linking); Prolene (synthetic nonabsorbable); and Vicryl (synthetic absorbable). Control peritoneum samples were incubated without implant. Cytokine concentrations and corresponding gene expression were measured by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, respectively. Further evaluation included assessment of tissue viability and implant-cytokine adsorption.

RESULTS

Incubation of human peritoneal explants with Biodesign or Strattice was associated with a significant reduction in interleukin-6, interleukin-1β, and tumour necrosis factor alpha protein and gene expression compared with control. These could not be explained by reduced cell viability or implant-cytokine adsorption. Incubation of explants in Biodesign-conditioned media displayed a similar effect to incubation of explants with Biodesign itself.

CONCLUSIONS

Human peritoneal explants cultured with different mesh implant materials show an altered inflammatory cytokine response suggesting a tissue-specific response. Downregulation of key inflammatory cytokines by the peritoneum exposed to non-cross-linked biological implants may be mediated by the release of soluble factors from these implants inhibiting cytokine gene expression. This ex vivo human peritoneal system provides a novel preclinical model to investigate peritoneum-implant interactions.

Poly-4-Hydroxybutyrate (P4HB) Scaffold Internal Support: Preliminary Experience with Direct Implant Opposition During Complex Breast Revisions

BACKGROUND

The GalaFLEX scaffold is a mesh composed of resorbable poly-4-hydroxybutyrate (P4HB) monofilament fibers that aids in providing immediate internal soft tissue support, similar to that offered by an underwire bra, after breast reduction, lift, or augmentation.

OBJECTIVES

Our goal was to explore the possibility of using GalaFLEX as an internal support to prevent future sagging, predominantly in the lower pole of the breast. This preliminary study investigated GalaFLEX as a direct alternative to implants in a variety of complex revisional breast cases. Our intention was to establish a safety and efficacy profile in an effort to promote further investigation.

METHODS

A retrospective case series of 5 patients over 2 years were evaluated. Inclusion criteria were capsular contracture with concerns over soft tissue coverage and future ptosis, along with complicated muscle coverage deficits secondary to plane switching.

RESULTS

A retrospective review of photographs taken at the most recent follow-up consistently showed retention of implant position and soft implants. Additionally, patients presented with a mean ± SD Baker Grade Contraction score of 2.8 ± 0.9189 preoperatively compared with a score of 1 ± 0 postoperatively.

CONCLUSIONS

This preliminary study shows the initial safety of GalaFLEX but indicates the need for a multicenter, exhaustive study. Its versatility for complex revisional cases combined with acceptable aesthetic outcomes makes GalaFLEX an invaluable tool for plastic surgeons to consider.

LEVEL OF EVIDENCE: 4

Non-Cross-Linked Collagen Mesh Performs Best in a Physiologic, Noncontaminated Rat Model

BACKGROUND

In laparoscopic incisional hernia repair, direct contact between the prosthesis and abdominal viscera is inevitable and may lead to adhesions. Despite the large variety of mesh prosthesis, little is known about their in vivo behavior. Biological meshes are considered to have many advantages, but due to their price they are rarely used. A rat model was used to assess biological and conventional synthetic meshes on their in vivo characteristics.

DESIGN

One-hundred twenty male Wistar rats were randomized into five groups of 24 rats. A mesh was implanted intraperitoneally and fixated with nonresorbable sutures. The following five meshes were implanted: Parietene (polypropylene), Permacol (cross-linked porcine acellular dermal matrix), Strattice (non-cross-linked porcine acellular dermal matrix), XCM Biologic (non-cross-linked porcine acellular dermal matrix), and Omyra Mesh (condensed polytetrafluoroethylene). The rats were sacrificed after 30, 90, or 180 days. Incorporation, shrinkage, adhesions, abscess formation, and histology were assessed for all meshes.

RESULTS

All animals thrived postoperatively. After 180 days, Permacol, Parietene, and Omyra Mesh had a significantly better incorporation than Strattice ( P = .001, P = .019, and P = .037 respectively). After 180 days, Strattice had significantly fewer adhesions on the surface of the mesh than Parietene ( P < .001), Omyra Mesh ( P = .011), and Permacol ( P = .027). After 30 days, Permacol had significantly stronger adhesions than Strattice ( P = .030). However, this difference was not significant anymore after 180 days. After 180 days, there was significantly less shrinkage in Permacol than in Strattice ( P = .001) and Omyra Mesh ( P = .050).

CONCLUSION

Based on incorporation, adhesions, mesh shrinkage, and histologic parameters, Strattice performed best in this experimental rat model.

Biological Implant for Complex Abdominal Wall Reconstruction: A Single Institution Experience and Review of Literature

AIM

To present our single institution and surgeon's complex abdominal wall reconstructions (CAWR) experience with Permacol™ mesh through a non-randomized study.

PATIENTS AND METHOD

Data of 51 consecutive patients were prospectively collected between 2003 and 2015. Patients had a median of 3 comorbidities (range 0-10) and 68% were Center for Disease Control class II-IV. The mean previous repair was 1.3 (range, 0-12), and 25 (44%) had a mesh in situ. The median defect size was 625 cm².

RESULTS

Among the 56 CAWR procedures, in 16 (29%) bowel resection/anastomosis was performed. The overall post-operative complication rate was 45%, and it was wound-related except from 1 patient dead for myocardial infarction. One was lost at follow-up. Five were re-operated for recurrence with a second Permacol mesh, leading to 14 (26%) overall recurrences at a mean follow-up of 44 months (range, 4-123). In 33 (59%) cases, fascial closure was achieved. The mesh placement was intraperitoneal in 89%, retro-muscular in 9% and supra-fascial in 1% of cases. A multivariate analysis showed that predictor risk for recurrence was more than 3 previous repairs, wound class III-IV, whereas age, type of comorbidities, defect size and fascial closure did not influence the recurrence. Median post-operative performance status was 0 (range; 0-3). A satisfaction questionnaire was obtained in 43 patients, and 86% of them were satisfied with the outcome.

CONCLUSIONS

Biological materials have the potential to reduce morbidity and improve outcome of definitive repair of CAWR.

Nitro-Oleic Acid (NO2-OA) Release Enhances Regional Angiogenesis in a Rat Abdominal Wall Defect Model

Ventral hernia is often addressed surgically by the placement of prosthetic materials, either synthetic or from allogeneic and xenogeneic biologic sources. Despite advances in surgical approaches and device design, a number of postsurgical limitations remain, including hernia recurrence, mesh encapsulation, and reduced vascularity of the implanted volume. The in situ controlled release of angiogenic factors from a scaffold facilitating abdominal wall repair might address some of these issues associated with suboptimal tissue reconstruction. Furthermore, a biocomposite material that combines the favorable mechanical properties achievable with synthetic materials and the bioactivity associated with xenogeneic tissue sources would be desirable. In this report, an abdominal wall repair scaffold has been designed based on a microfibrous, elastomeric poly(ester carbonate)urethane urea matrix integrated with a hydrogel derived from decellularized porcine dermis (extracellular matrix [ECM] gel) and poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with nitro-oleic acid (NO₂-OA). NO₂-OA is an electrophilic fatty acid nitro-alkene derivative that, under hypoxic conditions, induces angiogenesis. This scaffold was utilized to repair a rat abdominal wall partial thickness defect, hypothesizing that the nitro-fatty acid release would facilitate increased angiogenesis at the 8-week endpoint. The quantification of neovascularization was conducted by novel methodologies to assess vessel morphology and spatial distribution. The repaired abdominal wall defects were evaluated by histopathologic methods, including quantification of the foreign body response and cellular ingrowth. The results showed that NO₂-OA release was associated with significantly improved regional angiogenesis. The combined biohybrid scaffold and NO₂-OA-controlled release strategy also reduced scaffold encapsulation, increased wall thickness, and enhanced cellular infiltration. More broadly, the three components of the composite scaffold design (ECM gel, polymeric fibers, and PLGA microparticles) enable the tuning of performance characteristics, including scaffold bioactivity, degradation, mechanics, and drug release profile, all decisive factors to better address current limitations in abdominal wall repair or other soft tissue augmentation procedures.

Single-center ventral hernia repair with porcine dermis collagen implant

INTRODUCTION

This study aims to evaluate the outcomes and utilization of porcine acellular dermal collagen implant (PADCI) during VHR at a large tertiary referral center.

METHODS

Records of 5485 patients who underwent VIHR from June 1995 to August 2014 were retrospectively reviewed to identify patients >18 years of age who had VIHR with PADCI reinforcement. Use of multiple mesh reinforcement products, inguinal hernias, and hiatal hernias were exclusion criteria. The primary outcome was hernia recurrence, and secondary outcomes were early complications and surgical site occurrences (SSOs). Uni- and multivariate analyses assessed risk factors for recurrence after PADCI reinforced VIHR.

RESULTS

There were 361 patients identified (54.5% female, mean age of 56.7 ± 12.5 years, and mean body mass index (BMI) of 33.0 ± 9.9 kg/m²). Hypertension (49.5%), diabetes (24.3%), and coronary artery disease (14.4%) were the most common comorbidities, as was active smoking (20.7%). Most were classified as American Association of Anesthesiologists (ASA) Class 3 (61.7%). Hernias were distributed across all grades of the ventral hernia working group (VHWG) grading system: grade I 93 (25.7%), grade II 51 (14.1%), grade III 113 (31.3%), and grade IV 6 (1.6%). Most VIHR were performed from an open approach (96.1%), and were frequently combined with concomitant surgical procedures (47.9%). Early postoperative complications (first 30 days) were reported in 39.0%, with 71 being SSO. Of the 19.7% of patients with SSO, there were 31 who required procedural intervention. After a mean follow-up of 71.5 ± 20.5 months, hernia recurrence was documented in 34.9% of patients. Age and male gender were predictors of recurrence on multivariate analysis.

CONCLUSION

To the best of our knowledge, this is the largest retrospective single institutional study evaluating PADCI to date. Hernias repaired with PADCI were frequently in patients undergoing concomitant operations. Reinforcement with PADCI may be considered a temporary closure, with a relatively high recurrence rate, especially among patients who are older, male, and undergo multiple explorations in a short perioperative period.

Characteristics of different mesh types for abdominal wall repair in an experimental model of peritonitis

BACKGROUND

The use of synthetic mesh to repair a potentially contaminated incisional hernia may lead to higher failure rates. A biological mesh might be considered, but little is known about long-term results. Both biological and synthetic meshes were investigated in an experimental model of peritonitis to assess their characteristics in vivo.

METHODS

Male Wistar rats were randomized into five groups and peritonitis was induced. A mesh was implanted after 24 h. Five meshes were investigated: Permacol™ (cross-linked collagen), Strattice™ (non-cross-linked collagen), XCM Biologic^® (non-cross-linked collagen), Omyra^® Mesh (condensed polytetrafluoroethylene) and Parietene™ (polypropylene). The rats were killed after either 30, 90 or 180 days. Incorporation and shrinkage of the mesh, adhesion coverage, strength of adhesions and histology were analysed.

RESULTS

Of 135 rats randomized, 18 died from peritonitis. Some 180 days after implantation, both XCM Biologic^® and Permacol™ had significantly better incorporation than Strattice™ (P = 0·003 and P = 0·009 respectively). Strattice™ had significantly fewer adhesions than XCM Biologic^® (P = 0·001) and Permacol™ (P = 0·020). Thirty days after implantation, Permacol™ had significantly stronger adhesions than Strattice™ (P < 0·001). Shrinkage was most prominent in XCM Biologic^® , but no significant difference was found compared with the other meshes. Histological analysis revealed marked differences in foreign body response among all meshes.

CONCLUSION

This experimental study suggested that XCM Biologic^® was superior in terms of incorporation, macroscopic mesh infection, and histological parameters such as collagen deposition and neovascularization. There must be sufficient overlap of mesh during placement, as XCM Biologic^® showed a high rate of shrinkage. Surgical relevance The use of synthetic mesh to repair a potentially contaminated incisional hernia is not supported unequivocally, and may lead to a higher failure rate. A biological mesh might be considered as an alternative. There are few long-term studies, as these meshes are expensive and rarely used. This study evaluated the use of biological mesh in a contaminated environment, and investigated whether there is an ideal mesh. A new non-cross-linked biological mesh (XCM Biologic^® ) was evaluated in this experiment. The new non-cross-linked biological mesh XCM Biologic^® performed best and may be useful in patients with a potentially contaminated incisional hernia.

Acellular Dermal Matrix (Permacol®) for Heterologous Immediate Breast Reconstruction after Skin-Sparing Mastectomy in Patients with Breast Cancer: A Single-Institution Experience and a Review of the Literature

OBJECTIVE

Skin-sparing mastectomy (SSM) with immediate heterologous reconstruction is a safe oncological option in surgical therapy of early breast cancer. Permacol^® is an acellular dermal matrix (ADM) placed between the implant and the skin to improve lower pole projection and implant coverage. The aim of our study was to evaluate the outcome with a focus on patient satisfaction after 6 months and to analyze physical changes of ADM.

METHODS

10 patients who underwent SSM with Permacol^® were analyzed retrospectively. All patients were followed using a satisfaction questionnaire and an ultrasound evaluation of the tissue thickness of the pectoralis muscle and the Permacol^®.

RESULTS

No intraoperative complications were observed. One patient required removal of the implant for necrosis after 3 months. Half of the patients underwent secondary corrective surgery. A statistically significant thinning of the pectoralis muscle was observed, compared to the thickening of the Permacol^®. A majority of the patients were satisfied with the operation, and we found a correlation between lower body mass index and patient satisfaction.

CONCLUSION

In our small case series Permacol^®-assisted immediate reconstruction is shown to be an option for selected cases. Physical changes of Permacol^® result in a symmetrical coverage of the implant, which may improve cosmetic outcome.

Design Strategies and Applications of Biomaterials and Devices for Hernia Repair

Hernia repair is one of the most commonly performed surgical procedures worldwide, with a multi-billion dollar global market. Implant design remains a critical challenge for the successful repair and prevention of recurrent hernias, and despite significant progress, there is no ideal mesh for every surgery. This review summarizes the evolution of prostheses design toward successful hernia repair beginning with a description of the anatomy of the disease and the classifications of hernias. Next, the major milestones in implant design are discussed. Commonly encountered complications and strategies to minimize these adverse effects are described, followed by a thorough description of the implant characteristics necessary for successful repair. Finally, available implants are categorized and their advantages and limitations elucidated, including non-absorbable and absorbable (synthetic and biologically derived) prostheses, composite prostheses, and coated prostheses. This review not only summarizes the state of the art in hernia repair, but also suggests future research directions toward improved hernia repair utilizing novel materials and fabrication methods.

Immediate, Multistaged Approach to Infected Synthetic Mesh: Outcomes After Abdominal Wall Reconstruction With Porcine Acellular Dermal Matrix

BACKGROUND

Infection of synthetic mesh after abdominal wall hernia repair is a complex problem. The purpose of this study was to determine whether a staged approach to abdominal wall reconstruction (AWR) using a porcine acellular dermal matrix (PADM) is beneficial in the setting of infected synthetic mesh.

METHODS

The authors performed a retrospective review of 27 patients who underwent immediate, staged complex AWR using PADM from 2007 to 2012.

RESULTS

After a component separation, primary fascial closure was achieved in 21/27 (78%) patients, whereas 6/22 (22%) received a bridged hernia repair with PADM. Wound-related complications developed in 7/27 (26%) patients including wound dehiscence 6/27 (22%), surgical site infection 5/27 (19%), and hematoma 1/27 (4%). The hernia recurrence rate observed by 32 months was 19%. A bridged hernia repair and the development of a postoperative infection were associated with hernia recurrence, P<0.05.

CONCLUSIONS

A 2-stage approach to AWR with PADM can provide a safe and effective solution for patients with infected synthetic mesh.

MECHANICAL CHARACTERIZATION OF ANIMAL DERIVED GRAFTS FOR SURGICAL IMPLANTATION

Bioprostheses obtained from animal models are often adopted in abdominal surgery for repair and reconstruction. The functionality of these prosthetic implants is related also to their mechanical characteristics that are analyzed here. This work illustrates a constitutive model to describe the short-term mechanical response of Permacol[Formula: see text] bioprostheses. Experimental tests were developed on tissue samples to highlight mechanical non-linear characteristics and viscoelastic phenomena. Uni-axial tensile tests were developed to evaluate the strength and strain stiffening. Incremental uni-axial stress relaxation tests were carried out at nominal strain ranging from 10% to 20% and to monitor the stress relaxation process up to 400[Formula: see text]s. The constitutive model effectively describes the mechanical behavior found in experimental testing. The mechanical response appears to be independent on the loading direction, showing that the tissue can be considered as isotropic. The viscoelastic response of the tissue shows a strong decay of the stress in the first seconds of the relaxation process. The investigation performed is aimed at a general characterization of the biomechanical response and addresses the development of numerical models to evaluate the biomechanical performance of the graft with surrounding host tissues.

A dual-stage approach to contaminated, high-risk ventral hernia repairs

BACKGROUND

The Modified Hernia Grading System (MHGS) was developed to risk stratify complex ventral hernia repairs (VHRs). MHGS grade 3 patients have mesh infections, dirty or contaminated fields, and/or violation of the alimentary tract. Reported surgical site infection (SSI) rates are over 40% after single-stage VHR in contaminated fields. In an attempt to decrease the SSI rate in MHGS grade 3 patients, we developed a dual-stage VHR (DSVHR) approach.

METHODS

We reviewed adult general surgery patients undergoing DSVHR between January 2010 and June 2014. All patients were MHGS grade 3. Primary end point was 30-d superficial and deep SSI. Secondary end points included other surgical site occurrences, 6-mo recurrence, and mesh excision rates.

RESULTS

Fifteen patients underwent DSVHR. Mean age was 56 y, and median body mass index was 38.3 kg/m(2). Operative indication included enterocutaneous fistulas (ECF; n = 6), ECF with infected mesh (n = 2), infected mesh (n = 2), and VHR requiring bowel resection (n = 5). Thirty-one operative procedures were performed with median of 2.5 d between procedures. Fascial closure was re-established in 12 patients; five patients had underlay biologic mesh placement; seven underwent component separation with retrorectus mesh placement (synthetic [n = 2], biologic [n = 5]). The remaining patients underwent bridging repair with biologic mesh. One patient developed a recurrence after 6 mo, whereas a single patient had a recurrence of their ECF. Four (27%) patients developed a SSI, with an additional four (27%) experiencing a surgical site occurrence. There were no postoperative mesh infections.

CONCLUSIONS

DSVHR in MHGS grade 3 patients is associated with a lower SSI rate than previously reported for those undergoing single-stage repairs.

Retro-rectus repair of complex incisional hernia leads to low recurrence rate

BACKGROUND

To assess the outcome of retro-rectus repair of complex abdominal wall repair (CAWR) in a single institution in relation to the use of biologic and synthetic mesh.

METHOD

A retrospective review was undertaken of complex abdominal wall repairs performed by a single surgical team, assessing the outcome of the retro-rectus repair and factors affecting the outcome.

RESULTS

Between 2007 and 2013, 57 (33 male) patients underwent CAWR retro-rectus repair. The material used was assessed as either synthetic or biologic (cross-linked porcine dermal collagen). The Ventral Hernia Working Group grades were similar between groups of patients having a repair with synthetic and biologic mesh. Median follow-up in the synthetic group was 18 months (1-80.5) and 18.4 months (0.5-70.7) in the biologic group. There was no statistical difference in seroma, wound infection or haematoma rates. No fistulae occurred in either group. Overall recurrence was 3.4% and there was no statistical difference between groups.

CONCLUSION

The retro-rectus repair technique is associated with a low rate of recurrence and is now the technique of choice. The choice of material, biologic or synthetic, in Ventral Hernia Working Group grades 1-3 remains controversial.

Tissue Expanders in Skin Deficient Ventral Hernias Utilizing Component Separation

Skin deficient complex ventral hernias are complicated surgical cases that have multimodal approaches. There is no current consensus on the management of those patients who also have concomitant stomas or enterocutaneous fistula. We present 2 cases in which the senior authors were able to apply tissue expanders above and between the abdominal wall in patients with an enterocutaneous fistula or stoma. After expansion and final closure, the patients did not experience recurrent hernias.

Remodeling of Noncrosslinked Acellular Dermal Matrices in a Rabbit Model of Ventral Hernia Repair

Background: Bioprostheses represent a significant advance in the abdominal wall reconstruction since they become degraded until their complete elimination in the recipient organism. This study examines remodeling in the host of three noncrosslinked porcine dermal collagen biomeshes: Strattice™ (St; LifeCell Corp.), XCM Biologic® Tissue Matrix (XCM; Synthes CMF) and Protexa® (Pr; Deco Med S.R.L.). Methods: Partial ventral hernia defects created in New Zealand White rabbits were repaired using the biomeshes that were placed in an inlay, preperitoneal position. At 14 and 90 days after implantation, explants were assessed in terms of their host tissue incorporation by morphological studies, collagen gene/protein expression (quantitative real-time PCR/immunofluorescence), macrophage response (immunohistochemistry) and biomechanical strength. Results: There were no cases of mortality or infection. Among our macroscopic findings, the mesh detachment detected in one third of the Pr implants at 90 days was of note. The host tissue response to all the biomeshes was similar at both time points, with a tendency observed for their encapsulation. There were no appreciable signs of mesh degradation. The extent of host tissue infiltration and collagenization was greater for St and Pr than for XCM. Macrophages were observed in zones of inflammation and tissue infiltration inside the mesh. XCM showed a greater macrophage response at 90 days (p < 0.05). Improved tensile strength was observed for St (p < 0.05) over Pr and unrepaired defects. Conclusions:St showed the best behavior, featuring good collagenization and tensile strength while also inducing a minimal foreign body reaction.

Decreased hernia recurrence using autologous platelet-rich plasma (PRP) with Strattice™ mesh in a rodent ventral hernia model

BACKGROUND

Recurrence after ventral hernia repair (VHR) remains a multifactorial problem still plaguing surgeons today. Some of the many contributing factors include mechanical strain, poor tissue-mesh integration, and degradation of matrices. The high recurrence rate witnessed with the use of acellular dermal matrices (ADM) for definitive hernia repair has reduced their use largely to bridging repair and breast reconstruction. Modalities that improve classic cellular metrics of successful VHR could theoretically result in improved rates of hernia recurrence; autologous platelet-rich plasma (PRP) may represent one such tool, but has been underinvestigated for this purpose.

METHODS

Lewis rats (32) had chronic ventral hernias created surgically and then repaired with Strattice™ mesh alone (control) or mesh + autologous PRP. Samples were harvested at 3 and 6 months postoperatively and compared for gross, histologic, and molecular outcomes of: neovascularization, tissue incorporation, peritoneal adhesions, hernia recurrence, and residual mesh thickness.

RESULTS

Compared to control at 3 months postoperatively, PRP-treated rats displayed significantly more neovascularization of implanted mesh and considerable upregulation of both angiogenic genes (vEGF 2.73-fold, vWF 2.21-fold) and myofibroblastic genes (αSMA 9.68-fold, FSP-1 3.61-fold, Col1a1 3.32-fold, Col31a1 3.29-fold). Histologically, they also showed enhanced tissue deposition/ingrowth and diminished chronic immune cell infiltration. Peritoneal adhesions were less severe at both 3 (1.88 vs. 2.94) and 6 months (1.63 vs. 2.75) by Modified Hopkins Adhesion Scoring. PRP-treated rats experienced decreased hernia recurrence at 6 months (0/10 vs. 7/10) and had significantly improved ADM preservation as evidenced by quantification of residual mesh thickness.

CONCLUSIONS

PRP is an autologous source of pro-regenerative growth factors and chemokines uniquely suited to soft tissue wound healing. When applied to a model of chronic VHR, it incites enhanced angiogenesis, myofibroblast recruitment and tissue ingrowth, ADM preservation, less severe peritoneal adhesions, and diminished hernia recurrence. We advocate further investigation regarding PRP augmentation of human VHR.

Use of a porcine dermal collagen implant for contaminated abdominal wall reconstruction in a 105-year-old woman: a case report and review of the literature

INTRODUCTION

Repair of contaminated abdominal wall defect in a geriatric patient is a challenge for the surgeon. We present the case of the oldest patient (105-years old) to successfully undergo a single-stage repair of a contaminated abdominal wall defect with a Permacol™ implant.

CASE PRESENTATION

A 105-year-old Caucasian woman presented to our emergency room with a clinical and radiological diagnosis of small bowel obstruction due to prior operative adhesions. She underwent laparotomy with small bowel resection and primary closure of her abdomen. There was total eventration of her bowel through the suture line 9 days after surgery. She underwent a second laparotomy that revealed no signs of peritonitis or turbid fluid. Her abdomen was closed with a 15 × 10 cm Permacol™ implant sutured sublay with prolene sutures. Her postoperative period was unremarkable. After a follow-up period of 3 years and 2 months, there was no sign of recurrent hernia or wound contamination.

CONCLUSION

We suggest that Permacol™ mesh can be considered an efficient alternative to primary closure or synthetic mesh in geriatric patients with contaminated abdominal wall defects.

Characterisation and comparison of the host response of 6 tissue-based surgical implants in a subcutaneous in vivo rat model

BACKGROUND

Hernia repair often involves fascial augmentation using biologic prostheses. Small processing changes during preparation modulate host tissue response, which influence material efficacy and longevity. In this pilot study, a rat model was used to determine the specific influence of tissue origin, decellularisation treatment and 1,6-hexamethylene diisocyanate (HMDI) cross-linking.

METHODS

Materials (1 cm2) were implanted subcutaneously into 6-week-old Wistar rats (4 materials per animal, n=6/material per time point) for 2, 5, 7, 14 and 28 days. Histologic processing was carried out after resin infiltration, observing classical histopathology and pathologic indexing. Materials comprised 6 tissue-based grafts covering both experimental and commercial porcine decellularised dermal and small intestinal submucosal materials.

RESULTS

Subcutaneous delivery of biologics demonstrated material-specific inflammatory/host responses. Controlled variations of the PermacolTM manufacturing process showed sodium dodecyl sulfate (SDS) was the most proinflammatory decellularisation reagent, and HMDI cross-linking had no effect on host response. All materials remained recoverable after 28 days, although SurgisisTM had partially resorbed.

CONCLUSION

Differences in host responses exist between biologic implants for hernia repair in this rat model. It is postulated that these modifications are induced during processing and may have an effect on the clinical outcome of hernia repair.

Acute and chronic local inflammatory reaction after implantation of different extracellular porcine dermis collagen matrices in rats

Two cross-linked acellular porcine dermal collagen matrices (Permacol and NRX) were implanted into rats and the acute and chronic local inflammatory tissue reactions were investigated after 7, 14, 28, and 112 days. Both membranes were stable in vivo for up to 112 days. All investigated immune cell populations (CD68+ macrophages, CD163+ macrophages, T lymphocytes, MHC class II positive cells, mast cells, and NK cells) were present. Their amount decreased significantly over time compared to day 7 after implantation. A change from an acute to a chronic inflammation and an associated shift from proinflammatory M1-like to anti-inflammatory M2-like macrophages were observed. In the early phase there was a significant correlation of T cells to CD68+ (M1-like) macrophages, whereas in the chronic phase T lymphocytes were positively correlated with CD163+ (M2-like) macrophages. The material NRX showed an enhanced inflammatory reaction in comparison to Permacol possibly caused by material characteristics such as a twofold higher thickness of the membrane, roughness, and water absorption capacity. Nevertheless, a more pronounced regenerative process as, for example, indicated by nestin expression demonstrated its possible suitability for applications as wound repair material.

Effectiveness of porcine dermal collagen in giant hernia closure in patients with deleterious fascia constitution after orthotopic liver transplantation

Incisional hernias (IHs) occur universally after orthotopic liver transplantation (OLT). This study aimed to investigate the effectiveness of porcine dermal collagen (PDC) as a closing aid in giant hernias after OLT in a prospective trial. If direct closure (DC) was not feasible due to the hernia size and abdominal wall constitution, a PDC mesh was implanted. All patients from the PDC and DC groups were followed prospectively for 24 months. IH recurrence rates served as the primary endpoint, and the development of infections and wound healing disorders served as the secondary endpoints. Recurrence rate was 21% (4/19) in DC patients and 12% (2/16) in PDC patients (P = 0.045). Implant site infections occurred in five of PDC and one of DC patients (P < 0.05). All of them were managed with antibiotics; two of the PDC patients required surgical drainage. Histological analysis of PDC mesh biopsies indicated good angiogenesis and integration of the PDC into the abdominal wall. PDC was effective in our study for incisional hernia repair, and our results compared favourably with those of patients in whom direct hernia closure was feasible.

Outcome of Abdominal Wall Hernia Repair with Biologic Mesh: Permacol™ versus Strattice™

The use of biologic mesh in abdominal wall operations has gained popularity despite a paucity of outcome data. Numerous biologic products are available with virtually no clinical comparison studies. A retrospective study was conducted to compare patients who underwent abdominal wall hernia repair with Permacol™ (crosslinked porcine dermis) and Strattice™ (noncrosslinked porcine dermis). Of 270 reviewed patients, 195 were implanted with Permacol™ and 75 with Strattice™. Ventral hernia repairs comprised the majority (85% for Permacol, 97% for Strattice™). Postoperative infection rate was lower in the Strattice™ group (5 vs 21%, P < 0.01). In the Permacol™ group only, the overall complication rates were significantly higher in patients with infected versus clean wounds (55 vs 35%, P < 0.05) and in obese patients (body mass index 40 kg/m2 or greater [57 vs 34%], P < 0.01). Short-term complication and recurrence rates were higher when mesh was used as a fascial bridge: 51 versus 28 per cent for Permacol™, 58 versus 20 per cent for Strattice™. The hernia recurrence was similar in both groups. In this review of patients undergoing abdominal hernia repair with biologic mesh, Strattice™ mesh was associated with a lower short-term complication rate compared with Permacol™, but the hernia recurrence rate was similar.

Porcine dermis implants in soft-tissue reconstruction: current status

Soft-tissue reconstruction for a variety of surgical conditions, such as abdominal wall hernia or pelvic organ prolapse, remains a challenge. There are numerous meshes available that may be simply categorized as either synthetic or biologic. Within biologic meshes, porcine dermal meshes have come to dominate the market. This review examines the current evidence for their use and the limitations of knowledge. Although there is increasing evidence to support their safety, long-term follow-up studies that support their efficacy are lacking. Numerous clinical trials that remain ongoing may help elucidate their precise role in soft-tissue reconstruction.

Bioprosthetic tissue matrices in complex abdominal wall reconstruction

Background:

Complex abdominal defects are difficult problems encountered by surgeons in multiple specialties. Although current evidence supports the primary repair of these defects with mesh reinforcement, it is unclear which mesh is superior for any given clinical scenario. The purpose of this review was to explore the characteristics of and clinical relevance behind bioprosthetic tissue matrices in an effort to better clarify their role in abdominal wall reconstruction.

Methods:

We reviewed the peer-reviewed literature on the use of bioprosthetic mesh in human subjects. Basic science articles and large retrospective and prospective reviews were included in author’s analysis. The clinical performance and characteristics of 13 bioprosthetic tissue matrices were evaluated.

Results:

The majority of the products evaluated perform well in contaminated fields, where the risk of wound-healing difficulties is high. Clinical outcomes, which included infection, reherniation, and bulge formation, were variable, and the majority of the studies had a mean follow-up of less than 24 months.

Conclusions:

Although bioprosthetic matrix has a multitude of indications within the growing field of abdominal wall reconstruction, the functionality, regenerative capacity, and long-term fate of these products have yet to be fully established. Furthermore, the clinical performance, indications, and contraindications for each type of matrix need to be fully evaluated in long-term outcome studies.

Fascia lata allografts as biological mesh in abdominal wall repair: preliminary outcomes from a retrospective case series

BACKGROUND

The use of biological meshes in management of infected abdominal hernias or in abdominal fields at high risk of infection (potentially contaminated or with relevant comorbidities) is well established. Available products include xenogenic patches or decellularized dermal allografts. Despite their biomechanical features, banked fascial allografts have not been investigated yet in this setting. The authors evaluated the safety and effectiveness of banked fascia lata allografts as biological meshes in abdominal wall repair.

METHODS

A consecutive series of patients affected by abdominal wall defects and who were candidates for repair by means of a biological mesh and treated in the authors' institution with banked fascia lata allografts were reviewed retrospectively. Data from clinical and instrumental follow-up evaluations up to 48 months (average, 23 months) were analyzed.

RESULTS

Twenty-one patients (aged 1 to 86 years) with abdominal wall defects resulting from traumatic (n = 1), neoplastic (n = 6), or multiple previous laparotomies (n = 14) were treated from January of 2008 to October of 2012. Operations had no relevant postoperative complications. At clinical/instrumental follow-up examinations, no major signs of recurrence, laxity, infection of grafts, or other related pathologic symptoms were recorded. Three patients suffered from temporary minor complications (e.g., wound seroma, partial cutaneous dehiscence). At instrumental (computed tomographic scan or magnetic resonance imaging) evaluations, the neofascial tissue appeared stable until medium-term follow-up (3 to 6 months), later being gradually degraded and apparently replaced by host tissue.

CONCLUSION

According to limited preliminary outcomes, banked fascia lata allografts seem to provide a biocompatible, safe, and effective alternative to other biological meshes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Complete horizontal skin cell resurfacing and delayed vertical cell infiltration into porcine reconstructive tissue matrix compared to bovine collagen matrix and human dermis

BACKGROUND

Xenogenous dermal matrices are used for hernia repair and breast reconstruction. Full-thickness skin replacement is needed after burn or degloving injuries with exposure of tendons or bones. The authors used a human skin organ culture model to study whether porcine reconstructive tissue matrix (Strattice) is effective as a dermal tissue replacement.

METHODS

Skin cells or split-thickness skin grafts were seeded onto human deepidermized dermis, Strattice, and Matriderm. Cellular resurfacing and matrix infiltration were monitored by live fluorescence imaging, histology, and electron microscopy. Proliferation, apoptosis, cell differentiation, and adhesion were analyzed by immunohistochemistry.

RESULTS

Epithelial resurfacing and vertical proliferation were reduced and delayed with both bioartificial matrices compared with deepidermized dermis; however, no differences in apoptosis, cell differentiation, or basement membrane formation were found. Vertical penetration was greatest on Matriderm, whereas no matrix infiltration was found on Strattice in the first 12 days. Uncompromised horizontal resurfacing was greatest with Strattice but was absent with Matriderm. Strattice showed no stimulatory effect on cellular inflammation.

CONCLUSIONS

Matrix texture and surface properties governed cellular performance on tissues. Although dense dermal compaction delayed vertical cellular ingrowth for Strattice, it allowed uncompromised horizontal resurfacing. Dense dermal compaction may slow matrix decomposition and result in prolonged biomechanical stability of the graft. Reconstructive surgeons should choose the adequate matrix substitute depending on biomechanical requirements at the recipient site. Strattice may be suitable as a dermal replacement at recipient sites with high mechanical load requirements.

Collagen-Based Substrates with Tunable Strength for Soft Tissue Engineering

Through the use of mechanical reinforcement of collagen matrices, mechanically strong and compliant 3D tissue mimetic scaffolds can be generated that act as scaffolds for soft tissue engineering. Collagen has been widely used for the development of materials for repair, augmentation or replacement of damaged or diseased tissue. Herein we describe a facile method for the layer-by-layer fabrication of robust planar collagen fiber constructs. Collagen gels cast in a phosphate buffer were dried to form dense collagen mats. Subsequent gels were layered and dried atop mats to create multilayer constructs possessing a range of tunable strengths (0.5 - 11 MPa) and stiffness (1 - 115 MPa). Depending on processing conditions and crosslinking of constructs, strain to failure ranged between 9 to 48%. Collagen mats were constructed into hernia patches that prevented hernia recurrence in Wistar rats.

Influence of the carboxymethyl chitosan anti-adhesion solution on the TGF-β1 in a postoperative peritoneal adhesion rat

The aim of this paper was to investigate the effect of carboxymethyl chitosan anti-adhesion solution on prevention of postsurgical adhesion. Forty adult male Wistar rats were randomly divided into three groups: 0.9% normal saline solution (group A), hyaluronic acid gels (group B) and carboxymethyl chitosan anti-adhesion solution (group C). The animals were treated with normal saline, hyaluronic acid gels or carboxymethyl chitosan anti-adhesion solution at the time of surgery. After 2 or 3 weeks, the degree of adhesions and histological effects were determined. The adhesions in groups B and C were significantly decreased, and the levels of TGF-β1 and hydroxyproline in group C were significantly lower than that in group A (P < 0.05). The histopathology in group C showed fewer inflammatory cells and fibroblasts. Carboxymethyl chitosan anti-adhesion solution can effectively prevent postoperative adhesion which is a promising drug delivery system in the context of postsurgical anti-adhesion.