Full-thickness Abdominal Wall Research Articles

Host tissue integration process in abdominal wall defect repair: a comparison of two porcine-derived grafts in a long-term study

Background: The aim of this study was to compare the host tissue integration process and biomechanical behaviour after implantation of porcine small intestine submucosa (PSIS) and porcine acellular dermal matrix (PADM) grafts in a rat abdominal wall defect model during a long-term follow-up of 360 days.Objectives: Full-thickness abdominal wall defects were created in 40 Sprague–Dawley rats and repaired with either PSIS or PADM grafts. Rats were sacrificed at 14, 30, 90 and 360 days to evaluate the presence of herniation, infection, adhesions and changes in thickness and strength properties of the regenerated tissue at the defect site. Histopathology and immunohistochemistry were performed to evaluate the host tissue integration process assessed by the level of collagen deposition, vascularization and inflammatory host sub-chronic and chronic responses.Results: PADM grafts had greater strength in vitro (p < 0.01). Moreover, the strength of the PADM grafts integrated with the surrounding host tissues was greater than that of the PSIS grafts at 360 days postimplantation (p < 0.05). A stronger integration into the host tissue was observed for the PADM grafts, which showed oriented bands of collagen deposition intermixed with similar newly formed blood vessels compared to that of PSIS grafts after 360 days. The PADM grafts showed slower infiltration of macrophages but developed into a more heavily infiltrated tissue compared to the PSIS grafts (p < 0.05). The level of leukocyte infiltration after implantation was similar in both grafts (p > 0.05).Conclusion: PADM grafts exhibit more delayed but also more effective host integration than PSIS grafts during the 360 days following implantation, supporting the development of more robust abdominal wall strength.

A new rat model for orthotopic abdominal wall allotransplantation.

Background:Abdominal wall, one of the most commonly transplanted composite tissues, is less researched and lacking animal models. Its clinical necessities were emphasized in multiple case series to reconstruct large abdominal defects. Previous animal models have only studied components of the abdominal wall transplant. We describe findings from a new model that more likely reflect clinical transplantation.Methods:Full-thickness hemiabdominal wall flap was procured from Brown Norway (BN) rats and transplanted to an orthotopic defect on Lewis rats. Three groups were studied: group 1: Lewis to Lewis syngeneic; group 2: BN to Lewis control; and group 3: BN to Lewis with postoperative cyclosporine. Vascular imaging and cross vessel section were performed along with full-thickness abdominal wall. Immune cell profiling with flow cytometry at different time points was studied in all groups.Results:Syngeneic group had no rejection. Control group consistently showed rejection around postoperative day 6. With cyclosporine treatment, however, transplant and recipient tissue integration was observed. Flow cytometry revealed that innate immunity is responsible for the initial inflammatory events following abdominal wall engraftment. Adaptive immunity cells, specifically interferon-γ-producing T helper (Th) 1 and interleukin-17-producing Th17 cells, dramatically and positively correlate with rejection progression of abdominal wall transplants.Conclusions:Technical, histological, and immunological aspects of a new rat model are described. These results give clues to what occurs in human abdominal wall transplantation. In addition, Th1, a proinflammatory cell, was found to be a potential biomarker for allograft rejection.

Full thickness abdominal wall defect in growing rats as a model for congenital diaphragmatic hernia prosthetic repair

BackgroundLarge congenital diaphragmatic hernia may require prosthetic correction. Acellular collagen matrices were introduced to avoid complications owing to the use of synthetic patches. We tested 3 different ACM for reconstruction of an abdominal wall defect in an animal model that mimics the fast growth during infancy. MethodsPelvisoft® (CR Bard, Covington, GA) and 2 investigational ACM were used for primary reconstruction of a full thickness abdominal wall defect. 3months-old rats (n=26) were allowed to survive for 90days after implantation. Anatomical, tensiometric and histological analyses were performed. Based on good outcomes, we did the same with 1month-old rats (n=54). Unoperated rats were used for obtaining reference tensiometric values of selected native tissues. ResultsMajor wound complications were exclusively observed in 1month-old rats. All explants in both groups thinned significantly (p<0.03) and had an elastic modulus increasing over time, far above that from native tissues at 90days of life. Both investigational ACM induced a more vigorous foreign body reaction than Pelvisoft®. ConclusionsThe shift from 3 to 1month-old rats was associated with wound complications. Pelvisoft® showed a better biocompatibility than the 2 investigational ACM. Passive biomechanical properties of all explants were still not comparable to that of native tissues.

Abdominal wall reconstruction by a regionally distinct biocomposite of extracellular matrix digest and a biodegradable elastomer

Current extracellular matrix (ECM) derived scaffolds offer promising regenerative responses in many settings, however in some applications there may be a desire for more robust and long lasting mechanical properties. A biohybrid composite material that offers both strength and bioactivity for optimal healing towards native tissue behavior may offer a solution to this problem. A regionally distinct biocomposite scaffold composed of a biodegradable elastomer (poly(ester urethane)urea) and porcine dermal ECM gel was generated to meet this need by a concurrent polymer electrospinning/ECM gel electrospraying technique where the electrosprayed component was varied temporally during the processing. A sandwich structure was achieved with polymer fiber rich upper and lower layers for structural support and an ECM-rich inner layer to encourage cell ingrowth. Increasing the upper and lower layer fiber content predictably increased tensile strength. In a rat full thickness abdominal wall defect model, the sandwich scaffold design maintained its thickness whereas control biohybrid scaffolds lacking the upper and lower fiber-rich regions failed at 8 weeks. Sandwich scaffold implants also showed higher collagen content 4 and 8 weeks after implantation, exhibited an increased M2 macrophage phenotype response at later times and developed biaxial mechanical properties better approximating native tissue. By employing a processing approach that creates a sheet-form scaffold with regionally distinct zones, it was possible to improve biological outcomes in body wall repair and provide the means for further tuning scaffold mechanical parameters when targeting other applications. Copyright © 2013 John Wiley & Sons, Ltd.

Tissue Expander‐Assisted Ventral Hernia Repair for the Skin‐Grafted Damage Control Abdomen

In the article under discussion, Carr presents a series of three patients with late reconstruction of skin grafted large ventral hernias [1]. What makes his article exceptional is that he has used tissue expansion before reconstructing the hernias. Tissue expansion is more a tradition of pediatric plastic surgeons and is rarely used in the treatment of abdominal wall defects. In his work, tissue expansion was used in patients with enterostomies that were not published before. He did not encounter any infectious complications in his patients which is significant. Nevertheless, the number of patients is so small that it is not possible to draw very strong conclusions regarding this treatment method. The report can be judged more or less as an extended case study. Moreover, there are a few remarks that I would like to make. In the introduction the author claims that after damagecontrol surgery many patients are now surviving with skingraft-on-bowel ventral hernias. In the past this has been the case, but the number of skin grafted open abdomen patients has become strongly reduced lately. This is so because of the use of negative pressure devices with mesh-mediated traction in the initial phase of open abdomen treatment. With such techniques it is now rare for an open abdomen patient to end up having a skin grafted hernia [2]. Carr also states that: ‘‘operative steps do not include any mention of what to do in the patient who does not have sufficient skin to close the wound after the skin graft is removed.’’ This might be true according to the references used in this article, but for a reconstructive surgeon a large full-thickness abdominal wall defect is a straightforward indication for a flap reconstruction [3]. For fascial closure, Carr has used component separation and acellular dermal matrix (ADM) mesh with the bridging method. According to current experience, a bridged ADM is only a temporary solution for hernia repair. A bulking or recurrent hernia is to be expected in long run [4]. In this series one patient already had a recurrent hernia, and two were good at one year of follow-up and it is to be seen if this might show up after the follow-up period for these two patients. Late correction of a ventral hernia after skin expansion is not a piece of cake. The defect should be closed with a material more durable than ADM in the secondary phase. The risk of a wound complication is evident because the expanded thin skin has to be released in order to replace the ADM with a new mesh. For these reasons my choice would be a flap reconstruction is this kind of case. With a thigh flap one can get a living fascia to replace the missing fascia and skin. Under a flap one can use a mesh for temporary closure to make sure that the hernia will not recur. Tissue expansion is principally an easy operation. Creating a pocket for an expander is not difficult. Nevertheless, tissue expansion is combined with a lot of problems that are faced by surgeons who use it a lot. Placing the expanders, choosing the form and size, and determining filling intervals and the amount of filling, etc. require a lot of experience to be done safely and effectively. There are well known complications with expanders like infection, extrusion, and rupture of the implant, for which the surgeon has to be prepared. In one case reported by Carr, one of the expanders ruptured and was not replaced by another. Because of this, the author could not remove the skin graft completely, leading to an expected wound necrosis and secondary healing. Looking back, he should have completed the expansion as planned by replacing the ruptured implant with another. Carr states that ‘‘what is unique about the experience described in this article is that the tissue expanders were H. Kuokkanen (&) Tampere University Hospital, Tampere, Finland e-mail: hannu.kuokkanen@pshp.fi

Behaviour of a New Composite Mesh for the Repair of Full-Thickness Abdominal Wall Defects in a Rabbit Model

IntroductionComposite biomaterials designed for the repair of abdominal wall defects are composed of a mesh component and a laminar barrier in contact with the visceral peritoneum. This study assesses the behaviour of a new composite mesh by comparing it with two latest-generation composites currently used in clinical practice.MethodsDefects (7x5cm) created in the anterior abdominal wall of New Zealand White rabbits were repaired using a polypropylene mesh and the composites: PhysiomeshTM; VentralightTM and a new composite mesh with a three-dimensional macroporous polyester structure and an oxidized collagen/chitosan barrier. Animals were sacrificed on days 14 and 90 postimplant. Specimens were processed to determine host tissue incorporation, gene/protein expression of neo-collagens (RT-PCR/immunofluorescence), macrophage response (RAM-11-immunolabelling) and biomechanical resistance. On postoperative days 7/14, each animal was examined laparoscopically to quantify adhesions between the visceral peritoneum and implant.ResultsThe new composite mesh showed the lowest incidence of seroma in the short term. At each time point, the mesh surface covered with adhesions was greater in controls than composites. By day 14, the implants were fully infiltrated by a loose connective tissue that became denser over time. At 90 days, the peritoneal mesh surface was lined with a stable mesothelium. The new composite mesh induced more rapid tissue maturation than PhysiomeshTM, giving rise to a neoformed tissue containing more type I collagen. In VentralightTM the macrophage reaction was intense and significantly greater than the other composites at both follow-up times. Tensile strengths were similar for each biomaterial.ConclusionsAll composites showed optimal peritoneal behaviour, inducing good peritoneal regeneration and scarce postoperative adhesion formation. A greater foreign body reaction was observed for VentralightTM. All composites induced good collagen deposition accompanied by optimal tensile strength. The three-dimensional macroporous structure of the new composite mesh may promote rapid tissue regeneration within the mesh.

The in vivo evaluation of tissue‐based biomaterials in a rat full‐thickness abdominal wall defect model

Hernias are defects in which an anatomical fascia is breached resulting in ectopic positioning of an organ into an orifice which routinely does not contain it. Intervention often involves repositioning translocated organs and repair of damaged fascia using exogenous grafts. Despite hernia prevalence, repairs can still fail due to postoperative complications, such as chronic pain and decreased mobility. This study compared repair capacities and characterized the foreign body response elicited by a number of hernia repair grafts to deduce their bulk inflammatory properties while also concluding the point in their fabrication when these are inferred. Materials derived from human dermis (Alloderm(®) ), porcine dermis (Permacol™, patch A, patch D and Strattice(®) ), porcine small-intestinal submucosa (Surgisis™) and a synthetic (multifilament Surgipro™) were implanted into a rat full-thickness abdominal wall excision model, incubated for up to 2 years and characterized histopathologically. Surgisis™ resorbed the fastest of the materials tested (1-3 months) resulting in a mechanically stable parietal peritoneum. Decellularization using sodium dodecyl sulfate (patch A) stimulated a large early inflammatory response which ultimately may have contributed to increased resorption of porcine dermal matrix however the remaining materials typically persisted throughout the 2-year incubation. Cross-linking porcine dermis using 1,6-hexamethylene disocyanate (vs. an identical noncross-linked counterpart) showed no difference in cell recruitment or material integration over 2 years. Typically Strattice(®) and Alloderm(®) recruited larger early populations of cells than Permacol™; however, over extended periods of time in vivo this response normalized.

Development of a Reliable Model of Total Abdominal Wall Transplantation

Among the most common complications associated with abdominal organ transplantation are issues with abdominal wall closure. This difficulty, along with the recent rise in the use of vascularized composite allotransplantation, has led surgeons to the notion of abdominal wall transplantation. The authors have developed a novel surgical model for a full-thickness total abdominal wall transplant based on a unilateral pedicle between fully major histocompatibility complex-mismatched rat strains. An established cuff technique was used to anastomose the donor's common iliac vessels to the recipient's femoral vessels. Three groups (n = 6 per group) received FK506 monotherapy, 0.25, 0.50, or 0.75 mg/kg per day. The transplants were assessed daily for evidence of rejection by visual inspection. Hematoxylin and eosin skin biopsies and fluorescence-activated cell sorting analysis of the recipients' peripheral blood were performed. No signs of rejection were observed in the animals receiving FK506, 0.50 or 0.75 mg/kg per day. Those receiving 0.25 mg/kg per day, however, displayed a mixed rejection response. Flow cytometric analysis did not show evidence of donor-specific chimerism. A full-thickness abdominal wall graft based on a unilateral pedicle is a technically feasible and reliable small-animal surgical model. The use of greater than or equal to 0.50 mg/kg per day FK506 results in 100 percent graft survival. Future plans are to use this model to investigate the immunologic interaction of a concomitant solid organ and an abdominal wall allograft, as would likely occur in the clinical situation.

Spontaneous Regression of Primary Abdominal Wall Desmoid Tumors: More Common than Previously Thought

The relevance of the initial observational approach for desmoid tumors (DTs) remains unclear. We investigated a new conservative management treatment for primary abdominal wall DTs. Data were collected from 147 patients between 1993 and 2012. The initial therapeutic approaches were categorized as front-line surgery [surgery group (SG), n = 41, 28 %] and initial observation or medical treatment [nonsurgery group (NSG), n = 106, 72 %]. The cumulative incidence of the last strategy modification was estimated using competing risk methods with variable censoring times. Of the 147 patients, 143 were female (97 %). In the SG, 27 patients (66 %) required full-thickness abdominal wall mesh repair. In the NSG, 102 patients (96 %) underwent initial observation and four received medical treatment. In the NSG, the 1- and 3-year incidences of changing to medical treatment (no further changes during the follow-up) were 19 % [95 % confidence interval (CI) 11-28] and 25 % (95 % CI 17-35), respectively, and the 1- and 3-year incidences of a final switch to surgery were 14 % (95 % CI 8-22) and 16 % (95 % CI 9-24), respectively. An initial tumor size of >7 cm was associated with a higher strategy modification risk (p = 0.004). Of the 102 patients initially observed, 29 experienced spontaneous regression over a median follow-up period of 32 months. All second-intent resections were macroscopically completed, with R0 resections achieved in 82 % of patients. This study supports an initial nonsurgical approach to abdominal wall DTs ≤7 cm, followed by surgery based on tumor growth in select cases.

Histopathological Comparison of Mosquito Net with Polypropylene Mesh for Hernia Repair: An Experimental Study in Rats.

Use of mosquito net, in place of polypropylene mesh, had been reported for tension-free hernia repair, as a better cost-effective option. This experimental histopathological study was performed in rats to find out the tissue response and the foreign body reaction and its comparison between commercial polypropylene mesh and the sterilized mosquito net. This experimental study was conducted in the Department of Surgery, Government NSCB, Medical College, Jabalpur (Madhya Pradesh), India. It was carried out in 40 albino rats. A 1.5 × 0.5-cm hernial defect was created by excising full-thickness abdominal wall muscle. All rats underwent on-lay mesh repair of hernial defect (polypropylene mesh, n = 20; mosquito net, n = 20). Half of rats in each group were sacrificed on day 14, and the other half, on day 90. Sections of containing mesh were examined histopathologically for inflammatory infiltrate, giant cells, and collagen deposition. Mosquito net group showed significantly greater number of giant cells and inflammatory cells at 14 and 90days (p < 0.0001, p < 0.001, p < 0.05, and p < 0.001, respectively), as compared to polypropylene group. Grades of collagen fiber deposition were almost equal in both groups, both at 14 and 90days (p > 0.05 and p > 0.05, respectively). Results of mosquito net are comparable to conventional polypropylene mesh. In a setup, where cost-effectiveness is of primary importance, use of mosquito net for tension-free hernia repair can be an acceptable alternative as proven histologically, to commercially available polypropylene mesh.

Effect of Cross-Linked and Non–Cross-Linked Acellular Dermal Matrices on the Expression of Mediators Involved in Wound Healing and Matrix Remodeling

Molecular mechanisms that direct the extent of the foreign body reaction to implanted biological meshes and their subsequent incorporation are poorly understood. The purpose of this study was to compare the influence of non-cross-linked human dermis (AlloDerm) with that of cross-linked porcine dermis (Permacol) on the expression of genes critical for wound healing and tissue remodeling in a rat ventral hernia model. Full-thickness abdominal wall defects were repaired with AlloDerm, Permacol, or suture repair with no mesh (n = 10 rats per group). Explants were harvested 90 days after repair and divided for histologic, immunohistochemical, and gene expression analyses. Real-time quantitative polymerase chain reaction arrays were used to profile the expression of 84 wound healing-associated genes at the tissue/mesh interface. Both meshes induced the differential expression (≥ 3-fold change relative to suture repair, p ≤ 0.01) of extracellular matrix components, remodeling enzymes, and inflammatory cytokines. Genes most markedly up-regulated included matrix metalloproteinase-9 (Permacol, 66-fold; AlloDerm, 19-fold) and chemokine (C-C motif) ligand 12 (Permacol, 24-fold; AlloDerm, 71-fold). Immunohistochemistry using antibodies against matrix metalloproteinase-9 and chemokine (C-C motif) ligand 12 confirmed differential expression at the protein level (p < 0.001). Histologically, AlloDerm demonstrated overall better remodeling characteristics than Permacol. Permacol elicits increased protease expression and reduced cellular and vascular infiltration compared with AlloDerm 90 days after implantation, indicative of delayed remodeling induced by cross-linking. Increased understanding of the host response to implanted materials ultimately will enable the development of improved meshes with enhanced wound healing properties and fewer graft-related complications.

Gastroschisis is a defect of the Umbilical ring: Evidence from Morphological evaluation of stillborn fetuses

Gastroschisis (GS) is usually described as an abdominal wall defect, to the right of a normally inserted umbilical cord, without membraneous covering of the extruded organs. However, precise anatomical descriptions are lacking in the literature. Our aims were to provide evidence that allows reconsideration of its current definition, as well as an explanation for prenatal death, based on detailed observation of stillborn fetuses with GS and a review of the literature. Prenatal studies, clinical examinations, and histological findings of five stillborn fetuses with isolated GS are described and photographic evidence is provided. In all five cases, the umbilical cord was only attached to the left side of the umbilical ring, while the right side remained uncovered, allowing evisceration of abdominal organs. Histological evidence of mucoid-like tissue at the free border of the ring suggests that at that site the cord was initially inserted and later detached. Characteristics of the umbilical ring, bowel dilatation, and autopsy findings of acute asphyxia strongly support compression of umbilical vessels as the cause of fetal death. Based on these findings, on the lack of evidence in the literature demonstrating full-thickness abdominal wall separating the defect from the umbilical cord, and on a critical review of the proposed mechanisms favoring the hypothesis of a defect separate from the umbilical ring, we propose that GS represents a failure in the normal attachment between umbilical cord and umbilical ring. The consistent clinical course of fetuses with prenatal demise suggests careful targeted monitoring during late gestation.

Dynamic Reconstruction of Full-Thickness Abdominal Wall Defects Using Free Innervated Vastus Lateralis Muscle Flap Combined With Free Anterolateral Thigh Flap

Reconstruction of full-thickness abdominal wall defects remains a difficult surgical challenge. Although various reconstructive methods, including artificial mesh, pedicled and free flaps, have been reported, most reported reconstruction of only the fascia layer, leaving the resected rectus abdominis muscle unreconstructed. However, recent studies suggested the importance of dynamic reconstruction with functional muscle in preventing abdominal hernia in the long-term. According to the principle of reconstructive surgery, "replace lost tissue with similar tissue," a functionally and aesthetically ideal reconstruction is to reconstruct all components of the abdominal wall structure, including skin, subcutaneous fat, fascia, and muscle. We present 2 cases with full-thickness abdominal wall defects in the upper abdominal region, which we reconstructed with a free innervated vastus lateralis muscle flap combined with a free anterolateral thigh flap. The motor nerve of the vastus lateralis muscle was sutured with the intercostal nerve, and reinnervation was confirmed by electromyography. This method allows reconstruction of all components of the abdominal wall with a single flap, and dynamic reconstruction is achieved which will reduce the risk of postoperative hernia. We believe this method can be a good option for reconstruction of full-thickness abdominal wall defects with long-term stability.

A non-biological model system to simulate the in vivo mechanical behavior of prosthetic meshes

A simple model system using synthetic materials was developed to simulate the in vivo mechanical behavior of prosthetic meshes. Two types of prosthetic meshes, SPMM (heavy-weight) and Gynemesh M (light-weight, partly absorbable) were embedded in dry conditions in an elastomeric matrix. These composites were characterized using two different testing configurations, i.e., uniaxial and biaxial tension. Stiffness parameters were calculated from the non-linear membrane tension versus stretch curves at different levels of membrane tension.The present model system qualitatively reproduces and even clarifies – as it is not affected by biological scatter – the findings of an analogous animal study (full thickness abdominal wall defect rabbit model). Biaxial tangent moduli are higher for SPMM than for Gynemesh M. A ranking of meshes according to uniaxial tangent moduli depends on the load level. At low tensions SPMM is stiffer than Gynemesh M, at moderate levels SPMM is more compliant than Gynemesh M. Stiffness values of meshes ingrown in native rabbit abdominal wall tissue are quantitatively determined based on data from the present protocol.Experiments using mesh elastomer composites were qualified as an effective tool for a mechanical characterization of prosthetic meshes. They are useful for an engineering optimization of textile meshes before a final validation in animal studies.

One-year outcome of biological and synthetic bioabsorbable meshes for augmentation of large abdominal wall defects in a rabbit model

BackgroundLong-term efficacy of biological and synthetic bioabsorbable meshes for large hernia repair is currently unclear. This rabbit study is aimed at investigating 1-y outcome of biological and synthetic bioabsorbable meshes for augmentation of large abdominal wall defects. Materials and methodsIn 46 rabbits, an 11 × 4 cm, full-thickness abdominal wall defect was repaired primarily, or with cross-linked (Permacol, Collamend) or non-cross-linked (Surgisis 4-ply, Surgisis Biodesign) biological, synthetic bioabsorbable (GORE BIO-A Tissue Reinforcement [TR], TIGR Matrix Surgical Mesh [MSM]), or polypropylene (Bard Mesh) meshes, using the underlay augmentation technique. One year after surgery, primary outcome was recurrence; secondary outcomes were tensile strength, histologic degree of tissue remodeling, and intraabdominal adhesion formation. ResultsOnly two Surgisis 4-ply animals (50%) presented with a recurrent hernia. All GORE BIO-A TR meshes were completely resorbed and, as after primary repair, well-organized connective tissue without inflammation was present, with moderate adhesion formation and sufficient tensile strength. Cross-linked biological and TIGR MSM meshes demonstrated highest tensile strength but were only partially incorporated, with similar foreign body reaction and adhesion formation as polypropylene meshes in the TIGR MSM group, and minimal degradation and moderate adhesion formation in the cross-linked biological group. In the non-cross-linked biological group sufficient tensile strength and moderate adhesion formation were found, with pronounced inflammation if mesh remnants were present. ConclusionsSynthetic bioabsorbable GORE BIO-A TR meshes were associated with optimal tissue remodeling, with complete resorption, presence of well-organized tissue, and no inflammation. However, mesh augmentation had no advantages regarding recurrence rate versus primary repair of large abdominal wall defects.

A challenging case study: small bowel transplantation with a unique twist

Small bowel transplants are a challenging procedure. Simon Turley presents a case study highlighting the considerable challenges faced by stoma care nurses in the management of these patients. The case study presents a UK’s first in transplant surgery with a unique twist — a small bowel transplant and a full-thickness abdominal wall replacement. A Bishop–Koop ileostomy was formed, but proved challenging to manage because of its extremely low position incorporated within the lower abdominal suture line; dehiscence of the upper abdominal wound added another care dimension. Collaborative working enabled good patient care, despite a poor outcome.

Laparoscopic morgagni hernia repair using single-site umbilical and full-thickness abdominal wall repair: Technical report of two cases

Single incision laparoscopic surgery is used in many centres for routine cases such as appendectomy, splenectomy and cholecystectomy. Morgagni hernias are uncommon and account for 1-2% of all congenital diaphragmatic hernia. We report our first laparoscopic repair of two Morgagni hernias, using a single umbilical incision and full-thickness abdominal wall repair with standard straight laparoscopic instruments. Operative time was short and compared favourably with the laparoscopic repair.

Report of three cases of unusual anterior abdominal wall defects in Fallujah General Hospital during the year 2010

Abdominal wall defects occur when the normal sequence of the gastro intestinal tract development is interrupted. Gastroschisis represents a herniation of abdominal contents through a paramedian full-thickness abdominal wall fusion defect without involving the umbilical cord. Evisceration usually only contains intestinal loops and has no surrounding membrane unlike omphalocoele. It is unusual for a newborn with gastroschisis to have other serious birth defects. Neonates with gastroschisis have better prognosis than those with omphalocele. Very rarely is gastroschisis associated with herniation of other organs, and their presence makes the prognosis worse.I report three cases of unusual anterior abdominal wall defects during the year 2010, each having specific associated abnormalities. One was stillborn, and the other two died shortly after delivery.

Reconstruction d’une perte de substance de pleine épaisseur de la paroi abdominale sous-ombilicale par un lambeau fasciocutané antérolatéral de cuisse pédiculé

Looking at a full-thickness abdominal wall defect, it is necessary to use reconstructive surgery techniques. The authors present an original case of reconstruction of the abdominal wall, using an anterolateral thigh flap (ALT) harvested with vascularised fascia lata. We describe the advantages of this technique, which has rarely been used for this indication. An 80-year-old woman presenting a full-thickness abdominal wall defect of 15×18cm was reconstructed by a pedicled ALT flap. Skin wound healing was obtained within 15 days, with no complication. There was no donor site sequela. The pedicled ALT flap appears to be a good solution for hypogastric abdominal wall defect in a one step procedure. Vacularised fascia lata bring with the cutaneous flap is useful to reconstruct the abdominal fascia.

Influence of Acellular Dermal Matrices on the Expression of Mediators Involved in Wound Healing and Tissue Remodeling

INTRODUCTION: Biologic meshes for reconstructive procedures have been introduced recently in an effort to create a graft that demonstrates improved integration into host tissue and resistance to infection compared to synthetics. However, no currently available biologic mesh has demonstrated optimal biocompatibility (1). Molecular mechanisms that direct the extent of the foreign body reaction to implanted biologics and their subsequent incorporation are poorly understood. We therefore compared the influence of two commonly used biologic meshes on the expression of genes critical for wound healing and tissue remodeling in a rat ventral hernia model. METHODS: Full thickness abdominal wall defects were repaired using non-cross-linked human dermis (Alloderm, LifeCell Inc.; n=10), cross-linked porcine dermis (Permacol, Covidien; n=10), or suture repair (no mesh; n=10). Explants were harvested 90 days after repair and divided for histological, immunohistochemical, and mRNA analyses. Real-time quantitative PCR arrays were used to profile the expression of 84 wound healing-associated genes at the tissue-mesh interface. RESULTS: Both meshes induced the differential expression (≥3-fold change relative to suture repair, p≤0.01) of extracellular matrix components, remodeling enzymes, and inflammatory cytokines (Permacol, 16 genes; Alloderm, 3 genes). Genes most markedly upregulated included matrix metalloproteinase (MMP) 9 (Permacol, 66-fold, p=0.02; Alloderm, 19-fold, p=0.01) and the monocyte and fibrocyte chemoattractant CCL12 (Permacol 24-fold, p<0.001; Alloderm 71-fold, p=0.06). Histologically Alloderm demonstrated overall better remodeling characteristics than Permacol. Immunohistochemistry using antibodies against MMP9 (Figures 1 and 2) confirmed differential expression at the protein level, with significantly increased expression in Permacol samples compared to Alloderm (p<0.001).Figure 1: MMP9 expression in Alloderm explant.Figure 2: MMP9 expression in Permacol explant.CONCLUSION: Permacol elicits increased protease expression and reduced cellular and vascular infiltration compared to Alloderm 90 days after implantation, indicative of delayed remodeling induced by cross-linking. Increased understanding of the host response to implanted materials ultimately will enable the development of improved meshes with enhanced wound healing properties and fewer graft-related complications. DISCLOSURES: Supported in part by a Victoria S. and Bradley L. Geist Foundation grant (to Dr. Lisa M. Pierce). The views expressed in this manuscript are those of the authors and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the US Government.