Full-thickness Abdominal Wall Research Articles

Injectable Double Crosslinked Hydrogel-Polypropylene Composite Mesh for Repairing Full-Thickness Abdominal Wall Defects.

Abdominal wall defects are common clinical diseases, and mesh repair is the standard treatment method. The most commonly used polypropylene (PP) mesh in clinical practice has the advantages of good mechanical properties, stable performance, and effective tissue integration effect. However, direct contact between abdominal viscera and PP mesh can lead to severe abdominal adhesions. To prevent this, the development of a hydrogel-PP composite mesh with anti-adhesive properties may be an effective measure. Herein, biofunctional hydrogel loaded with rosmarinic acid is developed by modifying chitosan and Pluronic F127, which possesses suitable physical and chemical properties and commendable in vitro biocompatibility. In the repair of full-thickness abdominal wall defects in rats, hydrogels are injected onto the surface of PP mesh and applied to intraperitoneal repair. The results indicate that the use of hydrogel-PP composite mesh can alleviate abdominal adhesions resulting from traditional PP mesh implantation by decreasing local inflammatory response, reducing oxidative stress, and regulating the fibrinolytic system. Combined with the tissue integration ability of PP mesh, hydrogel-PP composite mesh has great potential for repairing full-thickness abdominal wall defects.

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.

Heterotopic intestine and abdominal wall transplantation in a miniature swine: A model for graft immunology.

In order to accurately monitor graft immunology, we have developed a method for performing intestine and abdominal wall transplantation heterotopically in miniature swine. The procedure consisted of simultaneous segmental terminal ileum and full-thickness abdominal wall transplantation in Lanyu miniature swine, with the intestinal and the abdominal wall grafts being placed on the recipient's bilateral rear flank. Five transplantations were technically successful. One animal died on the first post-transplant day due to anesthesia-related issues, three abdominal wall and four intestinal grafts survived, while one abdominal wall graft failed due to vascular thrombosis. Acute cellular rejection (ACR) of the intestinal graft could occur preceding, simultaneously with or following ACR of the abdominal wall graft. Our experimental model demonstrates the technical feasibility of heterotopic intestine and abdominal wall transplantation in miniature swine without grafting in gastrointestinal continuity. This model could be suitable for further studies of graft immunology.

Efficient Decellularization of the Full-Thickness Rat-Derived Abdominal Wall to Produce Acellular Biologic Scaffolds for Tissue Reconstruction: Promising Evidence Acquired from In Vitro Results.

Functional restoration of abdominal wall defects represents one of the fundamental challenges of reconstructive surgery. Synthetic grafts or crosslinked animal-derived biological grafts are characterized by significant adverse reactions, which are mostly observed after their implantation. The aim of this study was to evaluate the efficacy of the decellularization protocol to produce a completely acellular full-thickness abdominal wall scaffold. Full-thickness abdominal wall samples were harvested from Wistar rats and submitted to a three-cycle decellularization process. Histological, biochemical, and DNA quantification analyses were applied to evaluate the effect of the decellularization protocol. Mechanical testing and immunogenicity assessment were also performed. Histological, biochemical, and DNA analysis results showed efficient decellularization of the abdominal wall samples after the third cycle. Decellularized abdominal wall scaffolds were characterized by good biochemical and mechanical properties. The data presented herein confirm the effective production of a rat-derived full-thickness abdominal wall scaffold. Expanding this approach will allow the exploitation of the capacity of the proposed decellularization protocol in producing acellular abdominal wall scaffolds from larger animal models or human cadaveric donors. In this way, the utility of biological scaffolds with preserved in vivo remodeling properties may be one step closer to its application in clinical studies.

Multifunctional Fluorinated Lubricant Infused Poly(4-hydroxybutyrate) (P4HB) Membranes for Full Thickness Abdominal Wall Defect Repair.

Abdominal wall defect caused by surgical trauma, congenital rupture, or tumor resection may result in hernia formation or even death. Tension-free abdominal wall defect repair by using patches is the gold standard to solve such problems. However, adhesions following patch implantation remain one of the most challenging issues in surgical practice. The development of new kinds of barriers is key to addressing peritoneal adhesions and repairing abdominal wall defects. It's already well recognized that ideal barrier materials need to have good resistance to nonspecific protein adsorption, cell adhesion, and bacterial colonization for preventing the initial development of adhesion. Herein, electrospun poly(4-hydroxybutyrate) (P4HB) membranes infused with perfluorocarbon oil were used as physical barriers. The oil-infused P4HB membranes can greatly prevent protein attachment and reduce blood cell adhesion in vitro. We further showed that the perfluorocarbon oil-infused P4HB membranes can reduce bacterial colonization. The in vivo study revealed that perfluoro-(decahydronaphthalene) infused P4HB membranes can significantly prevent peritoneal adhesions in the classic abdominal wall defects model and accelerate defect repair, as evidenced by gross examination and histological evaluation. This work provides a safe fluorinated lubricant-impregnated P4HB physical barrier to inhibit the formation of postoperative peritoneal adhesions and efficiently repair soft-tissue defects. This article is protected by copyright. All rights reserved.

Efficacy of Supercritical Fluid Decellularized Porcine Acellular Dermal Matrix in the Post-Repair of Full-Thickness Abdominal Wall Defects in the Rabbit Hernia Model

Damage to abdominal wall integrity occurs in accidents, infection and herniation. Repairing the hernia remains to be one of the most recurrent common surgical techniques. Supercritical carbon dioxide (SCCO2) was used to decellularize porcine skin to manufacture acellular dermal matrix (ADM) for the reparation of full-thickness abdominal wall defects and hernia. The ADM produced by SCCO2 is chemically equivalent and biocompatible with human skin. The ADM was characterized by hematoxylin and eosin (H&E) staining, 4,6-Diamidino-2-phenylindole, dihydrochloride (DAPI) staining, residual deoxyribonucleic acid (DNA) contents and alpha-galactosidase (α-gal staining), to ensure the complete decellularization of ADM. The ADM mechanical strength was tested following the repair of full-thickness abdominal wall defects (4 × 4 cm) created on the left and right sides in the anterior abdominal wall of New Zealand White rabbits. The ADM produced by SCCO2 technology revealed complete decellularization, as characterized by H&E, DAPI staining, DNA contents (average of 26.92 ng/mg) and α-gal staining. In addition, ADM exhibited excellent performance in the repair of full-thickness abdominal wall defects. Furthermore, the mechanical strength of the reconstructed abdominal wall after using ADM was significantly (p < 0.05) increased in suture retention strength (30.42 ± 1.23 N), tear strength (63.45 ± 7.64 N and 37.34 ± 11.72 N) and burst strength (153.92 ± 20.39 N) as compared to the suture retention (13.33 ± 5.05 N), tear strength (6.83 ± 0.40 N and 15.27 ± 3.46 N) and burst strength (71.77 ± 18.09 N) when the predicate device materials were concomitantly tested. However, the efficacy in hernia reconstruction of ADM is substantially equivalent to that of predicate material in both macroscopic and microscopic observations. To conclude, ADM manufactured by SCCO2 technology revealed good biocompatibility and excellent mechanical strength in post-repair of full-thickness abdominal wall defects in the rabbit hernia model.

Modifications in Abdominal Wall Graft Retrieval: When the Donor Closure Is Not Guaranteed

Twenty percent of intestinal transplant recipients will require a surgical alternative to conventional primary abdominal wall closure. Abdominal wall transplant is adevelopingtechnique that is increasingly performed for this purpose in isolated intestinal or multivisceral recipients; however, adequate closure of the donor is paramount while simultaneously obtaining a large enough graft. The aim of this study is to describe alternative surgical techniques for closure of the donor in cases in which abdominal wall graft extraction hinders subsequent donor abdominal closure. We describe the cases of 2 young donors in whom intestinal extraction was not carried out and in whom wall closure was not feasible, following standard techniques after abdominal wall graft extraction. We performed 2 different procedures to obtain adequate closure. 1. Hemifascia and hemiabdominal wall graft extraction: It is an option when the recipients require an extension of the abdominal aponeurosis yet have enough skin to guarantee skin closure. The perfusion of both epigastric arteries is needed. The remaining cutaneous half is used for closing the donor's abdomen.2. Hemiabdominal wall graft extraction: Full-thickness abdominal wall is harvested from the donor, selecting the most vascularized half. It is an alternative for recipients who need a skin implant in addition to an aponeurosis extension. This option should be used for recipients who do not require a large fascial graft but do require a significant cutaneous graft. The nontransplanted half of full-thickness abdominal wall is used for donor closure. Abdominal wall transplant allows forexpansion of the abdominal cavity in organ recipients and reduces the risk of compartmental syndrome and subsequent ischemia. However, the donor wall defect must be considered. The choice of donation technique was based on the magnitude of the defect in the donor as well as the size of defect to be covered in the recipient while ensuring a tight and complete closure of the donor's abdomen. Abdominal wall graft extraction can be performed using nonconventional techniques that account for the extension and type of coverage needed by the recipient while guaranteeing proper closure of the donor.

Multifunctional hydrogel based on dopamine-modified hyaluronic acid, gelatin and silver nanoparticles for promoting abdominal wall defect repair

Abdominal wall defects are often accompanied by severe infections and complications, creating a significant challenge for clinicians. There is an urgent need to develop a novel wound dressing that can effectively prevent intra-abdominal infection and promote the healing of defective abdominal walls. Based on a hydrogel dressing containing hyaluronic acid (HA) and gelatin (GT), herein we integrated dopamine with a catechol structure to enhance its antioxidant and adherent properties. HA is oxidized to form an aldehyde group, and subsequently grafted with dopamine. The dopamine-modified HA undergoes amidation reaction with GT at different concentrations. In addition, silver nanoparticles (AgNPs) were introduced to the hydrogel to enhance the antibacterial properties. The in vitro studies on GT/DA-HA demonstrated excellent physical and chemical properties, biodegradability, and biocompatibility. In a rat full-thickness skin defect model and a full-thickness abdominal wall defect model, the GT/DA-HA hydrogel could accelerate the healing process by improving wet adhesion, reducing wound inflammation, and promoting angiogenesis and formation of granulation tissues. The multifunctional hydrogel developed in this study shows great potential for treating full-thickness abdominal wall defects.

A Trilayer Dressing with Self-Pumping and pH Monitoring Properties for Promoting Abdominal Wall Defect Repair.

Due to abdominal infection, excessive wound exudation, and intestinal fistula formation, the treatment of full-thickness abdominal wall defects has become a difficult challenge for clinic doctors. This clinical problem cannot be resolved with existing biomaterials. To facilitate the repair of the abdominal wall, we developed a novel wound dressing with directional biofluid transport. We used electrospinning to spin a trilayer dressing consisting of hydrolyzed poly-acrylonitrile (HPAN)/Curcumin (CUR), polyurethane (PU), and polycaprolactone (PCL). In vitro results show that the three-layer wound dressing is biocompatible, capable of directional transport of excessive wound exudation, preventing reverse penetration, and monitoring the pH of the wound. Furthermore, in vivo results show the trilayer wound dressing improves the wound microenvironment, reduces inflammatory factors, promotes angiogenesis, and accelerates abdominal wall repair. Thus, we believe that the novel trilayer electrospinning dressing could facilitate abdominal wall defect repair.

Predictive Value of Tissue-induced Oxidative Stress on Urogynecology Synthetic Graft Reinforcement: An Experimental Animal Study

Background: The success of urogynecology synthetic grafts depends on adequate tissue reinforcement. This experimental animal study aimed to determine the abdominal wall reinforcement achieved by different urogynecology synthetic grafts, including the influence of inflammatory cells, collagen deposits, and tissue-induced oxidative stress. Methods: Electron microscopic analysis of six different grafts, all with Polypropylene as their major component, was performed to determine the primary mesh characteristics. Full-thickness abdominal wall defects were repaired using monofilament, multifilament, and coated grafts in male Wistar rats. After six weeks, the animals were sacrificed and the inflammatory response, collagen deposition, and oxidative stress levels were quantified. Using the digital acquisition system (Hottinger Baldwin Messetechnik (HBM) “Catman Easy”, Darmstadt, Germany), mechanical testing of the native grafts and of the reinforced abdominal wall was conducted and measured in a controlled environment. Multivariate analysis was performed to determine the predictive value of inflammatory cell numbers, collagen amount, oxidative stress, and native graft strength on the final abdominal wall reinforcement. Results: The inflammatory response was significantly more prominent with the multifilament polypropylene compared to the low-weight monofilament polypropylene (p < 0.05). Collagen deposits varied between the groups, reaching statistical significance only for multifilament polypropylene vs. titanium-coated polypropylene (p < 0.05). The oxidative stress results demonstrated a positive correlation with graft weight, regardless of coating or different graft structures (p < 0.05). The number of inflammatory cells and collagen amount did not influence the final abdominal reinforcement, while tissue-induced oxidative stress presented with a negative influence in all groups. Conclusions: Tissue-induced oxidative stress negatively affected grafts in this animal experiment. This finding might be useful (at least partially) in predicting the effectiveness of urogynecology synthetic graft tissue reinforcement and also, in promoting this reinforcement.

Abdominal Wall Skin Loss Defects Reconstruction Using Pedicled Anterolateral Thigh Flap

It was extremely difficult to deal with the complex full-thickness abdominal wall defect post serious trauma. The pedicled anterolateral thigh flap had been reported to be applied in reconstructing full-thickness abdominal wall defect in lower abdomen and groin. However, less cases in upper abdominal wall defect reconstructed by anterolateral thigh flap were reported due to some limitations. The aim of this study was to introduce our experiences in applying anterolateral thigh flap in upper abdominal wall defect reconstructing. In this study, seven patients with a large area of upper full-thickness defect in abdominal wall complicated with multiple organ damage were retrospectively identified due to acute trauma. Immediate organ-repair surgeries were performed. Meanwhile, the patients underwent complete debridement in the zone of abdominal wall defect, together with anti-infective treatment. Then, the appropriate timing was chosen to perform pedicled anterolateral thigh flap for reconstructing large area of full-thickness defect involving the upper abdomen. Postoperative follow-up data demonstrated that all the flaps survived, with no hernia complications or other discomforts. The outcome of the patients was also good. Thus, we conclude that pedicled anterolateral thigh flap was feasible to repair full-thickness defect in upper abdominal wall as long as well designed.

Abdominal Wall Reconstruction Using Omental Flap with Mesh Repair following Resection of Aggressive Abdominal Wall Neoplasms

Background: Resection of large anterior abdominal wall tumors causes large full-thickness abdominal wall defects, and the repair of these defects remains a challenging point. Methods: Between July 2016 and February 2021, we retrospectively reviewed the internal database registry of the Oncology Center, Mansoura University (OCMU), Egypt, for patients with large abdominal wall defects after abdominal wall tumors resection and repair with omental flaps and synthetic polypropylene (PP) mesh. Thirty-two patients met the inclusion criteria. They were analyzed for demographics and operative data including defect size, mesh size, intra-abdominal tumor extension, and postoperative outcomes and complications. Results: Thirty-Two patients with abdominal wall neoplasm underwent local resection in our center and the defect was closed with an omental flap and PP mesh. The mean operative time was 143.75 ± 30.77 min. The mean size of the abdominal wall defect was 50.8 cm² (range: 25–90 cm²). The meshes used in reconstruction had a mean size of 89.5 cm² (range: 55–130 cm²). The median follow-up period of the patients was 13.5 months (range: 5–54 months). Postoperative complications included infection (n = 4 cases), seroma (n = 2 cases), hematoma (n = 1 case), and abnormal sensation (n = 5 cases). Tumor recurrence was reported in 2 cases, and no cases developed incisional hernia during the follow-up period. Conclusion: Immediate use of omental flap with synthetic PP mesh for reconstruction of abdominal wall defects is a feasible technique and has avoided the complications associated with the use of synthetic mesh alone.

Reconstruction of Large Full-Thickness Abdominal Wall Defects Using a Free Functional Latissimus Dorsi Muscle

IntroductionThe large full-thickness abdominal wall defect has to be treated by considering anatomical and functional requirements. The abdominal wall must regain total physiological function, which means that the full thickness abdominal wall defect must be reconstructed anatomically, not only according to the anatomical requirements but also maintaining the functional dynamic voluntary movement. Defects in the abdominal wall alter respiratory mechanics and can impair the diaphragm function. Additionally, muscles of the anterolateral abdominal wall increase the stability of the lumbar region of the vertebral column by tensing the thoracolumbar fascia and by increasing intraabdominal pressure.Materials and MethodsThe timing and method of reconstruction must be chosen depending upon the etiology of the defect. Severe traumatic injuries, abdominal wall infections, necrotizing soft tissue loss, or sepsis needs to undergo staged reconstruction following adequate debridement to control the infectious process, establish the zone of injury, and for proper treatment of intraabdominal pathology, thereby achieving temporary primary closure using split-thickness skin grafting to the viscera. At the time of definitive reconstruction, deep skin graft dermabrasion give us a facial-like layer with adequate strength to stabilize the static abdominal wall. This dermal layer is supported by free functional (innervated) latissimus dorsi muscle (fLDM), giving full anatomical coverage and functional stability. After oncologic resections full-thickness abdominal wall reconstruction was performed immediately with a combination of fLDM flaps and meshes.ResultsA total of 14 patients underwent abdominal wall reconstruction using the fLDM flap. Staged reconstruction was applied in 8 cases. In the remaining six cases, two had no mesh support, three had synthetic mesh, and one had a fascial graft, which were covered with fLDM flap. There were no free flaps failure. One flap revision due to venous anastomosis thrombosis was performed. Donor site seromas occurred in 5 cases and were treated with punction and direct doxycycline injection. Electromyographic testing postoperatively confirmed reinnervation of transplanted LDM.ConclusionUsing fLDM as a definitive solution, we are not only able to repair soft tissue defects, but also reconstruct voluntary contractility and dynamic natural functional abdominal wall. Transplanted LDM offers enough contractile capacity and strength to replace the function of the missing abdominal wall muscles.

Multifunctional Electrospun Textiles for Wound Healing.

The novel multifunctional electrospun textiles were fabricated by incorporating sheet-like kaolinite and silver nanoparticles (AgNps) into a polyurethane (PU) textile by using electrostatic spinning to promote wound-healing process. Threedimensional network of PU electrospun textiles offered an appropriate framework for loading kaolinite nanosheets and AgNps. Moreover, the kaolinite nanosheets healed bleeding wounds by accelerating plasma absorption, increasing blood cell concentrations, and stimulating coagulation factors. Furthermore, the AgNps killed microbes by destroying the cell membrane, while the deleterious effects were controlled by incorporation into the electrospun textile. The therapeutic effects of multifunctional electrospun textile in treating full-thickness abdominal wall defect were explored. The wound healing process could be accelerated via the textile by restoring the abdominal physiological environment, reducing the inflammatory response, and promoting collagen deposition, angiogenesis, and epithelization.

Closing the abdomen: update on the current surgical toolkit.

Achieving abdominal wall closure after intestinal transplantation (ITx) is one of the crucial surgical challenges. This problem is present in 25-50% of all transplants due to reduction in abdominal domain, fistulae and extensive adhesions due to previous surgeries. Failure to achieve closure is an independent risk factor for mortality and graft loss. The aim of this paper is to summarize the current options to achieve this. Successful closure of the abdomen requires a tension-free repair. Primary closure of the fascia can be reinforced with synthetic or biological mesh. For more complex fascial defects bridging mesh, nonvascularised or vascularised rectus fascia can be utilised. If all components of the abdominal wall are affected, then a full-thickness abdominal wall transplantation may be necessary. A variety of successful techniques have been described by different groups to enable abdominal wall closure after ITx. Emerging developments in preoperative imaging, reconstructive surgery and immunology have expanded the surgical toolkit available. Crucial is a tailor-made approach whereby patients with expected closure issues are identified prior to surgery and the simplest technique is chosen.

A simple technique for definite closure of full thickness abdominal wall defect in open abdomen after temporary applied split thickness graft

Open abdomen (OA) has gained a wide acceptance in the management of abdominal surgical catastrophes. Definite reconstruction of OA is an operative challenge as various methods are used. Dynamic techniques are preferred for the closure of OA. If other methods fail to close the OA, then temporary split thickness skin graft can be applied and refer the definite closure for later. We used a modification of an existing technique, in a 47-year-old female patient with a big midline incisional hernia due to temporary closure of OA with partial-thickness skin graft, who was operated for permanent closure of the defect. In order to avoid complications from extensive dissection, we invaginated the grafted area and realigned the recti muscles with on lay mesh reinforcement with excellent outcome. This technique of inverting the previous grafted area when it can be applied is an easy and safe method with rewarding results.

Microvascular Free Tissue Transfer for Reconstruction of Complex Abdominal Wall Defects.

Patients with significant loss of abdominal wall soft tissue represent a reconstructive challenge. The purpose of this study was to describe the authors' experience using microvascular free tissue transfer to repair complex abdominal wall defects with insufficient overlying soft tissue. In this report, the authors highlight their techniques and experiences in performing microvascular free tissue transfer to the abdominal wall for these massive, complex defects. In total, 14 patients who underwent 16 free-flap reconstructions were included in the series. The patients' mean age was 50 ± 14 years, and mean body mass index was 27 ± 5 kg/m2. The mean hernia defect size was 412 ± 149 cm2. Ten flaps were fasciocutaneous anterolateral thigh flaps, one myocutaneous anterolateral thigh flap, two subtotal thigh flaps, one myocutaneous latissimus dorsi flap, one parascapular/latissimus dorsi flap, and one free filet of the lower leg. Five cases (36 percent) developed hernia recurrence, and seven developed surgical site complications. All flaps survived, with no total flap loss. This report highlights that microsurgical free tissue transfer in combination with mesh repair is a safe and reliable method for restoring complex, large, full-thickness abdominal wall defects. This case series illustrates a number of techniques and considerations that are of importance to achieve a favorable outcome when faced with these complex defects. Therapeutic, IV.

New technique for abdominal wall procurement. Initial experience.

Difficulty in obtaining adequate abdominal wall closure due to loss of the abdominal domain is a frequent complication of multivisceral, isolated intestinal transplantation and in some cases of liver transplantation. Various methods for primary closure have been proposed, including the use of synthetic and biological meshes, as well as full-thickness abdominal wall and non-vascularized rectus fascia grafts. We describe a novel technique for abdominal wall procurement in which the graft is perfused synchronously with the abdominal organs and can be transplanted as a full-thickness wall or as a non-vascularized rectus fascia graft. We performed six transplants of non-vascularized rectus fascia in three intestinal transplants, one multivisceral transplant, and two liver transplants. The size of the covered abdominal wall defects ranged from 17cm × 7cm to 25cm × 20cm. Only one patient developed graft infection secondary to enterocutaneous fistula requiring surgical correction and removal of the fascia graft. This patient, as well as two other patients, died due to sepsis. Our procurement technique allows removal of the rectus fascia graft to cover the abdominal wall defect, providing a feasible solution for treatment of abdominal wall defects in recipients after abdominal organ transplantation.

P049 SAFETY AND EFFICACY OF ABSORBABLE AND NON-ABSORBABLE FIXATION SYSTEMS FOR INTRAPERITONEAL MESH FIXATION: AN EXPERIMENTAL STUDY IN SWINE

Abstract Aim Choice of the best fixation system in terms of safety and effectiveness for intraperitoneal mesh placement in hernia surgery remains controversial. The aim of this study was to compare the performance of four fixation systems in a swine model of intraperitoneal mesh fixation. Material and Methods Fourteen Landrace swine were utilized and the experiment included two stages. Initially, four pieces of polypropylene mesh with hydrogel barrier coating1 were fixed intraperitoneally to reinforce 4 small full thickness abdominal wall defects created with diathermy. Each mesh was anchored with a different tack device between titanium2, steel3 or absorbable (4,5) fasteners. The second stage took place after 60 days and included euthanasia, laparoscopy, and laparotomy. The primary endpoint was to compare the peel strength of the compound tack/mesh from the abdominal wall. Secondary parameters were the extent and quality of visceral adhesions to the mesh, the degree of mesh shrinkage and the histological response around the tacks. Results Thirteen out of 14 animals survived the experiment and 10 were included in the final analysis. Steel tacks had higher peel strength when compared to titanium and absorbable fasteners. No significant differences were noted regarding the secondary endpoints. Conclusions Steel fasteners provided higher peel strength that the other devices in this swine model of intraperitoneal mesh fixation. Our findings generate the hypothesis that this type of fixation may be superior in a clinical setting. Clinical trials with long-term follow-up are required to assess the safety and efficacy of mesh fixation systems in hernia surgery.

Successful Utilization of Poly-4-Hydroxybutyrate Mesh in High Risk, Complex Abdominal Wall Reconstructions with Photo-Microscopic Analysis.

Background: Biosynthetic resorbable mesh offers encouraging alternative for reinforcement in complex hernia repairs. This study evaluated outcomes of P4HB, absorbable polymer scaffold, in high-risk patients undergoing complex abdominal hernia repairs. Materials and Methods: This is a retrospective outcomes analysis of a prospectively kept database. Patient/wound characteristics, perioperative findings, short/mid-term outcomes of our cohort were analyzed. Endpoints included hernia recurrences, wound events and any complications. ACS NSQIP online risk calculator was used for each patient to obtain predicted outcomes as virtual matched control group. We also performed a full-thickness abdominal wall biopsy at 14-months post mesh implantation for histologic evaluation. Results: 28 patients with mean age 57 years and mean BMI 31 were analyzed. 21 patients (75%) had preexisting infections. 20 (71%) of patients had class I wounds per CDC classification at time of surgery. However, 19 of these 20 had wound or deep organ/space infections prior to surgery. Repair types included restoration of Linea Alba with retromuscular mesh placement in 23 patients (82%) with 22 of them requiring additional myofascial release. 5 patients (18%) had only mesh placement. Postoperatively, 11 patients (39%) had complications with zero hernia recurrence and zero mesh explantation at maximum of 42 months of follow up. Conclusion: P4HB can be successfully used in high-risk operative fields with no postoperative mesh explantation, despite serious complications such as infected hematomas. Histologic evaluation of the human tissue, 14-months post-implantation of P4HB confirms mesh presence with surrounding dense collagen scaffold formation and minimal inflammatory response.