Decellularized human cadaveric dermis provides a safe alternative for primary inguinal hernia repair in contaminated surgical fields

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.

Quality by Design: Development of Safe and Efficacious Full-Thickness Acellular Dermal Matrix Based on EuroGTPII Methodologies

Background

The activities of tissue establishments are constantly and rapidly evolving. The development of a new type of allograft, full-thickness acellular dermal matrix, with high mechanical properties to be used in tendon repair surgeries and abdominal wall reconstruction, has determined the need for quality by design process in order to assess evidence of quality, safety and efficacy. The EuroGTPII methodologies were specifically tailored to perform the risk assessment, identify and suggest tests in order to mitigate the potential risk consequences of a novel tissue preparation implementation.

Methods

The new allograft and associated preparation processes were assessed using the EuroGTP methodologies and characterized to properly evaluate the novelty (Step 1), identify and quantify the potential risks and risk consequences (Step 2), and define the extent of pre-clinical and clinical assessments required to mitigate the risks identified in the assessment (Step 3).

Results

Four risk consequences associated with the preparation process were identified: (i) implant failure related with tissue procurement and the reagents used during the decellularization protocol; (ii) unwanted immunogenicity related with the processing; (iii) disease transmission linked with the processing, reagents used, reduction in the reliability of microbiology testing and the storage conditions; and (iv) toxicity related to the reagents used and handling of the tissue during clinical application. The outcome of the risk assessment was a low level of risk. Nevertheless, it determined the need for a series of risk mitigation strategies proposed to reduce each individual risk and to provide additional evidence of the safety and efficacy of full-thickness acellular dermal matrix grafts.

Conclusion

EuroGTPII methodologies allow us to identify the risks and ensure the correct definition of pre-clinical assessments required to address and mitigate the potential risk consequences, before proceeding with clinical use of the new allografts in patients.

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.

Symptomatic hernia of the thigh musculature requiring reconstruction: A rare late presenting sequela after fascial release for compartment syndrome

Acute compartment syndrome (ACS) of the lower extremity is a surgical emergency, often secondary to severe crush injury, and requires immediate fascial release. In treatment of ACS, the underlying fascia is left unrepaired and the subsequent fascial defect does not generally cause negative consequences. Here, we present a 24-year-old man who developed symptomatic muscle herniation 3-years after undergoing fascial release secondary to ACS of the anterior thigh. Given the size of the defect, reconstruction was performed using Acellular Dermal Matrix (ADM). The patient did well, with no complications 6 months postoperatively. Symptomatic muscle herniation following fasciotomy can be treated with hernia reduction and fascial repair. When primary closure is not possible, Acelluar Dermal Matrix (ADM) is an option for successful fascial reconstruction.

A New Human-Derived Acellular Dermal Matrix for 1-Stage Coverage of Exposed Tendons in the Foot

The closure of wounds associated with soft tissue defects is surgically challenging, frequently requiring extensive plastic surgery and free flaps. The combination of ADM and STSG is an innovative method used to cover such wounds. The human-derived ADMs (H-ADMs) are the most described in the literature but according to European legislations, Companies H-ADMs outside the EC are not allowed to commercialize them in Europe, H-ADMs being “human products” and not “medical devices”, so being ruled by European legislations on transplants. The Skin Bank of the Bufalini Hospital (Cesena, Italy) obtained in 2009 the approval for the production and distribution of the first human cadaver-donor derived ADM from the Italian National Transplant Center and National Health Institute, we called with the Italian acronym M.O.D.A. (Matrice Omologa Dermica Acellulata). We present here the first use of a new H-ADM for treatment of distal lower extremity wounds with exposed tendons managed in one-stage pocedure with STSG. The excellent performance suggests that in cases where autologous tissue is unavailable or undesirable, the use of M.O.D.A. in one-stage procedure represents a promising alternative for covering wounds associated with tendons exposition.

Emergency repair of complicated abdominal wall hernias: WSES guidelines

PURPOSE

In July 2013, the World Society of Emergency Surgery (WSES) held the first Consensus Conference on emergency repair of abdominal wall hernias in adult patients with the intention of producing evidence-based guidelines to assist surgeons in the management of complicated abdominal wall hernias. Guidelines were updated in 2017 in keeping with varying clinical practice: benefits resulting from the increased use of biological prosthesis in the emergency setting were highlighted, as previously published in the World Journal of Emergency Surgery. This executive summary is intended to consolidate knowledge on the emergency management of complicated hernias by providing the broad readership with a practical and concise version of the original guidelines.

METHODS

This executive manuscript summarizes the WSES guidelines reporting on the emergency management of complicated abdominal wall hernias; statements are highlighted focusing the readers' attention on the main concepts presented in the original guidelines.

CONCLUSIONS

Emergency repair of complicated abdominal hernias remains one of the most common and challenging surgical emergencies worldwide. WSES aims to provide an essential version of the evidence-based guidelines focusing on the timing of intervention, laparoscopic approach, surgical repair following the Centers for Disease Control and Prevention (CDC) wound classification, antimicrobial prophylaxis and anesthesia in the emergency setting.

The angiogenesis in decellularized scaffold-mediated the renal regeneration

There are increasing numbers of patients underwent partial nephrectomy, and recovery of disturbed renal function is imperative post partial nephrectomy. We previously have demonstrated the decellularized (DC) scaffolds could mediate the residual kidney regeneration and thus improve disturbed renal function after partial nephrectomy. However, the cellular changes including the angiogenesis in the implanted DC scaffold has not yet been elaborated. In this study, we observed that the scaffold promoted the proliferation of human umbilical vein endothelial cells (HUVEC) that adhered to the DC scaffold in vitro. We next examined the pathological changes of the implanted DC graft in vivo, and found a decreased volume of the scaffold and a dramatic angiogenesis within the scaffold. The average microvessel density (aMVD) increased at the early stage, while decreased at the later stage post transplantation. Expression level of vascular endothelial growth factor (VEGF) showed similar dynamic changes. In addition, many endothelial cells (ECs) and endothelial progenitor cells (EPCs) were distributed in the region which contained active angiogenesis in the scaffold. However, the implanted graft became fibrosis and the angiogenesis degraded at final stage roughly 8 weeks post transplantation. Our data indicate that DC scaffold can be vascularized in vivo and possible mechanisms are discussed.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

2017 update of the WSES guidelines for emergency repair of complicated abdominal wall hernias

Emergency repair of complicated abdominal wall hernias may be associated with worsen outcome and a significant rate of postoperative complications. There is no consensus on management of complicated abdominal hernias. The main matter of debate is about the use of mesh in case of intestinal resection and the type of mesh to be used. Wound infection is the most common complication encountered and represents an immense burden especially in the presence of a mesh. The recurrence rate is an important topic that influences the final outcome. A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013 with the aim to define recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel. In 2016, the guidelines have been revised and updated according to the most recent available literature.

A surgical multi-layer technique for pelvic reconstruction after total exenteration using a combination of pedicled omental flap, human acellular dermal matrix and autologous adipose derived cells

•A multi-layer technique for reconstruction after pelvic exenteration is proposed.•Human acellular dermal matrix used in reconstruction after total pelvic exenteration.•A reconstructive technique based on human dermis, omental flap and fat is proposed.

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.

Biocompatibility evaluation of tissue-engineered decellularized scaffolds for biomedical application

Biomaterials based on seeding of cells on decellularized scaffolds have gained increasing interest in the last few years and suggested to serve as an alternative approach to bioengineer artificial organs and tissues for transplantation. The reaction of the host toward the decellularized scaffold and transplanted cells depends on the biocompatibility of the construct. Before proceeding to the clinical application step of decellularized scaffolds, it is greatly important to apply a number of biocompatibility tests in vitro and in vivo. This review describes the different methodology involved in cytotoxicity, pathogenicity, immunogenicity and biodegradability testing for evaluating the biocompatibility of various decellularized matrices obtained from human or animals.

Systemic inflammatory cytokine analysis to monitor biomaterial augmented tissue healing

PURPOSE

Hernias can be repaired by reinforcement of damaged fascia using biomaterials to provide stabilisation. Repair materials are usually porous, through which cells infiltrate, proliferate and secrete ECM. Their efficacy relies on good tissue integration and resolution of host defence mechanisms. Therefore, understanding the dynamics by which biomaterials interact with tissue will provide knowledge to advance prosthesis design. Furthermore, determining host response in real time would provide significant advantage both clinically and scientifically over the current terminal process of histology.

METHODS

3 materials comprising synthetic and composite (synthetic materials hybridised with a resorbable biologic component) meshes were implanted into a rat full-thickness abdominal wall excision model. Their efficacy was evaluated using histopathology whilst also monitoring systemic concentrations of cytokines associated with inflammation and wound healing to predict material outcome over 12 weeks.

RESULTS

The noncomposite material (polyester) and Material B (polypropylene mesh with oligocaprone film and polydioxanone glue) stimulated the largest degree of adhesion from the 3 materials tested, although after 28 days adhesions were stronger to Material B. Histologically, all 3 materials integrated well with abdominal musculature and infiltrated completely with cells.

CONCLUSIONS

Analysis of systemic inflammation biomarkers confirmed inflammation elicited by surgeries and meshes irrespective of their composition. However, at an early postoperative endpoint (i.e., 1 week), some biomarkers, namely, IL-18 and RANTES, appeared to discriminate the noncomposite mesh from the composite materials, although in this study all materials successfully repaired the defects without recurrence or external indicators of postoperative chronic pain.

Emerging Trends in Abdominal Wall Reinforcement: Bringing Bio-Functionality to Meshes

Abdominal wall hernia is a recurrent issue world-wide and requires the implantation of over 1 million meshes per year. Because permanent meshes such as polypropylene and polyester are not free of complications after implantation, many mesh modifications and new functionalities have been investigated over the last decade. Indeed, mesh optimization is the focus of intense development and the biomaterials utilized are now envisioned as being bioactive substrates that trigger various physiological processes in order to prevent complications and to promote tissue integration. In this context, it is of paramount interest to review the most relevant bio-functionalities being brought to new meshes and to open new avenues for the innovative development of the next generation of meshes with enhanced properties for functional abdominal wall hernia repair.

A Simplified Approach for Arthroscopic Repair of Rotator Cuff Tear with Dermal Patch Augmentation

Here, we describe an arthroscopic method specifically developed to augment rotator cuff repair using a flexible acellular dermal patch (ADP). In this method, an apparently complex technique is simplified by utilizing specific steps to augment a rotator cuff repair. In this method, using a revised arthroscopic technique, rotator cuff repair was performed. This technique allowed easy passage of the graft, excellent visualization, minimal soft tissue trauma, and full four-corner fixation of an ADP. Twelve patients underwent rotator cuff repair with augmentation using the combination of this method and ADP. Due to the technique and biomechanical characteristics of the material, the repairs have been stable and with high patient satisfaction.

A primer on wound healing in colorectal surgery in the age of bioprosthetic materials

Wound healing is a complex, dynamic process that is vital for closure of cutaneous injuries, restoration of abdominal wall integrity after laparotomy closure, and to prevent anastomotic dehiscence after bowel surgery. Derangements in healing have been described in multiple processes including diabetes mellitus, corticosteroid use, irradiation for malignancy, and inflammatory bowel disease. A thorough understanding of the process of healing is necessary for clinical decision making and knowledge of the current state of the science may lead future researchers in developing methods to enable our ability to modulate healing, ultimately improving outcomes. An exciting example of this ability is the use of bioprosthetic materials used for abdominal wall surgery (hernia repair/reconstruction). These bioprosthetic meshes are able to regenerate and remodel from an allograft or xenograft collagen matrix into site-specific tissue; ultimately being degraded and minimizing the risk of long-term complications seen with synthetic materials. The purpose of this article is to review healing as it relates to cutaneous and intestinal trauma and surgery, factors that impact wound healing, and wound healing as it pertains to bioprosthetic materials.

Decellularization of human dermis using non-denaturing anionic detergent and endonuclease: a review

Decellularized human dermis has been used for a number of clinical applications including wound healing, soft tissue reconstruction, and sports medicine procedures. A variety of methods exist to prepare this useful class of biomaterial. Here, we describe a decellularization technology (MatrACELL^®) utilizing a non-denaturing anionic detergent, N-Lauroyl sarcosinate, and endonuclease, which was developed to remove potentially immunogenic material while retaining biomechanical properties. Effective decellularization was demonstrated by a residual DNA content of ≤4 ng/mg of wet weight which represented >97 % DNA removal compared to unprocessed dermis. Two millimeter thick MatrACELL processed human acellular dermal matrix (MH-ADM) exhibited average ultimate tensile load to failure of 635.4 ± 199.9 N and average suture retention strength of 134.9 ± 55.1 N. Using an in vivo mouse skin excisional model, MH-ADM was shown to be biocompatible and capable of supporting cellular and vascular in-growth. Finally, clinical studies of MH-ADM in variety of applications suggest it can be an appropriate scaffold for wound healing, soft tissue reconstruction, and soft tissue augmentation.

DermACELL: a novel and biocompatible acellular dermal matrix in tissue expander and implant-based breast reconstruction

BACKGROUND

Acellular dermal matrices present a new alternative to supporting expanders and implants for breast reconstruction in breast cancer patients following mastectomy. However, some studies have suggested that acellular dermal matrix may increase the complication rates in certain clinical settings. DermACELL acellular dermal matrix offers advanced processing in order to attempt to decrease bio-intolerance and complications.

METHODS

Ten consecutive patients that presented for breast reconstruction and were candidates for tissue expanders underwent the procedure with the use of an acellular dermal matrix. The patients underwent postoperative expansion/adjuvant cancer therapy, then tissue expander exchange for permanent silicone breast prostheses. Patients were followed through the postoperative course to assess complication outcomes. Histologic evaluation of host integration into the dermal matrix was also assessed.

RESULTS

Of the ten patients, eight completed reconstruction while two patients failed reconstruction. The failures were related to chronic seromas and infection. Histology analysis confirms rapid integration of mesenchymal cells into the matrix compared to other acellular dermal matrices.

CONCLUSIONS

Based on our observations, DermACELL is an appropriate adjunct to reconstruction with expanders. Histological analysis of vascularization and recellularization support the ready incorporation of DermACELL into host tissue. Level of Evidence: Level IV, therapeutic study.

Clinical Outcomes for Breast Cancer Patients Undergoing Mastectomy and Reconstruction with Use of DermACELL, a Sterile, Room Temperature Acellular Dermal Matrix

Background. Decellularized human skin has been used in a variety of medical applications, primarily involving soft tissue reconstruction, wound healing, and tendon augmentation. Theoretically, decellularization removes potentially immunogenic material and provides a clean scaffold for cellular and vascular in growth. The use of acellular dermal matrix in two-stage postmastectomy breast reconstruction is described. Methods. Ten consecutive breast cancer patients were treated with mastectomies and immediate reconstruction from August to November 2011. There were 8 bilateral and 1 unilateral mastectomies for a total of 17 breasts, with one exclusion for chronic tobacco use. Reconstruction included the use of a new 6 × 16 cm sterile, room temperature acellular dermal matrix patch (DermACELL) soaked in a cefazolin bath. Results. Of the 17 breasts, 15 reconstructions were completed; 14 of them with expander to implant sequence and acellular dermal matrix. Histological analysis of biopsies obtained during trimming of the matrix at the second stage appeared nonremarkable with evidence of normal healing, cellularity, and vascular infiltration. Conclusion. Postoperative observations showed that this cellular dermal matrix appears to be an appropriate adjunct to reconstruction with expanders. This acellular dermal matrix appeared to work well with all patients, even those receiving postoperative chemotherapy, postoperative radiation, prednisone, or warfarin sodium.

WSES guidelines for emergency repair of complicated abdominal wall hernias

Emergency repair of complicated abdominal hernias is associated with poor prognosis and a high rate of post-operative complications.A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013, during the 2nd Congress of the World Society of Emergency Surgery with the goal of defining recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel.

Whole-organ re-engineering: a regenerative medicine approach to digestive organ replacement

Recovery from end-stage organ failure presents a challenge for the medical community, considering the limitations of extracorporeal assist devices and the shortage of donors when organ replacement is needed. There is a need for new methods to promote recovery from organ failure and regenerative medicine is an option that should be considered. Recent progress in the field of tissue engineering has opened avenues for potential clinical applications, including the use of microfluidic devices for diagnostic purposes, and bioreactors or cell/tissue-based therapies for transplantation. Early attempts to engineer tissues produced thin, planar constructs; however, recent approaches using synthetic scaffolds and decellularized tissue have achieved a more complex level of tissue organization in organs such as the urinary bladder and trachea, with some success in clinical trials. In this context, the concept of decellularization technology has been applied to produce whole organ-derived scaffolds by removing cellular content while retaining all the necessary vascular and structural cues of the native organ. In this review, we focus on organ decellularization as a new regenerative medicine approach for whole organs, which may be applied in the field of digestive surgery.

Coughing-induced bowel transection in a patient with an incarcerated inguinal hernia: a case report

Introduction

Although blunt trauma to a hernia-containing bowel is known to cause bowel perforation, this report documents the first incident of a small bowel transection following a non-traumatic event.

Case presentation

We report the case of a 49-year-old African American man with a chronic incarcerated inguinal hernia awaiting elective repair. He presented to the Emergency Department with abdominal pain following an episode of coughing. On examination, he was found to have peritonitis. He underwent exploratory laparotomy, and had a complete small bowel transection. A bowel resection with primary anastomosis was performed, as well an inguinal hernia repair.

Conclusion

Chronic hernia incarceration can lead to weakening and ischemia of the bowel, and minimal trauma can lead to perforation of the weakened segment. In such presentations, bowel resection and repair of the defect with a biological material is safe and feasible.

Abdominal hernia repair with a decellularized dermal scaffold seeded with autologous bone marrow-derived mesenchymal stem cells

Surgeons usually use synthetic polymer meshes for abdominal wall hernia repair. However, synthetic polymer meshes exhibit a lack of growth and related complications. In this study, we produced a tissue-engineered patch for abdominal hernia repair. Autologous bone-marrow-derived mesenchymal stem cells (BMSCs) were isolated and proliferated in vitro; decellularized dermal scaffolds (DSs) were prepared using enzymatic process; and then BMSCs were seeded onto the DSs for the construction of tissue-engineered patches. Under general anesthesia, rabbits underwent creation of abdominal wall defects and which were repaired with BMSC-seeded DSs, acellular DSs, and skin sutures only, respectively. Animals were sacrificed after 2 months for assessing the histological and gross examination. Abdominal hernias were absent in animals repaired with cell-seeded group, and abdominal hernias or bulges appeared in all animals repaired with acellular group. All the animals that were not repaired died within 10 days. The cell-seeded implants were thicker and indicated good angiogenesis compared with that of the acellular implants, both in histological and gross examination. The tissue-engineered patches prepared with BMSCs seeding on DSs can be used for abdominal wall hernia repair.

Natural orifice translumenal endoscopic surgery inguinal hernia repair: a survival canine model

INTRODUCTION

With over 20 million repairs performed worldwide annually, inguinal hernias represent a significant source of disability and loss of productivity. Natural orifice translumenal endoscopic surgery (NOTES™), as a potentially less invasive form of surgery may reduce postoperative disability and accelerate return to work. The objective of this study was to assess the safety and short-term effectiveness of transgastric inguinal herniorrhaphy using a biologic mesh in a survival canine model.

MATERIALS AND METHODS

Under general anesthesia with the animal in Trendelenburg position, a gastrostomy was created. A 4 × 6 cm acellular dermal implant was deployed endoscopically across the myopectineal orifice, draped over the cord structures, and secured with Bioglue. Following completion of bilateral repairs the animals were survived for 14 days. At the end of the study period, the animals were euthanized and a necropsy performed. Cultures of a random site within the peritoneal cavity and at the site of implant deployment were obtained. In addition, a visual inspection of the peritoneal cavity was performed.

RESULTS

All animals thrived postoperatively and did not manifest signs of peritonitis or sepsis at any point. At necropsy accurate placement and adequate myopectineal coverage was confirmed in all subjects. Cultures of a random site within the peritoneal cavity and at the site of implant deployment had no growth.

DISCUSSION

This study confirms that NOTES-inguinal herniorrhaphy using a biologic implant can be performed safely. In addition, the transgastric technique provided good short-term myopectineal coverage without infectious sequelae.

Umbilical Herniorrhaphy Reinforced with Biologic Mesh

The true recurrence rate after umbilical hernia repair in not known. After simple closure, the reported rate of recurrence in the literature is as high as 54 per cent. With synthetic mesh repair, the recurrence rates are lowered to less than 10 per cent. However, synthetic mesh is associated with complications such as enterocutaneous fistula and mesh infections. This preliminary study looks at the safety and effectiveness of biologic extracellular matrix mesh reinforcement in the repair of umbilical hernias. We retrospectively reviewed all patients who underwent repair of an umbilical hernia defect (2-3 cm) with primary approximation of the margins and reinforced using a biologic mesh placed beneath the umbilical fascia from 2007 to 2009. Demographic data were collected. Patients were followed prospectively at 2 weeks, 8 weeks, 6 months, and 1 year. Data were reviewed for postoperative complications, hernia recurrence, and patient satisfaction. During the study period, 16 patients completed the 1 year follow-up. There were 10 men and six women. Ages ranged from 28 to 75 years with a mean age of 47.6 years. The hernias were 2 to 3 cm in size. Complications were minimal. Overall patient satisfaction with the procedure was high. There were no mesh infections. During a mean follow-up of 12 months, only one patient had recurrent hernia (6%). This preliminary evaluation shows promise for an alternative treatment of umbilical hernias using biologic extracellular matrix mesh added as an underlay to reinforce a primary closure. The biologic mesh has a low incidence of infection and complications and results in high patient satisfaction. This preliminary study begs for a randomized, prospective evaluation with long-term follow-up.

Development of an acellular bioengineered matrix with a dominant vascular pedicle

BACKGROUND

This study assessed the feasibility of creating a tissue engineering platform by decellularization of fasciocutaneous tissue.

MATERIALS AND METHODS

A fasciocutaneous flap based upon the superficial inferior epigastric artery was harvested from the abdominal wall of 8-wk-old male Sprague-Dawley rats. All cellular components were removed by sequential treatment with sodium azide, DNAse, and sodium deoxycholate. The degree of decellularization was qualitatively assessed by histology and quantitatively assessed by spectrophotometry. Persistence of relevant extracellular matrix proteins was shown following staining with orcein and hematoxylin. The duration of circuit patency was determined by continuous perfusion with a peristaltic perfusion pump.

RESULTS

Gross and histologic examination demonstrated removal of cellular constituents with preservation of tissue matrix architecture, including macrochannels and microchannels. This was confirmed by the application of spectrophotometry to DNA isolates, which showed that the decellularized flap retained 4.04 ng/μL DNA, compared with the non-processed control, which retained 37.03 ng/μL DNA, and the acellular control, which was read as having 0.65 ng/μL DNA. The extracellular matrix of vessel walls was shown to remain intact. Peristaltic perfusion of the cannulated pedicle inflow channel with phosphate buffered saline at a rate of 200 μL/min confirmed circuit patency for 6 h.

CONCLUSION

Fasciocutaneous flaps harvested with an intact vascular pedicle and associated tissue vascular network can be successfully decellularized and perfused ex vivo. This methodology, which is scalable to human size tissues, provides promise as a technique for the production of customizable engineered tissues.

Synthesis of a tissue-engineered periosteum with acellular dermal matrix and cultured mesenchymal stem cells

Periosteal grafts can aid in bone repair by providing bone progenitor cells and acting as a barrier to scar tissue. Unfortunately, these grafts have many of the same disadvantages as bone grafts (donor site morbidity and limited donor sites). In this article, we describe a method of synthesizing a periosteum-like material using acellular human dermis and osteoblasts or mesenchymal stem cells (MSC). We show that osteoblasts readily attach to and proliferate on the acellular human dermis in vitro. In addition, osteoblasts retained the potential for differentiation in response to bone morphogenetic protein stimulation. Cells grown on the acellular human dermis were efficiently transfected with adenoviruses with no evidence of cellular toxicity. To assess for in vivo cell delivery and bone-forming potential, the acellular human dermis was seeded with green fluorescent protein (GFP)-positive MSCs, transfected with bone morphogenetic protein 2, wrapped around the adductor muscle in syngeneic mice, and used to treat critical-sized mandibular defects in nude rats. After 3 weeks, GFP-positive cells were still present, and bone had replaced the interface between the muscle and the constructs. After 6 weeks, critical-sized bone defects had been successfully healed. In conclusion, we show that an acellular human dermis can be used to synthesize a tissue-engineered periosteum capable of delivering cells and osteoinductive proteins.

Feasibility study of natural orifice transluminal endoscopic surgery inguinal hernia repair

BACKGROUND

A potentially less-invasive technique, transluminal surgery, may reduce or eliminate pain and decrease time to full return of activities after abdominal operations. Inguinal hernia repair is perfectly suited to the transgastric endoscopic approach and has not been previously reported.

OBJECTIVE

Our purpose was to evaluate the feasibility of transgastric bilateral inguinal herniorrhaphy (BIH).

DESIGN

Feasibility study with a nonsurvival canine model.

INTERVENTIONS

Under general anesthesia, male mongrel dogs weighing 20 to 30 kg had a dual-channel endoscope introduced into the peritoneal cavity over a percutaneously placed guidewire. An overtube with an insufflation channel was used. Peritoneoscopy was performed, and bilateral deep and superficial inguinal rings were identified. The endoscope was removed, premounted with a 4 x 6 cm acellular human dermal implant and then readvanced intraperitoneally through the overtube. The implant was then deployed across the entire myopectineal orifice and draped over the cord structures. Bioglue was then applied endoscopically, and the implant was attached to the peritoneum. After completion of bilateral repairs, the animals were killed and necropsy performed.

RESULTS

Five dogs underwent pure natural orifice transluminal endoscopic surgery (NOTES) intraperitoneal onlay mesh (IPOM) BIH. Accurate placement and adequate myopectineal coverage was accomplished in all subjects. At necropsy no injuries to the major structures were noted but Bioglue misapplication with contamination of unintended sites did occur.

LIMITATIONS

Our study involved only a small number of subjects in nonsurvival experiments, and no gastric closure was used.

CONCLUSIONS

Many of the characteristics of inguinal hernia repair are especially well suited to the transgastric approach. The repair is in line with the transgastric endoscope vector, bilateral defects are adjacent, and the IPOM technique does not require significant manipulation or novel instrumentation.

Are biologic grafts effective for hernia repair?: a systematic review of the literature

Biologic grafts for hernia repair are a relatively new development in the world of surgery. A thorough search of the Medline database for uses of various biologic grafts in hernia shows that the evidence behind their application is plentiful in some areas (ventral, inguinal) and nearly absent in others (parastomal). The assumption that these materials are only suited for contaminated or potentially contaminated surgical fields is not borne out in the literature, with more than 4 times the experience being reported in clean fields and the average success rates being higher (93% vs 87%). Outcomes prove to be highly dependent on material source, processing methods and implant scenarios with failure rates ranging from zero to more than 30%. Small intestinal submucosa (SIS) grafts have an aggregate failure rate of 6.7% at 19 months whereas acellular human dermis (AHD) grafts have a failure rate of 13.6% at 12 months. Chemically cross-linked grafts have much less published data than the non-cross-linked materials. In particular, the search found 33 articles for SIS, 32 for AHD, and 13 for cross-linked porcine dermis. Furthermore, the cumulative level of evidence for each graft material was fairly low (2.6 to 2.9), and only 1 material (SIS) had level 1 evidence reported in any hernia type (inguinal and hiatal). Together, biologic grafts have published evidence showing success rates better than 90% overall and more than 2000 years of cumulative implant time. Improvements in materials, techniques, and patient selection are likely to improve these numbers as this field of surgery matures.

Prosthetic abdominal wall hernia repair in emergency surgery: from polypropylene to biological meshes

The use of nonabsorbable prosthetic materials such as polypropylene, polyester, and ePTFE, have expanded and are now widely used in reparative surgery for abdominal wall hernias.There are still difficulties to find correct indication for prosthetic implant in emergency hernia surgery: as a matter of fact there is still a great debate if to use non-absorbable prostheses in potentially or truly infected operating fields [e.g. after intestinal resections].All these problems can be avoided with the use of absorbable prosthetic materials such as those composed of lactic acid polymers or lactic and glycolic acid copolymers: however, the use of these absorbable prosthesis exposes the patient to a rapid and inevitable hernia recurrence.It is important to remember that prosthetic repair has been proven to have a significant less risk of recurrence than repair with direct sutures.Recently, new "biologic" prosthetic materials have been developed and proposed for the clinical use in infected fields. These materials can be called "remodeling" for the way by which they are replaced after their placement within the patient. The "remodeling" process is made possible through a process of incorporation, where a reproduction of a site-specific tissue similar to the original host tissue is created.

New "biological" meshes: the need for a register. The EHS Registry for Biological Prostheses: call for participating European surgeons

Non-absorbable prosthetic materials in hernia surgery can cause relatively rare complications, which include chronic pain, a feeling of stiffness with reduced compliance of the abdominal wall, prosthetic erosion/fistulisation and an increased risk of persistent deep infection. Recently, to avoid these problems, new "biological" prosthetic materials have been developed and proposed for clinical use. These materials are all essentially composed of an extracellular matrix stripped of its cellular components, and differ substantially only in their source (porcine small intestine submucosa, porcine dermis or cadaveric human dermis). Because of the numerous variables involved, it is very difficult to conduct a randomised controlled trial. Therefore, the European Hernia Society (EHS) has decided to start the EHS Registry for Biological Prostheses (ERBP). This is a prospective registry in Europe on the use of collagen meshes in (potentially) contaminated circumstances or clean surgical fields. The registry intends to collect some preoperative data on the patient and indication, intraoperative data and outcome data.

Combined Endorectal Advancement Flap with Alloderm® Graft Repair of Radiation and Cryoablation-Induced Rectourethral Fistula

Rectourethral fistula is a potentially devastating disease for the patient and difficult management problem for the physician. We report a case of radiation and salvage cryoablation-induced rectourethral fistula for treatment of prostate cancer successfully repaired with a combined endorectal advancement flap with Alloderm® graft. The surgical technique is described in detail. The patient is now one year post-repair with no evidence of recurrence.

Amyand Hernia: What Lies Beneath–A Proposed Classification Scheme to Determine Management

Acute appendicitis in a hernia sac occurs exceptionally. An 80-year-old male patient underwent emergency surgery for an incarcerated right inguinal hernia found to contain a gangrenous appendix. His brief improvement after an emergency herniotomy with appendectomy was followed by intestinal obstruction caused by advanced colon cancer. The unique features and individualized management of the four published types of Amyand hernia are reviewed. Rather than simply being an anatomical curiosity, Amyand hernias require individualized attention to decide how to manage both the appendix and the hernia. Clinical scrutiny, a high index of suspicion for surgical comorbidities, and a common sense approach may improve outcomes.