Acellular dermal matrices in abdominal wall reconstruction: a systematic review of the current evidence

Improvement in Biocompatibility and Biointegration of Human Acellular Dermal Matrix through Vacuum Plasma Surface Treatment

Efforts are ongoing to enhance the functionality of human acellular dermal matrices (hADMs), which are extensively utilized in reconstructive surgeries. Among these efforts, plasma treatments, particularly vacuum plasma treatments, have recently emerged in the medical field. This study aims to investigate the efficacy of a vacuum plasma treatment in enhancing the biocompatibility and biointegration of hADMs. Utilizing a plasma activator (ACTILINK reborn, Plasmapp Co., Ltd., Daejeon, Republic of Korea), hADMs were treated and evaluated through in vitro and in vivo analyses. Hydrophilicity changes were gauged by the blood absorption times, while SEM imaging was used to analyze physical surface deformation. Protein adsorption was measured with fluorescently labeled bovine serum albumin and fibronectin. For the in vivo study, mice were implanted with plasma-treated and untreated hADMs, and the post-implantation effects were analyzed through histological and immunofluorescence microscopy. The plasma-treated hADMs demonstrated a significantly enhanced hydrophilicity compared to the untreated samples. SEM imaging confirmed the maintenance of the microroughness after the treatment. The treated hADMs showed a significant reduction in fibronectin adsorption, a critical factor for cellular adhesion. In vivo, the plasma-treated hADMs exhibited reduced capsule formation and enhanced fibroblast infiltration, indicating improved biocompatibility and integration. These findings highlight the potential of a plasma treatment to enhance the performance of hADMs in clinical settings, offering a promising avenue for improving reconstructive surgery outcomes.

In Vivo Efficacy of an Injectable Human Acellular Dermal Matrix

BACKGROUND

Human acellular dermal matrix (hADM) has found applications in a variety of settings, particularly in breast surgery. The most common hADM is a sheet. Recently, an injectable hADM has been introduced; we compared the biocompatibility and long-term structural integrity of, an injectable hADM and a sheet-type hADM in mice.

METHODS

An injectable hADM (experimental group) and a sheet-type hADM (control group) were implanted into sub-panniculus pockets on the backs of 50 mice. The animals were sacrificed 2, 4, 8, 12, or 24 weeks later and the hADMs and surrounding tissues were recovered and stained for histopathological analyses. The microscopic endpoints included the thickness of the hADM and capsule around the hADM, and the extents of fibroblast proliferation and neovascularization.

RESULTS

No animal developed a complication or infection. The capsule was significantly thinner in the experimental than the control group. There were no significant differences between groups in the hADM thickness. Microscopically, the fibroblast density inside the hADM was significantly higher in the experimental group. The fibroblasts inside of the hADM lay significantly deeper in the experimental group. Similarly, the experimental group exhibited significantly deeper microvessels inside the hADM.

CONCLUSIONS

The injectable hADM had a thinner capsule thickness (more biocompatible), than the sheet-type hADM. It maintained its thickness as well as the sheet-type hADM and had a more fibroblast proliferation and neovascularization. This means the tissue incorporation and long-term structural integrity of the injectable hADM may be as good as or better than that of the sheet-type hADM.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The increased angiogenic capacity and decreased inflammatory response when a mesh is used in combination with an omental flap. A prospective experimental study

BACKGROUND

The use of a surgical mesh for abdominal wall reconstruction is well established and has been used for long with minor complications, whereas the omental flap has been used for decades in reconstructive surgery.

AIM

To demonstrate the increased angiogenic capacity and the reduced inflammatory markers of a synthetic mesh when used in combination with an omental flap. Furthermore, we compare two independent meshes when used alone or in combination with the omental flap.

MATERIALS AND METHODS

Twenty-eight rats were included in the study. To determine the effect of using an omental flap under two different meshes, the animals were separated into four groups, i.e., group A (flap + mesh 1), group B (flap + mesh 1 + silicone), group C (flap + mesh 2), and group D (flap + mesh 2 + silicone). A silicone sheet was placed as a barrier between the mesh and the flap. All groups were sacrificed 8 weeks post-operatively.

RESULTS

The use of a silicone sheet barrier between any of the two synthetic meshes and the omental flap in an abdominal wall defect is accompanied by a markedly reduced angiogenesis in terms of a cluster of differentiation (CD)-34 (p < 0.001) and factor VIII (p = 0.0012) and by increased inflammatory response CD-68 (p = 0.0024) and visual scoring (p < 0.001).

CONCLUSIONS

Τhe increased angiogenic capacity and the reduced inflammatory markers of a synthetic surgical mesh when used in combination with an omental flap make it a useful option in the reconstruction of an abdominal wall defect on a large or contaminated wound.

Acellular dermal matrix in reconstructive surgery: Applications, benefits, and cost

Modern tissue engineering has made substantial advancements that have revolutionized plastic surgery. Acellular dermal matrix (ADM) is an example that has gained considerable attention recently. ADM can be made from humans, bovines, or porcine tissues. ADM acts as a scaffold that incorporates into the recipient tissue. It is gradually infiltrated by fibroblasts and vascularized. Fortunately, many techniques have been used to remove cellular and antigenic components from ADM to minimize immune system rejection. ADM is made of collagen, fibronectin, elastin, laminin, glycosaminoglycans, and hyaluronic acid. It is used in critical wounds (e.g., diabetic wounds) to protect soft tissue and accelerate wound healing. It is also used in implant-based breast reconstruction surgery to improve aesthetic outcomes and reduce capsule contracture risk. ADM has also gained attention in abdominal and chest wall defects. Some studies have shown that ADM is associated with less erosion and infection in abdominal hernias than synthetic meshes. However, its higher cost prevents it from being commonly used in hernia repair. Also, using ADM in tendon repair (e.g., Achilles tendon) has been associated with increased stability and reduced rejection rate. Despite its advantages, ADM might result in complications such as hematoma, seroma, necrosis, and infection. Moreover, ADM is expensive, making it an unsuitable option for many patients. Finally, the literature on ADM is insufficient, and more research on the results of ADM usage in surgeries is needed. This article aims to review the literature regarding the application, Benefits, and costs of ADM in reconstructive surgery.

Engineered nanovesicles from stromal vascular fraction promote angiogenesis and adipogenesis inside decellularized adipose tissue through encapsulating growth factors

Acellular matrix is a commonly used biomaterial in the field of biomedical engineering and revascularization is the key process to affect the effect of acellular matrix on tissue regeneration. The application of bioactive factors related to angiogenesis has been popular in the regulation of revascularization, but the immune system clearance, uncontrollable systemic reactions, and other factors make this method face challenges. Recent reports showed that engineered cells into nanovesicles can reorganize cell membranes and encapsulate cellular active factors, extending the in vitro preservation of cytokines. However, the problems of exogenous biological contamination and tumorigenicity restricted the clinical transformation and wide application of this method. Here, we for the first time engineer stromal vascular fraction (SVF) which is extracted from fat into nanovesicles (SVF-EVs) for angiogenesis in the acellular matrix. SVF-EVs not only promote the migration of vascular endothelial cells in vitro, but also facilitate the lipogenic differentiation of mesenchymal stem cells. In vivo, SVF-EVs enhanced the retention of decellularized adipose tissue after transplanting to the subcutaneous area of nude mice. Immunofluorescence staining further showed that SVF-EVs promoted the formation of vascular networks with large lumen diameter in the grafted acellular matrix, accompanied by adipocyte regeneration peripherally. These findings reveal that SVF-EVs can be a viable method for accelerating revascularization in acellular matrix, and this process of squeezing tissue into nanovesicles shows the potential for rapid clinical transformation.

A Comparative Study on Two Types of Porcine Acellular Dermal Matrix Sponges Prepared by Thermal Crosslinking and Thermal-Glutaraldehyde Crosslinking Matrix Microparticles

Common commercial porcine acellular dermal matrix (PADM) products take the form of a thin membrane. Given its dense structure, delaying vascularization after implantation remains an issue to be solved. In addition, overlaying multiple sheets to address deep wounds and large tissue defects that are difficult to repair by self-tissues could hinder tissue ingrowth, angiogenesis, and integration. Here, we creatively prepared PADM microparticles through a homogenizing treatment and crosslinked them to ADM sponges by thermal crosslinking (VT-ADM) and thermal-glutaraldehyde crosslinking (GA-ADM). The resulting VT-ADM was thicker than GA-ADM, and both maintained the natural dermal matrix microstructure and thermal stability. The porosity of GA-ADM (mean 82%) was lower than that of VT-ADM (mean 90.2%), but the mechanical strength and hydrophilicity were significantly higher. The two types of ADM sponges showed no obvious difference in cell adhesion and proliferation without cytotoxicity. Furthermore, the human adipose stem cells were co-cultured with ADM sponges which promoted proliferation, tube formation, and migration of endothelial cells, and the GA-ADM group exhibited better migration behavior. There were no markable differences among expressions of pro-angiogenesis genes, including vascular endothelial growth factor, insulin-like growth factor-1, and epidermal growth factor. In a nude mouse model, the VT-ADM and GA-ADM pre-cultured with human adipose stem cells for 1 week in advance were implanted subcutaneously. The VT-ADM and the GA-ADM showed great histocompatibility without local redness, swelling, or necrosis. The vascular density of the local skin flap above the material was visualized using indocyanine green and showed no statistical difference between the two groups. The collagen tissue deposition in the pores and vessel formation within the sponges increased with time. Although VT-ADM had a higher degradation rate in vivo, the integrity of the two scaffolds was preserved. Collectively, the VT-ADM and the GA-ADM retained a natural matrix structure and presented biocompatibility. Thus, the above-mentioned two crosslinking methods for ADM sponges are safe and practicable. The novel ADM sponges with good physicochemical and biological properties are no longer limited to membrane tissue regeneration but could also realize structure remodeling where they act as scaffolds for a soft tissue filler and three-dimensional reconstruction of the tissue with strength requirements.

Reoperation Through a Prosthetic-Reinforced Abdominal Wall and Its Association With Postoperative Outcomes and Longitudinal Health Care Utilization

Importance

Prosthetic reinforcement of critically sized incisional hernias is necessary to decrease hernia recurrence, but long-term prosthetic-mesh footprint may increase complication risk during subsequent abdominal operations.

Objective

To investigate the association of prior incisional hernia repair with mesh (IHRWM) with postoperative outcomes and health care utilization after common abdominal operations.

Design, Setting, and Participants

This was a population-based, retrospective cohort study of patients undergoing inpatient abdominal surgical procedures during the period of January 2009 to December 2016, with at least 1 year of follow-up within 5 geographically diverse statewide inpatient/ambulatory databases (Florida, Iowa, Nebraska, New York, Utah). History of an abdominal operation was ascertained within the 3-year period preceding the index operation. Patients admitted to the hospital with a history of an abdominal operation (ie, bariatric, cholecystectomy, small- or large-bowel resection, prostatectomy, gynecologic) were identified using the International Classification of Diseases, Ninth Revision and Tenth Revision, Clinical Modification procedure codes. Patients with prior IHRWM were propensity score matched (1:1) to controls both with and without a history of an abdominal surgical procedure based on clinical and operative characteristics. Data analysis was conducted from March 1 to November 27, 2021.

Main Outcomes and Measures

The primary outcome was a composite of adverse postoperative outcomes (surgical and nonsurgical). Secondary outcomes included health care utilization determined by length of hospital stay, hospital charges, and 1-year readmissions. Logistic and Cox regression determined the association of prior IHRWM with the outcomes of interest. Additional subanalyses matched and compared patients with prior IHR without mesh (IHRWOM) to those with a history of an abdominal operation.

Results

Of the 914 105 patients undergoing common abdominal surgical procedures (81 123 bariatric [8.9%], 284 450 small- or large-bowel resection [31.1%], 223 768 cholecystectomy [24.5%], 33 183 prostatectomy [3.6%], and 291 581 gynecologic [31.9%]), all 3517 patients (age group: 46-55 years, 1547 [44.0%]; 2396 majority sex [68.1%]) with prior IHRWM were matched to patients without a history of abdominal surgical procedures. After matching, prior IHRWM was associated with increased overall complications (odds ratio [OR], 1.43; 95% CI, 1.27-1.60), surgical complications (OR, 1.51; 95% CI, 1.34-1.70), length of hospital stay (mean increase of 1.03 days; 95% CI, 0.56-1.49 days; P < .001), index admission charges (predicted mean difference of $11 896.10; 95% CI, $6096.80-$17 695.40; P < .001), and 1-year unplanned readmissions (hazard ratio, 1.14; 95% CI, 1.05-1.25; P = .002). This trend persisted even when comparing matched patients with prior IHRWM to patients with a history of abdominal surgical procedures, and the treatment outcome disappeared when comparing patients with prior IHRWOM to those without a previous abdominal operation.

Conclusions and Relevance

Reoperation through a previously prosthetic-reinforced abdominal wall was associated with increased surgical complications and health care utilization. This risk appeared to be independent of a history of abdominal surgical procedures and was magnified by the presence of a prosthetic-mesh footprint in the abdominal wall.

Clinical applications of acellular dermal matrices: A review

INTRODUCTION

The extracellular matrix (ECM) plays an integral role in wound healing. It provides both structure and growth factors that allow for the organised cell proliferation. Large or complex tissue defects may compromise host ECM, creating an environment that is unfavourable for the recovery of anatomical function and appearance. Acellular dermal matrices (ADMs) have been developed from a variety of sources, including human (HADM), porcine (PADM) and bovine (BADM), with multiple different processing protocols. The objective of this report is to provide an overview of current literature assessing the clinical utility of ADMs across a broad spectrum of applications.

METHODS

PubMed, MEDLINE, EMBASE, Scopus, Cochrane and Web of Science were searched using keywords 'acellular dermal matrix', 'acellular dermal matrices' and brand names for commercially available ADMs. Our search was limited to English language articles published from 1999 to 2020 and focused on clinical data.

RESULTS

A total of 2443 records underwent screening. After removing non-clinical studies and correspondence, 222 were assessed for eligibility. Of these, 170 were included in our synthesis of the literature. While the earliest ADMs were used in severe burn injuries, usage has expanded to a number of surgical subspecialties and procedures, including orthopaedic surgery (e.g. tendon and ligament reconstructions), otolaryngology, oral surgery (e.g. treating gingival recession), abdominal wall surgery (e.g. hernia repair), plastic surgery (e.g. breast reconstruction and penile augmentation), and chronic wounds (e.g. diabetic ulcers).

CONCLUSION

Our understanding of ADM's clinical utility continues to evolve. More research is needed to determine which ADM has the best outcomes for each clinical scenario.

LAY SUMMARY

Large or complex wounds present unique reconstructive and healing challenges. In normal healing, the extracellular matrix (ECM) provides both structural and growth factors that allow tissue to regenerate in an organised fashion to close the wound. In difficult or large soft-tissue defects, however, the ECM is often compromised. Acellular dermal matrix (ADM) products have been developed to mimic the benefits of host ECM, allowing for improved outcomes in a variety of clinical scenarios. This review summarises the current clinical evidence regarding commercially available ADMs in a wide variety of clinical contexts.

Prosthetic meshes for hernia repair: State of art, classification, biomaterials, antimicrobial approaches, and fabrication methods

Worldwide, hernia repair represents one of the most frequent surgical procedures encompassing a global market valued at several billion dollars. This type of surgery usually requires the implantation of a mesh that needs the appropriate chemical, physical and biological properties for the type of repair. This review thus presents a description of the types of hernias, current hernia repair methods, and the state of the art of prosthetic meshes for hernia repair providing the most important meshes used in clinical practice by surgeons working in this area classified according to their biological or chemical nature, morphology and whether bioabsorbable or not. We emphasise the importance of surgical site infection in herniatology, how to deal with this microbial problem, and we go further into the future research lines on the production of advanced antimicrobial meshes to improve hernia repair and prevent microbial infections, including multidrug-resistant strains. A great deal of progress has been made in this biomedical field in the last decade. However, we are still far from an ideal antimicrobial mesh that can also provide excellent integration to the abdominal wall, mechanical performance, low visceral adhesion and minimal inflammatory or foreign body reactions, among many other problems.

Early Clinical and Patient-Reported Outcomes of a New Hybrid Mesh for Incisional Hernia Repair

INTRODUCTION

Consensus on the safety and efficacy of various types of mesh in reconstructing the abdomen has yet to be reached. Hybrid mesh products have been designed to address the need for a cost-effective mesh leveraging the tensile strength of a synthetic mesh while minimizing the prosthetic footprint within the abdominal wall through resorbable materials. In this study we evaluate early clinical outcomes and health related quality of life (HR-QOL) of a new Hybrid mesh, Synecor^TM, for Ventral Hernia Repair (VHR).

METHODS

Adult (>18 y old) patients undergoing VHR with Synecor^TM mesh by a single surgeon between 2017-2019 with ≥1-y follow-up were identified. We analyzed a composite of postoperative outcomes as well as the incidence of hernia recurrence, readmissions, mortality, and HR-QOL.

RESULTS

Thirty-five patients were included in our analysis with a median follow up of 2.1 y. The median age and BMI were 54.1 y and 33.2 kg/m², respectively. The rate of surgical site occurrences was 37.1%, with only one patient (2.9%) requiring surgical intervention. No patients developed a hernia recurrence. Overall HR-QOL improved significantly (preoperative mean 2.5 [SD 0.7] versus postoperative 3.4 [0.4]; P< 0.01), particularly in regards to pain, functional status, self-esteem and body image (all P < 0.05).

CONCLUSIONS

Abdominal reinforcement with Synecor^TM mesh at the time of VHR results in promising early recurrence rates, an acceptable safety risk profile, and an improvement in overall HR-QOL.

Application of acellular dermal matrix to reconstruct the defects after hypopharyngeal carcinoma resection

PURPOSE

Reconstruction of the defects and recovery of the laryngopharyngeal function after resection of hypopharyngeal carcinoma are crucial for patients to promote the rate of survival and the quality of life. We launched this study to explore the advantages and limitations of acellular dermal matrix applied in the reconstruction of the defects after hypopharyngeal carcinoma surgery.

MATERIALS AND METHODS

Collected the clinical and pathological data of patients with hypopharyngeal carcinoma, divided them into 2 groups according to the repair materials used (pectoralis major myocutaneous flap or acellular dermal matrix). The clinical data and postoperative complications were analyzed and compared.

RESULTS

No matter whether the pectoralis major myocutaneous flap or acellular dermal matrix was used to repair hypopharyngeal cancer resection defects, the postoperative complications, especially the pharyngeal fistula rate, were not significantly different. The postoperative drainage volume of patients with acellular dermal matrix was less than that of patients with pectoralis major myocutaneous flap.

CONCLUSIONS

Acellular dermal matrix is a safe and effective biomedical material for hypopharyngeal cancer operation defects repair and pharyngeal function reconstruction, which can simplify the operation process, reduce the postoperative drainage volume, and decrease the risk of wound infection or pharyngeal fistula.

Biologic Mesh in Surgery: A Comprehensive Review and Meta-Analysis of Selected Outcomes in 51 Studies and 6079 Patients

BACKGROUND

In recent decades, biologic mesh (BM) has become an important adjunct to surgical practice. Recent evidence-based clinical applications of BM include but are not limited to: reconstruction of abdominal wall defects; breast reconstruction; face, head and neck surgery; periodontal surgery; other hernia repairs (diaphragmatic, hiatal/paraesophageal, inguinal and perineal); hand surgery; and shoulder arthroplasty. Prior systematic reviews of BM in complex abdominal wall hernia repair had several shortcomings that our comprehensive review seeks to address, including exclusion of laparoscopic repair, assessment of risk of bias, use of an acceptable meta-analytic method and review of risk factors identified in multivariable regression analyses.

MATERIALS AND METHODS

We sought articles of BM for open ventral hernia repair reporting on early complications, late complications or recurrences and included minimum of 50. We used the quality in prognostic studies risk of bias assessment tool. Random effects meta-analysis was applied.

RESULTS

This comprehensive review selected 62 articles from 51 studies that included 6,079 patients. Meta-analytic pooling found that early complications are present in about 50%, surgical site occurrences (SSOs) in 37%, surgical site infections (SSIs) in 18%, reoperation in 7%, readmission in 20% and mortality in 3%. Meta-analytic estimates of late outcomes included overall complications (42%), SSOs (40%) and SSIs (22%). Specific SSOs included seroma (14%), hematoma (4%), abscess (10%), necrosis (5%), dehiscence (8%) and fistula formation (5%). Reoperation occurred in about 17%, mesh explantation in 9% and recurrence in 36%.

CONCLUSION

Estimates of nearly all outcomes from individual studies were highly heterogeneous and sensitivity analyses and meta-regressions generally failed to explain this heterogeneity. Recurrence is the only outcome for which there are consistent findings for risk factors. Bridge placement of BM is associated with higher risk of recurrence. Prior hernia repair, history of reintervention and history of mesh removal were also risk factors for increased recurrence.

Addition of platelet-rich plasma supports immune modulation and improved mechanical integrity in Alloderm mesh for ventral hernia repair in a rat model

The recurrence of ventral hernias continues to be a problem faced by surgeons, in spite of efforts toward implementing novel repair techniques and utilizing different materials to promote healing. Cadaveric acellular dermal matrices (Alloderm) have shown some promise in numerous surgical subspecialties, but these meshes still suffer from subsequent failure and necessitation of re-intervention. Here, it is demonstrated that the addition of platelet rich plasma to Alloderm meshes temporally modulates both the innate and cytotoxic inflammatory responses to the implanted material. This results in decreased inflammatory cytokine production at early time points, decreased matrix metalloproteinase expression, and decreased CD8+ T cell infiltration. Collectively, these immune effects result in a healing phenotype that is free from mesh thinning and characterized by increased material stiffness.

Acellular Dermal Matrices: Applications in Plastic Surgery

Modern advances in tissue engineering have transformed the plastic surgeon's management strategies across a wide variety of applications. Comprehension of the fundamentals of biologic constructs is critical to navigating the available armamentarium. It is essential that plastic surgeons become familiar with some of the existing methods for utilizing biologics as well as the advantages and limitations to their use. In this article, the authors describe the basic science of biologics with a focus on acellular dermal matrices (ADMs), and review the recent evidence behind their use for a variety of reconstructive and aesthetic purposes. The review is organized by system and examines the common indications, techniques, and outcomes pertaining to the application of ADMs in select anatomic areas. The final section briefly considers possible future directions for using biologics in plastic and reconstructive surgery.

What Exactly is Meant by "Loss of Domain" for Ventral Hernia? Systematic Review of Definitions

Large ventral hernias are a significant surgical challenge. "Loss of domain" (LOD) expresses the relationship between hernia and abdominal volume, and is used to predict operative difficulty and success. This systematic review assessed whether different definitions of LOD are used in the literature. The PubMed database was searched for articles reporting large hernia repairs that explicitly described LOD. Two reviewers screened citations and extracted data from selected articles, focusing on the definitions used for LOD, study demographics, study design, and reporting surgical specialty. One hundred and seven articles were identified, 93 full-texts examined, and 77 were included in the systematic review. Sixty-seven articles were from the primary literature, and 10 articles were from the secondary literature. Twenty-eight articles (36%) gave a written definition for loss of domain. These varied and divided into six broad groupings; four described the loss of the right of domain, six described abdominal strap muscle contraction, five described the "second abdomen", five describing large irreducible hernias. Six gave miscellaneous definitions. Two articles gave multiple definitions. Twenty articles (26%) gave volumetric definitions; eight used the Tanaka method [hernia sac volume (HSV)/abdominal cavity volume] and five used the Sabbagh method [(HSV)/total peritoneal volume]. The definitions used for loss of domain were not dependent on the reporting specialty. Our systematic review revealed that multiple definitions of loss of domain are being used. These vary and are not interchangeable. Expert consensus on this matter is necessary to standardise this important concept for hernia surgeons.

A Current Review of Long-Acting Resorbable Meshes in Abdominal Wall Reconstruction

Concern for chronic infection of a permanent synthetic material in contaminated and "high risk" ventral hernia repairs has led to the development and dissemination of slowly resorbable biosynthetic materials at a lower cost compared with biologic mesh counterparts. Here, we review the preclinical and clinical data available for each long-acting resorbable mesh, with a candid comparison to biologic and synthetic equivalents.

"Complex abdominal wall" management: evidence-based guidelines of the Italian Consensus Conference

To date, there is no shared consensus on a definition of a complex abdominal wall in elective surgery and in the emergency, on indications, technical details, complications, and follow-up. The purpose of the conference was to lay the foundations for a homogeneous approach to the complex abdominal wall with the primary intent being to attain the following objectives: (1) to develop evidence-based recommendations to define “complex abdominal wall”; (2) indications in emergency and in elective cases; (3) management of “complex abdominal wall”; (4) techniques for temporary abdominal closure. The decompressive laparostomy should be considered in a case of abdominal compartment syndrome in patients with critical conditions or after the failure of a medical treatment or less invasive methods. In the second one, beyond different mechanism, patients with surgical emergency diseases might reach the same pathophysiological end point of trauma patients where a preventive “open abdomen” might be indicated (a temporary abdominal closure: in the case of a non-infected field, the Wittmann patch and the NPWT had the best outcome followed by meshes; in the case of an infected field, NPWT techniques seem to be the preferred). The second priority is to create optimal both general as local conditions for healing: the right antimicrobial management, feeding—preferably by the enteral route—and managing correctly the open abdomen wall. The use of a mesh appears to be—if and when possible—the gold standard. There is a lot of enthusiasm about biological meshes. But the actual evidence supports their use only in contaminated or potentially contaminated fields but above all, to reduce the higher rate of recurrences, the wall anatomy and function should be restored in the midline, with or without component separation technique. On the other site has not to be neglected that the use of monofilament and macroporous non-absorbable meshes, in extraperitoneal position, in the setting of the complex abdomen with contamination, seems to have a cost effective role too. The idea of this consensus conference was mainly to try to bring order in the so copious, but not always so “evident” literature utilizing and exchanging the expertise of different specialists.

Quality measures in ventral hernia repair: a systematic review

BACKGROUND

The US healthcare system is shifting towards reimbursement for quality over quantity of care. Quality measures are tied to financial incentives in these healthcare models. It is important that surgeons become familiar with quality measures addressing ventral hernia repair and understand candidate measures that may drive future quality measure development.

STUDY DESIGN

We performed a systematic review of society websites, quality measure databases, and the literature (Pubmed, Embase/Scopus, and Google Scholar) for quality measures addressing ventral hernia surgery. Clinical practice guidelines were included as candidate quality measures. All measures were categorized as structure, process or outcome according to Donabedian domains, as well as within the six National Quality Strategy (NQS) domains.

RESULTS

Thirty quality measures and candidate measures were identified. Eight candidate measures from the American Hernia Society addressed ventral hernia repair, and 22 quality measures in general surgery were also relevant to ventral hernia repair. Of the candidate measures, 6 (75%) were outcome and 2 (25%) were process measures. Of existing general surgery quality measures, 9 (41%) were outcome and 13 (59%) were process measures. No structural measures were identified. Overall, the majority of measures addressed NQS priorities of effective clinical care (33%) and patient safety (27%), while few addressed other domains.

CONCLUSION

Both the Donabedian domains of quality and NQS priorities were unequally represented in the current measures addressing ventral hernia repair. Recognizing and addressing the under-represented areas will provide a more balanced framework for developing quality measures and ensure that ventral hernia surgery is appropriately evaluated in value-based payment models.

Gelfoam Interposition Minimizes Risk of Fistula and Postoperative Bleeding in Modified-Furlow Palatoplasty

Failure to accomplish a tension-free, watertight closure predisposes the palatoplasty patient to fistula formation. Perioperative bleeding also places the patient at risk for adverse airway events (AAE). This study introduces the incorporation of a hemostatic gelatin sponge (Gelfoam) into layered palatoplasty to minimize adverse postoperative bleeding and fistula formation. A retrospective chart review was performed to identify subjects who underwent Furlow palatoplasty with insertion of Gelfoam from 2010 to 2015. Exclusion criteria include age >3 years, prior palate surgery, <30-day follow-up, immunosuppressive state, and diagnosis of Treacher-Collins or Apert Syndrome. Demographic data include age, sex, cleft laterality, prior surgeries, Veau classification, Pierre Robin status, and tracheostomy dependence. Primary outcome was fistula formation. Secondary outcomes included perioperative metrics and AAE.One hundred subjects met criteria, 45% female. Average age was 14.6 months. Subjects with syndromes comprised 28%, with 16% diagnosed with Pierre Robin. Two subjects were tracheostomy-dependent. Prior cleft and mandibular procedures were performed in 55%. Isolated palatal defects were seen in 46%, unilateral lip and palate in 41%, and bilateral lip and palate in 13%. The majority of defects were Veau II and III (35% and 34%, respectively). Adverse airway events occurred in 2%, one of which resulted in reintubation. One subject (1%) was found to have a postoperative fistula.The incorporation of Gelfoam in the modified-Furlow palatoplasty results in a low rate of oronasal fistula (1%) and low perioperative risk of AAE. Further prospective comparison of this method to others will be the focus of future work.

Predictors of complications after direct-to-implant breast reconstruction with an acellular dermal matrix from a multicentre randomized clinical trial

BACKGROUND

In the multicentre randomized trial BRIOS (Breast Reconstruction In One Stage), direct-to-implant (DTI) breast reconstruction with an acellular dermal matrix (ADM) was associated with a markedly higher postoperative complication rate compared with two-stage tissue expander/implant breast reconstruction. This study aimed to identify factors that contribute to the occurrence of complications after DTI ADM-assisted breast reconstruction.

METHODS

Data were obtained from the BRIOS study, including all patients treated with DTI ADM-assisted breast reconstruction. Logistic regression analyses were performed to identify factors predictive of postoperative complications.

RESULTS

Fifty-nine patients (91 breasts) were included, of whom 27 (35 breasts) developed a surgical complication. Reoperations were performed in 29 breasts (32 per cent), with prosthesis removal in 22 (24 per cent). In multivariable analyses, mastectomy weight was associated with complications (odds ratio (OR) 1·94, 95 per cent c.i. 1·33 to 2·83), reoperations (OR 1·70, 1·12 to 2·59) and removal of the implant (OR 1·55, 1·11 to 2·17). Younger patients (OR 1·07, 1·01 to 1·13) and those who received adjuvant chemotherapy (OR 4·83, 1·15 to 20·24) more frequently required reoperation. In univariable analyses, adjuvant radiotherapy showed a trend towards more complications (OR 7·23, 0·75 to 69·95) and removal of the implant (OR 5·12, 0·76 to 34·44), without reaching statistical significance.

CONCLUSION

Breast size appeared to be the most significant predictor of complications in DTI ADM-assisted breast reconstruction. The technique should preferably be performed in patients with small to moderate sized breasts. Registration number: NTR5446 ( http://www.trialregister.nl).

Cross-Linked Cholecyst-Derived Extracellular Matrix for Abdominal Wall Repair

Abdominal wall repair frequently utilizes either nondegradable or biodegradable meshes, which are found to stimulate undesirable biological tissue responses or which possess suboptimal degradation rate. In this study, a biologic mesh prototype made from carbodiimide cross-linked cholecyst-derived extracellular matrix (EDCxCEM) was compared with small intestinal submucosa (Surgisis^®), cross-linked bovine pericardium (Peri-Guard^®), and polypropylene (Prolene^®) meshes in an in vivo rabbit model. The macroscopic appearance and stereological parameters of the meshes were evaluated. Tailoring the degradation of the EDCxCEM mesh prevents untimely degradation, while allowing cellular infiltration and mesh remodeling to take place in a slower but predictable manner. The results suggest that the cross-linked biodegradable cholecyst-derived biologic mesh results in no seroma formation, low adhesion, and moderate stretching of the mesh. In contrast to Surgisis, Peri-Guard, and Prolene meshes, the EDCxCEM mesh showed a statistically significant increase in the volume fraction (V_v) of collagen (from 34% to 52.1%) in the central fibrous tissue region at both day 28 and 56. The statistically high length density (L_v), of blood vessels for the EDCxCEM mesh at 28 days was reflected also by the higher cellular activity (high V_v of fibroblast and moderate V_v of nuclei) indicating remodeling of this region in the vicinity of a slowly degrading EDCxCEM mesh. The lack of mesh area stretching/shrinkage in the EDCxCEM mesh showed that the remodeled tissue was adequate to prevent hernia formation. The stereo-histological assays suggest that the EDCxCEM delayed degradation profile supports host wound healing processes including collagen formation, cellular infiltration, and angiogenesis. The use of cross-linked CEM for abdominal wall repair is promising.

Multipoint Suture Fixation Technique for Abdominal Wall Reconstruction with Component Separation and Onlay Biological Mesh Placement

Component separation with mesh reinforcement has become the primary modality for complex abdominal wall reconstruction. However, many fundamental questions remain unanswered, such as whether underlay versus overlay mesh placement is superior, and what is the best means of suture fixation technique for mesh placement? This study presents the senior author's technique for onlay biologic mesh placement with multipoint suture fixation in combination with component separation and its subsequent low recurrence rates. This is a retrospective review of the senior author's cases of component separation with onlay biologic mesh placement during his tenure at the home institution of the University of Alabama at Birmingham. A total of 75 patients were included, all of whom underwent complex abdominal wall reconstruction from September 2002 to April 2012. Patients were excluded from the dataset if their surgery occurred less than two years before date of data collection to give a minimum 2-year follow-up. Patients were identified by Current Procedural Terminology codes for component separation and their charts reviewed by the home institution's electronic medical record. Data point entries included patient demographics and comorbidities, concomitant procedures such as bowel resection or panniculectomy, and characteristics of the reconstruction such as type of mesh used. Primary data endpoints were complications following surgery, particularly recurrence and laxity. A total of 75 patients were included in the study from September 2002 to April 2012 with a minimum 2-year follow-up period. The recurrence rate was 13 per cent and the rate of laxity 2.7 per cent. There was one death (1.35%). The most frequent complication was seromas at a rate of 17 per cent. Multipoint fixation suture technique for abdominal wall reconstruction with component separation and onlay biologic mesh is a reproducible technique with reliably low recurrence rates.

Non-crosslinked porcine acellular dermal matrix in pediatric abdominal wall reconstruction: a case series

INTRODUCTION

The use of biologic mesh where native tissue deficiencies limit reconstructive options has been well documented in the adult population, with increasing use to address the special requirements of complex abdominal wall reconstruction. There is, however, little documented evidence as to the safety and efficacy of these products in the pediatric population.

METHODS

This retrospective case series details 5 pediatric cases of complicated abdominal hernia repair with Strattice®, a non-crosslinked porcine acellular dermal matrix. Outcomes measured include recurrence, infection, seroma formation, symptomatic bulging, and need for mesh removal. Defect size, mesh size, and history of prior abdominal operations and infection were also recorded.

RESULTS

Patients received Strattice® with an average area of 132.2 (24-250)cm² and primary closure was achieved over a mesh underlay in three (60%) patients, while the remaining required a bridging approach secondary to lateral defects. Complications included suture extrusion, requiring suture removal, hernia recurrence without bulge, noted incidentally, and seroma formation, requiring placement of drains.

DISCUSSION/CONCLUSIONS

In conclusion, the use of porcine ADM in pediatric patients appears to be potentially safe and efficacious in the context of complex abdominal wall defects, including those with substantial contamination. Our small series builds on previous reports in this difficult patient population. Although additional study, with larger subject pools, would assist in solidifying the observations seen in this and other series, initial findings suggest that porcine ADM is a valuable tool in the treatment of these complex patients.

LEVEL OF EVIDENCE

Case series: Treatment study, Level IV.

Abdominal Wall Allograft: Preclinical Biomechanical Investigation of a Novel Reconstructive Adjunct

INTRODUCTION

Acellular dermal matrices have revolutionized abdominal wall reconstruction; however, device failure and hernia recurrence remain significant problems. Fascia grafts are a reconstructive adjunct with increased tensile strength compared with acellular dermal matrices; however, clinical use is limited by insufficient donor material and donor site morbidity. To this end, we investigate the biomechanical properties of human abdominal wall allografts (AWAs) consisting of the anterior rectus sheath from xiphoid to pubis.

METHODS

After cadaveric procurement of 6 human AWAs, the tissue was divided horizontally and a matched-sample study was performed with specimens randomized to 2 groups: fresh, unprocessed versus processed with gamma irradiation and decellularization. Specimens were evaluated for physical properties, DNA content, tensile strength, and electron microscopy.

RESULTS

All AWA donors were male, with a mean age of 55.2 years (range, 35-74 years). Procured AWAs had a mean length of 21.70 ± 1.8 cm, width of 14.30 ± 1.32 cm, and area of 318.50 cm, and processing resulted in a 98.3% reduction in DNA content. Ultimate tensile strength was significantly increased after tissue processing, and after subcutaneous implantation, processed AWA demonstrated 4-fold increased tensile strength compared with unprocessed AWAs.

CONCLUSIONS

Acellular AWAs represent a novel reconstructive adjunct for abdominal wall reconstruction with the potential of replacing "like with like" without additional donor site morbidity or antigenicity.

Characterization of an Acellular Scaffold for a Tissue Engineering Approach to the Nipple-Areolar Complex Reconstruction

A significant number of patients undergo mastectomies and breast reconstructions every year using many surgical-based techniques to reconstruct the nipple-areolar complex (NAC). Described herein is a tissue engineering approach that may permit a human NAC onlay graft during breast reconstruction procedures. By applying decellularization, which is the removal of cellular components from tissue, to an intact whole donor NAC, the extracellular matrix (ECM) structure of the NAC is preserved. This creates a biologically derived scaffold for cells to repopulate and regenerate the NAC. A detergent-based decellularization method was used to derive whole NAC scaffolds from nonhuman primate rhesus macaque NAC tissue. Using both histological and quantitative analyses for the native and decellularized tissues, the derived ECM graft was assessed. The bioactivity of the scaffold was evaluated following cell culture with bone marrow-derived mesenchymal stem cells (BMSCs). The data presented here demonstrate that scaffolds are devoid of cells and retain ECM integrity and a high degree of bioactivity. The content of collagen and glycosaminoglycans were not significantly altered by the decellularization process, whereas the elastin content was significantly decreased. The proliferation and apoptosis of seeded BMSCs were found to be approximately 65 and <1.5%, respectively. This study characterizes the successful decellularization of NAC tissue as compared to native NACs based on structural protein composition, lubricating protein retention, the maintenance of adhesion molecules, and bioactivity when reseeded with cells. These histological and quantitative analyses provide the foundation for a novel approach to NAC reconstruction.

Long-Term Outcomes after Abdominal Wall Reconstruction with Acellular Dermal Matrix

BACKGROUND

Long-term outcomes data for hernia recurrence rates after abdominal wall reconstruction (AWR) with acellular dermal matrix (ADM) are lacking. The aim of this study was to assess the long-term durability of AWR using ADM.

STUDY DESIGN

We studied patients who underwent AWR with ADM at a single center in 2005 to 2015 with a minimum follow-up of 36 months. Hernia recurrence was the primary end point and surgical site occurrence (SSO) was a secondary end point. The recurrence-free survival curves were estimated by Kaplan-Meier product limit method. Univariate and multivariable Cox proportional hazards regression models and logistic regression models were used to evaluate the associations of risk factors at surgery with subsequent risks for hernia recurrence and SSO, respectively.

RESULTS

A total of 512 patients underwent AWR with ADM. After excluding those with follow-up less than 36 months, 191 patients were included, with a median follow-up of 52.9 months (range 36 to 104 months). Twenty-six of 191 patients had a hernia recurrence documented in the study. The cumulative recurrence rates were 11.5% at 3 years and 14.6% by 5 years. Factors significantly predictive of hernia recurrence developing included bridged repair, wound skin dehiscence, use of human cadaveric ADM, and coronary disease; component separation was protective. In a subset analysis excluding bridged repairs and human cadaveric ADM patients, cumulative hernia recurrence rates were 6.4% by 3 years and 8.3% by 5 years. The crude rate of SSO was 25.1% (48 of 191). Factors significantly predictive of the incidence of SSO included at least 1 comorbidity, BMI ≥30 kg/m², and defect width >15 cm.

CONCLUSIONS

Use of ADM for AWR was associated with 11.5% and 14.6% hernia recurrence rates at 3- and 5-years follow-up, respectively. Avoiding bridged repairs and human cadaveric ADM can improve long-term AWR outcomes using ADM.

Incarcerated and eventrated abdominal wall hernia reconstruction with autologous double-layer dermal graft in the field of purulent peritonitis-A case report

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This is the first applied autologous dermal graft for eventrated hernia in an emergency case.

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Terminal ileum and ascending colon were perforated into the hernia sac causing dirty operating field.

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It was impossible to close the 223 cm² gap with sutures, biological mesh was not available.

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Specially prepared grafts were applied to reconstruct the gap in a double- layer tension free fashion.

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No hernia recurrency was observed 8 months after the surgery.

Introduction

Double-layer dermal grafts are used for the management of complicated abdominal wall hernias in obese, high risk patients. The method has not yet been used in case of emergency in septic/dirty environment.

Case report

A 76-year old female patient (BMI 36.7 kg/m²) was admitted with mechanical bowel obstruction and sepsis caused by a third time recurred, incarcerated and eventrated abdominal wall hernia. During the emergency surgery perforation of the terminal ileum and the ascending colon was detected, along with a feculent peritonitis and extended abdominal wall necrosis. Extended right hemicolectomy and necrectomy of the abdominal wall were performed. The surgery resulted in an abdominal wall defect measuring 223 cm², for the management of which direct closure was not possible. Using a specific method, an autologous dermal graft was prepared from the redundant skin. The first dermal graft was placed under the abdominal wall with 5 cm overlap, and the second layer was placed onto the first layer with 3 cm overlap in a perforated fashion. The operating time was 250 min. No significant intra-abdominal pressure elevation was measured. No reoperation was performed. On the fifth postoperative day, the patient was mobilised. She was discharged in satisfactory general condition on the 18th postoperative day. There is no recurrent hernia 8 months after the surgery.

Discussion

Abdominal wall reconstruction was possible in a necrotic, purulent environment by using a de-epithelised autologous double layer dermal graft, without synthetic or biological graft implantation. The advantage of the procedure was cost-effectivity, and the disadvantage was that only in an obese patient is the sufficient quantity of dermal graft available.

Conclusion

A homogeneous internal and perforated outer dermal graft was suitable for bridging the abdominal gap in the case of an obese, high risk patient. Autologous dermal grafts can be a safe and feasible alternative to biological meshes in emergency abdominal wall surgeries. Evaluation of a case series can be the next cornerstone of the method described above.

Partial versus complete removal of the infected mesh after abdominal wall hernia repair

BACKGROUND

To compare the results with complete mesh removal (CMR) versus partial mesh removal (PMR) in the treatment of mesh infection after abdominal wall hernia repair (AWHR).

METHODS

Retrospective review of all patients who underwent surgery for mesh infection between January 2004 and May 2014 at a tertiary center.

RESULTS

Of 3470 cases of AWHR, we reported 66 cases (1.9%) of mesh infection, and 48 repairs (72.7%) required mesh explantation. CMR was achieved on 38 occasions, while PMR was undertaken ten times. We observed more postoperative complications in CMR than PMR group (p = 0.04). Three patients with intestinal fistula were reoperated in postoperative period after a difficult mesh removal; one of them died due to multiple organ failure. The overall recurrence rate after explantation was 47.9%: recurrence was more frequent in CMR group (p = 0.001), although persistent or new mesh infection was observed more frequently with PMR (p = 0.001).

CONCLUSIONS

Although PMR has less postoperative morbidity, shorter duration of hospitalization and lower rate of recurrence than CMR, prosthetic infection persists in up to 50% of cases.

In Vitro Enzymatic Degradation of Tissue Grafts and Collagen Biomaterials by Matrix Metalloproteinases: Improving the Collagenase Assay

Matrix metalloproteinase-1 and -8 are active during the wound healing and remodelling processes, degrading native extracellular matrix and implantable devices. However, traditional in vitro assays utilize primarily matrix metalloproteinase-1 to mimic the in vivo degradation microenvironment. Herein, we assessed the influence of various concentrations of matrix metalloproteinase- 1 and 8 (50, 100, and 200 U/mL) as a function of pH (5.5 and 7.4) and time (3, 6, 9, 12, and 24 h) on the degradation profile of three tissue grafts (chemically cross-linked Permacol, nonchemically cross-linked Permacol and nonchemically cross-linked Strattice) and a collagen biomaterial (nonchemically cross-linked collagen sponge). Chemically cross-linked and nonchemically cross-linked Permacol samples exhibited the highest resistance to enzymatic degradation, while nonchemically cross-linked collagen sponges exhibited the least resistance to enzymatic degradation. Qualitative and quantitative degradation analysis of all samples revealed a similar degradation profile over time, independently of the matrix metalloproteinase used and its respective concentration and pH. These data indicate that matrix metalloproteinase-1 and matrix metalloproteinase-8 exhibit similar degradation profile in vitro, suggesting that matrix metalloproteinase-8 should be used for collagenase assay.

Complex ventral hernia repair with a human acellular dermal matrix and component separation: A case series

We present a case series of 19 patients requiring complex abdominal hernia repairs. Patients presented with challenging clinical histories with 95% having multiple significant comorbidities including overweight or obesity (84%), hypertension (53%), diabetes (42%), cancer (26%), and pulmonary disease (16%). The majority of patients (68%) had prior abdominal infections and 53% had at least one failed prior hernia repair. Upon examination, fascial defects averaged 282 cm². Anterior and posterior component separation was performed with placement of a human acellular dermal mesh. Midline abdominal closure under minimal tension was achieved primarily in all cases. Post-operative complications included 2 adverse events (11%) – one pulmonary embolism and one post-operative hemorrhage requiring transfusion; 6 wound-related complications (32%), 1 seroma (5%) and 1 patient with post-operative ileus (5%). Operative intervention was not required in any of the cases and most patients made an uneventful recovery. Increased patient age and longer OR time were independently predictive of early post-operative complications. At a median 2-year follow-up, three patients had a documented hernia recurrence (16%) and one patient was deceased due to unrelated causes.

Conclusion

Patients at high risk for post-operative events due to comorbidities, prior abdominal infection and failed mesh repairs do well following component separation reinforced with a human bioprosthetic mesh. Anticipated post-operative complications were managed conservatively and at a median 2-year follow-up, a low rate of hernia recurrence was observed with this approach.

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Intraperitoneal placement of acellular dermal matrix using component separation.

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Acceptable recurrence rates of 16% at 2 years of follow up.

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Correlation in age and complication chances.

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Retrorectus technique possibly the best surgical technique for hernia repair.

Biologic versus Synthetic Mesh Reinforcement: What are the Pros and Cons?

Preserving patients' native tissues has posed many challenges for surgeons. Increased life expectancy is leading to a proportionately older surgical population with weaker tissues. The growing population of morbidly obese patients in addition to those with multiple comorbidities which influence the native strength and perfusion of tissues compounds the surgeon's challenge. Certainly, there is a rising demand for materials to replace or augment a patient's native tissue when it has been compromised. Over time, the number of products available has increased substantially. The ideal substitute, however, is debatable. The manufacturing and processing of these materials has become more complex and this has resulted in a significant increase in cost. The composition of the mesh, clinical scenario, and operative technique all interact to impact the long-term results. Surgeons require a thorough understanding of these products to guide proper selection and use, to ensure optimal outcomes for patients, and to properly steward financial resources. This review will outline the properties of commonly used materials, highlighting the strength and weakness of each. It will then discuss recommendations regarding mesh selection, coding, and reimbursement. While general principles and trends can be highlighted, further studies of biologic versus synthetic meshes are clearly necessary.

Acellular Dermal Matrix in Reconstructive Breast Surgery: Survey of Current Practice among Plastic Surgeons

Background:

Acellular dermal matrices (ADMs) in plastic surgery have become increasingly popular particularly for breast reconstruction. Despite their advantages, questions exist regarding their association with a possible increased incidence of complications. We describe a collective experience of plastic surgeons’ use of ADMs in reconstructive breast surgery using an internet-based survey.

Methods:

Members of the American Society of Plastic Surgeons were recruited through voluntary, anonymous participation in an online survey. The web-based survey garnered information about participant demographics and their experience with ADM use in breast reconstruction procedures. After responses were collected, all data were anonymously processed.

Results:

Data were ascertained through 365 physician responses of which 99% (n = 361) completed the survey. The majority of participants were men (84.5%) between 51 and 60 years (37.4%); 84.2% used ADM in breast reconstruction, including radiated patients (79.7%). ADM use was not favored for nipple reconstruction (81.5%); 94.6% of participants used drains, and 87.8% administered antibiotics postoperatively. The most common complications were seroma (70.9%) and infection (16%), although 57.4% claimed anecdotally that overall complication rate was unchanged after incorporating ADM into their practice. High cost was a deterrent for ADM use (37.5%).

Conclusions:

Plastic surgeons currently use ADM in breast reconstruction for both immediate and staged procedures. Of those responding, a majority of plastic surgeons will incorporate drains and use postoperative antibiotics for more than 48 hours.

A review of cellularization strategies for tissue engineering of whole organs

With the advent of whole organ decellularization, extracellular matrix scaffolds suitable for organ engineering were generated from numerous tissues, including the heart, lung, liver, kidney, and pancreas, for use as alternatives to traditional organ transplantation. Biomedical researchers now face the challenge of adequately and efficiently recellularizing these organ scaffolds. Herein, an overview of whole organ decellularization and a thorough review of the current literature for whole organ recellularization are presented. The cell types, delivery methods, and bioreactors employed for recellularization are discussed along with commercial and clinical considerations, such as immunogenicity, biocompatibility, and Food and Drug Administartion regulation.

Porcine acellular dermal matrix for delayed abdominal wall closure after pediatric liver transplantation

Children are one of the groups with the highest mortality rate on the waiting list for LT. Primary closure of the abdominal wall is often impossible in the pediatric population, due to a size mismatch between a large graft and a small recipient. We present a retrospective cohort study of six pediatric patients, who underwent delayed abdominal wall closure with a biological mesh after LT, and in whom early closure was impossible. A non-cross-linked porcine-derived acellular dermal matrix (Strattice(™) Reconstructive Tissue Matrix; LifeCell Corp, Bridgewater, NJ, USA) was used in all of the cases of the series. After a mean follow-up of 26 months (21-32 months), all patients were asymptomatic, with a functional abdominal wall after physical examination. Non-cross-linked porcine-derived acellular dermal matrix (Strattice(™) ) is a good alternative for delayed abdominal wall closure after pediatric LT. Randomized controlled trials are necessary to determine the best moment and the best technique for abdominal wall closure.

Use of a Bioprosthetic Mesh in Complex Hernia Repair

Background. Implantation of synthetic meshes for reinforcement of abdominal wall hernias can be complicated by mesh infection, which often requires mesh explantation. The risk of mesh infection is increased in a contaminated environment or in patients who have comorbidities such as diabetes or smoking. The use of biological prostheses has been advocated because of their ability to resist infection. Initial results, however, have shown high hernia recurrence rates and wound occurrences. The objective of the present study is to evaluate early and mid-term outcomes in the largest French series that included 43 consecutive complex abdominal hernias repaired with biological prostheses. Materials and methods. Retrospective observational study of a prospective collected data bank. Patient demographics, history of previous repairs, intraoperative findings and degree of contamination, associated procedures, postoperative prosthetic-related complications, and long-term results were retrospectively reviewed. Results. There were 25 (58%) incisional, 14 parastomal, and 4 midline hernia repairs. Hernias were considered “clean” (n = 5), “clean-contaminated” (n = 19), “contaminated” (n = 12), or “dirty” (n = 7). Wound-related morbidity occurred in 17 patients; 4 patients needed reoperation for cutaneous necrosis or abscess. Smoking was the only risk factor associated with wound complication ( P = .022). No postoperative wound events required removal of the prosthesis. There were 4 hernia recurrences (9%). A previous attempt at repair ( P = .018) and no complete fascia closure ( P = .033) were associated with hernia recurrence. Conclusions. This study demonstrated that the use of bioprothesis in complex hernia repair allowed successful single-stage reconstruction. Wound-related complications were frequent. Cost-benefit analyses are important to establish the validity of these findings.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.