Onlay ventral hernia repairs using porcine non-cross-linked dermal biologic mesh

Poly-4-hydroxybutyrate Mesh for Ventral Hernia Repairs: A Single-Surgeon Experience

Background

Poly-4-hydroxybutyrate (P4HB) (Phasix) biosynthetic mesh was recently introduced as an alternative to synthetic and biologic meshes for ventral hernia repair (VHR). However, outcomes data are limited. This study aims to analyze outcomes of VHR with P4HB mesh and identify predictors of postoperative outcomes.

Methods

We performed a retrospective study of adults who underwent open VHR with P4HB by the senior author from 2014 to 2020 with >12 months' follow-up. Subgroup comparisons and multivariate logistic regression were performed.

Results

Inclusion criteria were met by 169 patients with a median of 15 months of follow-up. Overall, 21.9% had surgical site occurrences, 17.8% required reoperation, and 4.7% had recurrences. Patients with prior VHR (47.9%) experienced similar outcomes to those without. Patients with prior mesh infection (18.3%) had higher rates of postoperative mesh infection (6.5% vs 0.7%; P = .029) but did not have higher rates of reoperation. Retrorectus repairs (45.5%) had similar outcomes to onlay repairs (54.5%). Recurrence risk was increased by hypertension (odds ratio [OR] = 13.64; P = .046), immunosuppression (OR = 42.57; P = .004), and history of prior VHR (OR = 20.20; P = .014).

Conclusions

This study aimed to analyze outcomes of VHR augmented with P4HB mesh through retrospective review. VHR with P4HB mesh produces acceptable recurrence rates with favorable complication risks compared with biologic and synthetic meshes. Predictors of recurrence include a history of prior hernia repair, hypertension, and immunosuppression. A history of prior mesh infection seems to place patients at risk for developing subsequent infection but did not increase need for reoperation.

Outcomes of Complex Abdominal Wall Reconstruction After Oncologic Resection: 14-Year Experience at an NCI-Designated Cancer Center

BACKGROUND

Outcomes studies for abdominal wall reconstruction (AWR) in the setting of previous oncologic extirpation are lacking. We sought to evaluate long-term outcomes of AWR using acellular dermal matrix (ADM) after extirpative resection, compare them to primary herniorrhaphy, and report the rates and predictors of postoperative complications.

METHODS

We conducted a retrospective cohort study of patients who underwent AWR after oncologic resection from March 2005 to June 2019 at a tertiary cancer center. The primary outcome was hernia recurrence (HR). Secondary outcomes included surgical site occurrences (SSOs), surgical site infection (SSIs), length of hospital stay (LOS), reoperation, and 30-day readmission.

RESULTS

Of 720 consecutive patients who underwent AWR during the study period, 194 (26.9%) underwent AWR following resection of abdominal wall tumors. In adjusted analyses, patients who had AWR after extirpative resection were more likely to have longer LOS (β, 2.57; 95%CI, 1.27 to 3.86, p < 0.001) than those with primary herniorrhaphy, but the risk of HR, SSO, SSI, 30-day readmission, and reoperation did not differ significantly. In the extirpative cohort, obesity (Hazard ratio, 6.48; p = 0.003), and bridged repair (Hazard ratio, 3.50; p = 0.004) were predictors of HR. Radiotherapy (OR, 2.23; p = 0.017) and diabetes mellites (OR, 3.70; p = 0.005) were predictors of SSOs. Defect width (OR, 2.30; p < 0.001) and mesh length (OR, 3.32; p = 0.046) were predictors of SSIs. Concomitant intra-abdominal surgery for active disease was not associated with worse outcomes.

CONCLUSIONS

AWR with ADM following extirpative resection demonstrated outcomes comparable with primary herniorrhaphy. Preoperative risk assessment and optimization are imperative for improving outcomes.

A systematic review of outcome reporting in incisional hernia surgery

Background

The incidence of incisional hernia is up to 20 per cent after abdominal surgery. The management of patients with incisional hernia can be complex with an array of techniques and meshes available. Ensuring consistency in reporting outcomes across studies on incisional hernia is important and will enable appropriate interpretation, comparison and data synthesis across a range of clinical and operative treatment strategies.

Methods

Literature searches were performed in MEDLINE and EMBASE (from 1 January 2010 to 31 December 2019) and the Cochrane Central Register of Controlled Trials. All studies documenting clinical and patient-reported outcomes for incisional hernia were included.

Results

In total, 1340 studies were screened, of which 92 were included, reporting outcomes on 12 292 patients undergoing incisional hernia repair. Eight broad-based outcome domains were identified, including patient and clinical demographics, hernia-related symptoms, hernia morphology, recurrent incisional hernia, operative variables, postoperative variables, follow-up and patient-reported outcomes. Clinical outcomes such as hernia recurrence rates were reported in 80 studies (87 per cent). A total of nine different definitions for detecting hernia recurrence were identified. Patient-reported outcomes were reported in 31 studies (34 per cent), with 18 different assessment measures used.

Conclusions

This review demonstrates the significant heterogeneity in outcome reporting in incisional hernia studies, with significant variation in outcome assessment and definitions. This is coupled with significant under-reporting of patient-reported outcomes.

Prelamination of Vascularized Tensor Fascia Lata for Complex Abdominal Wall Reconstruction

ABSTRACT

There are 2 to 5 million laparotomies performed in the United States annually. Of these, 250,000 to 350,000 will undergo a ventral hernia repair. Repairs are often complicated by recurrence and infection. These risks are significantly increased in previously infected repairs, with reported recurrence rates varying from 17% to 28% after repair of infected ventral hernias, double the rates reported for first-time uninfected repairs. We describe here a novel treatment strategy involving the creation then use of bilateral prelaminated permanent mesh-reinforced tensor fascia latae flaps for abdominal wall reconstruction in patients who have recurrent ventral hernias and had undergone previous repairs complicated by infection. Previous repairs included anterior components separation, thereby making subsequent fascial release techniques and achievement of a reinforced repair extremely unlikely. Three patients were treated by a single surgeon using this 2-stage technique. There have been no incidences of recurrence and no infections after 2 to 10 years. In these patients, the only conventional option would have been a bridged repair with absorbable mesh. Combining the advantages of permanent mesh and well-vascularized autologous tissue optimizes the repair's tensile strength while mitigating the chance of recurrent infection associated with the use of permanent mesh. We propose that this strategy may be an appropriate treatment option for patients with recurrent ventral hernias that have not responded to other conventional modalities of treatment.

The Role of Mesh Implants in Surgical Treatment of Parastomal Hernia

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

Retrospective analysis of defect reconstruction after abdominal wall tumor resection in 30 patients

PURPOSE

It is difficult to manage the full-thickness defect that is created by radical resection of an abdominal wall tumor. This report aimed to review our institutional experience with immediate reconstruction using mesh reinforcement after abdominal wall tumor resection.

METHODS

We retrospectively examined patients who underwent abdominal wall tumor resection with immediate mesh-reinforced reconstruction between April 2014 and November 2018. The patients' records were reviewed to collect data regarding their demographic characteristics, surgical procedures, and complications.

RESULTS

We identified 30 eligible patients, including 5 who underwent simultaneous resection of affected intra-abdominal organs or tissues. The median size of the resulting abdominal wall defect was 60 cm² (interquartile range: 32-127.5 cm²) and the median mesh size was 150 cm² (interquartile range: 150-225 cm²). The median operative time was 85 min (interquartile range: 60-133.8 min), the mean hospital stay was 19.4 ± 9.0 days, and the mean follow-up period was 28.6 ± 16.0 months. The complications included seroma (n = 4), infection (n = 2), massive hematoma (n = 1), and abnormal sensation (n = 3). Tumor recurrence was observed in two patients, and three patients died because of cancer progression. No patient developed a ventral hernia or abdominal bulging.

CONCLUSION

Immediate mesh-reinforced reconstruction is feasible and effective for patients who require abdominal wall tumor resection.

Poly-4-hydroxybutyrate (Phasix™) mesh onlay in complex abdominal wall repair

BACKGROUND

Poly-4-hydroxybutyric acid (P4HB, Phasix™) is a biosynthetic polymer that degrades by hydrolysis that can be woven into a mesh for use in soft tissue reinforcement. Herein, we describe our initial experience performing complex abdominal wall repair (CAWR) utilizing component separation and P4HB mesh as onlay reinforcement.

METHODS

All patients undergoing CAWR between June 2014 and May 2017 were followed prospectively for postoperative outcomes. Only those patients who underwent components separation with primary repair of the fascial edges followed by onlay of P4HB mesh were included in this study.

RESULTS

105 patients (52 male, 53 female; mean age 59.2 years, range 22-84) met inclusion criteria. Mean BMI was 29.1 (range 16-48); 52% patients had prior attempted hernia repair, most with multiple medical comorbidities (71% of patients with ASA 3 or greater). 30% of cases were not clean at the time of repair (CDC class 2 or greater). Median follow-up was 36 months (range 9-63). Eighteen patients (17%) developed a hernia recurrence ranging from 2 to 36 months postoperatively. Five (5%) patients developed a localized superficial infection treated with antibiotics, three (2.8%) required re-operation for non-healing wounds, and six (6%) patients developed seroma.

CONCLUSIONS

These data demonstrate a relatively low rate of hernia recurrence, seroma, and other common complications of CAWR in a highly morbid patient population. Importantly, the rate of mesh infection was low and no patients required complete mesh removal, even when placed into a contaminated or infected surgical field.

Perineal Wound Complications After Extralevator Abdominoperineal Excision for Low Rectal Cancer

BACKGROUND

Reconstruction of the pelvic floor defect caused by extralevator abdominoperineal excision poses a challenge for the surgeon.

OBJECTIVE

The aim of this study was to analyze the long-term perineal wound complications in patients undergoing conventional primary closure versus biological mesh-assisted repair after extralevator abdominoperineal excision.

DESIGN

This was a single-institution retrospective observational study.

SETTINGS

The study was conducted at a tertiary academic medical center.

PATIENTS

Patients with low advanced rectal cancer undergoing extralevator abdominoperineal excision from August 2008 to December 2016 (N = 228) were included.

INTERVENTIONS

All of the patients received extralevator abdominoperineal excision operation.

MAIN OUTCOME MEASURES

The primary outcome measure was perineal wound complications after the operation.

RESULTS

Of the 228 patients who underwent extralevator abdominoperineal excision, 174 received biological mesh repair and 54 received primary closure. Preoperative radiotherapy was administered to 89 patients (51.1%) in the biological mesh group and 20 patients (37.0%) in the primary closure group. The biological mesh group had significantly lower rates of perineal wound infection (11.5% vs 22.2%; p = 0.047), perineal hernia (3.4% vs 13.0%; p = 0.022), wound dehiscence (0.6% vs 5.6%; p = 0.042), and total perineal wound complications (14.9% vs 35.2%; p = 0.001) compared with the primary closure group. Multivariable logistic regression analysis showed preoperative radiotherapy (p < 0.001), conventional primary closure (p < 0.001), and intraoperative bowel perforation (p= 0.001) to be significantly associated with perineal procedure-related complications.

LIMITATIONS

This was a single-center retrospective study.

CONCLUSIONS

Although perineal wound repair with biological mesh prolongs the operative time of perineal portion, the perineal drainage retention time, and the length of hospital stay, it may reduce perineal procedure-related complications and improve wound healing. Preoperative radiotherapy and intraoperative bowel perforation appear to be independent predictors of perineal complications. See Video Abstract at http://links.lww.com/DCR/B42. COMPLICACIONES DE LA HERIDA PERINEAL DESPUÉS DE LA EXCISIÓN ABDOMINOPERINEAL EXTRA-ELEVADORA EN CASO DE CÁNCER DE RECTO BAJO: La reconstrucción del defecto en el suelo pélvico, resultado de una resección abdominoperineal extra-elevadora plantea un desafío para el cirujano.El analisis de las complicaciones de la herida perineal a largo plazo en pacientes sometidos a un cierre primario convencional versus una reparación asistida por malla biológica después de una resección abdominoperineal extra-elevadora.Estudio retrospectivo observacional en una sola institución.Investigación realizada en un centro médico académico terciario.Se incluyeron los pacientes con cáncer rectal bajo avanzado que se sometieron a una resección abdominoperineal extra-elevadora desde agosto de 2008 hasta diciembre de 2016 (n= 228).Todos aquellos pacientes que fueron sometidos a una resección abdominoperineal extra-elevadora.Todas las complicaciones de la herida perineal en el postoperatorio.De los 228 pacientes que se sometieron a una resección abdominoperineal extra-elevadora, 174 fueron reparados con una malla biológica y 54 se beneficiaron de un cierre primario. La radioterapia preoperatoria se administró a 89 (51,1%) pacientes en el grupo de malla biológica y 20 (37,0%) pacientes en el grupo de cierre primario. El grupo de malla biológica tuvo tasas significativamente más bajas de infección de la herida perineal (11.5% vs. 22.2%; p = 0.047), hernia perineal (3.4% vs. 13.0%; p = 0.022), dehiscencia de la herida (0.6% vs. 5.6%; p = 0,042) y complicaciones perineales de la herida (14,9% frente a 35,2%; p = 0,001) en comparación con el grupo de cierre primario. El análisis de regresión logística multivariable mostró que la radioterapia preoperatoria (p <0.001), el cierre primario convencional (p <0.001) y la perforación intestinal intra-operatoria (p = 0.001) se asociaron significativamente como complicaciones relacionadas con el procedimiento perineal.Estudio retrospectivo de centro único.Aunque la reparación de la herida perineal con malla biológica prolonga el tiempo perineal de la operación, la presencia y duración del drenaje perineal y la hospitalización pueden reducir las complicaciones relacionadas con el procedimiento perineal y mejorar la cicatrización de la herida. La radioterapia preoperatoria y la perforación intestinal intra-operatorias parecen ser predictores independientes de complicaciones perineales. Vea el Resumen del Video en http://links.lww.com/DCR/B42.

Onlay Technique in Incisional Hernia Repair-A Systematic Review

Introduction: A meta-analysis that compared the onlay vs. sublay technique in open incisional hernia repair identified better outcomes for the sublay operation. Nonetheless, an Expert Consensus Guided by Systematic Review found the onlay mesh location useful in certain settings. Therefore, all studies on the onlay technique were once again collated and analyzed.

Materials and Methods: A systematic search of the available literature was performed in August 2018 using Medline, PubMed, Scopus, Embase, Springer Link, and the Cochrane Library. For the present analysis 42 publications were identified as relevant.

Results: In five prospective randomized trials and 17 observational studies the postoperative complication rates ranged between 5 and 76%, with a mean value of 33.5%. The recurrence rates in these studies also ranged between 0 and 32%, with a mean value of 9.9%. Hence, compared with the literature data on the sublay operation, more post-operative complications, in particular wound complications and seroma, with a comparable recurrence rate, were identified.

Conclusion: When the onlay technique is used in certain settings for incisional hernia repair, a careful dissection technique and prophylactic measures (drainage, abdominal binders, fibrin sealant) should be employed to prevent wound complications and seroma formation.

What is the evidence for the use of biologic or biosynthetic meshes in abdominal wall reconstruction?

INTRODUCTION

Although many surgeons have adopted the use of biologic and biosynthetic meshes in complex abdominal wall hernia repair, others have questioned the use of these products. Criticism is addressed in several review articles on the poor standard of studies reporting on the use of biologic meshes for different abdominal wall repairs. The aim of this consensus review is to conduct an evidence-based analysis of the efficacy of biologic and biosynthetic meshes in predefined clinical situations.

METHODS

A European working group, "BioMesh Study Group", composed of invited surgeons with a special interest in surgical meshes, formulated key questions, and forwarded them for processing in subgroups. In January 2016, a workshop was held in Berlin where the findings were presented, discussed, and voted on for consensus. Findings were set out in writing by the subgroups followed by consensus being reached. For the review, 114 studies and background analyses were used.

RESULTS

The cumulative data regarding biologic mesh under contaminated conditions do not support the claim that it is better than synthetic mesh. Biologic mesh use should be avoided when bridging is needed. In inguinal hernia repair biologic and biosynthetic meshes do not have a clear advantage over the synthetic meshes. For prevention of incisional or parastomal hernias, there is no evidence to support the use of biologic/biosynthetic meshes. In complex abdominal wall hernia repairs (incarcerated hernia, parastomal hernia, infected mesh, open abdomen, enterocutaneous fistula, and component separation technique), biologic and biosynthetic meshes do not provide a superior alternative to synthetic meshes.

CONCLUSION

The routine use of biologic and biosynthetic meshes cannot be recommended.

An Immunopathological Evaluation of the Porcine Cholecyst Matrix as a Muscle Repair Graft in a Male Rat Abdominal Wall Defect Model

With the increasing use of animal-based biomaterials for regenerative medical applications, the need for their safety assessment is paramount. A porcine cholecyst-derived scaffold (CDS), intended as a muscle repair graft, prepared by a nondetergent/enzymatic method was engrafted in a rat abdominal wall defect model. Host tissue–scaffold interface samples were collected 2, 8, and 16 weeks postimplantation and evaluated by histopathology, immunohistochemistry, and electron microscopy. The nature of the tissue reaction was compared with those induced by a jejunum-derived scaffold (JDS) prepared by the same method and a commercial-grade small intestinal submucosa (CSIS) scaffold. A study of the immunopathological response in major lymphoid tissues and immunophenotyping for M1 and M2 macrophages was performed at the host tissue–scaffold interface. Further, “irritancy scores” for CDS and JDS were determined using CSIS as the reference material. Both CDS and JDS appeared to be potential biomaterials for muscle grafts, but the former stimulated a skeletal muscle tissue remodeling response predominated by M2 macrophages. The data support the notion that biomaterials with similar biocompatibility, based on local tissue response on implantation, may cause differential immunogenicity. Additionally, CDS compared to JDS and CSIS was found to be less immunotoxic.

The extracellular matrix of the gastrointestinal tract: a regenerative medicine platform

The synthesis and secretion of components that constitute the extracellular matrix (ECM) by resident cell types occur at the earliest stages of embryonic development, and continue throughout life in both healthy and diseased physiological states. The ECM consists of a complex mixture of insoluble and soluble functional components that are arranged in a tissue-specific 3D ultrastructure, and it regulates numerous biological processes, including angiogenesis, innervation and stem cell differentiation. Owing to its composition and influence on embryonic development, as well as cellular and organ homeostasis, the ECM is an ideal therapeutic substrate for the repair of damaged or diseased tissues. Biologic scaffold materials that are composed of ECM have been used in various surgical and tissue-engineering applications. The gastrointestinal (GI) tract presents distinct challenges, such as diverse pH conditions and the requirement for motility and nutrient absorption. Despite these challenges, the use of homologous and heterologous ECM bioscaffolds for the focal or segmental reconstruction and regeneration of GI tissue has shown promise in early preclinical and clinical studies. This Review discusses the importance of tissue-specific ECM bioscaffolds and highlights the major advances that have been made in regenerative medicine strategies for the reconstruction of functional GI tissues.

Matrix-Bound Nanovesicles Recapitulate Extracellular Matrix Effects on Macrophage Phenotype

The early macrophage response to biomaterials has been shown to be a critical and predictive determinant of downstream outcomes. When properly prepared, bioscaffolds composed of mammalian extracellular matrix (ECM) have been shown to promote a transition in macrophage behavior from a proinflammatory to a regulatory/anti-inflammatory phenotype, which in turn has been associated with constructive and functional tissue repair. The mechanism by which ECM bioscaffolds promote this phenotypic transition, however, is poorly understood. The present study shows that matrix-bound nanovesicles (MBV), a component of ECM bioscaffolds, are capable of recapitulating the macrophage activation effects of the ECM bioscaffold from which they are derived. MBV isolated from two different source tissues, porcine urinary bladder and small intestinal submucosa, were found to be enriched in miRNA125b-5p, 143-3p, and 145-5p. Inhibition of these miRNAs within macrophages was associated with a gene and protein expression profile more consistent with a proinflammatory rather than an anti-inflammatory/regulatory phenotype. MBV and their associated miRNA cargo appear to play a significant role in mediating the effects of ECM bioscaffolds on macrophage phenotype.

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.

Synthetic versus Biologic Mesh in Single-Stage Repair of Complex Abdominal Wall Defects in a Contaminated Field

BACKGROUND

Synthetic meshes have been used with varying rates of success in a contaminated setting, although their use is not widely accepted because of concerns for infection. A biologic mesh (BM) is assumed to be more resistant to infection than a synthetic mesh; however, sparse clinical data support this theory. The hypothesis for this study: Uncoated polypropylene synthetic mesh (USM) can be used to obtain a durable repair in the setting of a contaminated abdominal wall reconstruction (AWR) in a single-stage procedure with comparable infectious outcomes to a biologic mesh repair.

PATIENTS AND METHODS

We performed a retrospective chart review on contaminated AWR, comparing 34 BM with 24 USM with infection as the primary outcome of interest. Secondary outcomes were re-admission and re-operation. We also investigated the microbial isolates that were cultured.

RESULTS

Mesh groups were similar in their demographics, duration of surgery, previous mesh, surgical site class, and source of contamination. Length of stay was 4 d longer in BM, p = 0.01. Overall infection rate was 50% for BM vs. 29.2% for USM, p = 0.18. Treatment in case of infection was similar across both groups. Gram positive bacteria comprised 39% of BM microbiology vs. 63% for USM. Re-admission rate was 52.9% for BM versus 45.8% for USM, p > 0.5. The BMs re-admitted for surgical site infection/abdominal abscess were 38.9% versus 55.6% for USM. No USM were re-admitted for seroma versus 33.3% of BM, p = 0.06. Re-operation rate was 26.5% for BM versus 33.3% for USM, p > 0.5. Procedures performed at re-operation were similar between groups. Regression analysis did not demonstrate an association between mesh type and our outcomes.

CONCLUSION

Our results show that synthetic meshes are not inferior to biologic meshes in contaminated AWR. This is important in view of the tremendous cost disparity between these two products and the questionable ability of biologic mesh to offer a durable hernia repair.

Matrix-bound nanovesicles within ECM bioscaffolds

Biologic scaffold materials composed of extracellular matrix (ECM) have been used in a variety of surgical and tissue engineering/regenerative medicine applications and are associated with favorable constructive remodeling properties including angiogenesis, stem cell recruitment, and modulation of macrophage phenotype toward an anti-inflammatory effector cell type. However, the mechanisms by which these events are mediated are largely unknown. Matrix-bound nanovesicles (MBVs) are identified as an integral and functional component of ECM bioscaffolds. Extracellular vesicles (EVs) are potent vehicles of intercellular communication due to their ability to transfer RNA, proteins, enzymes, and lipids, thereby affecting physiologic and pathologic processes. Formerly identified exclusively in biologic fluids, the presence of EVs within the ECM of connective tissue has not been reported. In both laboratory-produced and commercially available biologic scaffolds, MBVs can be separated from the matrix only after enzymatic digestion of the ECM scaffold material, a temporal sequence similar to the functional activity attributed to implanted bioscaffolds during and following their degradation when used in clinical applications. The present study shows that MBVs contain microRNA capable of exerting phenotypical and functional effects on macrophage activation and neuroblastoma cell differentiation. The identification of MBVs embedded within the ECM of biologic scaffolds provides mechanistic insights not only into the inductive properties of ECM bioscaffolds but also into the regulation of tissue homeostasis.

Repair of Postoperative Abdominal Hernia in a Child with Congenital Omphalocele Using Porcine Dermal Matrix

Introduction. Incisional hernias are a common complication appearing after abdominal wall defects reconstruction, with omphalocele and gastroschisis being the most common etiologies in children. Abdominal closure of these defects represents a real challenge for pediatric surgeons with many surgical techniques and various prosthetic materials being used for this purpose. Case Report. We present a case of repair of a postoperative ventral hernia occurring after congenital omphalocele reconstruction in a three-and-a-half-year-old child using an acellular, sterile, porcine dermal mesh. Conclusion. Non-cross-linked acellular porcine dermal matrix is an appropriate mesh used for the reconstruction of abdominal wall defects and their postoperative complications like large ventral hernias with success and preventing their recurrence.

Outcomes following placement of non-cross-linked porcine-derived acellular dermal matrix in complex ventral hernia repair

Repair of complex ventral hernias frequently results in postoperative complications. This study assessed postoperative outcomes in a consecutive cohort of patients with ventral hernias who underwent herniorrhaphy using components separation techniques and reinforcement with non–cross-linked intact porcine-derived acellular dermal matrix (PADM) performed by a single surgeon between 2008 and 2012. Postoperative outcomes of interest included incidence of seroma, wound infection, deep-vein thrombosis, bleeding, and hernia recurrence determined via clinical examination. Of the 47 patients included in the study, 25% were classified as having Ventral Hernia Working Group grade 1 risk, 62% as grade 2, 2% as grade 3, and 11% as grade 4; 49% had undergone previous ventral hernia repair. During a mean follow-up of 31 months, 3 patients experienced hernia recurrence, and 9 experienced other postoperative complications: 4 (9%) experienced deep-vein thrombosis; 3 (6%), seroma; 2 (4%), wound infection; and 2 (4%), bleeding. The use of PADM reinforcement following components separation resulted in low rates of postoperative complications and hernia recurrence in this cohort of patients undergoing ventral hernia repair.

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.

Incisional reinforcement in high-risk patients

Hernia formation after surgical procedures continues to be an important cause of surgical morbidity. Incisional reinforcement at the time of the initial operation has been used in some patient populations to reduce the risk of subsequent hernia formation. In this article, reinforcement techniques in different surgical wounds are examined to identify situations in which hernia formation may be prevented. Mesh use for midline closure, pelvic floor reconstruction, and stoma site reinforcement is discussed. Additionally, the use of retention sutures, closure of the open abdomen, and reinforcement after component separation are examined using current literature. Although existing studies do not support the routine use of mesh reinforcement for all surgical incisions, certain patient populations appear to benefit from reinforcement with lower rates of subsequent hernia formation. The identification and characterization of these groups will guide the future use of mesh reinforcement in surgical incisions.

Porcine dermis implants in soft-tissue reconstruction: current status

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

A modified approach to component separation using biologic graft as a load-sharing onlay reinforcement for the repair of complex ventral hernia

BACKGROUND

Components separation has been proposed as a means to close large ventral hernia without undue tension. We report a modification on open components separation that allows for the incorporation of onlaid noncrosslinked porcine acellular dermal matrix (Strattice, LifeCell Corp, Branchburg, NJ) as a load-sharing structure.

METHODS

This was a retrospective case series including all cases using Strattice from July 2008 through December 2009. Data evaluated included patient demographics, comorbidities associated with risk of recurrence, hernia grade, and postoperative complications. The primary outcomes were hernia recurrence and surgical site occurrences.

RESULTS

There were 58 patients; 60.8% presented with a recurrent incisional hernia. Average length of follow-up was 384 days. There were 4 hernia recurrences (7.9%). Complications included surgical site infection (20.7%), seroma (15.5%), and hematoma (5%) requiring intervention. Four deaths occurred in the series due to causes unrelated to the hernia repair, only 1 within 30 days of operation.

CONCLUSIONS

This series demonstrates that components separation reinforced with noncrosslinked porcine acellular dermal matrix onlay is an efficacious, single-stage repair with a low rate of recurrence and surgical site occurrences.