Long-term outcomes (& gt; 5-year follow-up) with porcine acellular dermal matrix (Permacol) in incisional hernias at risk for infection. Hernia. 2015;19:135-140. [PMID: 24129420 DOI: 10.1007/s10029-013-1165-9]

Advances, challenges, and future directions in the clinical translation of ECM biomaterials for regenerative medicine applications

Extracellular Matrix (ECM) scaffolds and biomaterials have been widely used for decades across a variety of diverse clinical applications and have been implanted in millions of patients worldwide. ECM-based biomaterials have been especially successful in soft tissue repair applications but their utility in other clinical applications such as for regeneration of bone or neural tissue is less well understood. The beneficial healing outcome with the use of ECM biomaterials is the result of their biocompatibility, their biophysical properties and their ability to modify cell behavior after injury. As a consequence of successful clinical outcomes, there has been motivation for the development of next-generation formulations of ECM materials ranging from hydrogels, bioinks, powders, to whole organ or tissue scaffolds. The continued development of novel ECM formulations as well as active research interest in these materials ensures a wealth of possibilities for future clinical translation and innovation in regenerative medicine. The clinical translation of next generation formulations ECM scaffolds faces predictable challenges such as manufacturing, manageable regulatory pathways, surgical implantation, and the cost required to address these challenges. The current status of ECM-based biomaterials, including clinical translation, novel formulations and therapies currently under development, and the challenges that limit clinical translation of ECM biomaterials are reviewed herein.

Bridged repair of large ventral hernia defects using an ovine reinforced biologic: A case series

Introduction

Of all hernia types, large ventral hernias have the most impact on patient quality of life, however they are also the most difficult type of hernia to repair and are associated with high rates of complications. This case series describes repair of large ventral hernias with an ovine reinforced biologic in a complex patient cohort with comorbidities and concomitant procedures.

Methods

The author performed bridged repair with an ovine reinforced biologic in 19 consecutive high-risk patients over a 5-year period. In all cases the reinforced biologic was used as an underlay.

Outcomes

Of the 19 patients, six (32%) experienced a surgical site occurrence including infection, seroma, abscess, fistula, bioloma, or bowel obstruction. Three patients (16%) had recurrences with two out of three of the recurrences occurring within 6 months of surgery.

Conclusions

Rates of SSO's and recurrences using ovine reinforced tissue matrix (RTM) were in line with or better than other published studies of bridged repair utilizing biologic or synthetic mesh reinforcement. Ovine RTM's should therefore be considered in complex large ventral hernia repairs.

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Large ventral hernias greatly impact patient quality of life.

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In some cases, large ventral hernias necessitate bridged repair with mesh.

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19 patients received bridged repair with an ovine reinforced matrix.

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Mean follow up of 23 months showed low complication and recurrence rates.

Current practices in complex abdominal wall reconstruction in the Americas: need for national guidelines?

BACKGROUND

Component separation (CS) procedures have become an important part of surgeons' armamentarium. However, the exact criteria for training, procedure/mesh choice, as well as patient selection for CS remains undefined. Herein we aimed to identify trends in CS utilization between various cohorts of practicing surgeons.

STUDY DESIGN

Members of the Americas Hernia Society were queried using an online survey. Responders were stratified according to their experience, practice profile (private vs academic, general vs hernia surgery), and volume (low (< 10/year) vs high) of CS procedures. We used Chi-squared tests to evaluate significant associations between surgeon characteristics and outcomes.

RESULTS

275 responses with overwhelming male preponderance (88%) were collected. The two most common self-identifiers were "general" (66%) and "hernia" (28%) surgeon. PCS was the most commonly (67%) used type of CS; endoscopic ACS was least common (3%). Low-volume surgeons were more likely to utilize the ACS (p < 0.05). Only 7% of respondents learned PCS during their residency, as compared to 36% that use ACS. 65% felt 0-10 cases was sufficient to become proficient in their preferred technique. 10 cm-wide defect was the most common indication for CS; 23% used it for 5-8 cm defects. Self-identified "hernia" and high-volume surgeons were more likely to use synthetic mesh in the setting of previous wound infections and/or contaminated field (p < 0.05). More general/low-volume surgeons use biologic mesh. Contraindications to elective CS varied widely in the cohort, and 9.5% would repair poorly optimized patients electively. Severe morbid obesity was the most feared comorbidity to preclude CS.

CONCLUSION

The use of CS varies widely between surgeons. In this cohort, we discovered that PCS was the most commonly used technique, especially by hernia/high-volume surgeons. There are differences in mesh utilization between high-volume and low-volume surgeons, specifically in contaminated fields. Despite its prevalence, CS training, indications/contraindications, and patient selection must be better defined.

A Biologic Surgical Implant in Complex Abdominal Wall Repair: 3-Year Follow-Up Results of a Multicentric Prospective Study

Purpose

Despite the advancements in the reinforcement and closure techniques available, complex abdominal wall reconstruction (CAWR) remains a challenging surgical undertaking with considerable risk of postoperative complications. Biological meshes were developed that may help to complement standard closure techniques and offer an alternative to synthetic meshes, which carry significant risks with their use in complex cases.

Patients and Methods

A total of 114 patients underwent surgical treatment for CAWR with a Permacol™ (a biologic surgical implant). The study objective was to evaluate the short-term (6 months), mid-term (12–24 months), and long-term (36 months) clinical outcomes (through 36 months) associated with the use of a biologic surgical implant in these cases.

Results

The cumulative hernia recurrence rate was 18.7% (17/91) at 24 months and 22.4% (19/85) at 36 months. Twelve (14.1%) subjects required reoperation for hernia repair within 36 months for repair of recurrent hernias. Between 6- and 36-months post-surgery, patients reported improvement in their Carolina comfort scale (CSS) measures of severity of pain, sensation of mesh, and movement limitations.

Conclusion

A biologic surgical implant can provide long-term benefit to complex abdominal wall repairs in patients staged grade III according to the Ventral Hernia Working Group (VHWG).

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.

Comparative study of biological versus synthetic prostheses in the treatment of ventral hernias classified as grade II/III by the Ventral Hernia Working Group

AIM OF THE STUDY

The implantation of biological prostheses in an at-risk environment has seen increasing use. Their markedly higher cost compared to synthetic prostheses makes it important to analyse their usefulness in terms of actual benefit and cost-effectiveness. This study aims to examine the relevance of bioprostheses during surgical repair of Grade II/III ventral hernias as classified by the Ventral hernia working group (VHWG).

MATERIALS AND METHODS

This study analysed the data of 119 patients requiring non-emergency repair of VHWG II/III grade hernias between 2010 and 2017. The results of patients who were treated with a bioprosthesis (n=59) were compared to those receiving a synthetic prosthesis (n=60). The primary outcome was surgical site infection (SSI) at 90 days. The secondary endpoints were hernia recurrence rate, cost of the prosthesis, duration of hospital stay and re-hospitalisation rate.

RESULTS

The two groups were shown to be comparable by analysis of demographic, pre- and intraoperative data. The SSI rate was significantly higher in the bioprosthesis group (20% vs. 7%; P=0.010), as was the recurrence rate (56% vs. 28%; P=0.003) with a median follow-up of 40 months. The cost of the bioprosthesis was significantly higher than that of the synthetic prosthesis (€3363 vs. €249; P<0.010).

CONCLUSION

In this retrospective study, the use of a bioprosthesis for repair of VHWG II/III ventral hernias was associated with a higher rate of both SSI and hernia recurrence at a cost 13 times greater than the use of a synthetic prosthesis.

The use of Permacol® biological mesh for complex abdominal wall repair

BACKGROUND

Complex abdominal wall repair (CAWR) remains challenging, especially in contaminated fields where the use of a synthetic mesh is associated with prohibitively complication rates. Consequently, biological mesh has been proposed as an alternative. The aim of our study was to evaluate the safety and efficacy of using Permacol® in patients who had CAWR.

METHODS

We retrospectively reviewed the files of patients who had CAWR using the Permacol® mesh. Analysis included patients' preoperative characteristics, procedural parameters, and early and late post-operative complications including mainly recurrence. A multivariate regression model was performed to determine factors that influence 24-months recurrence rate.

RESULTS

Between January 2009 and December 2018, 75 patients. The most common indication was hernia in a contaminated field (48.0%) and abdominal wall defect greater than 10 cm in diameter (36%). Overall, 44% of our patients were Centers for Disease Control (CDC) class II or III and 81.3% fall into category II or III according to the Ventral Hernia Working Group (VHWG) classification. Recurrence rate of our series was 9.3%. Complete fascial closure was achieved in 60 patients (80%). Upon univariate analysis complete fascial closure, posterior component separation, seroma drainage, BMI >30 kg/m2 and age >65 years, VHWD grade >2, DINDO CLAVIEN class > 2 affected the recurrence rate at 2 years follow up. When subcutaneous drains are placed prophylactically, recurrence rates drop from 38.7% (5/14) to 3.3% (2/61 patients) when drains are placed at the time of operation (p=0.02). Only fascial closure affected the 24-months recurrence rate on multivariate analysis (p<0.001).

CONCLUSIONS

Permacol® surgical implant use for CAWR is safe with a relatively low rate of hernia recurrence at 2 years. Prophylactic subcutaneous drain placement may reduce the risk of hernia recurrence. The presence of contaminated fields does not appear to influence hernia recurrence when Permacol® is used, in fact, the only factor that affects recurrence rate at 24-months on multivariate analysis is completeness of the fascial closure.

Decellularized xenografts in regenerative medicine: From processing to clinical application

Decellularized xenografts are an inherent component of regenerative medicine. Their preserved structure, mechanical integrity and biofunctional composition have well established them in reparative medicine for a diverse range of clinical indications. Nonetheless, their performance is highly influenced by their source (ie species, age, tissue) and processing (ie decellularization, crosslinking, sterilization and preservation), which govern their final characteristics and determine their success or failure for a specific clinical target. In this review, we provide an overview of the different sources and processing methods used in decellularized xenografts fabrication and discuss their effect on the clinical performance of commercially available decellularized xenografts.

Experimental Extracellular Matrix of the Xenoperitoneum: Comprehensive Assessment of a New Biological Material for Plastic Surgery of Anterior Abdominal Wall Defects

A new biological implant, extracellular matrix of bovine peritoneum, was developed and obtained for plastic surgery of the anterior abdominal wall defects. The material was implanted to rats into the anterior abdominal wall. The content of rejection markers (TNF, IL-2, C-reactive protein) and the morphological picture of the implantation zone at the early stages (30 days) after surgery were evaluated. The studied material at this stage demonstrated adequate biocompatibility; the formation of mature, consistent contact with the tissues of the anterior abdominal wall and minimum tissue inflammatory reactions were observed.

What results can be expected one year after complex incisional hernia repair with biosynthetic mesh?

BACKGROUND

Incisional hernia is a frequent complication after midline laparotomy. The current standard repair includes the use of a synthetic mesh to prevent recurrence. However, the use of a synthetic mesh in a contaminated field carries a higher risk of mesh infection. In this setting biologic and biosynthetic meshes can be used as they resist to infection, but these are absorbable meshes. This raises the question of the risk of recurrence as the mesh disappears. Phasix® is a biosynthetic mesh getting absorbed in 12-18 months. The aim of this study was to assess the 1-year recurrence rate after abdominal-wall repair with a Phasix® mesh.

METHODS

All patients undergoing ventral hernia repair between 2016 and 2018 at the University Hospital of Dijon using a Phasix® mesh were prospectively included in a database. They were all followed-up with a physical exam and a routine CT scan at one year. All postoperative complications were recorded.

RESULTS

Twenty-nine patients were included in the study (55.2% women), with a mean BMI of 30,25 kg/m². Nineteen meshes were sublay and 10 intraperitoneal. Complications at 1 month were mainly mild: Clavien-Dindo I and II (61.1%). No mesh was explanted. There was no chronic infection. The mean length of stay was 11.5 days. The 1-year recurrence rate was 10.3%.

CONCLUSION

Patients having undergone complex ventral hernia repair with a Phasix® mesh have a 1-year recurrence rate of 10.3%. No severe surgical site occurrence was detected. A longer follow-up in a larger number of patients could confirm the place of this mesh in abdominal-wall repair.

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.

Extracellular matrix-based biomaterials as adipose-derived stem cell delivery vehicles in wound healing: a comparative study between a collagen scaffold and two xenografts

BACKGROUND

Stem cell therapies represent a promising tool in regenerative medicine. Considering the drawbacks of direct stem cell injections (e.g. poor cell localisation), extracellular matrix-based biomaterials (e.g. scaffolds and tissue grafts), due to their compositional biofunctionality and cytocompatibility, are under investigation as potential stem cell carriers.

METHODS

The present study assessed the potential of three commercially available extracellular matrix-based biomaterials [a collagen/glycosaminoglycan scaffold (Integra™ Matrix Wound Dressing), a decellularised porcine peritoneum (XenoMEM™) and a porcine urinary bladder (MatriStem™)] as human adipose-derived stem cell delivery vehicles.

RESULTS

Both tissue grafts induced significantly (p < 0.01) higher human adipose-derived stem cell proliferation in vitro over the collagen scaffold, especially when the cells were seeded on the basement membrane side. Human adipose-derived stem cell phenotype and trilineage differentiation potential was preserved in all biomaterials. In a splinted wound healing nude mouse model, in comparison to sham, biomaterials alone and cells alone groups, all biomaterials seeded with human adipose-derived stem cells showed a moderate improvement of wound closure, a significantly (p < 0.05) lower wound gap and scar index and a significantly (p < 0.05) higher proportion of mature collagen deposition and angiogenesis (the highest, p < 0.01, was observed for the cell loaded at the basement membrane XenoMEM™ group). All cell-loaded biomaterial groups retained more cells at the implantation side than the direct injection group, even though they were loaded with half of the cells than the cell injection group.

CONCLUSIONS

This study further advocates the use of extracellular matrix-based biomaterials (in particular porcine peritoneum) as human adipose-derived stem cell delivery vehicles. Comparative analysis of a collagen scaffold (Integra™ Matrix Wound Dressing) and two tissue grafts [decellularised porcine peritoneum (XenoMEM™) and porcine urinary bladder (MatriStem™)] as human adipose-derived stem cells carriers.

Porcine mesothelium matrix as a biomaterial for wound healing applications

The increasing economic burden of wound healing in healthcare systems requires the development of functional therapies. Xenografts with preserved extracellular matrix (ECM) structure and biofunctional components overcome major limitations of autografts and allografts (e.g. availability) and artificial biomaterials (e.g. foreign body response). Although porcine mesothelium is extensively used in clinical practice, it is under-investigated for wound healing applications. Herein, we compared the biochemical and biological properties of the only two commercially available porcine mesothelium grafts (Meso Biomatrix® and Puracol® Ultra ECM) to traditionally used wound healing grafts (Endoform™, ovine forestomach and MatriStem®, porcine urinary bladder) and biomaterials (Promogran™, collagen/oxidized regenerated cellulose). The Endoform™ and the Puracol® Ultra ECM showed the highest (p<0.05) soluble collagen and elastin content. The MatriStem® had the highest (p<0.05) basic fibroblast growth factor (FGFb) content, whereas the Meso Biomatrix® had the highest (p<0.05) transforming growth factor beta-1 (TGF-β1) and vascular endothelial growth factor (VEGF) content. All materials showed tissue-specific structure and composition. The Endoform™ and the Meso Biomatrix® had some nuclei residual matter. All tissue grafts showed similar (p>0.05) response to enzymatic degradation, whereas the Promogran™ was not completely degraded by matrix metalloproteinase (MMP)-8 and was completely degraded by elastase. The Promogran™ showed the highest (p<0.05) permeability to bacterial infiltration. The Promogran™ showed by far the lowest dermal fibroblast and THP-1 attachment and growth. All tested materials showed significantly lower (p<0.05) tumor necrosis factor-alpha (TNF-α) expression than the lipopolysaccharides group. The MatriStem® and the Puracol® Ultra ECM promoted the highest (p<0.05) number of micro-vessel formation, whereas the Promogran™ the lowest (p<0.05). Collectively, these data confer that porcine mesothelium has the potential to be used as a wound healing material, considering its composition, resistance to enzymatic degradation, cytocompatibility, and angiogenic potential.

Long term comparative evaluation of two types of absorbable meshes in partial abdominal wall defects: an experimental study in rabbits

PURPOSE

Synthetic prosthetic materials that are fully absorbable seek to reduce the host foreign body reaction and promote host tissue regeneration. This preclinical trial was designed to analyse, in the long term, the behaviour of two prosthetic meshes, one synthetic and one composed of porcine collagen, in abdominal wall reconstruction.

METHODS

Partial defects were created in the abdominal walls of New Zealand rabbits and repaired using a synthetic absorbable mesh (Phasix™) or a non-crosslinked collagen bioprosthesis (Protexa™). After 3, 6, 12 and 18 months, specimens were recovered for light microscopy and collagen expression analysis to examine new host tissue incorporation, macrophage response and biomechanical strength.

RESULTS

Both materials showed good host tissue incorporation in line with their spatial structure. At 18 months postimplant, Protexa™ was highly reabsorbed while the biodegradation of Phasix™ was still incomplete. Collagenization of both materials was good. Macrophage counts steadily decreased over time in response to Phasix™, yet persisted in the collagen meshes. At 18 months, zones of loose tissue were observed at the implant site in the absence of herniation in both implant types. The stress-stretch behaviour of Phasix™ implants decreased over time, being more pronounced during the period of 12-18 months. Nevertheless, the abdominal wall repaired with Protexa™ became stiffer over time.

CONCLUSION

Eighteen months after the implant both materials showed good compatibility but the biodegradation of Phasix™ and Protexa™ was incomplete. No signs of hernia were observed at 18 months with the stress-stretch relations being similar for both implants, regardless of the more compliant abdominal wall repaired with Protexa™ at short term.

A retrospective, Italian multicenter study of complex abdominal wall defect repair with a Permacol biological mesh

Complex abdominal wall defects (CAWDs) can be difficult to repair and using a conventional synthetic mesh is often unsuitable. A biological mesh might offer a solution for CAWD repair, but the clinical outcomes are unclear. Here, we evaluated the efficacy of a cross-linked, acellular porcine dermal collagen matrix implant (Permacol) for CAWD repair in a cohort of 60 patients. Here, 58.3% patients presented with a grade 3 hernia (according to the Ventral Hernia Working Group grading system) and a contaminated surgical field. Permacol was implanted as a bridge in 46.7%, as an underlay (intraperitoneal position) in 38.3% and as a sublay (retromuscolar position) in 15% of patients. Fascia closure was achieved in 53.3% of patients. The surgical site occurrence rate was 35% and the defect size significantly influenced the probability of post-operative complications. The long-term (2 year) hernia recurrence rate was 36.2%. This study represents the first large multi-centre Italian case series on Permacol implants in patients with a CAWD. Our data suggest that Permacol is a feasible strategy to repair a CAWD, with acceptable early complications and long-term (2 year) recurrence rates.

Absorbable Polyglactin vs. Non-Cross-linked Porcine Biological Mesh for the Surgical Treatment of Infected Incisional Hernia

BACKGROUND

The use of absorbable meshes during contaminated or infected incisional hernia (IH) repair is associated with high morbidity and recurrence rates. Biological meshes might be more appropriate but have been described in highly heterogeneous series. This study aimed at comparing the efficacy of absorbable vs. biological meshes for the treatment of contaminated or infected IH in a homogeneous series with a standardized technique.

METHODS

Data of all patients operated on between 2008 and 2015 for contaminated or infected IH, using an absorbable (A) Vicryl® or a biological (B) Strattice® mesh, were reviewed. Patient characteristics, infectious complication rates, and recurrence-free outcome (RFO) were compared between the two groups. A propensity score methodology was applied to a Cox regression model to deal with unbalanced characteristics between groups.

RESULTS

Patient demographics in A (n = 57) and in B (n = 24) were similar except that B patients had larger parietal defects (p < 0.001) and higher Center for Disease Control (CDC) wound class (p = 0.034). Patients in A had statistically significantly more postoperative early (61.4% vs. 33.3%, p = 0.03) and late (31.2% vs. 8.3%, p = 0.046) infectious complications. Six-, 12-, and 36-month RFO rates were 77%, 47%, and 24%, and 96%, 87%, and 82% in A and B, respectively, p < 0.001. Raw multivariable Cox regression analysis found that B (HR = 0.1, 95% CI [0.03-0.34], p < 0.001) was independently associated with prolonged RFO (HR = 0.091, 95% CI [0.045-0.180], p < 0.001).

CONCLUSION

Biological meshes seem to be superior to absorbable meshes in patients with contaminated or infected incisional hernia. These results need to be confirmed by prospective randomized trials.

Repair of complex abdominal wall hernias with a cross-linked porcine acellular matrix: cross-sectional results of a Dutch cohort study

BACKGROUND

The use of synthetic mesh in potentially contaminated and contaminated incisional hernias may lead to a higher morbidity and mortality. Biological meshes may provide a solution, but since these meshes are rarely used, little is known about long-term results. The aim of this cohort study was to evaluate the long-term clinical efficacy and patient satisfaction following Permacol™ in complex abdominal wall hernia repair (CAWHR) patients in a cross-sectional fashion.

MATERIALS AND METHODS

All patients were operated for CAWHR with Permacol™ in the Netherlands between 2009 and 2012. The design was a multicenter cross-sectional cohort study. The STROCSS statement was followed. Patients were interviewed, underwent abdominal examination, and completed quality-of-life questionnaires. ClinicalTrials.gov Identifier NCT02166112. Research Registry Identifier researchregistry4713.

RESULTS

Seventy-seven patients were seen in the outpatient clinic. Their hernias were classified as potentially contaminated in 25 patients (32.5%) and infected in 52 patients (67.5%). The mean follow-up was 22.2 ± 12.6 months. The most frequent postoperative complication was wound infection (n = 21; 27.3%), meshes had to be removed in five patients (6.5%). By the time of their visit to the outpatient clinic, 22 patients (28.6%) had a recurrence of whom ten (13%) had undergone reoperation. Thirty-nine patients (50.6%) had bulging of the abdominal wall. Quality-of-life questionnaires revealed that patients graded their health status with a mean 6.8 (± 1.8) out of 10 points.

CONCLUSION

Bulging and recurrence are frequently observed in patients treated with Permacol™ for CAWHR. Considering both recurrence and bulging as undesirable outcomes of treatment, a total of 46 patients (59.7%) had an unfavorable outcome. Infection rates were high, but comparable with similar patient cohorts. Quality-of-life questionnaires revealed that patients were satisfied with their general health, but scored significantly lower on most quality-of-life modalities of the Short Form-36 questionnaire.

Prophylactic onlay reinforcement with absorbable mesh (polyglactin) is associated with less early wound complications after kidney transplantation: A preliminary study

Incidence of wound complications after kidney transplantation (KTx) is still considerable. Here, we report the impact of prophylactic absorbable polyglactin (Vicryl®) mesh reinforcement on the incidence of short-term post-KTx wound complications. Sixty-nine patients were analyzed; 23 with and 46 without preventive onlay mesh reinforcement. Surgical site infections (SSI) were seen in six (26%) patients in the mesh group and in 17 (37%) patients in no-mesh group. A lower, but not statistically significant, rate of early postoperative wound complications occurred in the mesh group. Wound complications were observed in seven (30%) patients in the mesh group and in 23 (50%) patients in the no-mesh group. There was no association between mesh placement and SSI incidence (odds ratios [OR] 0.60, 95% confidence interval [CI] 0.20-1.82, p = 0.369) and wound complications (OR 0.44, 95% CI 0.15-1.26, p = 0.126). Therefore, we conclude that mesh reinforcement does not increase the risk of SSI and overall wound complications. Long-term outcomes have to be evaluated in a randomized trial setting. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:67-72, 2020.

Lessons learned from 227 biological meshes used for the surgical treatment of ventral abdominal defects

PURPOSE

The advantages of biological meshes for ventral hernia repair are still under debate. Given the high financial cost, the proper indications for biological meshes should be clarified to restrict their use to properly selected patients.

METHODS

A retrospective database was instituted to register all cases of abdominal wall defect treated with biological meshes from 1/2010 to 3/2016.

RESULTS

A total of 227 patients (mean age: 64 years) whose ventral abdominal defects were reconstructed with a biological mesh were included in the study. Patients were divided according to the 2010 four-level surgical-site complication risk grading system proposed by the Ventral Hernia Working Group (VHWG): Grade 1 (G1, 12 cases), Grade 2 (G2, 68 cases), Grade 3 (G3, 112 cases), and Grade 4 (G4, 35 cases). The surgical site complication rate was higher in patients with one or more risk factors (33.6% vs 19% in patients with no risk factors) (P = 0.68). Statistically significant risk factors associated with the onset of one or more postoperative surgical site complications included: diabetes, coronary artery disease, immunosuppression, and obesity. Recurrence was more common in patients with surgical site complications and mainly associated with infection (38.9%) and wound necrosis (44.4%), and in cases of inlay positioning of the mesh (36%).

CONCLUSIONS

Due to their high costs, biological mesh should not be used in G1 patients. In infected fields (G4), they should only be used if no other surgical solution is feasible. There is a clear need to prospectively evaluate the performance of biological meshes.

The Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development

Collagen is the oldest and most abundant extracellular matrix protein that has found many applications in food, cosmetic, pharmaceutical, and biomedical industries. First, an overview of the family of collagens and their respective structures, conformation, and biosynthesis is provided. The advances and shortfalls of various collagen preparations (e.g., mammalian/marine extracted collagen, cell-produced collagens, recombinant collagens, and collagen-like peptides) and crosslinking technologies (e.g., chemical, physical, and biological) are then critically discussed. Subsequently, an array of structural, thermal, mechanical, biochemical, and biological assays is examined, which are developed to analyze and characterize collagenous structures. Lastly, a comprehensive review is provided on how advances in engineering, chemistry, and biology have enabled the development of bioactive, 3D structures (e.g., tissue grafts, biomaterials, cell-assembled tissue equivalents) that closely imitate native supramolecular assemblies and have the capacity to deliver in a localized and sustained manner viable cell populations and/or bioactive/therapeutic molecules. Clearly, collagens have a long history in both evolution and biotechnology and continue to offer both challenges and exciting opportunities in regenerative medicine as nature's biomaterial of choice.

Systematic review of transversus abdominis release in complex abdominal wall reconstruction

BACKGROUND

Transversus abdominis release (TAR), as a type of posterior component separation, is a new myofascial release technique in complex ventral hernia repair. TAR preserves rectus muscle innervation, creates an immense retromuscular plane and allows bilaminar ingrowth of the mesh. The place of the TAR within the range of established anterior component separation techniques (CST) is unclear. Aim of this systematic literature review is to estimate the position of the TAR in the scope of ventral hernia repair techniques.

METHODS

MEDLINE, Embase, Pubmed and the Cochrane controlled trials register and Science citation index were searched using the following terms: 'posterior component separation', 'transversus abdominis release', 'ventral hernia repair', 'complex abdominal wall reconstruction'. To prevent duplication bias, only studies with a unique cohort of patients who underwent transversus abdominis release for complex abdominal wall reconstruction were eligible. Postoperative complications and recurrences had to be registered adequately. The rate of surgical site occurrences and recurrences of the TAR were compared with those after anterior CST, published earlier in two meta-analyses.

RESULTS

Five articles met our strict inclusion criteria, describing 646 TAR patients. Methodological quality per study was good. Mean hernia surface was 509 cm² and 88% of the hernias were located in the midline. Preoperative risk stratification was distributed in low risk (10%), co-morbid (55%), potentially contaminated (32%) and infected (3%). Pooled calculations demonstrated a mean SSO rate of 15% after TAR (20-35% after anterior CST) and a mean 2-year hernia recurrence rate of 4% (13% after anterior CST). Mean hernia surface was 300 cm² in anterior component separation studies.

CONCLUSION

This review demonstrates that the transversus abdominis release is a good alternative for anterior CST in terms of SSO and recurrence, especially in very large midline ventral hernias.

Approaches to cutaneous wound healing: basics and future directions

The skin provides essential functions, such as thermoregulation, hydration, excretion and synthesis of vitamin D. Major disruptions of the skin cause impairment of critical functions, resulting in high morbidity and death, or leave one with life-changing cosmetic damage. Due to the complexity of the skin, diverse approaches are needed, including both traditional and advanced, to improve cutaneous wound healing. Cutaneous wounds undergo four phases of healing. Traditional management, including skin grafts and wound dressings, is still commonly used in current practice but in combination with newer technology, such as using engineered skin substitutes in skin grafts or combining traditional cotton gauze with anti-bacterial nanoparticles. Various upcoming methods, such as vacuum-assisted wound closure, engineered skin substitutes, stem cell therapy, growth factors and cytokine therapy, have emerged in recent years and are being used to assist wound healing, or even to replace traditional methods. However, many of these methods still lack assessment by large-scale studies and/or extensive application. Conceptual changes, for example, precision medicine and the rapid advancement of science and technology, such as RNA interference and 3D printing, offer tremendous potential. In this review, we focus on the basics of wound treatment and summarize recent developments involving both traditional and hi-tech therapeutic methods that lead to both rapid healing and better cosmetic results. Future studies should explore a more cost-effective, convenient and efficient approach to cutaneous wound healing. Graphical abstract Combination of various materials to create advanced wound dressings.

"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.

Systematic review of the stage of innovation of biological mesh for complex or contaminated abdominal wall closure

Background

Achieving stable closure of complex or contaminated abdominal wall incisions remains challenging. This study aimed to characterize the stage of innovation for biological mesh devices used during complex abdominal wall reconstruction and to evaluate the quality of current evidence.

Methods

A systematic review was performed of published and ongoing studies between January 2000 and September 2017. Eligible studies were those where a biological mesh was used to support fascial closure, either prophylactically after midline laparotomy, or for reinforcement after repair of incisional hernia with midline incision. The primary outcome measure was the IDEAL framework stage of innovation. The key secondary outcome measure was the GRADE criteria for study quality.

Results

Thirty‐five studies including 2681 patients were included. Four studies considered mesh prophylaxis, 23 considered hernia repair, and eight reported on both. There was one published randomized trial (IDEAL stage 3), none of which was of high quality; the others were non‐randomized studies (IDEAL stage 2a). A detailed description of surgical technique was provided in most studies (27 of 35); however, no study reported outcomes according to the European Hernia Society consensus statement and only two described quality control of surgical technique during the study. From 21 ongoing randomized trials and observational studies, 11 considered repair of incisional hernia and 10 considered prophylaxis (seven in elective settings).

Conclusion

The evidence base for biological mesh is limited, and better reporting and quality control of surgical techniques are needed. Although results of ongoing trials over the next decade will improve the evidence base, further study is required in the emergency and contaminated settings.

Biological Implant for Complex Abdominal Wall Reconstruction: A Single Institution Experience and Review of Literature

AIM

To present our single institution and surgeon's complex abdominal wall reconstructions (CAWR) experience with Permacol™ mesh through a non-randomized study.

PATIENTS AND METHOD

Data of 51 consecutive patients were prospectively collected between 2003 and 2015. Patients had a median of 3 comorbidities (range 0-10) and 68% were Center for Disease Control class II-IV. The mean previous repair was 1.3 (range, 0-12), and 25 (44%) had a mesh in situ. The median defect size was 625 cm².

RESULTS

Among the 56 CAWR procedures, in 16 (29%) bowel resection/anastomosis was performed. The overall post-operative complication rate was 45%, and it was wound-related except from 1 patient dead for myocardial infarction. One was lost at follow-up. Five were re-operated for recurrence with a second Permacol mesh, leading to 14 (26%) overall recurrences at a mean follow-up of 44 months (range, 4-123). In 33 (59%) cases, fascial closure was achieved. The mesh placement was intraperitoneal in 89%, retro-muscular in 9% and supra-fascial in 1% of cases. A multivariate analysis showed that predictor risk for recurrence was more than 3 previous repairs, wound class III-IV, whereas age, type of comorbidities, defect size and fascial closure did not influence the recurrence. Median post-operative performance status was 0 (range; 0-3). A satisfaction questionnaire was obtained in 43 patients, and 86% of them were satisfied with the outcome.

CONCLUSIONS

Biological materials have the potential to reduce morbidity and improve outcome of definitive repair of CAWR.

Updates in Mesh and Biomaterials

Prior publications of the Surgical Clinics of North America have highlighted the technical challenges of abdominal wall reconstruction. This article provides an update on synthetic, biologic, and biosynthetic mesh research since the 2013 Surgical Clinics of North America hernia publication and highlights the future of mesh research. This update features research that has been conducted since the prior publication to guide surgeons to choose the best and most appropriate mesh for their patients.

Prophylactic placement of permanent synthetic mesh at the time of ostomy closure prevents formation of incisional hernias

BACKGROUND

Reversal of an enterostomy results in a high rate of incisional hernia at the ostomy site. Prophylactic mesh reinforcement of the fascial defect is typically not considered due to the contaminated nature of the case. We present the outcomes of a series of prophylactic mesh reinforcements with retromuscular, large-pore polypropylene at the time of enterostomy reversal.

METHODS

Retrospective review of all ostomy reversals was performed. All cases with placement of synthetic mesh reinforcement were identified from a prospectively maintained, hernia database. Primary end points were surgical site occurrence, surgical site infection, and hernia occurrence.

RESULTS

Ostomy reversal was performed in 359 patients; 91 were reinforced with mesh and 268 without mesh. Colostomy reversal was performed in 56.5% and ileostomy in 43.5%. The mesh group had a greater body mass index and a greater incidence of chronic obstructive pulmonary disease, but groups were otherwise similar. A midline incisional hernia was present in 45% of the mesh group vs 4.5% in the controls. Incidence of surgical site occurrence and surgical site infection were similar for mesh and control groups (21 vs 22.8%; P = .82 and 20 vs 19.8%; P = 1.000, respectively). Superficial surgical site infection was less with mesh (8 vs 16.4%; P = .039). Incidence of a hernia developing at the stoma site was decreased markedly with mesh (1% vs 17.2%; P < .001), as was the occurrence of a midline hernia (6% vs 19%; P = .004). Mesh was placed across the midline prophylactically in 29.7% of cases, which decreased midline hernia formation from 24.1% to 4% (P = .019).

CONCLUSION

Retromuscular placement of permanent synthetic mesh at the time of enterostomy reversal is effective in preventing development of incisional hernia without increased risk of surgical site occurrence or surgical site infection.

Patterns of Recurrence and Mechanisms of Failure after Open Ventral Hernia Repair with Mesh

Recurrence after ventral hernia repair (VHR) remains a significant complication. We sought to identify the technical aspects of VHR associated with recurrence. Patients who underwent open midline VHR between 2006 and 2013 (n = 261) were retrospectively evaluated. Patients with recurrence (Group 1, n = 48) were compared with those without recurrence (Group 2, n = 213). Smoking, diabetes, and body mass index were not different between groups. More patients in Group 1 underwent clean-contaminated, contaminated, or dirty procedures (43.8 vs 27.7%; P = 0.021). Group 1 had a higher incidence of surgical site occurrence (52.1 vs 32.9%; P = 0.020) and surgical site infection (43.8 vs 15.5%; P < 0.001). Recurrences were due to central mesh failure (CMF) (39.6%), midline recurrence after biologic or bioabsorbable mesh repair (18.8%), superior midline (16.7%), lateral (16.7%), and after mesh explantation (12.5%). Most CMF (78.9%) occurred with light-weight polypropylene (LWPP). Recurrence was higher if the midline fascia was unable to be closed. Recurrence with midweight polypropylene (MWPP) was lower than biologic (P < 0.001), bioabsorbable (P = 0.006), and light-weight polypropylene (P = 0.046) mesh. Fixation, component separation technique, and mesh position were not different between groups. Wound complications are associated with subsequent recurrence, whereas midweight polypropylene is associated with a lower overall risk of recurrence and, specifically, CMF.

Single-center ventral hernia repair with porcine dermis collagen implant

INTRODUCTION

This study aims to evaluate the outcomes and utilization of porcine acellular dermal collagen implant (PADCI) during VHR at a large tertiary referral center.

METHODS

Records of 5485 patients who underwent VIHR from June 1995 to August 2014 were retrospectively reviewed to identify patients >18 years of age who had VIHR with PADCI reinforcement. Use of multiple mesh reinforcement products, inguinal hernias, and hiatal hernias were exclusion criteria. The primary outcome was hernia recurrence, and secondary outcomes were early complications and surgical site occurrences (SSOs). Uni- and multivariate analyses assessed risk factors for recurrence after PADCI reinforced VIHR.

RESULTS

There were 361 patients identified (54.5% female, mean age of 56.7 ± 12.5 years, and mean body mass index (BMI) of 33.0 ± 9.9 kg/m²). Hypertension (49.5%), diabetes (24.3%), and coronary artery disease (14.4%) were the most common comorbidities, as was active smoking (20.7%). Most were classified as American Association of Anesthesiologists (ASA) Class 3 (61.7%). Hernias were distributed across all grades of the ventral hernia working group (VHWG) grading system: grade I 93 (25.7%), grade II 51 (14.1%), grade III 113 (31.3%), and grade IV 6 (1.6%). Most VIHR were performed from an open approach (96.1%), and were frequently combined with concomitant surgical procedures (47.9%). Early postoperative complications (first 30 days) were reported in 39.0%, with 71 being SSO. Of the 19.7% of patients with SSO, there were 31 who required procedural intervention. After a mean follow-up of 71.5 ± 20.5 months, hernia recurrence was documented in 34.9% of patients. Age and male gender were predictors of recurrence on multivariate analysis.

CONCLUSION

To the best of our knowledge, this is the largest retrospective single institutional study evaluating PADCI to date. Hernias repaired with PADCI were frequently in patients undergoing concomitant operations. Reinforcement with PADCI may be considered a temporary closure, with a relatively high recurrence rate, especially among patients who are older, male, and undergo multiple explorations in a short perioperative period.

Characteristics of different mesh types for abdominal wall repair in an experimental model of peritonitis

BACKGROUND

The use of synthetic mesh to repair a potentially contaminated incisional hernia may lead to higher failure rates. A biological mesh might be considered, but little is known about long-term results. Both biological and synthetic meshes were investigated in an experimental model of peritonitis to assess their characteristics in vivo.

METHODS

Male Wistar rats were randomized into five groups and peritonitis was induced. A mesh was implanted after 24 h. Five meshes were investigated: Permacol™ (cross-linked collagen), Strattice™ (non-cross-linked collagen), XCM Biologic^® (non-cross-linked collagen), Omyra^® Mesh (condensed polytetrafluoroethylene) and Parietene™ (polypropylene). The rats were killed after either 30, 90 or 180 days. Incorporation and shrinkage of the mesh, adhesion coverage, strength of adhesions and histology were analysed.

RESULTS

Of 135 rats randomized, 18 died from peritonitis. Some 180 days after implantation, both XCM Biologic^® and Permacol™ had significantly better incorporation than Strattice™ (P = 0·003 and P = 0·009 respectively). Strattice™ had significantly fewer adhesions than XCM Biologic^® (P = 0·001) and Permacol™ (P = 0·020). Thirty days after implantation, Permacol™ had significantly stronger adhesions than Strattice™ (P < 0·001). Shrinkage was most prominent in XCM Biologic^® , but no significant difference was found compared with the other meshes. Histological analysis revealed marked differences in foreign body response among all meshes.

CONCLUSION

This experimental study suggested that XCM Biologic^® was superior in terms of incorporation, macroscopic mesh infection, and histological parameters such as collagen deposition and neovascularization. There must be sufficient overlap of mesh during placement, as XCM Biologic^® showed a high rate of shrinkage. Surgical relevance The use of synthetic mesh to repair a potentially contaminated incisional hernia is not supported unequivocally, and may lead to a higher failure rate. A biological mesh might be considered as an alternative. There are few long-term studies, as these meshes are expensive and rarely used. This study evaluated the use of biological mesh in a contaminated environment, and investigated whether there is an ideal mesh. A new non-cross-linked biological mesh (XCM Biologic^® ) was evaluated in this experiment. The new non-cross-linked biological mesh XCM Biologic^® performed best and may be useful in patients with a potentially contaminated incisional hernia.

The role of open abdomen in non-trauma patient: WSES Consensus Paper

The open abdomen (OA) is defined as intentional decision to leave the fascial edges of the abdomen un-approximated after laparotomy (laparostomy). The abdominal contents are potentially exposed and therefore must be protected with a temporary coverage, which is referred to as temporal abdominal closure (TAC). OA use remains widely debated with many specific details deserving detailed assessment and clarification. To date, in patients with intra-abdominal emergencies, the OA has not been formally endorsed for routine utilization; although, utilization is seemingly increasing. Therefore, the World Society of Emergency Surgery (WSES), Abdominal Compartment Society (WSACS) and the Donegal Research Academy united a worldwide group of experts in an international consensus conference to review and thereafter propose the basis for evidence-directed utilization of OA management in non-trauma emergency surgery and critically ill patients. In addition to utilization recommendations, questions with insufficient evidence urgently requiring future study were identified.

Biomimetic collagen/elastin meshes for ventral hernia repair in a rat model

Ventral hernia repair remains a major clinical need. Herein, we formulated a type I collagen/elastin crosslinked blend (CollE) for the fabrication of biomimetic meshes for ventral hernia repair. To evaluate the effect of architecture on the performance of the implants, CollE was formulated both as flat sheets (CollE Sheets) and porous scaffolds (CollE Scaffolds). The morphology, hydrophylicity and in vitro degradation were assessed by SEM, water contact angle and differential scanning calorimetry, respectively. The stiffness of the meshes was determined using a constant stretch rate uniaxial tensile test, and compared to that of native tissue. CollE Sheets and Scaffolds were tested in vitro with human bone marrow-derived mesenchymal stem cells (h-BM-MSC), and finally implanted in a rat ventral hernia model. Neovascularization and tissue regeneration within the implants was evaluated at 6weeks, by histology, immunofluorescence, and q-PCR. It was found that CollE Sheets and Scaffolds were not only biomechanically sturdy enough to provide immediate repair of the hernia defect, but also promoted tissue restoration in only 6weeks. In fact, the presence of elastin enhanced the neovascularization in both sheets and scaffolds. Overall, CollE Scaffolds displayed mechanical properties more closely resembling those of native tissue, and induced higher gene expression of the entire marker genes tested, associated with de novo matrix deposition, angiogenesis, adipogenesis and skeletal muscles, compared to CollE Sheets. Altogether, this data suggests that the improved mechanical properties and bioactivity of CollE Sheets and Scaffolds make them valuable candidates for applications of ventral hernia repair.

STATEMENT OF SIGNIFICANCE

Due to the elevated annual number of ventral hernia repair in the US, the lack of successful grafts, the design of innovative biomimetic meshes has become a prime focus in tissue engineering, to promote the repair of the abdominal wall, avoid recurrence. Our meshes (CollE Sheets and Scaffolds) not only showed promising mechanical performance, but also allowed for an efficient neovascularization, resulting in new adipose and muscle tissue formation within the implant, in only 6weeks. In addition, our meshes allowed for the use of the same surgical procedure utilized in clinical practice, with the commercially available grafts. This study represents a significant step in the design of bioactive acellular off-the-shelf biomimetic meshes for ventral hernia repair.

Effectiveness and versatility of biological prosthesis in transplanted patients

AIM

To emphasize the effectiveness and versatility of prosthesis, and good tolerance by patients with incisional hernia (IH).

METHODS

From December 2001 to February 2016, 270 liver transplantations were performed at San Camillo Hospital. IH occurred in 78 patients (28.8%). IH usually appeared early within the first year post-orthotopic liver transplantation. In the first era, fascial defect was repaired by primary closure for defects smaller than 2.5 cm or with synthetic mesh for greater defects. Recently, we started using biological mesh (Permacol™, Covidien). We present a series of five transplanted patients submitted to surgery for abdominal wall defect correction repaired with biological mesh (Permacol™, Covidien).

RESULTS

In our cases, the use of biological prosthesis (Permacol™, Covidien) have proven to be effective and versatile in repairing hernia defects of different kinds; patients did not suffer infections of the prosthesis and no recurrence was observed. Furthermore, the prosthesis remains intact even in the years after surgery.

CONCLUSION

The cases that we presented show that the use of biological mesh (Permacol™, Covidien) in transplanted patients may be safe and effective, being careful in the management of perioperative immunosuppression and renal and graft function, although the cost of the product itself has been the main limiting factor and there is need for prospective studies for further evaluations.

Primary fascial closure with biologic mesh reinforcement results in lesser complication and recurrence rates than bridged biologic mesh repair for abdominal wall reconstruction: A propensity score analysis

BACKGROUND

Previous studies suggest that bridged mesh repair for abdominal wall reconstruction may result in worse outcomes than mesh-reinforced, primary fascial closure, particularly when acellular dermal matrix is used. We compared our outcomes of bridged versus reinforced repair using ADM in abdominal wall reconstruction procedures.

METHODS

This retrospective study included 535 consecutive patients at our cancer center who underwent abdominal wall reconstruction either for an incisional hernia or for abdominal wall defects left after excision of malignancies involving the abdominal wall with underlay mesh. A total of 484 (90%) patients underwent mesh-reinforced abdominal wall reconstruction and 51 (10%) underwent bridged repair abdominal wall reconstruction. Acellular dermal matrix was used, respectively, in 98% of bridged and 96% of reinforced repairs. We compared outcomes between these 2 groups using propensity score analysis for risk-adjustment in multivariate analysis and for 1-to-1 matching.

RESULTS

Bridged repairs had a greater hernia recurrence rate (33.3% vs 6.2%, P < .001), a greater overall complication rate (59% vs 30%, P = .001), and worse freedom from hernia recurrence (log-rank P <.001) than reinforced repairs. Bridged repairs also had a greater rate of wound dehiscence (26% vs 14%, P = .034) and mesh exposure (10% vs 1%, P = .003) than mesh-reinforced abdominal wall reconstruction. When the treatment method was adjusted for propensity score in the propensity-score-matched pairs (n = 100), we found that the rates of hernia recurrence (32% vs 6%, P = .002), overall complications (32% vs 6%, P = .002), and freedom from hernia recurrence (68% vs 32%, P = .001) rates were worse after bridged repair. We did not observe differences in wound healing and mesh complications between the 2 groups.

CONCLUSION

In our population of primarily cancer patients at MD Anderson Cancer Center bridged repair for abdominal wall reconstruction is associated with worse outcomes than mesh-reinforced abdominal wall reconstruction. Particularly when employing acellular dermal matrix, reinforced repairs should be used for abdominal wall reconstruction whenever possible.

Development of a novel murine model for treatment of infected mesh scenarios

BACKGROUND

Indications regarding hernia repair after removal of previously infected prostheses remain unclear. Patients may receive staged primary repair or single-stage reconstructions, neither of which may be ideal. Although animal models have simulated contamination by direct inoculation of implants with bacteria, there remains a paucity of literature, which simulates a field following mesh infection and removal. We aimed to develop a murine model to mimic this complex scenario to allow for further testing of various implants.

METHODS

Thirty-six female CL57BL/6J mice underwent implantation of a 0.7 × 0.7 cm polyester mesh in the dorsal subcutaneous position. Wounds were closed and inoculated with 100 µL containing 1 × 10⁴ CFU of GFP-labeled MSSA. After 2 weeks, the infected mesh was removed and the cavity was copiously irrigated with saline. Mice were split into four groups: with three groups receiving new polyester, polypropylene, and porcine mesh and remaining as non-mesh controls. Mice were survived for another 2 weeks and underwent necropsy. Gross infection was evaluated at 2 and 4 weeks. Tissue homogenization and direct plating to recover GFP MSSA was completed at 4 weeks.

RESULTS

At 2 weeks, all mice were noted to have gross mesh infection. One animal died due to overwhelming infection and wound breakdown. At 4 weeks, 5/6 (83 %) control mice who did not have a second mesh implantation had full clearance of their wounds. In contrast, 9/10 (90 %) mice with re-implantation of polypropylene were noted to have pus and recovery of GFP MSSA on plating. This was also observed in 100 % of mice with polyester and porcine mesh.

CONCLUSION

Our novel murine model demonstrates that mesh re-implantation after infected mesh removal results in infection of the newly placed prosthesis, regardless of the material characteristic or type. This model lays foundation for development and investigation of implants for treatment strategies following infected mesh removal.

Outcomes of Retromuscular Porcine Biologic Mesh Repairs Using Transversus Abdominis Release Reconstruction

BACKGROUND

Optimal mesh reinforcement and operative technique for major abdominal wall reconstructions (AWR) remain debatable. Posterior component separation via transversus abdominis release (TAR) allows for wide sublay mesh reinforcement with durable reconstruction, and has been gaining popularity in recent years. Although biologic mesh has been associated with mixed results, outcomes of AWR with bioprosthetics have not been well elucidated to date. We evaluated our outcomes of TAR reconstructions with retromuscular porcine biologic mesh reinforcement.

STUDY DESIGN

Consecutive patients undergoing AWR using TAR with biologic mesh sublay reinforcement were identified in our prospective databases and analyzed. We characterized patient demographics and perioperative details. Main outcomes measures included wound complications and hernia recurrence.

RESULTS

Between 2007 and 2014, seventy-seven patients (mean age 56 years, mean BMI 35 kg/m(2)) underwent AWR using TAR with biologic mesh. Mean hernia size was 306 ± 128 cm(2) with mean width of 14.3 ± 3.3 cm. The vast majority of patients had grade 3 hernias (92%) and more than half had a history of wound infection (55%). There were 22 (28.6%) surgical site infections consisting of 14 deep, 7 superficial, and 1 organ-space surgical site infections. There were no incidences of chronic mesh infection or explantation. In patients with at least 12 months follow-up (mean duration 28.2 months), there were 8 (12.5%) recurrences.

CONCLUSIONS

Complex hernias repaired with TAR and retromuscular porcine biologic mesh reinforcement are associated with a low rate of serious perioperative wound/mesh complications. Additionally, our approach resulted in a fairly low rate of hernia recurrences in this complex cohort of patients. We believe that the TAR approach and retromuscular mesh placement can be beneficial when biologic mesh reinforcement is chosen during complex and/or contaminated abdominal wall reconstructions.

The use of an acellular porcine dermal collagen implant in the repair of complex abdominal wall defects: a European multicentre retrospective study

BACKGROUND

The use of biological materials for the repair of complex abdominal wall defects has increased over the years; however, the role of these materials in routine practice remains unclear. The aim of the study was to evaluate clinical outcomes following the use of Permacol™ porcine collagen surgical implant in complex abdominal wall repair.

METHODS

This subset analysis of seven European sites from a multicentre retrospective study included patients undergoing open or laparoscopic surgery and treated with Permacol™ surgical implant. Inguinal, parastomal, diaphragmatic, perineal, and hiatal repairs were excluded. Only patients with at least 12 months of follow-up after surgery were included.

RESULTS

A total of 109 patients (56 males and 53 females) were included. Patients had a median of two comorbidities (range 0-6). Thirty-three per cent of patients were treated for recurrent hernia. All but one case used an open approach. Sixty-six per cent were Center for Disease Control wound class II-IV at the time of surgery. Fascial closure was achieved in 69%. Median follow-up length was 720 days (range 368-2857). Recurrence rates at 1 and 2 years were 9.2 and 18.3 %, respectively, and were higher in cases without fascial closure. One-year recurrence was higher following use of an onlay technique (P = 0.025). In a multivariate analysis, among 16 comorbidities examined only fascial closure significantly impacted 1-year recurrence (P = 0.049).

CONCLUSIONS

Data from this large retrospective multicentre European study strongly suggest the use of Permacol™ porcine collagen surgical implant to be safe and effective for complex abdominal wall repair. The recurrence rate was impacted by fascial closure.