Experimental evaluation of four biologic prostheses for ventral hernia repair

Implant-Based Breast Reconstruction with Bovine Pericardium: Our Approach Using Tutopatch® and Review of Literature

OBJECTIVES

To describe the usage and advantages of bovine pericardium mesh (Tutopatch®) in breast reconstruction and to compare different mesh materials used in immediate breast reconstruction.

METHODS

Our study involved a single-center, retrospective analysis of 103 patients (comprising 114 breasts) who underwent immediate implant-based breast reconstruction using bovine pericardium bovine matrix. The procedures were performed by the same surgical team between April 2018 and May 2023.

RESULTS

The rates of early and late complications were examined after a median follow-up period of 30.2 ± 5.5 months. The results revealed that the rates of early complications stood at 9.7%, while late complications were observed in 14.5% of the cases. The most common late complication was seroma formation (7.7%) which six were resolved without any surgical intervention.

CONCLUSION

Tutopatch® can be used as an extension of the muscle to cover the prosthesis. It forms an extra layer over the silicone implant that helps to decrease the complications as capsular contracture and implant exposure. It also represents a significant 85 % reduction in cost when compared to a similar-sized mesh materials.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

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

BACKGROUND

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

AIM

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Study on the preparation and properties of acellular matrix from the skin of silver carp (Hypophthalmichthys molitrix)

Acellular matrices are mainly composed of mammalian tissues, and aquatic tissues with lower biological risks and less religious restrictions are considered alternatives to mammalian tissues. The acellular fish skin matrix (AFSM) has been commercially available. Silver carp has the advantages of farmability, high yield and low price, but there are few studies on the silver carp acellular fish skin matrix (SC-AFSM). In this study, an acellular matrix with low DNA and endotoxin was prepared from the skin of silver carp. After treatment with trypsin/sodium dodecyl sulfate and Triton X-100 solutions, the DNA content in SC-AFSM reached 11.03 ± 0.85 ng/mg, and the endotoxin removal rate was 96.8%. The porosity of SC-AFSM was 79.64% ± 0.17%, which is favorable for cell infiltration and proliferation. The relative cell proliferation rate of SC-AFSM extract was 117.79% ± 15.26%. The wound healing experiment showed that SC-AFSM had no adverse acute pro-inflammatory response, which had a similar effect as commercial products in promoting tissue repair. Therefore, SC-AFSM has great application potential in biomaterials.

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

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

First-year complications after immediate breast reconstruction with a biological and a synthetic mesh in the same patient: A randomized controlled study

Background

Even though meshes and matrices are widely used in breast reconstruction, there is little high‐quality scientific evidence for their risks and benefits. The aim of this study was to compare first‐year surgical complication rates in implant‐based immediate breast reconstruction with a biological mesh with that of a synthetic mesh, in the same patient.

Methods

This study is a clinical, randomized, prospective trial. Patients operated on with bilateral mastectomy and immediate breast reconstruction were randomized to biological mesh on one side and synthetic mesh on the other side.

Results

A total of 48 breasts were randomized. As the synthetically and the biologically reconstructed breasts that were compared belonged to the same woman, systemic factors were exactly the same in the two groups. The most common complication was seroma formation with a frequency of 38% in the biological group and 3.8% in the synthetical group (p = .011). A higher frequency of total implant loss could be seen in the biologic mesh group (8.5% vs. 2%), albeit not statistically significant (p = .083).

Conclusions

In the same patient, a synthetic mesh seems to yield a lower risk for serious complications, such as implant loss, than a biological mesh.

Comparison of inflammatory response and synovial metaplasia in immediate breast reconstruction with a synthetic and a biological mesh: a randomized controlled clinical trial

The aim of this study was to compare inflammatory response and synovial metaplasia in implant-based immediate breast reconstruction with a biological mesh (Veritas^®) with that of a synthetic mesh (TIGR^® Matrix Surgical Mesh). We hypothesize that the inflammatory response and formation of synovial metaplasia might be different and the rate of capsular contracture therefore different. The patients were recruited from the Gothenburg TIGR^®/Veritas^® Study (ClinicalTrials.Gov identifier NCT02985073). All referrals for bilateral immediate breast reconstruction were assessed for inclusions. During the operation, the patients were randomized to which sides the biological and the synthetic mesh were going to be applied. During the implant exchange biopsies were taken. Biopsies were taken from 30 breasts in 15 patients. There seem to be more myofibroblast and neovascularization in the biological meshes than in the synthetic and the collagen fibers seem to be aligned in an irregular pattern with both parallel and vertical fibers. In the synthetic meshes, there were more giant cells and foreign body reaction and the collagen fibers were loosely and well aligned, oriented parallel to the surface of the implant. Synovial metaplasia was seen in the majority of both the biological and the synthetic meshes. The histological patterns in early capsules from biological and synthetic meshes vary considerably. Nonetheless, it is unknown what role different cell types have in capsular formation in the long run and there was no difference in clinical capsular contracture at the clinical follow-up in this study.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Adhesion prevention in ventral hernia repair: an experimental study comparing three lightweight porous meshes recommended for intraperitoneal use

BACKGROUND

In ventral hernia repair, when prosthetic material is placed intraperitoneally, it may lead to an inflammatory reaction resulting in adhesions between the mesh and abdominal viscera. Several meshes have been developed to minimize this process. In this experimental study, the ability of different combined meshes to attenuate the adhesion formation was examined.

METHODS

Three commercially available lightweight porous combined meshes were placed intraperitoneally to repair an abdominal wall defect in rats: DynaMesh-IPOM (PVDF + PP), TiMesh (titanium-coated filament PP) and C-QUR/FX (omega-3 fatty acid-coated filament PP). The DynaMesh-CICAT (PVDF) was implanted in the control group. Adhesion formation was macroscopically evaluated and scored after 7 and 21 days.

RESULTS

All animals except two presented intra-abdominal adhesions. None of the meshes examined in the study demonstrated to prevent adhesions. C-QUR/FX reduced adhesion formation at 7 days' follow-up compared with all other meshes but by 21 days this effect was diminished. Between 7 and 21 days adhesion extension significantly decreased for TiMesh. TAS did not show significant modifications between 7 and 21 days' follow-up for each mesh.

CONCLUSIONS

The combined porous meshes tested in the present study demonstrated to reduce but not to prevent the adhesion formation, even if with some differences. Combined porous meshes could be chosen instead of simple meshes for retro-rectus preperitoneal prosthetic ventral hernia repair.

MECHANICAL CHARACTERIZATION OF ANIMAL DERIVED GRAFTS FOR SURGICAL IMPLANTATION

Bioprostheses obtained from animal models are often adopted in abdominal surgery for repair and reconstruction. The functionality of these prosthetic implants is related also to their mechanical characteristics that are analyzed here. This work illustrates a constitutive model to describe the short-term mechanical response of Permacol[Formula: see text] bioprostheses. Experimental tests were developed on tissue samples to highlight mechanical non-linear characteristics and viscoelastic phenomena. Uni-axial tensile tests were developed to evaluate the strength and strain stiffening. Incremental uni-axial stress relaxation tests were carried out at nominal strain ranging from 10% to 20% and to monitor the stress relaxation process up to 400[Formula: see text]s. The constitutive model effectively describes the mechanical behavior found in experimental testing. The mechanical response appears to be independent on the loading direction, showing that the tissue can be considered as isotropic. The viscoelastic response of the tissue shows a strong decay of the stress in the first seconds of the relaxation process. The investigation performed is aimed at a general characterization of the biomechanical response and addresses the development of numerical models to evaluate the biomechanical performance of the graft with surrounding host tissues.

Bovine fetal collagen reinforcement in a small animal model of hernia with component repair

BACKGROUND

Component separation is a surgical strategy used to achieve abdominal wall reconstruction for patients with significant ventral hernias. With an increasing number of variations in procedural techniques and materials, the development of a small animal model of this surgery would allow for the controlled evaluation of variables with analytics not available in human clinical studies. To test this model, we investigated the reinforcement of these component repairs in rats with a bovine fetal collagen (BFC) scaffold.

METHODS

Fifty Sprague Dawley rats were randomized into either component repair alone or BFC reinforced component repair. At time points up to 1 y, these groups were evaluated for hernia formation, strength of repair, strength of mesh-muscle interface, and histology of the repair site.

RESULTS

Anterior component separation was achievable and reproducible in this small animal model. Significantly fewer hernias were found in BFC reinforced repairs. The change in transverse abdominal length was lower for reinforced repairs indicating less external oblique retraction, and reinforced repairs were consistently stronger than controls through 1 y. BFC was revascularized and repopulated with host cells but not rapidly degraded.

CONCLUSIONS

This small animal model of hernia repair with anterior component separation was effective in evaluating the reinforcement of a hernia repair with mesh. It may be useful in future work for the controlled, comparative investigation of different repair techniques and mesh materials in anterior component separation hernia repairs. Additionally, bovine fetal collagen was found to effectively reinforce component repairs and undergo an assimilation process including rapid revascularization and repopulation with host cells followed by gradual extracellular matrix remodeling.

Characterisation and comparison of the host response of 6 tissue-based surgical implants in a subcutaneous in vivo rat model

BACKGROUND

Hernia repair often involves fascial augmentation using biologic prostheses. Small processing changes during preparation modulate host tissue response, which influence material efficacy and longevity. In this pilot study, a rat model was used to determine the specific influence of tissue origin, decellularisation treatment and 1,6-hexamethylene diisocyanate (HMDI) cross-linking.

METHODS

Materials (1 cm2) were implanted subcutaneously into 6-week-old Wistar rats (4 materials per animal, n=6/material per time point) for 2, 5, 7, 14 and 28 days. Histologic processing was carried out after resin infiltration, observing classical histopathology and pathologic indexing. Materials comprised 6 tissue-based grafts covering both experimental and commercial porcine decellularised dermal and small intestinal submucosal materials.

RESULTS

Subcutaneous delivery of biologics demonstrated material-specific inflammatory/host responses. Controlled variations of the PermacolTM manufacturing process showed sodium dodecyl sulfate (SDS) was the most proinflammatory decellularisation reagent, and HMDI cross-linking had no effect on host response. All materials remained recoverable after 28 days, although SurgisisTM had partially resorbed.

CONCLUSION

Differences in host responses exist between biologic implants for hernia repair in this rat model. It is postulated that these modifications are induced during processing and may have an effect on the clinical outcome of hernia repair.

To cross-link or not to cross-link? Cross-linking associated foreign body response of collagen-based devices

Collagen-based devices, in various physical conformations, are extensively used for tissue engineering and regenerative medicine applications. Given that the natural cross-linking pathway of collagen does not occur in vitro, chemical, physical, and biological cross-linking methods have been assessed over the years to control mechanical stability, degradation rate, and immunogenicity of the device upon implantation. Although in vitro data demonstrate that mechanical properties and degradation rate can be accurately controlled as a function of the cross-linking method utilized, preclinical and clinical data indicate that cross-linking methods employed may have adverse effects on host response, especially when potent cross-linking methods are employed. Experimental data suggest that more suitable cross-linking methods should be developed to achieve a balance between stability and functional remodeling.

Blood vessel matrix seeded with cells: a better alternative for abdominal wall reconstruction-a long-term study

PURPOSE

The aim of this study was to present abdominal wall reconstruction using a porcine vascular graft seeded with MSC (mesenchymal stem cells) on rat model.

MATERIAL AND METHODS

Abdominal wall defect was prepared in 21 Wistar rats. Acellular porcine-vascular grafts taken from aorta and prepared with Triton X were used. 14 aortic grafts were implanted in place, of which 7 grafts were seeded with rat MSC cells (Group I), and 7 were acellular grafts (Group II). As a control, 7 standard polypropylene meshes were used for defect augmentation (Group III). The assessment method was performed by HE and CD31 staining after 6 months. The mechanical properties have been investigated by Zwick&Roell Z0.5.

RESULTS

The strongest angiogenesis and lowest inflammatory response were observed in Group I. Average capillaries density was 2.75, 0.75, and 1.53 and inflammatory effect was 0.29, 1.39, and 2.72 for Groups I, II, and III, respectively. The means of mechanical properties were 12.74 ± 1.48, 7.27 ± 1.56, and 14.4 ± 3.7 N/cm in Groups I and II and control, respectively.

CONCLUSIONS

Cell-seeded grafts have better mechanical properties than acellular grafts but worse than polypropylene mesh. Cells improved mechanical and physiological properties of decellularized natural scaffolds.

Laparoscopic ventral rectopexy using biologic mesh for the treatment of obstructed defaecation syndrome and/or faecal incontinence in patients with internal rectal prolapse: a critical appraisal of the first 100 cases

BACKGROUND

Laparoscopic ventral mesh rectopexy (LVR) is gaining wider acceptance as the preferred procedure to correct internal as well as external rectal prolapse associated with obstructed defaecation syndrome and/or faecal incontinence. Very few reports exist on the use of biologic mesh for LVR. The aim of our study was to report the complication and recurrence rate of our first 100 cases of LVR for symptomatic internal rectal prolapse and/or rectocele using a porcine dermal collagen mesh.

METHODS

Prospectively collected data on LVR for internal rectal prolapse were analysed. Surgical complications and functional results in terms of faecal incontinence (measured with the Faecal Incontinence Severity Index = FISI) and constipation (measured with the Wexner Constipation Score = WCS) at 3, 6 and 12 months were analysed. It was considered an improvement if FISI or WCS scores were reduced by at least 25 % and a cure if the FISI score decreased to <10 and the WCS decreased to <5.

RESULTS

Between April 2009 and April 2013, 100 consecutive female patients (mean age 63 years, range 24-88 years) underwent LVR. All patients had internal rectal prolapse (grade III [n = 25] and grade IV [n = 75] according to the Oxford classification) and rectocele. Mean operative time was 85 ± 40 min. Conversion rate to open technique was 1 %. There was no post-operative mortality. Overall 16 patients (16 %) experienced 18 complications, including rectal perforation (n = 1), small bowel obstruction (n = 2), urinary tract infection (n = 8), subcutaneous emphysema (n = 3), wound haematoma (n = 2), long lasting sacral pain (n = 1) and incisional hernia (1). Median post-operative length of stay was 2 days. Ninety-eight out of 100 patients completed follow-up. At the end of follow-up, the mean FISI score improved from 8.4 (±4.0 standard deviation (SD) p = 0.003) to 3.3 ± 2.3 SD (p = 0.04). Incontinence improved in 37 out of 43 patients (86 %), and 31 patients (72 %) were cured. Similarly, the mean WCS score improved from 18.4 ± 11.6 SD to 5.4 ± 4.1 SD (p = 0.04). Constipation improved in 82 out of 89 patients (92 %), and 70 patients (79 %) were cured. No worsening of continence status, constipation or sexual function was observed. Fourteen patients (14 %) experienced persistence or recurrence of prolapse.

CONCLUSIONS

LVR using biologic mesh is a safe and effective procedure for improving symptoms of obstructed defaecation and faecal incontinence in patients with internal rectal prolapse associated with rectocele.

Organ bioengineering for the newborn

Regenerative medicine has recently been established as an emerging interdisciplinary field focused on the repair; replacement or regeneration of cells, tissues and organs. It involves various disciplines, which are focused on different aspects of the regeneration process such as cell biology, gene therapy, bioengineering, material science and pharmacology. In this article, we will outline progress on tissue engineering of specific tissues and organs relevant to paediatric surgery.

Biologic versus nonbiologic mesh in ventral hernia repair: a systematic review and meta-analysis

BACKGROUND

The current standard of treatment for most ventral hernias is a mesh-based repair. Little is known about the safety and efficacy of biologic versus nonbiologic grafts. A meta-analysis was performed to examine two primary outcomes: recurrence and wound complication rates.

METHODS

Electronic databases and reference lists of relevant articles were systematically searched for all clinical trials and cohort studies published between January 1990 and January 2012. A total of eight retrospective studies, with 1,229 patients, were included in the final analysis.

RESULTS

Biologic grafts had significantly fewer infectious wound complications (p < 0.00001). However, the recurrence rates of biologic and nonbiologic mesh were not different. In subgroup analysis, there was no difference in recurrence rates and wound complications between human-derived and porcine-derived biologic grafts.

CONCLUSIONS

Use of biologic mesh for ventral hernia repair results in less infectious wound complications but similar recurrence rates compared to nonbiologic mesh. This supports the application of biologic mesh for ventral hernia repair in high-risk patients or patients with a previous history of wound infection only when the significant additional cost of these materials can be justified and synthetic mesh is considered inappropriate.

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

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

Bovine versus Porcine Acellular Dermal Matrix: A Comparison of Mechanical Properties

BACKGROUND

Porcine and bovine acellular dermal matrices (PADM and BADM, respectively) are the most commonly used biologic meshes for ventral hernia repair. A previous study suggests a higher rate of intraoperative device failures using PADM than BADM. We hypothesize that this difference is, in part, related to intrinsic mechanical properties of the matrix substrate and source material. The following study directly compares these 2 matrices to identify any potential differences in mechanical properties that may relate to clinical outcomes.

METHODS

Sections of PADM (Strattice; Lifecell, Branchburg, N.J.) and BADM (SurgiMend; TEI Biosciences, Boston, Mass.) were subjected to a series of biomechanical tests, including suture retention, tear strength, and uniaxial tensile strength. Results were collected and compared statistically.

RESULTS

In all parameters, BADM exhibited a superior mechanical strength profile compared with PADM of similar thickness. Increased BADM thickness correlated with increased mechanical strength. In suture tear-through testing with steel wire, failure of the steel wire occurred in the 4-mm-thick BADM, whereas the matrix material failed in all other thicknesses of BADM and PADM.

CONCLUSIONS

Before implantation, BADM is inherently stronger than PADM at equivalent thicknesses and considerably stronger at increased thicknesses. These results corroborate clinical data from a previous study in which PADM was associated with a higher intraoperative device failure rate. Although numerous properties of acellular dermal matrix contribute to clinical outcomes, surgeons should consider initial mechanical strength properties when choosing acellular dermal matrices for load-bearing applications such as hernia repair.

Extraperitoneal and intraperitoneal behavior of several biological meshes currently used to repair abdominal wall defects

BACKGROUND

This study compares the behavior of several cross- and noncrosslinked biomeshes (Permacol®, CollaMend®, Surgisis®, Tutomesh®, and Strattice®) currently used for abdominal wall repair when implanted intraperitoneally and extraperitoneally. Material and Methods. Intraperitoneal (IP) implants were fixed on the parietal peritoneum and partial abdominal wall defects (EP) were repaired using each of the biomeshes, in the rabbit abdominal wall. After 90 days of implant, the biomeshes were examined to assess biomesh degradation, collagen I and III expression (Sirius red staining) and the host macrophage response (immunohistochemistry). Results. Following implant, the thinner noncrosslinked biomeshes Tutomesh and Surgisis, were almost fully degraded in both models. In contrast, Strattice behavior was similar to crosslinked biomeshes, showing negligible degree of degradation. This mesh also showed high expression of collagen I, similar to the crosslinked. The noncrosslinked materials elicited lower macrophage counts, significantly so for Strattice. In IP and EP models, Permacol showed similarly high macrophages while counts were lower for CollaMend and Surgisis in the EP model. Conclusions. The intra or extraperitoneal implant of the different meshes did not affect host tissue incorporation or mesh degradation. The crosslinked biomeshes induced a more intense macrophage response regardless of their IP or EP location.

Carbon nanotubes as VEGF carriers to improve the early vascularization of porcine small intestinal submucosa in abdominal wall defect repair

Insufficient early vascularization in biological meshes, resulting in limited host tissue incorporation, is thought to be the primary cause for the failure of abdominal wall defect repair after implantation. The sustained release of exogenous angiogenic factors from a biocompatible nanomaterial might be a way to overcome this limitation. In the study reported here, multiwalled carbon nanotubes (MWNT) were functionalized by plasma polymerization to deliver vascular endothelial growth factor₁₆₅ (VEGF₁₆₅). The novel VEGF₁₆₅-controlled released system was incorporated into porcine small intestinal submucosa (PSIS) to construct a composite scaffold. Scaffolds incorporating varying amounts of VEGF₁₆₅-loaded functionalized MWNT were characterized in vitro. At 5 weight percent MWNT, the scaffolds exhibited optimal properties and were implanted in rats to repair abdominal wall defects. PSIS scaffolds incorporating VEGF₁₆₅-loaded MWNT (VEGF–MWNT–PSIS) contributed to early vascularization from 2–12 weeks postimplantation and obtained more effective collagen deposition and exhibited improved tensile strength at 24 weeks postimplantation compared to PSIS or PSIS scaffolds, incorporating MWNT without VEGF₁₆₅ loading (MWNT–PSIS).

A retrospective study evaluating the use of Permacol™ surgical implant in incisional and ventral hernia repair

BACKGROUND

The outcome of incisional and ventral hernia repair depends on surgical technique, patient, and material. Permacol™ surgical implant (crosslinked porcine collagen) has been used for over a decade; however, there are few data on outcomes. This study is the largest retrospective multinational study to date to evaluate outcomes with Permacol™ surgical implant in the repair of incisional and ventral hernias.

METHODS

Data were collected retrospectively on 343 patients treated for 213 incisional and 130 ventral hernias. Data evaluated included patient demographics, wound classification, surgical technique, morbidity, and recurrence rates.

RESULTS

Median follow-up time was 649 days (max: 2857), median age 57 years (range 23-91), and BMI 32 kg/m(2) (range 17.6-77.8). Two or more comorbidities were present in 70% of patients. Open surgery was performed in 220 (64%) patients. Permacol™ surgical implant was used as an underlay (250), sublay (39), onlay (37), or inlay (17). Surgical techniques included component separation (89; 25.9%), modified Stoppa technique (197; 57.4%), and Rives-Stoppa (17; 5.0%). CDC Surgical Wound Classification was Class I (190), Class II (103), Class III (28), and Class IV (22). Complications were seen in 40.5% (139) of the patients, with seroma (19%) and wound infection (15%) as the most common. Mesh removal occurred in 1 (0.3%) patient. Kaplan-Meier analysis demonstrated that the probabilities for hernia recurrence at one, two, and three years were 5.8%, 16.6%, and 31.0%, respectively.

CONCLUSIONS

Permacol™ surgical implant was shown to be safe with relatively low rates of hernia recurrence.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01214252 (http://www.clinicaltrials.gov).

Bioprosthetic tissue matrices in complex abdominal wall reconstruction

Background:

Complex abdominal defects are difficult problems encountered by surgeons in multiple specialties. Although current evidence supports the primary repair of these defects with mesh reinforcement, it is unclear which mesh is superior for any given clinical scenario. The purpose of this review was to explore the characteristics of and clinical relevance behind bioprosthetic tissue matrices in an effort to better clarify their role in abdominal wall reconstruction.

Methods:

We reviewed the peer-reviewed literature on the use of bioprosthetic mesh in human subjects. Basic science articles and large retrospective and prospective reviews were included in author’s analysis. The clinical performance and characteristics of 13 bioprosthetic tissue matrices were evaluated.

Results:

The majority of the products evaluated perform well in contaminated fields, where the risk of wound-healing difficulties is high. Clinical outcomes, which included infection, reherniation, and bulge formation, were variable, and the majority of the studies had a mean follow-up of less than 24 months.

Conclusions:

Although bioprosthetic matrix has a multitude of indications within the growing field of abdominal wall reconstruction, the functionality, regenerative capacity, and long-term fate of these products have yet to be fully established. Furthermore, the clinical performance, indications, and contraindications for each type of matrix need to be fully evaluated in long-term outcome studies.

Use of the vascu-guard bovine pericardium patch for arteriotomy closure in carotid endarterectomy. Early and long-term results

BACKGROUND

To report the early and long-term results of Vascu-Guard bovine pericardium (BP) for patch angioplasty in carotid endarterectomy (CEA).

METHODS

We retrospectively analyzed the data of 256 CEAs with BP patch closure performed in 238 patients during the past 12 years in our department. Patch-related complications (restenosis, infection, and aneurysm formation) and early and late (12 to 144 months follow-up) clinical outcomes were recorded and statistically analyzed.

RESULTS

Thirty-day postoperative stroke rate was 1.2% (3/256) with zero mortality. Major complications occurred in 3.5% (9 of 256) of the procedures and cranial nerve injury in 4.3% (11 of 256). At 12 years, cumulative estimates of freedom from any stroke, stroke-free survival, and freedom from restenosis were 88.4% (standard error [SE]: 3.3%), 60% (SE: 7.8%), and 98.3% (SE: 0.8%), respectively. No patient experienced patch infection or aneurysm formation.

CONCLUSIONS

This series shows the efficacy, safety, and durability of CEA with BP patch closure, in both the short and long term. BP combines the advantages of vein and synthetic patches, representing a suitable option when performing CEA.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Biology of biological meshes used in hernia repair

Successful repair of most hernias requires the use of a prosthetic implant for reinforcement of the defect. Because of the need for prosthetic implants to resist infections as well to support repairs in contaminated or potentially contaminated fields, biological meshes have been developed to take the place of nondegradable synthetic meshes in cases where mesh infection is of high concern. The ideal is a biological matrix that resists infection while providing durable reinforcement of a hernia repair. This article reviews the validity of assumptions that support the purported notion of the biological behavior of biological meshes.

Porcine dermal collagen (permacol) for sternal reconstruction

In chest wall reconstruction after wide chest wall resection, the use of a musculocutaneous flap or prosthetic materials is inevitable for maintaining thoracic movement and a closed pleural cavity. We report a case of a 63-year-old male with a large invasive thymic carcinoma in the anterior mediastinum. The mass measured 6.8 cm and involved the sternum, left side of the parasternal area, ribs, and intercostal muscles. The patient underwent subtotal sternectomy, radical thymectomy, and reconstruction with biological mesh (Permacol). Successful chest wall reconstruction without any other complications was achieved, demonstrating the effectiveness of Permacol.

Initial experience with the use of foetal/neonatal bovine acellular dermal collagen matrix (SurgiMend™) for tissue-expander breast reconstruction

BACKGROUND

Acellular dermal matrix (ADM) is commonly used in staged breast reconstruction using tissue expanders (TEs). The literature on human ADM has reported variable outcomes, and there is a paucity of data for xenogenic sources of ADM. The aim of this study is to evaluate the early complications, risk factors and outcomes using SurgiMend™ in staged breast reconstruction.

METHODS

An Institutional Review Board (IRB)-approved, retrospective analysis of a single surgeon's experience was performed. From August 2009 to May 2011, 65 patients underwent staged breast reconstruction using 95 sheets of SurgiMend™. The nominal TE fill volume was 383 ± 83 cc (range 250-550), mean intra-operative fill volume was 148 ± 86 cc (range 0-350) and mean final fill volume was 413 ± 176 cc (range 100-800). The mean clinic follow-up time was 16.9 ± 8.7 months; mean age was 50.9 ± 11.7 years; and average body mass index (BMI) was 26.0 ± 5.5 kg m(-2). Correlation with risk factors and clinical outcomes were analysed.

RESULTS

The incidences of postoperative complications were: haematoma 3.2%, seroma 7.5% and re-operation due to infection 2.1%. Age, diabetes mellitus, and hypertension had a significant correlation with an increased overall complication rate. With respect to early complications, such as infection requiring re-operation, diabetes demonstrated a trend with an odds ratio of 11.69.

CONCLUSION

This study demonstrates that the use of SurgiMend™ is associated with low early complication rates and is well tolerated in staged breast reconstruction.

Nonwoven polypropylene prosthesis in large abdominal wall defects in rats

PURPOSE

To evaluate, in large abdominal wall defects surgically shaped in rats, if a synthetic polypropylene nonwoven prosthesis could be used as a therapeutic option to conventional polypropylene mesh.

METHODS

Twenty four (24) Wistar rats were enrolled into three groups. Group 1 (Simulation group) with an abdominal wall defect of 3 X 3 left untreated and Groups 2 and 3, respectively treated with a conventional polypropylene mesh and a polypropylene nonwoven (NWV) prosthesis to cover the breach. At the 45th postoperatively day, adhesion (area and strength) and vascularization of Groups 2 and 3 were evaluated. The histological preparations with Hematoxylin-Eosin, Tricromium of Masson, Pricrosirius red and polarization with birefringence, and also the structural analysis of the prostheses carried on by Thermogravimetry and Differential Scanning Calorimetry were also assessed.

RESULTS

There were no significant differences between the Groups 2 and 3.

CONCLUSION

In rats, the polypropylene nonwoven prosthesis showed to be safe and has to be considered as an alternative to conventional mesh manufactured by weaving in the treatment of great defects of the abdominal wall.

Abdominal wall defect repair with biological prosthesis in transplanted patients: single center retrospective analysis and review of the literature

The risk of fascial dehiscence, wound infection and incisional hernias in organ recipients is higher. Retrospective analysis of our departments database, checking the last 12 years (2000-2012), and of the literature (1966-2012) were conducted. In our database we found seven patients: five liver (71.4 %), one kidney (14.3 %), one multivisceral (14.3 %); five males (71.4 %), two females (28.6 %). Five (71.4 %) were operated in urgency setting and two in ordinary setting (28.6 %). The mean/median number of laparotomies before the incisional hernia is of 2.1/1 (range 1-5). In five patients swine intestinal submucosa (71.4 %) have been used and in two porcine dermal collagen (28.6 %). The mean/median age was 48.3/52 years (range 18-61). The mean/median body mass index was 26.7/27 (range 19-34). The mean/median for follow-up after intervention was 40.1/33 months (range 50-21). Recurrence rate was 14.3 %. Complication rate was 28.6 %. Adding the present report, the literature reports 70 cases. 20 % of prosthesis have been implanted inlay, 25.7 % underlay, in 5.7 % intraperitoneal and in 48.6 % were not specified. The mean age ranges from 0.7 to 48.3 years. Kidney, liver, pancreas, bowel and multivisceral transplant are reported. Porcine dermal collagen has been implanted in 24.3 %, human dermal collagen in 51.4 % and swine intestinal submucosa in 24.3 %. The immunosuppression regimens comprehend variable associations of tacrolimus, steroids, mycophenolate mofetil, sirolimus, thymoglobulin, azathioprine/basiliximab and daclizumab. The mean follow-up is 16.2 months. The mean complication rate is 9.4 %. Biological prosthesis seems to be useful and safe in abdominal wall repair surgery in transplanted patients.

Interstitial engraftment of adipose-derived stem cells into an acellular dermal matrix results in improved inward angiogenesis and tissue incorporation

Acellular dermal matrices (ADM) are commonly used in reconstructive procedures and rely on host cell invasion to become incorporated into host tissues. We investigated different approaches to adipose-derived stem cells (ASCs) engraftment into ADM to enhance this process. Lewis rat adipose-derived stem cells were isolated and grafted (3.0 × 10(5) cells) to porcine ADM disks (1.5 mm thick × 6 mm diameter) using either passive onlay or interstitial injection seeding techniques. Following incubation, seeding efficiency and seeded cell viability were measured in vitro. In addition, Eighteen Lewis rats underwent subcutaneous placement of ADM disk either as control or seeded with PKH67 labeled ASCs. ADM disks were seeded with ASCs using either onlay or injection techniques. On day 7 and or 14, ADM disks were harvested and analyzed for host cell infiltration. Onlay and injection techniques resulted in unique seeding patterns; however cell seeding efficiency and cell viability were similar. In-vivo studies showed significantly increased host cell infiltration towards the ASCs foci following injection seeding in comparison to control group (p < 0.05). Moreover, regional endothelial cell invasion was significantly greater in ASCs injected grafts in comparison to onlay seeding (p < 0.05). ADM can successfully be engrafted with ASCs. Interstitial engraftment of ASCs into ADM via injection enhances regional infiltration of host cells and angiogenesis, whereas onlay seeding showed relatively broad and superficial cell infiltration. These findings may be applied to improve the incorporation of avascular engineered constructs.