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Squid Ring Teeth Coated Mesh Improves Abdominal Wall Repair
Abstract
Background
Hernia repair is a common surgical procedure with mesh often used. Current mesh materials have a high incidence of repair failures, due to poor tissue integration, and complications such as seroma and pain. Polypropylene (PP) mesh is the standard material in hernia repair secondary to its material durability; however, failures still approach 15%. In this first time animal study, we hypothesized that squid ring teeth (SRT), a biologically-derived high strength protein, coated polypropylene (SRT-PP) mesh, would offer enhanced tissue integration and strength compared to standard PP mesh, while proving biocompatibility for in vivo use.
Materials and methods
Polypropylene mesh was coated with SRT. Mechanical properties and cell proliferation studies of the composite mesh were performed in vitro. Rats underwent inlay mesh implantation in an anterior abdominal wall defect model. Repair was assessed clinically and radiographically, with integration evaluated by histology and mechanical testing.
Results
Cell proliferation was enhanced on SRT-PP composite mesh. This was corroborated by abdominal wall histology, dramatically diminished cranio-caudal mesh contraction, improved strength testing, and higher tissue failure strain following in vivo implantation. There was no increase in complications with SRT, with regard to seroma or visceral adhesion. No foreign body reactions were noted on liver histology.
Conclusion
SRT-PP mesh showed better tissue integration than PP mesh. SRT is a high strength protein that is applied as a coating to augment mesh-tissue integration leading to improvements in abdominal wall stability with potential to reduce re-intervention for failures.
Materials employed in the treatment of conditions encountered in surgical and clinical practice frequently face barriers in translation to application. Shortcomings can be generalized through their reduced mechanical stability, difficulty in handling, and inability to conform or adhere to complex tissue surfaces. To overcome an amalgam of challenges, research has sought the utilization of polymer‐derived nanomaterials deposited in various fashions and formulations to improve the application and outcomes of surgical and clinical interventions. Clinically prevalent applications include topical wound dressings, tissue adhesives, surgical sealants, hemostats, and adhesion barriers, all of which have displayed the potential to act as superior alternatives to current materials used in surgical procedures. In this review, emphasis will be placed not only on applications, but also on various design strategies employed in fabrication. This review is designed to provide a broad and thought‐provoking understanding of nanomaterials as adjuvant tools for the assisted treatment of pathologies prevalent in surgery.
This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants
Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery
Cephalopods have evolved many interesting features that can serve as inspiration. Repetitive squid ring teeth (SRT) proteins from cephalopods exhibit properties such as strength, self-healing, and biocompatibility. These proteins have been engineered to design novel adhesives, self-healing textiles, and the assembly of 2d-layered materials. Compared to conventional polymers, repetitive proteins are easy to modify and can assemble in various morphologies and molecular architectures. This research update discusses the molecular biology and materials science of polypeptides inspired by SRT proteins, their properties, and perspectives for future applications.
Excerpt "Surgical Treatment-Evidence-Based and Problem-Oriented" is based upon a concept which the editors believe will become increasingly important in the preparation of clinical textbooks in the 21st century, namely the quality of the evidence upon which currently accepted clinical practice is based needs to be assessed frankly and taken into account when recommendations for patient treatment are made. As is apparent in many of the chapters in this volume, the authors are frequently forced to conclude that a higher level of evidence than is currently available would be necessary in order establish the validity of the currently accepted management of a wide variety of common surgical problems. The editors believe this is a fact of which both students and surgical practitioners need to be aware, so that they may be prepared to update and alter their clinical decision making on the basis of higher levels of evidence when these become available. The editors also hope that increasing awareness of the low level of evidence upon which much present day surgical practice is based will prompt surgeons from many countries to plan or at least participate in clinical trials to achieve a higher quality of evidence upon which to base a more rational clinical practice.
Cephalopods have evolved many interesting features that can serve as inspiration. Repetitive squid ring teeth (SRT) proteins from cephalopods exhibit properties such as strength, self-healing, and biocompatibility. These proteins have been engineered to design novel adhesives, self-healing textiles, and the assembly of 2d-layered materials. Compared to conventional polymers, repetitive proteins are easy to modify and can assemble in various morphologies and molecular architectures. This research update discusses the molecular biology and materials science of polypeptides inspired by SRT proteins, their properties, and perspectives for future applications.
Background:
New biodegradable synthetic and biologic hernia implants have been promoted for rapid integration and tissue reinforcement in challenging repairs, e.g. at the hiatus or in contaminated wound fields. Interestingly, experimental data to support or falsify this assumption is scarce.
Methods:
Synthetic (BioA(®)) and biologic implants (porcine and bovine collagen matrices Strattice(®) and Veritas(®)) have been tested in experimental onlay hernia repair in rats in observation periods of 30 and 60 days. The key outcome parameters were mesh integration and reinforcement of the tissue at the implant site over sutured and sealed defects as well as comparison to native abdominal wall. Macroscopic assessment, biomechanical analysis and histology with haematoxylin/eosin staining, collagen staining and van Willebrand factor staining for detection of neovascularization were performed.
Results:
BioA(®) was well integrated. Although the matrices were already fragmented at 60 days follow-up, hernia sites treated with synthetic scaffolds showed a significantly enhanced tissue deflection and resistance to burst force when compared to the native abdominal wall. In porcine and bovine matrices, tissue integration and shrinkage were significantly inferior to BioA(®). Histology revealed a lack of fibroblast ingrowth through mesh interstices in biologic samples, whereas BioA(®) was tightly connected to the underlying tissue by reticular collagen fibres.
Conclusions:
Strattice(®) and Veritas(®) yielded reduced tissue integration and significant shrinkage, prohibiting further biomechanical tests. The synthetic BioA(®) provides little inherent strength but reticular collagen remodelling led to an augmentation of the scar due to significantly higher burst force resistance in comparison to native tissue.
Significance
Squid have teeth-like structural [squid ring teeth (SRT)] proteins inside their suckers, which have segmented semicrystalline morphology with repetitive amorphous and crystalline domains. These proteins have high elastic modulus and toughness. However, a clear relationship between molecular structure and mechanical properties of this material remains elusive. To investigate the genetic basis of material properties in SRT sequences, we developed a new approach for the design and production of structural proteins. We show that the toughness and flexibility of these synthetic SRT mimics increase as a function of molecular weight, whereas the elastic modulus and yield strength remain unchanged. These results suggest that artificial proteins produced by our approach can help to illuminate the genetic basis of protein material behavior in SRT.
Purpose
A systematic review of literature led us to take note that little was known about the costs of incisional ventral hernia repair (IVHR).
Methods
Therefore we wanted to assess the actual costs of IVHR. The total costs are the sum of direct (hospital costs) and indirect (sick leave) costs. The direct costs were retrieved from a multi-centric cost analysis done among a large panel of 51 French public hospitals, involving 3239 IVHR. One hundred and thirty-two unitary expenditure items were thoroughly evaluated by the accountants of a specialized public agency (ATIH) dedicated to investigate the costs of the French Health Care system. The indirect costs (costs of the post-operative inability to work and loss of profit due to the disruption in the ongoing work) were estimated from the data the Hernia Club registry, involving 790 patients, and over a large panel of different Collective Agreements.
Results
The mean total cost for an IVHR in France in 2011 was estimated to be 6451€, ranging from 4731€ for unemployed patients to 10,107€ for employed patients whose indirect costs (5376€) were slightly higher than the direct costs.
Conclusion
Reducing the incidence of incisional hernia after abdominal surgery with 5 % for instance by implementation of the European Hernia Society Guidelines on closure of abdominal wall incisions, or maybe even by use of prophylactic mesh augmentation in high risk patients could result in a national cost savings of 4 million Euros.
Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure-property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and -assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine- and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials.
Abdominal wall hernia is one of the most common conditions encountered by general surgeons. Rising rates of abdominal wall hernia repair have been described; however, population-based evidence concerning incidence rates of emergent hernia repair and changes with time are unknown.
To examine trends in rates of emergent abdominal hernia repair within the United States for inguinal, femoral, ventral, and umbilical hernias from January 1, 2001, to December 31, 2010.
A retrospective analysis of adults with emergent hernia repair using National Center for Health Statistics data, a nationally representative sample of inpatient hospitalizations in the United States that occurred from January 1, 2001, to December 31, 2010. All emergent hernia repairs were identified during the study period.
Incidence rates per 100 000 person-years, age, and sex adjusted to the 2010 US census population estimates were calculated for selected subcategories of emergent hernia repairs and time trends were evaluated.
An estimated 2.3 million inpatient abdominal hernia repairs were performed from 2001 to 2010; of which an estimated 567 000 were performed emergently. A general increase in the rate of total emergent hernias was observed from 16.0 to 19.2 emergent hernia repairs per 100 000 person-years in 2001 and 2010, respectively. In 2010, emergent hernia rates were highest among adults 65 years and older, with 71.3 and 42.0 emergent hernia repairs per 100 000 person-years for men and women, respectively. As expected, femoral hernia rates were higher among women while emergent inguinal hernia rates were higher among men. Rates of emergent incisional hernia repair were high but relatively stable among older women, with 24.9 and 23.5 per 100 000 person-years in 2001 and 2010, respectively. However, rates of emergent incisional hernia repair among older men rose significantly, with 7.8 to 32.0 per 100 000 person-years from 2001 to 2010, respectively.
These increasing rates of emergent incisional hernia repair are troublesome owing to the significantly increased risk morbidity and mortality associated with emergent hernia repair. While this increased mortality risk is multifactorial, it is likely associated with older age and the accompanying serious comorbidities.
Polypropylene (PP) mesh shrinkage represents a serious complication, as a significant cause of pain and recurrence of pelvic organ prolapse or ventral hernias, frequently requiring several surgical interventions. The retraction seems to be caused by the host, in response to the implantation, through the occurrence of periprosthetic adhesions and fibrosis. We hypothesized that avoiding the postoperative adhesions can prevent PP mesh shrinkage.
Sixty rats were randomly assigned to three groups. A standardized hernia defect was induced on the abdominal wall, which was repaired using an extraperitoneal PP mesh alone (group 1), with application of a hyaluronate carboxymethylcellulose-based bioresorbable membrane (Seprafilm®, group 2), or an auto-cross-linked polysaccharide hyaluronan-based solution (Hyalobarrier® gel, group 3). Eight weeks after the procedure, a repeat laparotomy was performed. After scoring the adhesion and measuring the mesh surface, a microscopic study of the prosthesis-host tissue interfaces was performed.
Group 1 displayed a median shrinkage of 29 % of the mesh. The Seprafilm® group (p = 0.0238) and Hyalobarrier® gel group (p = 0.0072) displayed a significantly smaller reduction of 19.12 and 17 %, respectively. Control group 1 displayed a significantly greater adhesion score (30.40) than the Seprafilm® (11.67, p = 0.0028) and Hyalobarrier® gel groups (11.19, p = 0.0013). The fibrosis was reduced in the Hyalobarrier® gel group only.
This experimental study revealed that Hyalobarrier® gel and Seprafilm® can prevent PP mesh shrinkage and postoperative adhesions. They might be integrated in a mesh size-saving strategy, which should preserve the quality and durability of the surgical repair and limit the postoperative pain.
Component separation is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-cm wide defects in the midline area. Since its original description, components separation technique underwent multiple modifications with the ultimate goal to decrease the morbidity associated with the traditional procedure. The extensive subcutaneous lateral dissection had been associated with ischemia of the midline skin edges, wound dehiscence, infection, and seroma. Although the current trend is to proceed with minimally invasive component separation and to reinforce the fascia with mesh, the basic principles of the techniques as described by Ramirez et al in 1990 have not changed over the years. Surgeons who deal with the management of abdominal wall defects are highly encouraged to include this technique in their collection of treatment options.
To examine histological and histomorphometric techniques for measuring collagen in skeletal muscle.
The following staining methods were used in the study: hematoxylin and eosin, Masson's trichrome, reticulin, and picrosirius red, and immunostaining for collagen types I, II, III, IV, and V. Histomorphometric measurements were performed using Corel PhotoPaint and UTHSCSA Image Tool 3.0 software.
Both the Masson's trichrome and picrosirius red staining provided the best visualization for the measurement of collagen content.
This methodology is important for the identification and quantification of the different types of collagen in muscles and can be used in the investigation of the qualitative and quantitative influence of collagen on physical activities, aging, and diseases.
We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of
dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin,
surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides,
polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled
monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert
and bioactive surfaces via grafting of macromolecules.
The component separation technique (CST) has gained popularity among general surgeons in the management of giant abdominal hernia.
A systematic review of the MedLine and EMBASE databases was performed. 36 observational cohort studies were included for data-analysis and divided in 4 main groups: Open Anterior Approach (OAA), Transversus Abdominis Release (TAR), Laparoscopic Anterior Approach (LAA) and Perforator Preserving Approach (PPA). Surgical Site Occurrences (SSO) occurred in 21.4%, 23.7%, 20.3% and 16.0% respectively. Incidence of recurrence was 11.9% (OAA), 5.25% (TAR), 7.02% (LAA) and 6.47% (PPA) with a significant difference in the advantage of TAR over OAA (p < 0.001).
Limitations in this systematic review were a lack of randomized trials, a heterogenous population and non-standardized methods for measuring outcomes, all making it difficult to postulate conclusions about CST and its modifications. Based on pooled results of 36 studies, the prevalence of SSO is comparable between the techniques with an average of one in five and the prevalence of recurrences is highest when using the Open Anterior Approach at 11.9%.
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.
Importance:
Prosthetic mesh is frequently used to reinforce the repair of abdominal wall incisional hernias. The benefits of mesh for reducing the risk of hernia recurrence or the long-term risks of mesh-related complications are not known.
Objective:
To investigate the risks of long-term recurrence and mesh-related complications following elective abdominal wall hernia repair in a population with complete follow-up.
Design, setting, and participants:
Registry-based nationwide cohort study including all elective incisional hernia repairs in Denmark from January 1, 2007, to December 31, 2010. A total of 3242 patients with incisional repair were included. Follow-up until November 1, 2014, was obtained by merging data with prospective registrations from the Danish National Patient Registry supplemented with a retrospective manual review of patient records. A 100% follow-up rate was obtained.
Exposures:
Hernia repair using mesh performed by either open or laparoscopic techniques vs open repair without use of mesh.
Main outcomes and measures:
Five-year risk of reoperation for recurrence and 5-year risk of all mesh-related complications requiring subsequent surgery.
Results:
Among the 3242 patients (mean age, 58.5 [SD, 13.5] years; 1720 women [53.1%]), 1119 underwent open mesh repair (34.5%), 366 had open nonmesh repair (11.3%), and 1757 had laparoscopic mesh repair (54.2%). The median follow-up after open mesh repair was 59 (interquartile range [IQR], 44-80) months, after nonmesh open repair was 62 (IQR, 44-79) months, and after laparoscopic mesh repair was 61 (IQR, 48-78) months. The risk of the need for repair for recurrent hernia following these initial hernia operations was lower for patients with open mesh repair (12.3% [95% CI, 10.4%-14.3%]; risk difference, -4.8% [95% CI, -9.1% to -0.5%]) and for patients with laparoscopic mesh repair (10.6% [95% CI, 9.2%-12.1%]; risk difference, -6.5% [95% CI, -10.6% to -2.4%]) compared with nonmesh repair (17.1% [95% CI, 13.2%-20.9%]). For the entirety of the follow-up duration, there was a progressively increasing number of mesh-related complications for both open and laparoscopic procedures. At 5 years of follow-up, the cumulative incidence of mesh-related complications was 5.6% (95% CI, 4.2%-6.9%) for patients who underwent open mesh hernia repair and 3.7% (95% CI, 2.8%-4.6%) for patients who underwent laparoscopic mesh repair. The long-term repair-related complication rate for patients with an initial nonmesh repair was 0.8% (open nonmesh repair vs open mesh repair: risk difference, 5.3% [95% CI, 4.4%-6.2%]; open nonmesh repair vs laparoscopic mesh repair: risk difference, 3.4% [95% CI, 2.7%-4.1%]).
Conclusions and relevance:
Among patients undergoing incisional repair, sutured repair was associated with a higher risk of reoperation for recurrence over 5 years compared with open mesh and laparoscopic mesh repair. With long-term follow-up, the benefits attributable to mesh are offset in part by mesh-related complications.
To better understand the in vivo mechanical behavior of synthetic mesh implants, we designed a specific experimental protocol for the mechanical characterization of explanted mesh under uniaxial tension. The implantation of a mesh leads to the development of scar tissue and the formation of a new composite made of native tissue, a mesh implant and scar tissues. This study focused on three points: determining the minimum representative size of mesh implants required for mechanical test samples, highlighting the influence of healing, and defining the healing time required to ensure stabilized mechanical properties.
First, we determined the minimum representative size of mesh implants for the mechanical characterization with a study on a synthetic composite made of mesh and an elastomeric matrix mimicking the biological tissues. The size of the samples tested was gradually decreased. The downsizing process was stopped, when the mechanical properties of the composite were not preserved under uniaxial tension. It led to a sample representative size 3 cm long and 2 cm wide between the grips.
Then an animal study was conducted on Wistar rats divided into eight groups. One group was set as control, consisting of the healthy abdominal wall. The other seven groups underwent surgery as follows: one placebo (i.e., without mesh placement), and six with a mesh installation on the abdominal wall and healing time. The rats were sacrificed after different healing times ranging from 1 to 5 months. We observed the influence of healing and healing time on the mechanical response under uniaxial tension of the new composite formed by scar, native tissue, and textile.
It seems that 2 months are required to ensure the stabilization of the mechanical properties of the implanted mesh. We were not able to tell the control group (native abdominal wall) from the placebo group (native and scar tissue). This protocol was tested on two different prostheses after 3 months of healing. With this protocol, we were able to differentiate one mesh from another after host integration.
Self-healing materials, which enable an autonomous repair response to damage, are highly desirable for the long-term reliability of woven or non-woven textile. Polyelectrolyte layer-by-layer (LbL) films are of considerable interest as self-healing coatings due to the mobility of the components comprising the film. In this work mechanically stable self-healing films were fabricated through construction of a polyelectrolyte LbL composed of squid ring teeth (SRT) proteins. SRT is a structural protein with unique self-healing properties and high elastic modulus in both dry and wet conditions (>2GPa) due to semi-crystalline architecture. We demonstrate LbL construction of multilayers containing native and recombinant SRT proteins capable of self-healing defects. Additionally, we show these films are capable of utilizing functional biomolecules by incorporating an enzyme into the SRT multilayer. Urease was chosen as a model enzyme of interest to test the kinetics via fluorescence assay. Successful construction of the SRT films demonstrate the use of mechanically stable self-healing coating, which can incorporate biomolecules for more complex protective functionalities for advanced functional fabrics.
The idea of creating photonics tools for sensing, imaging and material characterization has long been pursued and many achievements have been made. Approaching the level of solutions provided by nature however is hindered by routine choice of materials. To this end recent years have witnessed a great effort to engineer mechanically flexible photonic devices using polymer substrates. On the other hand, biodegradability and biocompatibility still remains to be incorporated. Hence biomimetics holds the key to overcome the limitations of traditional materials in photonics design. Natural proteins such as sucker ring teeth (SRT) and silk for instance have remarkable mechanical and optical properties that exceed the endeavors of most synthetic and natural polymers. Here we demonstrate for the first time, toroidal whispering gallery mode resonators (WGMR) fabricated entirely from protein structures such as SRT of Loligo vulgaris (European squid) and silk from Bombyx mori. We provide here complete optical and material characterization of proteinaceous WGMRs, revealing high quality factors in microscale and enhancement of Raman signatures by a microcavity. We also present a most simple application of a WGMR as a natural protein add-drop filter, made of SRT protein. Our work shows that with protein-based materials, optical, mechanical and thermal properties can be devised at the molecular level and it lays the groundwork for future eco-friendly, flexible photonics device design.
The infrared spectra of a number of high polymers have been recorded in the range between and in order to explore the possibilities of this region for structural work on such compounds. The number of bands found varies from none (polyethylene) to eight (Saran). It has been found that the spectra of some polymers in this region depend upon the state of orientation and crystallinity in the specimen (e.g., mylar and rubber). The spectra of a few selected compounds will be discussed in detail to illustrate how tentative assignments of the observed bands may be made to a) group vibrations, b) skeletal vibrations, and c) intermolecular vibrations. The last class of vibrations is of particular interest in relation to hydrogen bonding.
Purpose of review:
Primary closure of the abdominal wall remains one of the early challenges of intestinal transplantation. Our aim is to review the role of abdominal wall transplantation in achieving tension-free closure of the abdomen.
Recent findings:
In total, 38 full-thickness vascularized abdominal wall transplants, six partial-thickness vascularized and 17 partial-thickness nonvascularized rectus facia grafts have been reported worldwide. Different techniques have been described. The most popular choice seems to be the full-thickness vascularized abdominal wall allograft, where the anastomosis is performed either in a micro- or macrovascular fashion. Temporary 'remote' revascularisation of the allograft has been performed in some cases onto the recipient's forearm vessels when there is a long anticipated cold ischaemia time (>5 h). Preliminary data suggest that the abdominal wall skin rejection might be an early predictor of intestinal rejection. Vascularized and nonvascularized rectus fascia may be effective when there is inadequate healthy muscle/fascia but sufficient skin cover.
Summary:
Several centres have already proved the technical and immunologic feasibility of partial or full-thickness abdominal wall transplantation. It is an effective option to achieve primary abdominal closure following intestinal transplantation and in its full-thickness form, it may be useful for monitoring rejection in visceral organs.
Preserving patients' native tissues has posed many challenges for surgeons. Increased life expectancy is leading to a proportionately older surgical population with weaker tissues. The growing population of morbidly obese patients in addition to those with multiple comorbidities which influence the native strength and perfusion of tissues compounds the surgeon's challenge. Certainly, there is a rising demand for materials to replace or augment a patient's native tissue when it has been compromised. Over time, the number of products available has increased substantially. The ideal substitute, however, is debatable. The manufacturing and processing of these materials has become more complex and this has resulted in a significant increase in cost. The composition of the mesh, clinical scenario, and operative technique all interact to impact the long-term results. Surgeons require a thorough understanding of these products to guide proper selection and use, to ensure optimal outcomes for patients, and to properly steward financial resources. This review will outline the properties of commonly used materials, highlighting the strength and weakness of each. It will then discuss recommendations regarding mesh selection, coding, and reimbursement. While general principles and trends can be highlighted, further studies of biologic versus synthetic meshes are clearly necessary.
Natural materials have been a fundamental part of human life since the dawn of civilization. However, due to exploitation of natural resources and cost issues, synthetic materials replaced bio-derived materials in the last century. Recent advances in bio- and nano-technologies pave the way for developing eco-friendly materials that could be produced easily from renewable resources at reduced cost and in a broad array of useful applications. This feature article highlights structural and functional characteristics of bio-derived materials, which will expedite the design fabrication and synthesis of eco-friendly and recyclable advanced nano-materials and devices.
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Background
Inability to reapproximate fascia in complex ventral hernia (CVH) repair remains challenging. Single-stage bridging reconstructions have been reported, however, with high rates of recurrence and wound complications. We describe a single-surgeon experience with bridging-biologic CVH repair.
Methods
We reviewed 37 patients undergoing CVH repair with bridging biologic mesh by the senior author from 1/1/2007–1/1/2013. Surgical history and operative characteristics were analyzed for predictors of hernia recurrence and wound complications.
Results
Average age was 53+15 years, BMI was 31.1+8.1 kg/m2, and history of prior repair in 18 patients. Common indications were trauma, intra-abdominal infection, and prior intra-abdominal surgery. Incidence of wound complications was 51.4%, most commonly wound breakdown and infection. With average follow up of 13 months, recurrence rate was 18.9% at an average of 8.2 months post-operatively. Analysis demonstrated post-operative wound infection as the only predictor of recurrence (OR=22.1, p=0.017).
Conclusion
Hernia recurrence rate was 18.9% with bridged biologic CVH repairs, strongly associated with post-operative wound infection. This suggests patients with post-operative infections may benefit from closer surveillance and more aggressive wound management.
The aim of this study was to investigate biomechanical and immunogenic properties of spider silk meshes implanted as fascia replacement in a rat in vivo model.
Meshes for hernia repair require optimal characteristics with regard to strength, elasticity, and cytocompatibility. Spider silk as a biomaterial with outstanding mechanical properties is potentially suitable for this application.
Commercially available meshes used for hernia repair (Surgisis and Ultrapro) were compared with handwoven meshes manufactured from native dragline silk of Nephila spp. All meshes were tied onto the paravertebral fascia, whereas sham-operated rats were sutured without mesh implantation. After 4 or 14 days, 4 weeks, and 4 or 8 months, tissue samples were analyzed concerning inflammation and biointegration both by histological and biochemical methods and by biomechanical stability tests.
Histological sections revealed rapid cell migration into the spider silk meshes with increased numbers of giant cells compared with controls with initial decomposition of silk fibers after 4 weeks. Four months postoperatively, spider silk was completely degraded with the formation of a stable scar verified by constant tensile strength values. Surgisis elicited excessive stability loss from day 4 to day 14 (P < 0.001), with distinct inflammatory reaction demonstrated by lymphocyte and neutrophil invasion. Ultrapro also showed decreasing strength and poor elongation behavior, whereas spider silk samples had the highest relative elongation (P < 0.05).
Hand-manufactured spider silk meshes with good biocompatibility and beneficial mechanical properties seem superior to standard biological and synthetic meshes, implying an innovative alternative to currently used meshes for hernia repair.
Introduction:
Complicated ventral hernias are often referred to tertiary care centers. Hospital costs associated with these repairs include direct costs (mesh materials, supplies, and nonsurgeon labor costs) and indirect costs (facility fees, equipment depreciation, and unallocated labor). Operative supplies represent a significant component of direct costs, especially in an era of proprietary synthetic meshes and biologic grafts. We aim to evaluate the cost-effectiveness of complex abdominal wall hernia repair at a tertiary care referral facility.
Methods:
Cost data on all consecutive open ventral hernia repairs (CPT codes 49560, 49561, 49565, and 49566) performed between 1 July 2008 and 31 May 2011 were analyzed. Cases were analyzed based upon hospital status (inpatient vs. outpatient) and whether the hernia repair was a primary or secondary procedure. We examined median net revenue, direct costs, contribution margin, indirect costs, and net profit/loss. Among primary hernia repairs, cost data were further analyzed based upon mesh utilization (no mesh, synthetic, or biologic).
Results:
Four-hundred and fifteen patients underwent ventral hernia repair (353 inpatients and 62 outpatients); 173 inpatients underwent ventral hernia repair as the primary procedure; 180 inpatients underwent hernia repair as a secondary procedure. Median net revenue (5,432; median direct costs for those using synthetic and biologic mesh were 500. Median net profit of 4,560, and the median net financial loss was 1,560 and 230, respectively.
Conclusions:
Ventral hernia repair is associated with overall financial losses. Inpatient synthetic mesh repairs are essentially budget neutral. Outpatient and inpatient repairs without mesh result in net financial losses. Inpatient biologic mesh repairs result in a negative contribution margin and striking net financial losses. Cost-effective strategies for managing ventral hernias in a tertiary care environment need to be developed in light of the financial implications of this patient population.
We investigated the impact of incisional hernia (IH) on quality of life and body image.
Open abdominal surgery patients were included in a prospective cohort study performed between 2007 and 2009 in an academic hospital. Main outcomes were incidence of IH after approximately 12 months and Short-Form 36 and body image questionnaire results.
There were 374 patients who were examined after a median follow-up period of 16 months (range, 10-24 mo). Seventy-five patients had developed IH (20%); 63 (84%) were symptomatic. Adjusted for age, sex, and Charlson Comorbidity Index score, patients with IH reported significantly lower mean scores for components physical functioning (P = .033), role physical (P = .002), and physical component summary (P = .010). A trend toward significance was found for general health (P = .061). Patients with IH reported significantly lower mean cosmetic scores (P = .002), and body image and total body image scores (both P < .001).
Patients with IH reported lower mean scores on physical components of health-related quality of life and body image.
Surface engineering is an important tool in understanding the molecular mechanism of protein adsorption and cell-surface interactions with the aim of rational design of surfaces for different biological applications. This article first briefly summarizes some of the commonly used approaches to control biological interactions at the solid–water interface. Next, two different approaches are presented from the authors’ research to engineer surfaces that address some of the problems and limitations of current approaches to modulate protein adsorption at surfaces. The first, “static” strategy involves modifying a surface with an amphiphilic comb polymer that presents short oligoethylene glycol side-chains. Two different fabrication methods to synthesize these non-fouling coatings are described including spin-coating and surface-initiated polymerization. The second, “active” strategy to control protein adsorption involves grafting a stimuli-responsive biopolymer, derived from an oligomeric sequence found in mammalian elastin to a surface. This polypeptide exhibits a lower critical solution temperature (LCST) transition in aqueous solution. Surfaces grafted with these polypeptides exhibit a hydrophilic-hydrophobic transition in response to increased temperature or salt concentration. The change in the interfacial properties can be exploited to create “active” polymer grafts that enable reversible, triggered binding of proteins onto surfaces in response to an external stimulus.
During sol-gel thin film formation via dipping, polymeric or particulate inorganic precursors are concentrated on the substrate surface by a complex process involving gravitational draining with concurrent drying and continued condensation reactions. The structure of films deposited from polymeric precursors depends on such factors as size and structure of the precursors, relative rates of condensation and evaporation, capillary pressure, and substrate withdrawal speed. Using polymeric silicate precursors, the porosity and refractive index of the deposited films may be varied as follows: volume percent porosity (0%–56%); pore radius (0–3.1 nm); surface area (1.2–263 m2 g-1); refractive index (1.18–1.45). For repulsive, monosized particulate precursors, higher coating rates promote ordering of the particles as manifested by a reduction in porosity from 36% (random dense packing) to about 25% (f.c.c. or h.c.p.).
The objective of this study was to determine the mesh contracture, adhesion, tissue ingrowth, and histologic characteristics of a novel absorbable barrier mesh (Ventrio™ ST Hernia Patch) compared to existing permanent (Ventrio™ Hernia Patch) and absorbable barrier meshes (Sepramesh™ IP Composite and PROCEED™ Surgical Mesh).
Standard laparoscopic technique was utilized to bilaterally implant meshes in 20 female Yorkshire pigs (n = 5 pigs/group). Meshes were fixated to the intact peritoneum with SorbaFix™ absorbable fixation devices. Mesh contracture, adhesion coverage, and adhesion tenacity were evaluated after 4 weeks. T-Peel testing and hematoxylin and eosin (H&E) staining were utilized to assess tissue ingrowth and host response.
A significantly greater percent area contracture was demonstrated for PROCEED™ (26.9%) compared to Ventrio™ ST (8.8%), Ventrio™ (14.5%) and Sepramesh™ (9.2%). Ventrio™ ST demonstrated similar adhesion area, tenacity, and tissue ingrowth compared to all other meshes. Histological scoring revealed a comparable host inflammatory response for all meshes, with a few exceptions. A greater number of giant cells were observed in Ventrio™ ST and Sepramesh™ near the multifilament polyglycolic acid (PGA) fibers; a greater number of macrophages were observed in PROCEED™ compared to Ventrio™; and a greater number of neutrophils were observed in PROCEED™, compared to Sepramesh™ (P < 0.05). Focal areas of hemorrhage were also observed on the visceral surface of PROCEED™.
Ventrio™ ST Hernia Patch demonstrated comparable contracture, adhesion, tissue ingrowth, and histologic characteristics compared to existing permanent and absorbable barrier meshes. Host inflammatory and fibrotic responses for all four meshes were minimal and representative of a biocompatible response.
Despite advances in surgical technique and prosthetic technologies, the risks for recurrence and infection are high following the repair of incisional ventral hernias. High-quality data suggest that all ventral hernia repairs should be reinforced with prosthetic repair materials. The current standard for reinforced hernia repair is synthetic mesh, which can reduce the risk for recurrence in many patients. However, permanent synthetic mesh can pose a serious clinical problem in the setting of infection. Assessing patients' risk for wound infection and other surgical-site occurrences, therefore, is an outstanding need. To our knowledge, there currently exists no consensus in the literature regarding the accurate assessment of risk of surgical-site occurrences in association with or the appropriate techniques for the repair of incisional ventral hernias. This article proposes a novel hernia grading system based on risk factor characteristics of the patient and the wound. Using this system, surgeons may better assess each patient's risk for surgical-site occurrences and thereby select the appropriate surgical technique, repair material, and overall clinical approach for the patient. A generalized approach and technical considerations for the repair of incisional ventral hernias are outlined, including the appropriate use of component separation and the growing role of biologic repair materials.
Billroth (1878) envisaged prostheses before Bassini's sutured cure (1887). Phelps (1894) reinforced with silver coils. Metals were replaced by plastic (Aquaviva 1944). Polypropylene (Usher 1962), resisting infection, became popular. Usher instituted tensionless, overlapping preperitoneal repair. Spermatic cord was parietalized, to obviate keyholing. Stoppa (1969) championed the sutureless Cheatle-Henry approach encasing the peritoneum. His technique, "La grande prosthese de renforcement du sac visceral" (GPRVS), was adopted by laparoscopists. Newman (1980) and Lichtenstein (1986) pioneered subaponeurotic positioning. Kelly (1898) inserted a plug into the femoral canal; Lichtenstein and Shore (1974) followed. Gilbert (1987) plugged the internal ring, and Robbins and Rutkow (1993) treated all groin herniae thus. Incisional herniation has been controlled by prefascial, retrorectus prosthetic placement (Rives-Flament 1973). ePTFE (Sher et al. 1980) is useful intraperitoneally, since it evokes few adhesions. Here, laparoscopy (Ger 1982) is competitive. Beginning in 1964 (Wirtschafter and Bentley), experimental and clinical studies have shown herniation may be associated with aging and genetic or acquired (smoking, etc.) systemic disease of connective tissue. These data, with prospective trials, all but mandate tensionless prosthetic repair.
Incisional hernias occur primarily as a result of high tension and inadequate healing of a previous incision, the latter of which is frequently related to infection at the surgical site. Despite recent advances in operative techniques, the recurrence rate remains unacceptably high. To evaluate the impact of different predisposing factors for the recurrence of incisional hernia, we reviewed retrospectively the medical records of 297 patients who had undergone incisional herniorrhaphy (188 tissue repairs, 109 mesh repairs) in our hospital. Demographic data (age and gender), type of repair, body mass index, hernia size, presence of chronic illnesses and wound complications were evaluated in a univariate and multivariate manner analysis. The overall recurrence rate was 30.3%, with the recurrence rate in patients who underwent tissue repair being 39.4% and that in patients following prosthetic repair 14.6%. The recurrence rate was significantly influenced by type of repair, obesity, hernia size, wound healing disorders and some chronic comorbidities. We conclude that it is necessary to become familiar with the risk factors for recurrence of incisional hernia in order to eliminate or decrease their effect on the positive outcome of incisional herniorrhaphy.
Many thousand laparotomy incisions are created each year and the failure rate for closure of these abdominal wounds is between 10-15%, creating a large problem of incisional hernia. In the past many of these hernias have been neglected and treated with abdominal trusses or inadequately managed with high failure rates. The introduction of mesh has not had a significant impact because surgeons are not aware of modern effective techniques which may be used to reconstruct defects of the abdominal wall. This review will cover recent advances in incisional hernia surgery which affect the general surgeon, and also briefly review advanced techniques employed by specialist surgeons in anterior abdominal wall surgery.
Surgical treatment of ventral hernias has changed dramatically over the past decades by the introduction of laparoscopy and prosthetic biomaterials for reinforcement of the abdominal wall. There are many meshes available on the market for laparoscopic ventral hernia repair (LVHR), and new meshes are introduced regularly. Experimental and clinical documentation for safety and efficacy are, however, often not available for the clinician. The choice of mesh may therefore be difficult in clinical practice. We present a review of the current literature regarding safety measures such as adhesions, fistulas, and infections as well as the available data on pain, recurrence, mesh shrinkage, and seroma formation after LVHR.
The literature was searched systematically using PubMed/MEDLINE and EMBASE for controlled studies, prospective descriptive series and retrospective case series.
The literature clearly points in the direction of very few mesh-related complications after LVHR. Experimental studies and theoretical considerations may argue for using a covered mesh, i.e., a composite mesh, or ePTFE for LVHR in humans, although it is important to stress that there are no human data at the moment to support this. Concerns about using pure polypropylene mesh in the intraperitoneal position may be re-evaluated with the experience of lightweight macropore meshes from open surgery in mind. There is a tendency towards greater shrinkage in ePTFE-based meshes but no differences seems to exist between different mesh materials in other relevant outcome parameters from clinical series.
The literature cannot give general recommendations for choice of mesh based on randomized controlled trials. The final choice of mesh for LVHR will therefore typically be based on surgeons' preference and cost while we await further data from randomized controlled clinical trials.
The ideal technique for the use of AlloDerm (LifeCell Corp) in complicated ventral hernia repair has not been defined. The expense of these products mandates careful evaluation to justify their widespread use. We compared two techniques of fascial bridging versus fascial reinforcement repair with regard to their longterm recurrence rates using AlloDerm.
We retrospectively studied patients with abdominal defects repaired with AlloDerm at our institution.
Thirty-seven patients with abdominal wall repairs using AlloDerm were identified between January 2004 and December 2005. Eleven patients underwent bridged fascial repair; 26 patients had reinforced fascial repair. There was no statistical significance between the 2 groups in terms of average age (57 versus 52 years), body mass index (35 versus 29 kg/m(2)), American Society of Anesthesiologists score (2.9 versus 2.5), or number of earlier abdominal operations (3.4 versus 3.5). The average sizes of AlloDerm used were 175 cm(2) for bridged and 89 cm(2) for reinforced repair (p=0.005). In patients with reinforced closure, primary repair was achieved with lateral component separation in 22 of 26 patients. Mean followup was 21.4 months (range 15 to 36 months). In the bridged group, 1 patient died on postoperative day 20. Of the remaining 10 patients, 8 patients (80%) developed recurrences. Seven patients required reoperation, but one patient refused repair. In the reinforced group, four patients were lost to followup and two patients died. Four of the remaining 20 patients (20%) developed recurrences that required repair; this was significantly different from the recurrence rate in the bridged group (p=0.009).
This study demonstrated that the method in which AlloDerm is used in abdominal wall reconstruction has a significant impact on recurrence rates. Based on our findings, AlloDerm should be used only as a reinforcement after primary fascial reappoximation.
Abdominal wall hernias are a frequent and formidable challenge for general surgeons. Several different surgical techniques and types of mesh prosthetics are available for repair. We evaluated outcomes of an open ventral hernia repair using a synthetic composite mesh.
We prospectively collected data on consecutive patients undergoing open ventral hernia repair using a synthetic composite mesh from January 1, 2000 to December 31, 2005 at four large medical centers. Four surgeons used a standardized surgical procedure for all patients.
The study consisted of 455 patients with an average age of 56 years; 54% were men. Sixty-nine percent of the patients underwent repairs for recurrent hernias. Mean defect size was 44 cm(2), and mean mesh size was 213 cm(2). Average length of hospital stay was 1.1 days. Thirty-one patients had 33 early complications (7%), and 3 patients (0.7%) required reoperation (one each for seroma, bowel injury, and wound breakdown). Early infection occurred in four patients (0.9%), and one patient required reoperation and graft removal. Late complications occurred in nine patients (2%), with two patients requiring reoperation. Late infections occurred in two patients (0.4%); both required antibiotic treatment. Recurrent hernias were observed in 6 patients (1%; 6 of 450 because of 5 patients with unknown recurrence) at a mean followup of 29.3 months.
In this large multicenter series, open ventral hernia repair using a composite mesh resulted in a short hospital stay, moderate complication rate, low infection rate, and low recurrence rate.
Fecal fistula: a late complication of Marlex mesh repair
- Z Kaufman
- M Engelberg
- M Zager
Kaufman Z, Engelberg M, Zager M. Fecal fistula: a late complication of Marlex mesh
repair. Dis Colon Rectum. 1981;24(7):543-4.
Impact of incisional hernia on health-related quality of life and body image: a prospective cohort study
- G H Van Ramshorst
- H H Eker
- Wcj Hop
- J Jeekel
- J F Lange
van Ramshorst GH, Eker HH, Hop WCJ, Jeekel J, Lange JF. Impact of incisional hernia
on health-related quality of life and body image: a prospective cohort study. The
American Journal of Surgery. 2012;204(2):144-50.
Programmable tandem repeat proteins inspired by squid ring teeth
- A Pena-Francesch
- N E Domeradzka
- H Jung
- B Barbu
- M Vural
- Y Kikuchi
- B D Allen
- M C Demirel
Pena-Francesch A, Domeradzka NE, Jung H, Barbu B, Vural M, Kikuchi Y, Allen BD,
Demirel MC, Programmable tandem repeat proteins inspired by squid ring teeth. APL
Materials, in press, 2017.
Ultrafast laser-probing spectroscopy for studying molecular structure of protein aggregates
Ultrafast laser-probing spectroscopy for studying molecular structure of protein
aggregates. Analyst. 2017;142(9):1434-41.
An experimental model for the study of collagen fibers in skeletal muscle
- Calvi Endc
- F X Nahas
- M V Barbosa
- J A Calil
- Ssm Ihara
- Silva Mds
Calvi ENdC, Nahas FX, Barbosa MV, Calil JA, Ihara SSM, Silva MdS, et al. An
experimental model for the study of collagen fibers in skeletal muscle. Acta cirurgica
brasileira. 2012;27(10):681-6.