The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform
William R Wagner - One of the best experts on this subject based on the ideXlab platform.
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non invasive characterization of polyurethane based tissue constructs in a rat Abdominal Repair model using high frequency ultrasound elasticity imaging
Biomaterials, 2013Co-Authors: Keisuke Takanari, Nicholas J Amoroso, William R Wagner, Yi Hong, Keewon Lee, Yadong Wang, Kang KimAbstract:The evaluation of candidate materials and designs for soft tissue scaffolds would benefit from the ability to monitor the mechanical remodeling of the implant site without the need for periodic animal sacrifice and explant analysis. Toward this end, the ability of non-invasive ultrasound elasticity imaging (UEI) to assess temporal mechanical property changes in three different types of porous, biodegradable polyurethane scaffolds was evaluated in a rat Abdominal Wall Repair model. The polymers utilized were saltleached scaffolds of poly(carbonate urethane) urea, poly(ester urethane) urea and poly(ether ester urethane) urea at 85% porosity. A total of 60 scaffolds (20 each type) were implanted in a full thickness muscle Wall replacement in the abdomens of 30 rats. The constructs were ultrasonically scanned every 2 weeks and harvested at weeks 4, 8 and 12 for compression testing or histological analysis. UEI demonstrated different temporal stiffness trends among the different scaffold types, while the stiffness of the surrounding native tissue remained unchanged. The changes in average normalized strains developed in the constructs from UEI compared well with the changes of mean compliance from compression tests and histology. The average normalized strains and the compliance for the same sample exhibited a strong linear relationship. The ability of UEI to identify herniation and to characterize the distribution of local tissue in-growth with high resolution was also investigated. In summary, the reported data indicate that UEI may allow tissue engineers to sequentially evaluate the progress of tissue construct mechanical behavior in vivo and in some cases may reduce the need for interim time point animal sacrifice.
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an elastomeric patch electrospun from a blended solution of dermal extracellular matrix and biodegradable polyurethane for rat Abdominal Wall Repair
Tissue Engineering Part C-methods, 2012Co-Authors: Yi Hong, Ryotaro Hashizume, Nicholas J Amoroso, William R Wagner, Stephen F Badylak, Keisuke Takanari, Ellen P Brennanpierce, John M FreundAbstract:A biodegradable elastomeric scaffold was created by electrospinning a mixed solution of poly(ester urethane)urea (PEUU) and porcine dermal extracellular matrix (dECM) digest, with PEUU included to provide elasticity, flexibility, and mechanical support and dECM used to enhance bioactivity and biocompatibility. Micrographs and differential scanning calorimetry demonstrated partial miscibility between PEUU and dECM. With greater dECM content, scaffolds were found to possess lower breaking strains and suture retention strength, although initial modulus was greater with higher dECM concentrations. The hybrid scaffolds containing 0% to 50% dECM had tensile strengths of 5 to 7 MPa, breaking strains of 138% to 611%, initial moduli of 3 to 11 Mpa, and suture retention strengths of 35 to 59 MPa. When hydrated, scaffolds were found to contract markedly with 50% dECM content. When used in a rat full-thickness Abdominal Wall replacement model, no herniation, infection, or tissue adhesion was observed after 4 and 8 we...
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an elastomeric patch electrospun from a blended solution of dermal extracellular matrix and biodegradable polyurethane for rat Abdominal Wall Repair
Tissue Engineering Part C-methods, 2012Co-Authors: Yi Hong, Ryotaro Hashizume, Nicholas J Amoroso, William R Wagner, Stephen F Badylak, Keisuke Takanari, Ellen P Brennanpierce, John M FreundAbstract:A biodegradable elastomeric scaffold was created by electrospinning a mixed solution of poly(ester urethane)urea (PEUU) and porcine dermal extracellular matrix (dECM) digest, with PEUU included to provide elasticity, flexibility, and mechanical support and dECM used to enhance bioactivity and biocompatibility. Micrographs and differential scanning calorimetry demonstrated partial miscibility between PEUU and dECM. With greater dECM content, scaffolds were found to possess lower breaking strains and suture retention strength, although initial modulus was greater with higher dECM concentrations. The hybrid scaffolds containing 0% to 50% dECM had tensile strengths of 5 to 7 MPa, breaking strains of 138% to 611%, initial moduli of 3 to 11 Mpa, and suture retention strengths of 35 to 59 MPa. When hydrated, scaffolds were found to contract markedly with 50% dECM content. When used in a rat full-thickness Abdominal Wall replacement model, no herniation, infection, or tissue adhesion was observed after 4 and 8 weeks with a scaffold containing 25% dECM or a control 100% PEUU scaffold. Scaffolds incorporating dECM were significantly thicker at the time of explant, with greater numbers of associated smooth muscle actin-positive staining cells than in the control, but minimal cellular infiltration and remodeling of the scaffold were detected regardless of dECM addition. The processing of dECM and PEUU from a mixed solution thus provided a scaffold with evidence of better bioactivity and with mechanical properties not achievable with digested dECM alone.
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Morphological and mechanical characteristics of the reconstructed rat Abdominal Wall following use of a wet electrospun biodegradable polyurethane elastomer scaffold
Biomaterials, 2010Co-Authors: Ryotaro Hashizume, Nicholas J Amoroso, Kazuro Fujimoto, Kimimasa Tobita, Michael S. Sacks, Yi Hong, Toshio Miki, Bradley B. Keller, William R WagnerAbstract:Abstract Although a variety of materials are currently used for Abdominal Wall Repair, general complications encountered include herniation, infection, and mechanical mismatch with native tissue. An approach wherein a degradable synthetic material is ultimately replaced by tissue mechanically approximating the native state could obviate these complications. We report here on the generation of biodegradable scaffolds for Abdominal Wall replacement using a wet electrospinning technique in which fibers of a biodegradable elastomer, poly(ester urethane)urea (PEUU), were concurrently deposited with electrosprayed serum-based culture medium. Wet electrospun PEUU (wet ePEUU) was found to exhibit markedly different mechanical behavior and to possess an altered microstructure relative to dry processed ePEUU. In a rat model for Abdominal Wall replacement, wet ePEUU scaffolds (1 × 2.5 cm) provided a healing result that developed toward approximating physiologic mechanical behavior at 8 weeks. An extensive cellular infiltrate possessing contractile smooth muscle markers was observed together with extensive extracellular matrix (collagens, elastin) elaboration. Control implants of dry ePEUU and expanded polytetrafluoroethylene did not experience substantial cellular infiltration and did not take on the native mechanical anisotropy of the rat Abdominal Wall. These results illustrate the markedly different in vivo behavior observed with this newly reported wet electrospinning process, offering a potentially useful refinement of an increasingly common biomaterial processing technique.
Dino J Ravnic - One of the best experts on this subject based on the ideXlab platform.
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squid ring teeth coated mesh improves Abdominal Wall Repair
Plastic and reconstructive surgery. Global open, 2018Co-Authors: Ashley N Leberfinger, Monika Hospodiuk, Abdon Penafrancesch, Bugra Ayan, Veli Ozbolat, Srinivas Koduru, Ibrahim T Ozbolat, Melik C Demirel, Dino J RavnicAbstract:Background Hernia Repair is a common surgical procedure with polypropylene (PP) mesh being the standard material for correction because of its durability. However, complications such as seroma and pain are common, and Repair failures still approach 15% secondary to poor tissue integration. In an effort to enhance mesh integration, we evaluated the applicability of a squid ring teeth (SRT) protein coating for soft-tissue Repair in an Abdominal Wall defect model. SRT is a biologically derived high-strength protein with strong mechanical properties. We assessed tissue integration, strength, and biocompatibility of a SRT-coated PP mesh in a first-time pilot animal study. Methods PP mesh was coated with SRT (SRT-PP) and tested for mechanical strength against uncoated PP mesh. Cell proliferation and adhesion studies were performed in vitro using a 3T3 cell line. Rats underwent either PP (n = 3) or SRT-PP (n = 6) bridge mesh implantation in an anterior Abdominal Wall defect model. Repair was assessed clinically and radiographically, with integration evaluated by histology and mechanical testing at 60 days. Results Cell proliferation was enhanced on SRT-PP mesh. This was corroborated in vivo by Abdominal Wall histology, dramatically diminished craniocaudal mesh contraction, improved strength testing, and higher tissue failure strain. There was no increase in seroma or visceral adhesion formation. No foreign body reactions were noted on liver histology. Conclusions SRT applied as a coating appears to augment mesh-tissue integration and improve Abdominal Wall stability following bridged Repair. Further studies in larger animals will determine its applicability for hernia Repair in patients.
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squid ring teeth coated mesh improves Abdominal Wall Repair
bioRxiv, 2017Co-Authors: Ashley N Leberfinger, Monika Hospodiuk, Abdon Penafrancesch, Bugra Ayan, Veli Ozbolat, Srinivas Koduru, Ibrahim T Ozbolat, Melik C Demirel, Dino J RavnicAbstract: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.
Volker Schumpelick - One of the best experts on this subject based on the ideXlab platform.
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influence of polyglactin coating on functional and morphological parameters of polypropylene mesh modifications for Abdominal Wall Repair
Biomaterials, 1999Co-Authors: Uwe Klinge, Markus Mulle, M Anurov, A Ottinge, Volker SchumpelickAbstract:Abstract Regarding oversized mechanical properties of most of the currently available materials a new mesh was developed (ETHICON ® , Norderstedt, Germany) and exactly adopted to the physiology of the human Abdominal Wall by reducing the amount of polypropylene (weight of 2 ; mesh A). The consecutive increase of pores size as well as the use of multifilaments led to a pronounced increase of flexibility. To improve the handling during operation the initial stiffness of this low-weight large pores mesh was increased by strengthening with different amounts of absorbable polyglactin (combination of glycolide and lactide) in various forms: by coating (mesh B), adding multifilament polyglactin filaments (mesh C, Vypro ® ) or both (mesh D), respectively. To test the consequences of the different supplementary techniques all mesh variants are implanted in a rat model. Over implantation intervals of 3, 7, 14, 21 and 90 days we measured the tensile strength, the resulting stiffness and surveyed the tissue response, particularly in regard to the extent of inflammation and to the induced fibrosis. The results proved a sufficient mechanical stability of the material reduced and pure polypropylene mesh A without restriction of the mobility of the Abdominal Wall compared with a group that had simple laparotomy and closure. The histological analysis of the interface showed a minor inflammatory reaction and a dense vascularisation. The addition of polyglactin multifilaments (mesh C) reduces the number of macrophages and granulocytes as indicators for acute inflammation, showing generally a scar formation limited merely to the perifilamentary region. The Abdominal Wall compliance remained unchanged compared with mesh A. The coating of the polypropylene with polyglactin (mesh B and D) appeared to change the tissue reaction remarkably, favouring the formation of a connective tissue capsule around the whole mesh. The mechanical testing revealed an apparent protrusion with an increase of curvature of the artificial Abdominal Wall at rising intraAbdominal pressures. The entire coating of the polypropylene surface with polyglactin induces an all embedding scar plate, filling out the pores and forming a tissue capsule. The complex interaction of tissue and implanted biomaterials with their distinct alterations of the tissue response confirms the necessity of in vivo experiments even after ‘minor’ modifications. Whereas the addition of polyglactin filaments appears to be favourable, the coating of polypropylene with polyglactin seems to hinder the incorporation of the mesh
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functional and morphological evaluation of different polypropylene mesh modifications for Abdominal Wall Repair
Biomaterials, 1998Co-Authors: B Klosterhalfen, Uwe Klinge, Volker SchumpelickAbstract:Abstract Modern surgical hernia Repair depends increasingly on synthetic meshes for the reconstruction of the Abdominal Wall. Despite the undisputed advantages of the polypropylene (PP) meshes currently available (Marlex ® , Prolene ® ), reports of complications after implantation are increasing. Although, serious complications such as perforation and fistula formation are rare, minor and local complaints such as seromas, misfeelings and a decreased Abdominal Wall mobility are observed in about one-half of the patients. In regard to the exaggerated strength of the currently available mesh modifications a reduction of the material should improve the integration of the meshes into the artificial Abdominal Wall. In the present study, the commercially available basic mesh Prolene ® has been compared to two newly constructed PP-mesh modifications with reduced amounts of PP. The modifications have gradually been adopted to the physiological requirements of Abdominal Wall stability and mobility by reducing the amount of PP to 64% (E-BLUE) and 24% (variant A) of the Prolene ® mesh (developed by ETHICON ® , Norderstedt, Germany). All PP-mesh variants have been implanted in a rat model and studied by 3D-photogrammetry, tensiometry, light- and electron microscopy, as well as morphometry over implantation intervals of 3, 7, 14, 21 and 90 days. The data show that current constructions of PP-meshes are oversized and definitely restrict Abdominal Wall mobility in the present model. Sufficient stability of the artificial Abdominal Wall is even guaranteed by PP-mesh modifications with a reduction of PP-quantity to about 25% of the Prolene ® mesh. The degree of fibrosis directly correlated with Abdominal Wall restriction, whereas the formation of connective tissue in the interface PP-fibre/host-issue depends on the amount and activity of the inflammatory reaction. The quantity and quality of inflammation, again, directly relies to the amount of PP and to the surface area in contact with the recipient tissues. Altogether, the present study suggests that a modification of the PP-meshes could be helpful to prevent major and minor complications of surgical PP-meshes.
Ashley N Leberfinger - One of the best experts on this subject based on the ideXlab platform.
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squid ring teeth coated mesh improves Abdominal Wall Repair
Plastic and reconstructive surgery. Global open, 2018Co-Authors: Ashley N Leberfinger, Monika Hospodiuk, Abdon Penafrancesch, Bugra Ayan, Veli Ozbolat, Srinivas Koduru, Ibrahim T Ozbolat, Melik C Demirel, Dino J RavnicAbstract:Background Hernia Repair is a common surgical procedure with polypropylene (PP) mesh being the standard material for correction because of its durability. However, complications such as seroma and pain are common, and Repair failures still approach 15% secondary to poor tissue integration. In an effort to enhance mesh integration, we evaluated the applicability of a squid ring teeth (SRT) protein coating for soft-tissue Repair in an Abdominal Wall defect model. SRT is a biologically derived high-strength protein with strong mechanical properties. We assessed tissue integration, strength, and biocompatibility of a SRT-coated PP mesh in a first-time pilot animal study. Methods PP mesh was coated with SRT (SRT-PP) and tested for mechanical strength against uncoated PP mesh. Cell proliferation and adhesion studies were performed in vitro using a 3T3 cell line. Rats underwent either PP (n = 3) or SRT-PP (n = 6) bridge mesh implantation in an anterior Abdominal Wall defect model. Repair was assessed clinically and radiographically, with integration evaluated by histology and mechanical testing at 60 days. Results Cell proliferation was enhanced on SRT-PP mesh. This was corroborated in vivo by Abdominal Wall histology, dramatically diminished craniocaudal mesh contraction, improved strength testing, and higher tissue failure strain. There was no increase in seroma or visceral adhesion formation. No foreign body reactions were noted on liver histology. Conclusions SRT applied as a coating appears to augment mesh-tissue integration and improve Abdominal Wall stability following bridged Repair. Further studies in larger animals will determine its applicability for hernia Repair in patients.
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squid ring teeth coated mesh improves Abdominal Wall Repair
bioRxiv, 2017Co-Authors: Ashley N Leberfinger, Monika Hospodiuk, Abdon Penafrancesch, Bugra Ayan, Veli Ozbolat, Srinivas Koduru, Ibrahim T Ozbolat, Melik C Demirel, Dino J RavnicAbstract: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.
Stephen F Badylak - One of the best experts on this subject based on the ideXlab platform.
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an elastomeric patch electrospun from a blended solution of dermal extracellular matrix and biodegradable polyurethane for rat Abdominal Wall Repair
Tissue Engineering Part C-methods, 2012Co-Authors: Yi Hong, Ryotaro Hashizume, Nicholas J Amoroso, William R Wagner, Stephen F Badylak, Keisuke Takanari, Ellen P Brennanpierce, John M FreundAbstract:A biodegradable elastomeric scaffold was created by electrospinning a mixed solution of poly(ester urethane)urea (PEUU) and porcine dermal extracellular matrix (dECM) digest, with PEUU included to provide elasticity, flexibility, and mechanical support and dECM used to enhance bioactivity and biocompatibility. Micrographs and differential scanning calorimetry demonstrated partial miscibility between PEUU and dECM. With greater dECM content, scaffolds were found to possess lower breaking strains and suture retention strength, although initial modulus was greater with higher dECM concentrations. The hybrid scaffolds containing 0% to 50% dECM had tensile strengths of 5 to 7 MPa, breaking strains of 138% to 611%, initial moduli of 3 to 11 Mpa, and suture retention strengths of 35 to 59 MPa. When hydrated, scaffolds were found to contract markedly with 50% dECM content. When used in a rat full-thickness Abdominal Wall replacement model, no herniation, infection, or tissue adhesion was observed after 4 and 8 we...
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an elastomeric patch electrospun from a blended solution of dermal extracellular matrix and biodegradable polyurethane for rat Abdominal Wall Repair
Tissue Engineering Part C-methods, 2012Co-Authors: Yi Hong, Ryotaro Hashizume, Nicholas J Amoroso, William R Wagner, Stephen F Badylak, Keisuke Takanari, Ellen P Brennanpierce, John M FreundAbstract:A biodegradable elastomeric scaffold was created by electrospinning a mixed solution of poly(ester urethane)urea (PEUU) and porcine dermal extracellular matrix (dECM) digest, with PEUU included to provide elasticity, flexibility, and mechanical support and dECM used to enhance bioactivity and biocompatibility. Micrographs and differential scanning calorimetry demonstrated partial miscibility between PEUU and dECM. With greater dECM content, scaffolds were found to possess lower breaking strains and suture retention strength, although initial modulus was greater with higher dECM concentrations. The hybrid scaffolds containing 0% to 50% dECM had tensile strengths of 5 to 7 MPa, breaking strains of 138% to 611%, initial moduli of 3 to 11 Mpa, and suture retention strengths of 35 to 59 MPa. When hydrated, scaffolds were found to contract markedly with 50% dECM content. When used in a rat full-thickness Abdominal Wall replacement model, no herniation, infection, or tissue adhesion was observed after 4 and 8 weeks with a scaffold containing 25% dECM or a control 100% PEUU scaffold. Scaffolds incorporating dECM were significantly thicker at the time of explant, with greater numbers of associated smooth muscle actin-positive staining cells than in the control, but minimal cellular infiltration and remodeling of the scaffold were detected regardless of dECM addition. The processing of dECM and PEUU from a mixed solution thus provided a scaffold with evidence of better bioactivity and with mechanical properties not achievable with digested dECM alone.
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Repair of the Thoracic Wall With an Extracellular Matrix Scaffold in a Canine Model
The Journal of surgical research, 2007Co-Authors: Thomas W. Gilbert, Alejandro Nieponice, Alan R. Spievack, John B. Holcomb, Sebastien Gilbert, Stephen F BadylakAbstract:Naturally derived extracellular matrix (ECM) scaffolds have been successfully used to promote constructive remodeling of injured or missing tissue in a variety of anatomical locations, including Abdominal Wall Repair. Furthermore, ECM scaffolds have shown the ability to resist infection and adhesion formation. The present study investigated the utility of an ECM scaffold, specifically, porcine urinary bladder matrix (UBM), for Repair of a 5 x 5 cm full-thickness lateral thoracic Wall defect in a canine model (n = 6) including 5-cm segments of the 6th and 7th rib. The resected portion of the 7th rib was replaced as an interpositional graft along with the UBM scaffold. As a control, a Gore-Tex patch was used to Repair the same defect (n = 2). The control animals healed by encapsulation of the Gore-Tex patch by dense collagenous tissue. The remodeled UBM grafts showed the presence of site-specific tissue, including organized fibrous connective tissue, muscle tissue, adipose tissue, and bone. Upon fluoroscopic examination, it was shown that both bony defects were replaced with new calcified bone. In the 6th rib space, new bone bridged the entire span. In the 7th rib space, there was evidence of bone formation between the interpositional graft and the existing bone, as well as de novo formation of organized bone in the shape of the missing rib segment parallel to the interpositional graft. This study shows that a naturally occurring ECM scaffold promotes site-specific constructive remodeling in a large thoracic Wall defect.
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intestine submucosa and polypropylene mesh for Abdominal Wall Repair in dogs
Journal of Surgical Research, 1996Co-Authors: Kevin M Clarke, Gary C Lantz, Kathleen S Salisbury, Stephen F Badylak, Michael C Hiles, Sherry VoytikAbstract:Continuing investigations of Abdominal body Wall reconstruction materials suggest that unacceptable implant complications continue and that the ideal material has not yet been found. This pilot study compared xenogeneic (porcine) small intestine submucosa (SIS) with polypropylene mesh (PPM) for Repair of created partial-thickness (six dogs) and full-thickness (six dogs) Abdominal Wall defects. Postoperative clinical evaluation of all dogs showed no evidence of implant failure. Dogs were euthanized at 1, 2, and 4 months after surgery. The SIS implants were completely replaced by host tissue at 4 months as determined by immunohistochemistry. The resultant Repair was well-organized, smooth, dense collagenous connective tissue that was well incorporated into the adjacent fascia and skeletal muscle fiber bundles. In the full-thickness defect dogs, omentum covered a significantly larger portion of PPM (P= 0.001) and was more firmly attached to PPM (P= 0.0001) compared to SIS/connective tissue Repair. We conclude that xenogeneic SIS can be used as an Abdominal body Wall Repair material in the dog and warrants further investigations.
