Polypropylene Mesh For Hernia Repair Research Articles

Bioresorbable films of polycaprolactone blended with poly(lactic acid) or poly(lactic-co-glycolic acid)

Recent complications on the use of polypropylene meshes for hernia repair has led to the development of meshes or films, which were based on resorbable polymers such as polycaprolactone (PCL), polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA). These materials are able to create suitable bioactive environment for the growth and development of cells. In this research, we mainly focused on the relations among structure, mechanical performance and biocompatiblity of PCL/PLA and PCL/PLGA and blends prepared by solution casting. The films were characterized regarding the chemical structure, morphology, physicochemical properties, cytotoxicity, biocompatibility and cell growth. All the films showed high tensile strength ranging from 9.5 to 11.8 MPa. SAXS showed that the lamellar stack structure typical for PCL was present even in the blend films while the morphological parameters of the stacks varied slightly with the content of PLGA or PLA in the blends. WAXS indicated preferential orientation of crystallites (and thus, also the lamellar stacks) in the blend films. In vitro studies revealed that PCL/PLGA films displayed better cell adhesion, spreading and proliferation than PCL/PLA and PCL films. Further the effect of blending on the degradation was investigated, to understand the significant variable within the process that could provide further control of cell adhesion. The results showed that the investigated blend films are promising materials for biomedical applications.

Lightweight versus Heavyweight mesh for open repair of inguinal hernia

Background Open repair of inguinal hernia with mesh is associated with a decreased risk of recurrence compared to hernia repair without mesh. However, the use of traditional heavyweight (HWM) polypropylene mesh in hernia repair has raised concerns about the higher incidence of postoperative chronic groin pain, persistent groin discomfort, foreign body sensations, testicular atrophy and impaired sensations in the groin. Lightweight mesh (LWM) is composed of a reduced component of reactive biomaterial and is considered an innovative measure to lessen the long term consequences of the mesh repair of inguinal hernia. Objectives The objective of this review is to systematically analyse the randomised, controlled trials (RCTs) to compare the effectiveness of LWM versus HWM in patients undergoing open inguinal hernia repair. Search methods The Cochrane Colorectal Cancer Group (CCCG) Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (Issue 1, 2012), MEDLINE (until March 2012), EMBASE (The Intelligent Gateway to Biomedical & Pharmacological Information until March 2012), and Science Citation Index Expanded (SCI-E until March 2012) using the medical subject headings (MeSH) terms were searched without date, language or age restrictions. Selection criteria RCTs comparing the effectiveness of LWM versus HWM in patients undergoing open inguinal hernia repair. Data collection and analysis At least two review authors independently scrutinised search results, selected eligible studies and extracted the data. This data was further confirmed by the third review author to check the accuracy. Main results Fourteen published articles on eleven RCTs encompassing 2589 patients undergoing open inguinal hernia repair either using LWM or HWM were retrieved from the electronic databases. There were 1282 patients in the LWM group and 1307 patients in the HWM group. Statistically, there was no difference between LWM and HWM in terms of duration of operation, postoperative complications, the risk of hernia recurrence and the risk of developing testicular atrophy. LWM was associated with lower postoperative pain score, early return to work and daily activities. In addition, LWM was associated with the reduced risk of developing chronic groin pain and the reduced risk of developing other groin symptoms such as groin discomfort, sensory impairment, regional hard feelings, point tenderness and foreign body sensations. Authors' conclusions LWM may not increase the risk of inguinal hernia recurrence. LWM seems to be associated with the reduced risk of developing chronic groin pain and other symptoms such as groin discomfort, sensory impairment, regional hard feelings, point tenderness and foreign body sensations. These outcomes should better be judged after long-term follow up and therefore, LWM may only be considered a viable alternative to HWM in open inguinal hernia repair instead of recommending its routine use.

Polypropylene mesh for hernia repair with controllable cell adhesion/de-adhesion properties.

Herein, a versatile bilayer system, composed by a polypropylene (PP) mesh and a covalently bonded poly(N-isopropylacrylamide) (PNIPAAm) hydrogel, is reported. The cell adhesion mechanism was successfully modulated by controlling the architecture of the hydrogel in terms of duration of PNIPAAm grafting time, crosslinker content, and temperature of material exposure in PBS solutions (below and above the LCST of PNIPAAm). The best in vitro results with fibroblast (COS-1) and epithelial (MCF-7) cells was obtained with a mesh modified with a porous iPP-g-PNIPAAm bilayer system, prepared via PNIPAAm grafting for 2 h at the lowest N,N'-methylene bis(acrylamide) (MBA) concentration (1 mM). Under these conditions, the detachment of the fibroblast-like cells was 50% lower than that of the control, after 7 days of cell incubation, which represents a high de-adhesion of cells in a short period. Moreover, the whole system showed excellent stability in dry or wet media, proving that the thermosensitive hydrogel was well adhered to the polymer surface, after PP fibre activation by cold plasma. This study provides new insights on the development of anti-adherent meshes for abdominal hernia repair.

Chitosan Cross-Linked Bio-based Antimicrobial Polypropylene Meshes for Hernia Repair Loaded with Levofloxacin HCl via Cold Oxygen Plasma

Polypropylene (PP) large pore size nets have been most widely used implants for hernia repair. Nevertheless, the growth of bacteria within PP mesh pores after operation is a major reason of hernia recurrence. Secondly, pre-operative prophylaxis during mesh implantation has failed due to the hydrophobic nature of PP meshes. Herein, chitosan cross-linked and levofloxacin HCl incorporated, antimicrobial PP mesh devices were prepared using citric acid as a bio-based and green cross-linking agent. The inert PP mesh fibers were surface activated using O2 plasma treatment at low pressure. Then, chitosan of different molecular weights (low and medium weight) were cross-linked with O2 plasma activated surfaces using citric acid. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy confirmed that chitosan was cross-linked with O2 plasma-treated PP mesh surfaces and formed a thin layer of chitosan and levofloxacin HCl on the PP mesh surfaces. Moreover, antimicrobial properties of chitosan and levofloxacin HCl-coated PP meshes were investigated using an agar plate release method. The coated PP meshes demonstrated excellent antimicrobial inhibition zone up to 10 mm. Thus, modified PP meshes demonstrated sustained antimicrobial properties for six continuous days against Staphylococcus aureus (SA) and Escherichia coli (EC) bacteria.

Experimental study on the use of a chlorhexidine-loaded carboxymethylcellulose gel as antibacterial coating for hernia repair meshes.

Biomaterials with an antimicrobial coating could avoid mesh-associated infection following hernia repair. This study assesses the use of a chlorhexidine-loaded carboxymethylcellulose gel in a model of Staphylococcus aureus mesh infection. A 1% carboxymethylcellulose gel containing 0.05% chlorhexidine was prepared and tested in vitro and in vivo. The in vitro tests were antibacterial activity (S. aureus; agar diffusion test) and gel cytotoxicity compared to aqueous 0.05% chlorhexidine (fibroblasts; alamarBlue). For the in vivo study, partial abdominal wall defects (5 × 2cm) were created in New Zealand white rabbits (n = 15) and inoculated with 0.25mL of S. aureus (106CFU/mL). Defects were repaired with a lightweight polypropylene mesh (Optilene) without coating (n = 3) or coated with a carboxymethylcellulose gel (n = 6) or chlorhexidine-loaded carboxymethylcellulose gel (n = 6). Fourteen days after surgery, bacterial adhesion to the implant (sonication, immunohistochemistry), host tissue incorporation (light microscopy) and macrophage reaction (immunohistochemistry) were examined. Carboxymethylcellulose significantly reduced the toxicity of chlorhexidine (p < 0.001) without limiting its antibacterial activity. While control and gel-coated implants were intensely contaminated, the chlorhexidine-gel-coated meshes showed a bacteria-free surface, and only one specimen showed infection signs. The macrophage reaction in this last group was reduced compared to the control (p < 0.05) and gel groups. When incorporated in the carboxymethylcellulose gel, chlorhexidine showed reduced toxicity yet maintained its bactericidal effect at the surgery site. Our findings suggest that this antibacterial gel-coated polypropylene meshes for hernia repair prevent bacterial adhesion to the mesh surface and have no detrimental effects on wound repair.

No increased risk of carcinogenesis with mesh-based hernia repairs

BackgroundThe use of synthetic mesh has been placed under considerable scrutiny. We sought to evaluate whether there is a link between placement of synthetic polypropylene mesh for hernia repair and a subsequent cancer diagnosis. MethodsAdult men undergoing mesh-based hernia repair from January 2008–December 2009 in New York State were identified and followed through December 2014. Control cohorts of men undergoing cholecystectomy and total knee replacement were control cohorts. Results1894 patients undergoing hernia repair, 912 patients in the cholecystectomy control cohort, and 1099 in the TKA control cohort with a cancer diagnosis. In the matched analyses of mesh-based hernia repair and cholecystectomy patients 6.5% vs. 7.1% developed cancer. In the matched analysis of hernia patients and TKA patients, 9.3% vs. 9.1% developed cancer. No association between mesh-based hernia surgery and increased risk of cancer was found. ConclusionsMesh-based hernia repair was not associated with an increased risk of subsequent development of cancer in men.

Structural Analysis and Application of n‐Alkyl Cyanoacrylate Surgical Adhesives to the Fixation of Meshes for Hernia Repair

The article deals with a comparative analysis of the parameters of the polymerization in physiological conditions of three commercially available alkyl cyanoacrylates, n-butyl cyanoacrylate (GLUBRAN 2), n-hexyl cyanoacrylate (IFABOND), and n-octyl cyanoacrylate (EVOBOND), the cell behavior of the corresponding polymers and the application of these adhesives in the fixation of surgical polypropylene meshes for hernia repair in an animal model of rabbits. The results obtained demonstrate that the curing process depends on the nature of the alkyl residue of the ester group of cyanoacrylate molecules, being the heat of polymerization lower for the octyl derivative in comparison with the hexyl and butyl, and reaching a maximum temperature of 35°C after a time of mixing with physiological fluids of 60-70 s. The cell behavior demonstrates that the three systems do not present toxicity for fibroblasts and low adhesion of cells, which is a positive result for application as tissue adhesives, especially for the fixation of abdominal polypropylene meshes for hernia repair. The animal experimentation indicates the excellent tolerance of the meshes fixed with the cyanoacrylic adhesives, during at least a period of 90 d, and guarantees a good adhesion for the application of hernia repair meshes.

Preclinical Bioassay of a Polypropylene Mesh for Hernia Repair Pretreated with Antibacterial Solutions of Chlorhexidine and Allicin: An In Vivo Study.

IntroductionProsthetic mesh infection constitutes one of the major complications following hernia repair. Antimicrobial, non-antibiotic biomaterials have the potential to reduce bacterial adhesion to the mesh surface and adjacent tissues while avoiding the development of novel antibiotic resistance. This study assesses the efficacy of presoaking reticular polypropylene meshes in chlorhexidine or a chlorhexidine and allicin combination (a natural antibacterial agent) for preventing bacterial infection in a short-time hernia-repair rabbit model.MethodsPartial hernia defects (5 x 2 cm) were created on the lateral right side of the abdominal wall of New Zealand White rabbits (n = 21). The defects were inoculated with 0.5 mL of a 106 CFU/mL Staphylococcus aureus ATCC25923 strain and repaired with a DualMesh Plus antimicrobial mesh or a Surgipro mesh presoaked in either chlorhexidine (0.05%) or allicin-chlorhexidine (900 μg/mL-0.05%). Fourteen days post-implant, mesh contraction was measured and tissue specimens were harvested to evaluate bacterial adhesion to the implant surface (via sonication, S. aureus immunolabeling), host-tissue incorporation (via staining, scanning electron microscopy) and macrophage response (via RAM-11 immunolabeling).ResultsThe polypropylene mesh showed improved tissue integration relative to the DualMesh Plus. Both the DualMesh Plus and the chlorhexidine-soaked polypropylene meshes exhibited high bacterial clearance, with the latter material showing lower bacterial yields. The implants from the allicin-chlorhexidine group displayed a neoformed tissue containing differently sized abscesses and living bacteria, as well as a diminished macrophage response. The allicin-chlorhexidine coated implants exhibited the highest contraction.ConclusionsThe presoaking of reticular polypropylene materials with a low concentration of chlorhexidine provides the mesh with antibacterial activity without disrupting tissue integration. Due to the similarities found with the antimicrobial DualMesh Plus material, the chlorhexidine concentration tested could be utilized as a prophylactic treatment to resist infection by prosthetic mesh during hernia repair.

Histopathological Comparison of Mosquito Net with Polypropylene Mesh for Hernia Repair: An Experimental Study in Rats.

Use of mosquito net, in place of polypropylene mesh, had been reported for tension-free hernia repair, as a better cost-effective option. This experimental histopathological study was performed in rats to find out the tissue response and the foreign body reaction and its comparison between commercial polypropylene mesh and the sterilized mosquito net. This experimental study was conducted in the Department of Surgery, Government NSCB, Medical College, Jabalpur (Madhya Pradesh), India. It was carried out in 40 albino rats. A 1.5 × 0.5-cm hernial defect was created by excising full-thickness abdominal wall muscle. All rats underwent on-lay mesh repair of hernial defect (polypropylene mesh, n = 20; mosquito net, n = 20). Half of rats in each group were sacrificed on day 14, and the other half, on day 90. Sections of containing mesh were examined histopathologically for inflammatory infiltrate, giant cells, and collagen deposition. Mosquito net group showed significantly greater number of giant cells and inflammatory cells at 14 and 90days (p < 0.0001, p < 0.001, p < 0.05, and p < 0.001, respectively), as compared to polypropylene group. Grades of collagen fiber deposition were almost equal in both groups, both at 14 and 90days (p > 0.05 and p > 0.05, respectively). Results of mosquito net are comparable to conventional polypropylene mesh. In a setup, where cost-effectiveness is of primary importance, use of mosquito net for tension-free hernia repair can be an acceptable alternative as proven histologically, to commercially available polypropylene mesh.

Lightweight versus Heavyweight mesh for open repair of inguinal hernia

Background Open repair of inguinal hernia with mesh is associated with a decreased risk of recurrence compared to hernia repair without mesh. However, the use of traditional heavyweight (HWM) polypropylene mesh in hernia repair has raised concerns about the higher incidence of postoperative chronic groin pain, persistent groin discomfort, foreign body sensations, testicular atrophy and impaired sensations in the groin. Lightweight mesh (LWM) is composed of a reduced component of reactive biomaterial and is considered an innovative measure to lessen the long term consequences of the mesh repair of inguinal hernia. Objectives The objective of this review is to systematically analyse the randomised, controlled trials (RCTs) to compare the effectiveness of LWM versus HWM in patients undergoing open inguinal hernia repair. Search methods The Cochrane Colorectal Cancer Group (CCCG) Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (Issue 1, 2012), MEDLINE (until March 2012), EMBASE (The Intelligent Gateway to Biomedical & Pharmacological Information until March 2012), and Science Citation Index Expanded (SCI-E until March 2012) using the medical subject headings (MeSH) terms were searched without date, language or age restrictions. Selection criteria RCTs comparing the effectiveness of LWM versus HWM in patients undergoing open inguinal hernia repair. Data collection and analysis At least two review authors independently scrutinised search results, selected eligible studies and extracted the data. This data was further confirmed by the third review author to check the accuracy. Main results Fourteen published articles on eleven RCTs encompassing 2589 patients undergoing open inguinal hernia repair either using LWM or HWM were retrieved from the electronic databases. There were 1282 patients in the LWM group and 1307 patients in the HWM group. Statistically, there was no difference between LWM and HWM in terms of duration of operation, postoperative complications, the risk of hernia recurrence and the risk of developing testicular atrophy. LWM was associated with lower postoperative pain score, early return to work and daily activities. In addition, LWM was associated with the reduced risk of developing chronic groin pain and the reduced risk of developing other groin symptoms such as groin discomfort, sensory impairment, regional hard feelings, point tenderness and foreign body sensations. Authors' conclusions LWM may not increase the risk of inguinal hernia recurrence. LWM seems to be associated with the reduced risk of developing chronic groin pain and other symptoms such as groin discomfort, sensory impairment, regional hard feelings, point tenderness and foreign body sensations. These outcomes should better be judged after long-term follow up and therefore, LWM may only be considered a viable alternative to HWM in open inguinal hernia repair instead of recommending its routine use.

Prospective randomized controlled study using polyethylene mesh for inguinal hernia meshplasty as a safe and cost-effective alternative to polypropylene mesh

Most patients who come to a general hospital in a developing country are poor. The most important prohibiting factor for use of polypropylene mesh in hernia repair is its exorbitant cost. Hence, research workers have been on the lookout for an equally effective but economically affordable mesh. Worldwide, surgical repair of inguinal hernia is the most common general surgery procedure performed at the present. Lifetime risk of groin hernia is 15% in males and 5% in females. Most of the patients who visit a general hospital are from either lower middle class or poor socioeconomic strata. The most important prohibiting factor for use of polypropylene mesh in hernia repair for the common man is its exorbitant cost. The aim of this study is to document the feasibility, safety and cost-effectiveness of the use of polyethylene mesh. A single blind, prospective, randomized controlled study, comparing 35 patients of two groups was conducted in a tertiary teaching hospital over a period of 5years. The patients in both groups underwent inguinal hernioplasty, and were administered similar antibiotics and analgesics. The postoperative course with regard to pain, seroma formation, infection, hospital stay, recurrence and scar quality was evaluated and compared. Statistical analysis was performed with Chi square test. The properties of both meshes were the same with respect to ease of handling, pain score, seroma formation, infection rate, resumption of daily activities, scar quality and mesh rejection. Recurrence rate was zero for both groups. Polyethylene mesh was 2,808 times cheaper than the commercially available polypropylene mesh. This study proved the safety, simplicity, efficacy and cost-effectiveness of polyethylene mesh for inguinal hernia meshplasty, insuring economical, accessible health care for the financially weak section of the population.

The effects of polypropylene mesh on femoral artery and femoral vein in mesh repair

Since the first description, the use of polypropylene mesh in hernia repair has gained wide acceptance. The aim of this study was to assess whether polypropylene mesh implantation has any effects on femoral blood vessels. A 0.5 × 1.0 cm polypropylene mesh was inserted into the rat femoral artery and vein on the right side. After 14, 28 and 90 days, the rats were reoperated. The meshes were excised for histological processing. Blood flow in the dorsum of the foot skin, femoral artery and vein were measured in all groups before mesh implantation and at 14, 28, and 90 days after mesh implantation. Following placement of mesh graft on vascular structures, inflammation and fibrosis developed to a varying degree depending on the time elapsed. On the other hand, fibrosis did not change the histological structure of vessels. There was a decrease in both arterial and venous circulation due to the pressure of the graft. These data suggest that fibrosis due to mesh graft can negatively affect blood flow in vessels due to mechanical pressure.

The role of TGF-β1 as a determinant of foreign body reaction to alloplastic materials in rat fibroblast cultures: comparison of different commercially available polypropylene meshes for hernia repair

Background Animal experiments on hernia repair demonstrated better biocompatibility of light-weight polypropylene meshes. However, implanted medical devices trigger a variety of adverse tissue responses, such as inflammation, fibrosis, infection and thrombosis, but the mechanisms involved in such responses remain largely unknown. This study aimed to determine the effect of transforming growth factor β1 (TGF-β1) on host tolerance by quantification of foreign body reaction in cultured fibroblasts depending on the amount and composition of implanted material used for hernia repair. Materials and methods An NRK-49F fibroblast culture was incubated in the presence of 4 commercially available meshes approved for hernia repair. A mesh-free cell suspension served as a control group, in which the influence of TGF-β1 on fibroblasts was evaluated. Levels of TGF-β1 in the supernatant were dynamically measured in a time interval of 6 to 96 h and cell proliferation rates were assessed colorimetrically using MTT test. Results A dose-dependent suppression of fibroblasts proliferation by TGF-β1 was observed. All meshes suppressed the secretion of TGF-β1 and conversely increased significantly cell proliferation in comparison to the control group ( p < 0.01) in the first 24 to 48 h of incubation. That effect was more pronounced in meshes partially containing absorbable material when compared to samples of pure polypropylene meshes ( p < 0.05) and to the control group ( p < 0.001). Conclusion Our experiment revealed that early biological reaction of connective tissue cells towards polypropylene meshes and their variants depended much more on the composition and type of the material than on its absolute amount. The assumption that material weight reduction alone might affect the foreign body reaction of mesh implants could not be confirmed by our in vitro study.

Laparoscopic retrieval of retroperitoneal vas deferens in vasovasostomy for postinguinal herniorrhaphy obstructive azoospermia

Iatrogenic injury to the vas deferens is a well-documented complication of inguinal hernia repair. Recently obstruction related to the use of polypropylene mesh for hernia repair has been reported. We describe a case using laparoscopy to mobilize the retroperitoneal vas and deliver it to the healthy vas proximal to the vas trapped in the cicatrix induced by mesh thus allowing a tension-free microsurgical repair. Case report. Outpatient male infertility practice. Obstructed azoospermic men with polypropylene mesh. Laparoscopic retrieval of retroperitoneal vas segment for primary microsurgical anastomosis. Patency of vas and presence of sperm. A tension-free, patent anastomosis was performed. Polypropylene mesh-induced fibrosis of the vas deferens can result in obstructive azospermia. Laparoscopy can be used to permit a microsurgical bypass of the obstructed segment.

The Argument for Lightweight Polypropylene Mesh in Hernia Repair

The development of polypropylene prosthetics revolutionized surgery for the repair of abdominal wall hernias. A tension-free mesh technique has drastically reduced recurrence rates for all hernias compared to tissue repairs and has made it possible to reconstruct large ventral defects that were previously irreparable. The repair of abdominal wall defects is one of the most commonly performed general surgical procedures, with over 1 million polypropylene implants inserted each year. Surprisingly, little research has been performed to investigate the interaction of abdominal wall forces on a ventral hernia repair or the required amount or strength of the foreign-body material necessary for an adequate hernia repair. The long-term consequences of implantable polypropylene prosthetics are not without concern. The body generates an intense inflammatory response to the prosthetic that results in scar plate formation, increased stiffness of the abdominal wall, and shrinkage of the biomaterial. Reducing the density of polypropylene and creating a ''light weight'' mesh theoretically induces less foreign-body response, results in improved abdominal wall compliance, causes less contraction or shrinkage of the mesh, and allows for better tissue incorporation. A review of the laboratory data and short-term clinical follow-up is reviewed to provide a strong basis or argument for the use of ''light weight'' prosthetics in hernia surgery.

Titanium coating of a polypropylene mesh for hernia repair: Effect on biocompatibilty

Titanium and its alloys are used worldwide in surgery. The favorable characteristics that make this material desirable for implantation are corrosion resistance and biocompatibility. Concerning hernia repair, a mesh modification has been developed using titanium layering of a polypropylene mesh implant, which is said to lead to an improved biocompatibility compared to commercially available mesh materials. To analyze the pure effect of titanium coating, two different mesh structures were studied using a standardized animal model. The titanium-coated monofilamentous, large porous, and lightweight mesh made of polypropylene and coated with titanium (PP+T) was compared to a pure polypropylene mesh manufactured with a similar structure and amount of material serving as a control (PP). In Sprague-Dawley rats, mesh samples were placed in a subcutaneuous position. Then 56, 84, and 182 days after mesh implantation, three animals from each group were sacrificed for morphological observations (amount of inflammatory and connective tissue formation, percentages of proliferating and apoptotic cells, percentage of macrophages). Both mesh modifications investigated showed an overall good biocompatibility. Macroscopic clinical observation after implantation of up to 182 days was uneventful. The tissue response to the PP as well as to the PP+T mesh was characterized by a moderate inflammatory tissue reaction limited to the perifilamentary region as is known for low weight, large porous, and monofilamentous mesh structures. No significant improvement of biocompatibility was found when analyzing the effect of titanium coating compared to the pure polypropylene mesh structure.

Vypro II® Mesh in Hernia Repair: Impact of Polyglactin on Long-Term Incorporation in Rats

Background: To the Vypro II^® mesh, a large-pore-sized multifilamentous polypropylene mesh for hernia repair, supplementary polyglactin 910 multifilaments were added to improve intraoperative handling. As it has been suggested that polyglactin induces fibroplastic reactions and wound complications, this study was designed to evaluate the long-term tissue reaction to polyglactin in the Vypro II mesh. Materials and Methods: Two mesh materials, the Vypro II composite mesh (PP + PG) and the pure polypropylene variant (PP), were compared after inlay implantation in a standardized rodent animal model. After 14, 28, 42, 56, 84 and 112 days of implantation, histological analysis of the inflammatory response was performed: material absorption, inflammatory tissue reaction, fibrosis and granuloma formation were investigated. Results: Total absorption of polyglactin filaments of the Vypro II mesh occurred between 56 and 84 days of implantation. Both the inflammatory and the fibrotic reaction were initially increased in the PP + PG mesh group. These differences disappeared in the following implantation period. After 112 days, inflammation was even less pronounced in the PP + PG mesh group. Conclusion: The present data confirm a short-term polyglactin-induced increase in inflammation and fibrosis around implanted Vypro II meshes in rats. With regard to the long-term tissue response, even an anti-inflammatory property of polyglactin multifilaments in low-weight and large-pored polypropylene meshes cannot be ruled out.

Functional and morphological evaluation of a low-weight, monofilament polypropylene mesh for hernia repair.

With more than 1 million implantations per year worldwide, mesh repair has become a standard procedure for the treatment of hernias. Apart from various technical problems, the type of material has been proven to be of considerable importance for the functional and histological outcome, particularly for long-term implantation. Whereas the advantageous application of low-weight, large-pore meshes based on multifilaments can be stated without doubt, it is still open whether similar results can be achieved on the basis of pure monofilaments. In the present study, a low-weight polypropylene mesh (LW) made purely of monofilaments was compared to a common heavy-weight polypropylene mesh (HW) in regard to the functional consequences and the tissue response. After implantation in rats as an inlay for 3--90 days, the abdominal-wall mobility of the implant region was recorded by 3D stereography, and the tensile strength of both the suture zone and the mesh was measured. The morphometry of the histological reaction in regard to the inflammatory infiltrate, the connective tissue, the number of granulocytes, macrophages, and fibroblasts served to reflect the tissue response. As parameters for the remodeling process at the interface the cellular activation was evaluated by TUNEL (DNA-strand breaks or apoptosis, respectively), Ki 67 (cell proliferation), and HSP 70 (cell stress). The measured tensile strength of the LW mesh confirmed a sufficient strength of the material-reduced mesh modification. After implantation the consecutive impairment of the abdominal-wall mobility was reduced compared to the HW mesh, concomitant to the reduced fibrotic level at the interface. At the end of the observation period the foreign-body reaction was significantly lowered for the LW mesh, almost reaching physiological values. In conclusion, these data confirm the improved biocompatibility of material-reduced mesh implants.