Evaluation of new prosthetic meshes for ventral hernia repair

Background In hernia repair, particularly laparoscopic hernia repair, direct contact between mesh and abdominal organs cannot always be avoided. Several mesh materials and composite meshes have been developed to decrease subsequent adhesion formation. Recently, new meshes have been introduced. In an experimental rat study, their value was established and compared with that of meshes already available on the market. Methods In 200 rats, eight different meshes were placed intraperitoneally and in direct contact with abdominal viscera. The following meshes were tested: polypropylene (Prolene), e-PTFE (Dualmesh), polypropylene– polyglecaprone composite (Ultrapro), titanium–polypropylene composite (Timesh), polypropylene with carboxymethylcellulose–sodium hyaluronate coating (Sepramesh), polyester with collagen-polyethylene glycol–glycerol coating (Parietex Composite), polypropylene–polydioxanone composite with oxidized cellulose coating (Proceed), and bovine pericardium (Tutomesh). At 7 and then at 30 days postoperatively, adhesion formation, mesh incorporation, tensile strength, shrinkage, and infection were scored by two independent observers. Results Parietex Composite, Sepramesh, and Tutomesh resulted in decreased surface coverage with adhesions, whereas Prolene, Dualmesh, Ultrapro, Timesh, and Proceed resulted in increased adhesion coverage. Parietex Composite, Prolene, Ultrapro, and Sepramesh resulted in the most mesh incorporation. Dualmesh and Tutomesh resulted in significantly increased shrinkage. There were no differences in mesh infection. Parietex Composite and Dualmesh resulted in a moderate inflammatory reaction, as compared with the mild reaction the other meshes exhibited. Conclusion Parietex Composite and Sepramesh combine minimal adhesion formation with maximum mesh incorporation and tensile strength. The authors recommend the use of these meshes for hernia repair in which direct contact with the abdominal viscera cannot be avoided.     

Evaluation of sepramesh biosurgical composite in a rabbit hernia repair model

BACKGROUND: In cases such as incisional hernia repair, polypropylene mesh (PPM) can be exposed to the underlying viscera and cause adhesions to the mesh. In this study, a composite prosthesis that was designed to be less susceptible to adhesion formation than PPM was evaluated in a rabbit incisional hernia repair model. MATERIALS AND METHODS: A 5 x 7-cm full-thickness defect was created in the abdominal wall of 30 female New Zealand White rabbits. Ten animals each were repaired with PPM, Bard Composix (PP/ePTFE), or Sepramesh biosurgical composite-a polypropylene mesh coated on one side with chemically modified sodium hyaluronate and carboxymethylcellulose (HA/CMC). The animals were sacrificed after 28 days and the overall performance, including adhesion formation and tissue integration by histology and mechanical testing, was evaluated. RESULTS: In the Sepramesh group, there was a significant reduction in the percentage of surface area covered by adhesions and a significant increase in the percentage of animals with no adhesions compared to standard materials. The tissue integration strength and overall cellular response were similar in all groups. A partially remesothelialized peritoneal surface was often apparent overlying the Sepramesh implant. CONCLUSIONS: Sepramesh biosurgical composite effectively repaired abdominal wall defects in rabbits and reduced adhesion development to the mesh compared to the use of a PPM and a PP/ePTFE composite.     

Prevention of adhesion formation to polypropylene mesh by collagen coating: A randomized controlled study in a rat model of ventral hernia repair

Introduction In laparoscopic incisional hernia repair with intraperitoneal mesh, concern exists about the development of adhesions between bowel and mesh, predisposing to intestinal obstruction and enterocutaneous fistulas. The aim of this study was to assess whether the addition of a collagen coating on the visceral side of a polypropylene mesh can prevent adhesion formation to the mesh.Method In 58 rats, a defect in the muscular abdominal wall was created, and a mesh was fixed intraperitoneally to cover the defect. Rats were divided in two groups; polypropylene mesh (control group) and polypropylene mesh with collagen coating (Parieten mesh). Seven and 30 days postoperatively, adhesions and amount and strength of mesh incorporation were assessed. Wound healing was studied by microscopy.Results With Parieten mesh, the mesh surface covered by adhesions was reduced after 30 days (42% vs 69%, p = 0.01), but infection rate was increased after both 7 (p = 0.001) and 30 days (p = 0.03), compared to the polypropylene group with no mesh infections. If animals with mesh infection were excluded in the analysis, the mesh surface covered by adhesions was reduced after 7 days (21% vs 76%, p = 0.02), as well as after 30 days (21 vs 69%, p < 0.001). Percentage of mesh incorporation was comparable in both groups. Mean tensile strength of mesh incorporation after 30 days was higher with Parieten mesh.Conclusion Although the coated Parieten mesh was more susceptible to mesh infection in the current model, a significant reduction of adhesion formation was still seen with the Parieten mesh after 30 days, with comparable mesh incorporation in the abdominal wall.     

Resistance to adhesion formation: A comparative study of treated and untreated mesh products placed in the abdominal cavity

Background: New materials have been devised to prevent postoperative adhesions when placing a prosthesis in contact with abdominal contents. Methods: Eighty rats underwent laparotomy and denudation of the serosa of the cecum and peritoneal covering of the abdominal wall. Five treated mesh products (Parietex Composite, Parietene Composite, Bard Composix E/X, Sepramesh, and Gore-Tex Dual Mesh) and one untreated mesh product (untreated Parietene) were randomly placed between the cecum and abdominal wall. A group without mesh was used as control. The animals were sacrificed at 21 days following surgery and analyzed for the presence of adhesions.Results: The incidence of adhesion formation, mean adhesion area, maximum adhesion length, and strength of adhesion separation were similar between Parietex Composite, Parietene Composite, and Bard Composix E/X, and they were significantly less than with Sepramesh, untreated Parietene, and the control group. Gore-Tex Dual Mesh resulted in less adhesions, adhesion area, mean strength of separation, and work of separation than the untreated Parietene group and the control group. Sepramesh resulted in less strength and work of separation compared to the control group. Conclusions: The incidence of adhesions and work and strength of adhesion separation are reduced when using a treated mesh, compared to the untreated mesh and the control group without mesh. Parietex Composite, Parietene Composite, Bard Composix E/X, and Gore-Tex Dual Mesh were superior to Sepramesh, untreated Parietene, and the control group in the prevention of adhesion formation.Disclosure statement: This study was sponsored by: Sofradim, Trévoux, France     

Peritoneal effects of prosthetic meshes used to repair abdominal wall defects: monitoring adhesions by sequential laparoscopy

BACKGROUND: The prosthetic materials currently used to repair abdominal wall defects sometimes have to be placed in contact with the visceral peritoneum. This interface is often a site of complications such as intestinal obstruction or fistulas due to adhesions. The aim of this study was to follow the process of adhesion formation in several prosthetic materials by sequential laparoscopy. MATERIAL AND METHODS: Defects (7 x 5 cm) were created in the abdominal wall of 30 New Zealand White rabbits and repaired using Surgipro polypropylene mesh (PP), Ultrapro monocryl-prolene mesh (UP), Dual Mesh expanded polytetrafluoroethylene (ePTFE), Composix (PP-ePTFE), Parietex Composite (polyester with collagen-polyethylene glycol-glycerol coating [PO-gl]), or PL-PU99 (PP-polyurethane) patches fixed to the edges of the defect by running polypropylene suture. Adhesions to the implants were laparoscopically determined at 3, 7, and 14 days after surgery. RESULTS: Percentage adhesion scores were significantly lower for ePTFE, PP-ePTFE, PO-gl, and PP-PU, compared to PP or UP. No differences were observed in adhesion scores recorded at 3, 7, and 14 days postimplant. Reticular prostheses were infiltrated by disorganized scar tissue with fibers concentric to the mesh filaments. In contrast, ePTFE implants were encapsulated by organized tissue, with fibers running parallel to the surface of biomaterial. All three composites achieved good recipient tissue integration and a homogeneous, organized, and well-vascularized neoperitoneum. CONCLUSION: At 14 days postimplant, laminar prostheses and composites showed similar results in terms of adhesion formation and integration within host tissue. Our findings suggest that both the composite prostheses and the laminar ePTFE performed very well in terms of reduced adhesion formation at the peritoneal interface.     

Use of composite prostheses in the repair of defects in the abdominal wall: prosthetic behaviour at the peritoneum.

OBJECTIVE: To compare the behaviour of two composite biomaterials in rabbit peritoneum. DESIGN: Animal study. SETTING: Faculty of Medicine, University of Alcalá, Spain. ANIMALS: 14 white New Zealand white rabbits divided into 2 groups of 7 each. INTERVENTIONS: Defects (7 x 5 cm) involving all the layers of the abdominal wall were created and repaired using Parietex Composite or Vypro prostheses. Fourteen days after implantation, prosthetic specimens were examined by microscopy, and morphometric and biomechanical analysis. MAIN OUTCOME MEASURES: Infection, healing, development of adhesions, and histological appearance of the interface. RESULTS: Firm adhesions were detected after the implant of Vypro while adhesion were loose in the Parietex group. The mean (SD) prosthetic surface area covered by adhesions was significantly greater in the Vypro group 22.3 (2.8) compared with 0.2 (0.02), p <0.01). The neoperitoneum formed after the implant of Parietex was well-organised and homogeneous and covered by a typical mesothelium, while in the Vypro it was disorganised, with a rough texture composed of prosthetic filaments and nodes. The neoperitonum was thicker in the Parietex group 154.0 (5.4) compared with 50.8 (2.3), p <0.05) while higher biomechanical resistance values were recorded in the Vypro group 30.4 (1.9) compared with 15.0 (2.73), p <0.05). CONCLUSIONS: While both biomaterials integrated well with tissue, Parietex behaved better at the peritoneal interface.     

Prevention of adhesions to polypropylene mesh

BACKGROUND: Polypropylene mesh used to repair abdominal wall hernias routinely induces dense adhesions if there is direct contact between the mesh and the viscera. Adhesions may lead later to difficult reoperation, intestinal obstruction, or enteric fistula. STUDY DESIGN: A 2.5-cm square defect was surgically created in the rat abdominal wall and replaced with: 1) polypropylene mesh, 2) Sepramesh (SM), or 3) SM plus Seprafilm. Each group included 20 animals. Adhesion area as a percent of the mesh surface was subjectively quantitated by means of laparoscopy and at sacrifice. Evaluations varied from 7 to 28 days after mesh placement. Tissues were harvested at intervals for scanning electron microscopy. RESULTS: Adhesions were complete by day 7, with no change in area thereafter. Adhesion-free mesh surfaces were found on scanning electron microscopy to be carpeted with mesothelial cells from day 5 on. Polypropylene mesh alone induced adhesions in all rats (20/20). The mean area involved was 92%. With SM, 9 of 20 were adhesion-free. The mean area was 15%. When Seprafilm was added to SM, minimal adhesions developed in 5 of 20 rats, the mean area being 2%. Four of the five were single point omental attachments. CONCLUSIONS: 1) Sepramesh alone reduces polypropylene mesh adhesions by roughly three-quarters. 2) Sepramesh plus Seprafilm nearly eliminates such visceral adhesions. 3) Mesothelial cell coverage of polypropylene mesh confers adhesion resistance.     

Evaluation of adhesion formation and host tissue response to intra-abdominal polytetrafluoroethylene mesh and composite prosthetic mesh

BACKGROUND: The purpose of this study was to measure the extent of adhesion formation to ePTFE mesh (DualMesh, W.L. Gore & Associates, Inc, Flagstaff, AZ) and two composite prosthetic materials, ePTFE and polypropylene (Bard Composix, C.R. Bard, Inc, Murray Hill, NJ) and hyaluronic acid/carboxymethylcellulose and polypropylene (Sepramesh, Genzyme Corp, Cambridge, MA) after their intra-abdominal placement on an intact peritoneum, simulating laparoscopic ventral hernia repair, and to evaluate host tissue response to the prosthetic biomaterials. MATERIALS AND METHODS: Through a midline laparotomy, a 2 x 2 cm piece of mesh (n = 60) was sewn to an intact peritoneum on each side of a midline incision in 30 New Zealand white rabbits. Mesh adhesions were scored using a modified Diamond scale (0 = 0%, 1 = 1-25%, 2 = 26-50%, 3 >50%) at 1, 3, 9, and 16 weeks by serial microlaparoscopy (2 mm). All laparoscopic evaluations were videotaped for blinded scoring by three surgeons. Host tissue response was graded (1-4) for inflammation, tissue ingrowth, and mesothelialization. The predominant cell type (polymorphonuclear leukocytes versus foreign body giant cell) was recorded. Statistical differences (P value <0.05*) were measured using a two-tailed t test and Kruskal-Wallis test. RESULTS: The mean adhesion score was significantly (P < 0.001) less for ePTFE mesh at 1, 3, 9, and 16 weeks compared with the two composite prosthetic materials. There were no differences in the mean adhesion scores between the two biosurgical composite meshes at any of the time intervals. There were no differences in the mean score for inflammation, tissue ingrowth and mesothelialization between any of the prosthetic biomaterials. The predominant cell type on all histological evaluations was polymorphonuclear leukocytes. CONCLUSIONS: Placing ePTFE mesh (DualMesh) intra-abdominal against an intact peritoneum results in significantly fewer adhesions than the composite prosthetic meshes during a 4-month follow-up. The host tissue response is equivalent for the three prosthetic biomaterials. The long-term consequences of increased adhesion formation to the composite meshes and the ultimate biocompatibility of the nonabsorbable and absorbable barriers on the polypropylene mesh are to be determined.     

Prevention of adhesions by bioresorbable tissue barrier following laparoscopic intraabdominal mesh insertion

Intraabdominal adhesions represent a significant problem because of the morbidity associated with adhesive disease, including small bowel obstruction, difficulties in reoperative surgery, and possibly chronic pain. Coating solution of sodium hyaluronate (Sepracoat; Genzyme Production-Surgical Products, Cambridge, MA) was studied in New Zealand white rabbits to determine its potential role for prevention of postoperative adhesions following laparoscopic intraabdominal mesh insertion. A 2-cm polypropylene mesh was inserted laparoscopically to the left iliac fossa and fixed to anterior abdominal wall using a single prolen suture. Group 1 (n = 10) acted as the control group. Mesh was coated using 4% sodium hyaluronate in phosphate buffered saline (Sepracoat) in Group 2 (n = 10). Fourteen days later, all animals underwent diagnostic laparoscopy, and findings were recorded. All animals then were killed, the abdominal cavities were inspected, and adhesions were graded from 0 to 4. All meshes were removed and sent for histologic examination. The degrees of inflammation, fibrosis, and congestion were scored. No adhesions were seen on trocar sites on both groups. Eight of 10 animals in the control group and 5 of 10 animals in the study group had intraabdominal adhesions. The scoring of adhesions revealed that study group had only one (10%) significant adhesion, whereas the control group had eight (80%; < 0.001). Our study suggests that the Sepracoat reduces the incidence and severity of abdominal adhesions following laparoscopic mesh insertion and should be considered as a prophylactic agent, especially in those undergoing laparoscopic transabdominal mesh repair for hernia.     

Coated meshes for hernia repair provide comparable intraperitoneal adhesion prevention

Background

Laparoscopic incisional hernia repair with intraperitoneal mesh is associated with a certain degree of adhesion formation to the mesh. This experimental study examined the efficacy of several coated meshes for adhesion reduction.

Methods

Five commercially available meshes with a layered coating were placed intraperitoneally in rats and followed up for 90 days: polypropylene and polyester meshes, both coated with absorbable collagen (Parietene Composite and Parietex Composite, respectively), and three polypropylene meshes respectively coated with absorbable omega-3 fatty acids (C-Qur Edge), absorbable cellulose (Sepramesh IP), and nonabsorbable expanded polytetrafluoroethylene (Intramesh T1). Uncoated polypropylene and collagen meshs (Parietene and Permacol, respectively) served as the control condition. Adhesions, incorporation, and tissue reaction were evaluated macro- and microscopically. Additionally, the development of the neoperitoneum was examined.

Results

All the coated meshes performed equally well in terms of adhesion reduction. The collagen mesh performed comparably, but the uncoated polypropylene mesh performed significantly worse. The different coatings led to very differing degrees of inflammation. Ingrowth was observed only at the place of suture but was comparable for all the meshes except C-Qur Edge, which showed the weakest incorporation. Development of a neoperitoneum on the mesh surface occurred independently of whether an absorbable or nonabsorbable coating or no coating at all was present.

Conclusions

Commercially available meshes with a layered coating deliver comparable adhesion reduction. The physical presence of a layered coating between the intraperitoneal content and the abdominal wall seems to be more important than the chemical properties of the coating in adhesion formation.     

Evaluation of Soft Tissue Attachments to a Novel Intra-abdominal Prosthetic in a Rabbit Model

Background. Laparoscopic ventral hernia repair requires placement of an intraperitoneal prosthetic. Composite mesh types have been developed to address the shortcomings of standard meshes. The authors evaluated the host reaction to intraperitoneal placement of a novel composite material. Materials and Methods. A comparison of an innovative polypropylene/polylactide composite mesh was made to Parietex Composite (PCO), Proceed, and DualMesh. Eighteen meshes per group were implanted on intact peritoneum in New Zealand White rabbits. The main outcome measures included the formation of visceral adhesions, adhesion tenacity, tensiometric measurements, and histological analysis. Evaluations of adhesions were made at 1, 4, and 16 weeks using a 2-mm minilaparoscopy. Results. There were no significant differences in the mean adhesion scores between the composite mesh types at week 1 (P = .15) and week 16 (P = .06). At 4 weeks, PCO had significantly fewer adhesions when compared with the other 3 mesh types (P = .02). Adhesion tenacity was also equivalent within the group at 16 weeks (P = .06). Tensiometry and histological analysis revealed no statistically significant differences between the mesh types. Conclusions. Four different composite mesh types had equivalent intra-abdominal soft tissue attachments in a rabbit model after a 16-week implantation period. PCO demonstrated the lowest mean adhesion score of each mesh type. Each mesh exhibited equivalent stiffness and energy to failure after explantation. The 4 composite mesh types demonstrated the successful formation of a neoperitoneum and comparable host biocompatibility as evidenced by similar degrees of inflammation.     

Assessment of adhesion formation to intra-abdominal polypropylene mesh and polytetrafluoroethylene mesh

BACKGROUND: The development of intra-abdominal adhesions, bowel obstruction, and enterocutaneous fistulas are potentially severe complications related to the intraperitoneal placement of prosthetic biomaterials. The purpose of this study was to determine the natural history of adhesion formation to polypropylene mesh and two types of polytetrafluoroethylene (ePTFE) mesh when placed intraperitoneally in a rabbit model that simulates laparoscopic ventral hernia repair. MATERIALS AND METHODS: Thirty New Zealand white rabbits were used for this study. A 10-cm midline incision was performed for intra-abdominal access and a 2 cm x 2 cm piece of mesh (n = 60) was sewn to an intact peritoneum on each side of the midline. Two types of ePTFE mesh (Dual Mesh and modified Dual Mesh, W.L. Gore & Assoc., Flagstaff, AZ) and polypropylene mesh were compared. The rate of adhesion formation was evaluated by direct visualization using microlaparoscopy (2-mm endoscope/trocar) at 7 days, 3 weeks, 9 weeks, and 16 weeks after mesh implantation. Adhesions to the prosthetic mesh were scored for extent (%) using the Modified Diamond Scale (0 = 0%, 1 50%). At necropsy the mesh was excised en bloc with the anterior abdominal wall for histological evaluation of mesothelial layer growth. RESULTS: The mean adhesion score for the polypropylene mesh was significantly greater (P < 0.05) than Dual Mesh at 9 weeks and 16 weeks and modified Dual Mesh at 7 days, 9 weeks, and 16 weeks. Fifty-five percent (n = 11) of the polypropylene mesh had adhesions to small intestine or omentum at necropsy compared to 30% (n = 6) of the Dual Mesh and 20% (n = 4) of the modified Dual Mesh. There was a significantly greater percentage (P < 0.003) of ePTFE mesh mesothelialized at explant (modified Dual Mesh 44.2%; Dual Mesh 55.8%) compared to the polypropylene mesh (12.9%). CONCLUSIONS: Serial microlaparoscopic evaluation of intraperitoneally implanted polypropylene mesh and ePTFE mesh in a rabbit model revealed a progression of adhesions to polypropylene mesh over a 16 week period. The pore size of mesh is critical in the development and maintenance of abdominal adhesions and tissue ingrowth. The macroporous polypropylene mesh promoted adhesion formation, while the microporous nature of the visceral side of the ePTFE served as a barrier to adhesions.     

Prevention of adhesion formation with use of sodium hyaluronate-based bioresorbable membrane in a rat model of ventral hernia repair with polypropylene mesh--a randomized, controlled study

BACKGROUND: There is a high incidence of adhesions after ventral hernia repair with polypropylene mesh. Hyaluronic acid (HA)-based membrane has been shown to reduce the incidence of adhesions in the absence of prosthetic mesh. The purpose of this study was to determine the effect of HA membrane on the quantity and grade of adhesions and its effect on strength of repair after abdominal wall repair with polypropylene mesh. METHODS: In 61 rats a full-thickness abdominal wall defect (excluding skin) was created, and a section of small bowel was abraded. The animals were randomized, receiving either HA membrane to cover the viscera or no membrane. The fascial defect was repaired with polypropylene mesh. Equal numbers of animals from each group were killed at 4 weeks and 8 weeks after surgery. Adhesion severity and percentage of mesh surface covered with adhesions were estimated. Tensile strength between mesh and muscle from each animal was measured. Sections of the mesh-muscle interface were examined histologically and measured for thickness and graded for inflammation and fibrosis. RESULTS: Fifty-five animals survived until the end point. Animals in the HA membrane group had a significant reduction in (1) grade of adhesions between small bowel and mesh at 4 weeks (P = .009) and 8 weeks (P = .000001), (2) grade of adhesions between colon and mesh at 8 weeks (P = .00003), and (3) percentage of mesh covered with adhesions at 4 weeks (P = .01) and 8 weeks (P = .0000002). There was no difference between the 2 groups in tensile strength of the repairs, tissue thickness, degree of inflammation, or degree of fibrosis. CONCLUSIONS: HA membrane reduces the quantity and grade of adhesions of both small and large bowel, to polypropylene mesh in a rat model of ventral hernia repair, without compromising strength of the repair.     

Detection of peritoneal adhesions using ultrasound examination for the evaluation of an innovative intraperitoneal mesh

Background: In this multicenter study, we evaluated the efficiency of a specific ultrasound examination in detecting postoperative bowel adhesions and assessed the adhesion rate associated with the intraperitoneal use of Parietex composite mesh (polyester mesh covered on the visceral side by a hydrophilic resorbable film). Methods: Eighty patients (36 male, 44 female; average age, 58.2 years [ranges 30–80]) were included in a study carried out at eight centers. The main inclusion criterion was the surgical treatment of incisional and umbilical hernias using an intraperitoneal mesh. The results of a preoperative ultrasound examination were compared to a macroscopic perioperative exploration. In addition, in 76 of the 80 patients, a postoperative ultrasound examination was repeated at 2 and 12 months. Results: The ultrasound findings for peritoneal adhesion detection were as follows: sensitivity, 77%; specificity, 74%; positive predictive value, 65%; negative predictive value, 84%; accuracy, 75%. Postoperative adhesions after 1 year were detected in 14% of patients. Conclusions: Although these patients had undergone repeated surgery and treated to be (obese) body mass index (mean, 28), the ultrasound exam had a high accuracy rate; when it was negative, there were no adhesions in 84% of cases. The use of a hydrophilic composite mesh is associated with a low rate of adhesions (14%).     

Sepramesh and postoperative peritoneal adhesions in a rat model

Purpose: The present study aimed to investigate the safety and the anti-postoperative peritoneal adhesion (PPA) characteristics of Sepramesh^® (Davol), a composite mesh made of polypropylene covered with Seprafilm, when intraperitoneally placed in a rat model.

Methods: Twenty male rats were randomized into a control group and a Sepramesh group. They underwent a primary surgical procedure aiming to induce a peritoneal injury in order to induce PPAs. In the Sepramesh group, the burnt peritoneum was covered with a 2-cm diameter disc of Sepramesh prosthesis. The mesh was fixed to the parietal peritoneum with four 3-0 absorbable stitches. PPAs were assessed during a second laparotomy 10 days later using quantitative and qualitative scoring systems.

Results: There was no difference in terms of mean number of PPAs between both groups. All the rats from the control group developed PPAs. In the Sepramesh group, no adhesions were observed at the site of the injured peritoneum that had been covered with the Sepramesh prosthesis, but PPAs occurred at the extremities of the mesh, where there was close contact between polypropylene and viscera, or where the fixation sutures were placed. The severity and the type of adhesions were significantly higher in the control group.

Conclusions: This study demonstrated that for the Sepramesh prostheses, the Seprafilm layer might be effective in PPA prevention, but damage caused by the section and fixation of Sepramesh should be limited in order to limit PPAs.     

Comparison of adhesive properties of five different prosthetic materials used in hernioplasty.

This experimental study was designed to assess and to compare intra-abdominal adhesions following the use of five commercially available prosthetic mesh grafts in the repair if abdominal wall defects. Sixty Wistar albino rats were randomly divided into six groups (n = 10). A 2 x 1 cm defect at abdominal wall was created and defects were closed either primarily or with one of the following prosthetic mesh grafts: monofilament polypropylene, polytetrafluoroethylene, sodium hyaluronate/carboxymethylcellulose-coated polypropylene, polypropylene/polyglactin 910 composite, or resorbable hydrophilic collagen-coated multifiber polyester. The severity of adhesions was graded, tensile strengths of adhesions were measured, and histopathological grades of inflammation and fibrosis were evaluated. Polypropylene mesh resulted in more adhesion formation in comparison to primary repair and other grafts used in this study, except polypropylene/polyglactin 910 composite mesh. In addition, the highest tensile strength of omental adhesions was detected in the polypropylene group (chi2 = 26.249; p = .0001). Polyester composite mesh caused the least adhesion formation among the groups. Sodium hyaluronate/carboxymethylcellulose-coated polypropylene and polyester composite meshes revealed the highest fibrosis scores (chi2 = 50.776; p = .0001). The highest inflammatory activity was detected in the polytetrafluoroethylene mesh group (chi2 = 16.564; p = .005). Thus, sodium hyaluronate/carboxymethylcellulose-coated polypropylene and polytetrafluoroethylene meshes following polyester composite mesh were the minimal adhesion-forming grafts in this study. Disadvantages of the polytetrafluoroethylene mesh were lower fibrotic activity and higher inflammatory reaction to the graft.     

Abdominal wall hernia repair: a comparison of sepramesh and parietex composite mesh in a rabbit hernia model

BACKGROUND: This study compared Parietex composite mesh (PCM) with Sepramesh (SM) in terms of strength of tissue incorporation, adhesion formation, and mesh shrinkage, using an animal model. STUDY DESIGN: A two-phase, prospective, randomized study using 44 New Zealand white rabbits. Each animal underwent creation of a standardized ventral hernia defect, followed by repair using either SM or PCM. Half of each group was sacrificed and examined at 1 month, and the remainder at 5 months. Outcomes measurements were strength of incorporation (SOI), type and area of adhesions (AA), and mesh shrinkage. RESULTS: SOI for PCM was much greater than for SM, both at 1 month (60.8 N versus 42.6 N) and 5 months (70.9 N versus 31.5 N). The incidence of bowel adhesions was lower with PCM than SM, both at 1 month (1 versus 6) and at 5 months (0 versus 4). At 5 months, PCM demonstrated lower AA, both as a percentage of the mesh (5.6% versus 12.8%) and in terms of absolute area involved (321 mm(2) versus 840 mm(2)). PCM underwent considerably more shrinkage than SM, at both 1 month (38.2% versus 18.1%) and 5 months (17.4% versus 6.1%). CONCLUSIONS: PCM demonstrated a substantially stronger SOI, which improved over time, and SOI of SM decreased. PCM was also superior in terms of adhesion prevention, but underwent considerably more shrinkage in this experimental model.     

Biologic meshes are not superior to synthetic meshes in ventral hernia repair: an experimental study with long-term follow-up evaluation

Background

In laparoscopic incisional hernia repair, direct contact between the prosthesis and the abdominal viscera is inevitable, which may lead to an inflammatory reaction resulting in abdominal adhesion formation. This study compared five different synthetic and biologic meshes in terms of adhesion formation, shrinkage, incorporation, and histologic characteristics after a period of 30 and 90 days.

Methods

In 85 rats, a mesh was positioned intraperitoneally in direct contact with the viscera. Five different meshes were implanted: Prolene (polypropylene), Parietex composite (collagen-coated polyester), Strattice (porcine dermis, non-cross-linked), Surgisis (porcine small intestine submucosa, non-cross-linked), and Permacol (porcine dermis, cross-linked). The meshes were tested in terms of adhesion formation, shrinkage, and incorporation after a period of 30 and 90 days. Additionally, collagen formation after 90 days was determined.

Results

Significantly less adhesion formation was observed with Parietex composite (5 %; interquartile range [IQR], 2–5 %) and Strattice (5 %; IQR, 4–10 %) in the long term. In contrast, organs were attached to Permacol with four of seven meshes (57 %), and adhesion coverage of Surgisis mesh was present in 66 % (IQR, 0–100 %) of the cases. After 90 days, the best incorporation was seen with the Parietex composite mesh (79 %; IQR, 61–83 %). After 90 days, major alterations in adhesion formation were seen compared with 30 days. Histologically, Strattice and Parietex composite showed a new mesothelial layer on the visceral side of the mesh. Microscopic degradation and new collagen formation were seen in the Surgisis group.

Conclusions

Parietex composite mesh demonstrated the best long-term results compared with all the other meshes. The biologic non-cross-linked mesh, Strattice, showed little adhesion formation and moderate shrinkage but poor incorporation. Biologic meshes are promising, but varying results require a more detailed investigation and demonstrate that biologic meshes are not necessarily superior to synthetic meshes. The significant changes that take place between 30 and 90 days should lead to careful interpretation of short-term experimental results.     

Comparison of Adhesive Properties of Five Different Prosthetic Materials Used in Hernioplasty

This experimental study was designed to assess and to compare intra-abdominal adhesions following the use of five commercially available prosthetic mesh grafts in the repair if abdominal wall defects. Sixty Wistar albino rats were randomly divided into six groups (n = 10). A 2 × 1 cm defect at abdominal wall was created and defects were closed either primarily or with one of the following prosthetic mesh grafts: monofilament polypropylene, polytetrafluoroethylene, sodium hyaluronate/carboxymethylcellulose-coated polypropylene, polypropylene/polyglactin 910 composite, or resorbable hydrophilic collagen-coated multifiber polyester. The severity of adhesions was graded, tensile strengths of adhesions were measured, and histopathological grades of inflammation and fibrosis were evaluated. Polypropylene mesh resulted in more adhesion formation in comparison to primary repair and other grafts used in this study, except polypropylene/polyglactin 910 composite mesh. In addition, the highest tensile strength of omental adhesions was detected in the polypropylene group (χ² = 26.249; p =. 0001). Polyester composite mesh caused the least adhesion formation among the groups. Sodium hyaluronate/carboxymethylcellulose-coated polypropylene and polyester composite meshes revealed the highest fibrosis scores (χ² = 50.776; p =. 0001). The highest inflammatory activity was detected in the polytetrafluoroethylene mesh group (χ² = 16.564; p =. 005). Thus, sodium hyaluronate/carboxymethylcellulose-coated polypropylene and polytetrafluoroethylene meshes following polyester composite mesh were the minimal adhesion-forming grafts in this study. Disadvantages of the polytetrafluoroethylene mesh were lower fibrotic activity and higher inflammatory reaction to the graft.     

Peritoneal adhesions to prosthetic materials

BACKGROUND: In many cases, incisional hernia repair requires the use of prosthetic materials. The aim of this experimental study in a rat model was to assess the role of polyglactin 910 mesh and fluoropassivated polyester mesh in preventing the formation of adhesions. METHODS: In the first experiment, the formation of peritoneal adhesions was assessed after insertion of polypropylene, polypropylene combined with polyglactin 910, or no mesh. In the second experiment, adhesion formations were compared after insertion of fluoropassivated polyester, polypropylene, and no mesh. RESULTS: The first experiment showed no significant difference in adhesion formations between the polypropylene mesh and the combined mesh; however, when no mesh was used, there were significantly fewer adhesions in both experiments (p < 0.01). The second experiment showed a significantly lower degree of adhesions and a lower Adhesion Index after insertion of fluoropassivated polyester mesh than when polypropylene mesh was used (p = 0.04). CONCLUSIONS: Adding polyglactin 910 mesh to polypropylene mesh to prevent the formation of adhesions is not an effective measure. Fluoropassivated polyester meshes appear to provide a better alternative to the use of polypropylene meshes for incisional hernia repair in humans in terms of the formation of adhesions.