Carboxymethylcellulose coated on visceral face of polypropylene mesh prevents adhesion without impairing wound healing in incisional hernia model in rats

The Role of Mesh Implants in Surgical Treatment of Parastomal Hernia

A parastomal hernia is a common complication following stoma surgery. Due to the large number of hernial relapses and other complications, such as infections, adhesion to the intestines, or the formation of adhesions, the treatment of hernias is still a surgical challenge. The current standard for the preventive and causal treatment of parastomal hernias is to perform a procedure with the use of a mesh implant. Researchers are currently focusing on the analysis of many relevant options, including the type of mesh (synthetic, composite, or biological), the available surgical techniques (Sugarbaker’s, “keyhole”, or “sandwich”), the surgical approach used (open or laparoscopic), and the implant position (onlay, sublay, or intraperitoneal onlay mesh). Current surface modification methods and combinations of different materials are actively explored areas for the creation of biocompatible mesh implants with different properties on the visceral and parietal peritoneal side. It has been shown that placing the implant in the sublay and intraperitoneal onlay mesh positions and the use of a specially developed implant with a 3D structure are associated with a lower frequency of recurrences. It has been shown that the prophylactic use of a mesh during stoma formation significantly reduces the incidence of parastomal hernias and is becoming a standard method in medical practice.

Assembled anti-adhesion polypropylene mesh with self-fixable and degradable in situ mussel-inspired hydrogel coating for abdominal wall defect repair

Construction of assembled anti-adhesion polypropylene mesh through in situ coating with self-fixable and degradable hydrogels.

Investigation into the optimal prosthetic material for wound healing of abdominal wall defects

The purpose of this experimental study is to investigate and compare the effects of prosthetic materials used for wound healing of abdominal wall hernias. A total of 60 rats were divided into five equal groups: Group I, control subjected to laparotomy; group II, abdominal wall defect 3×2 cm+polypropylene (PP) mesh; group III, abdominal wall defect 3×2 cm+PP mesh+hyaluronate and carboxymethylcellulose (H-CMC; Seprafilm^®); group IV, abdominal wall defect 3×2 cm+polytetrafluoroethylene (PTFE; Composix^™); and group V, abdominal wall defect 3×2 cm+polyethylene terephthalate (PET; Dacron^®). A total of 14 days after the surgery, rats were sacrificed and the meshes with the surrounding tissue were extracted in block. The breaking strength of the mesh from the fascia was recorded. The healing tissue was examined with the index of histopathology and the hydroxyproline value was analyzed using the Switzer method. Both the breaking strength and histopathological index of the wound healing were significantly improved in groups II and III compared with that in groups IV and V (P<0.001). Hydroxyproline values were the highest in group I (P<0.001). There was also a statistically significant difference between groups II and IV, and group V and the other groups (P<0.001). The present findings demonstrated that PP mesh and PP mesh+H-CMC had a superior breaking strength and improved histopathologic indices compared with PTFE and PET. Furthermore, hydroxyproline values were the lowest in the PET group. In conclusion, wound healing was improved in the PP mesh group and the PP mesh+H-CMC group compared with the PTFE and PET groups according to the present study parameters.

Past, Present and Future of Surgical Meshes: A Review

Surgical meshes, in particular those used to repair hernias, have been in use since 1891. Since then, research in the area has expanded, given the vast number of post-surgery complications such as infection, fibrosis, adhesions, mesh rejection, and hernia recurrence. Researchers have focused on the analysis and implementation of a wide range of materials: meshes with different fiber size and porosity, a variety of manufacturing methods, and certainly a variety of surgical and implantation procedures. Currently, surface modification methods and development of nanofiber based systems are actively being explored as areas of opportunity to retain material strength and increase biocompatibility of available meshes. This review summarizes the history of surgical meshes and presents an overview of commercial surgical meshes, their properties, manufacturing methods, and observed biological response, as well as the requirements for an ideal surgical mesh and potential manufacturing methods.

Emerging Trends in Abdominal Wall Reinforcement: Bringing Bio-Functionality to Meshes

Abdominal wall hernia is a recurrent issue world-wide and requires the implantation of over 1 million meshes per year. Because permanent meshes such as polypropylene and polyester are not free of complications after implantation, many mesh modifications and new functionalities have been investigated over the last decade. Indeed, mesh optimization is the focus of intense development and the biomaterials utilized are now envisioned as being bioactive substrates that trigger various physiological processes in order to prevent complications and to promote tissue integration. In this context, it is of paramount interest to review the most relevant bio-functionalities being brought to new meshes and to open new avenues for the innovative development of the next generation of meshes with enhanced properties for functional abdominal wall hernia repair.

Effectiveness of Hyalobarrier and Seprafilm to prevent polypropylene mesh shrinkage: a macroscopic and histological experimental study

INTRODUCTION AND HYPOTHESIS

Polypropylene (PP) mesh shrinkage represents a serious complication, as a significant cause of pain and recurrence of pelvic organ prolapse or ventral hernias, frequently requiring several surgical interventions. The retraction seems to be caused by the host, in response to the implantation, through the occurrence of periprosthetic adhesions and fibrosis. We hypothesized that avoiding the postoperative adhesions can prevent PP mesh shrinkage.

METHODS

Sixty rats were randomly assigned to three groups. A standardized hernia defect was induced on the abdominal wall, which was repaired using an extraperitoneal PP mesh alone (group 1), with application of a hyaluronate carboxymethylcellulose-based bioresorbable membrane (Seprafilm, group 2), or an auto-cross-linked polysaccharide hyaluronan-based solution (Hyalobarrier gel, group 3). Eight weeks after the procedure, a repeat laparotomy was performed. After scoring the adhesion and measuring the mesh surface, a microscopic study of the prosthesis-host tissue interfaces was performed.

RESULTS

Group 1 displayed a median shrinkage of 29% of the mesh. The Seprafilm group (p = 0.0238) and Hyalobarrier gel group (p = 0.0072) displayed a significantly smaller reduction of 19.12 and 17 %, respectively. Control group 1 displayed a significantly greater adhesion score (30.40) than the Seprafilm (11.67, p = 0.0028) and Hyalobarrier gel groups (11.19, p = 0.0013). The fibrosis was reduced in the Hyalobarrier gel group only.

CONCLUSION

This experimental study revealed that Hyalobarrier gel and Seprafilm can prevent PP mesh shrinkage and postoperative adhesions. They might be integrated in a mesh size-saving strategy, which should preserve the quality and durability of the surgical repair and limit the postoperative pain.

New polymer for intra-abdominal meshes--PVDF copolymer

PURPOSE

Full tissue integration without adhesion formation is still a challenge for intra-abdominal mesh materials. Purpose of this study was to investigate the adhesive potential and fibrocollagenous ingrowth of a polymer blend of polyvinylidene fluoride and hexafluorpropylene (co-PVDF), an established suture material in vascular surgery, when placed as a mesh in the intra-abdominal position. The results were compared with a matching polypropylene (PP) mesh.

METHODS

In an established rabbit model, mesh implantation was performed by laparoscopy in the intraperitoneal onlay mesh technique. After 7, 21, and 90 days the degree of adhesion formation, foreign body reaction, bridging, and shrinkage of mesh area were investigated.

RESULTS

In the early phase after 7 and 21 days we found significantly more adhesions for PP, but no differences after 90 days. Analysis of tissue reaction showed a significantly lower fibrotic reaction for co-PVDF. The degree of shrinkage revealed no significant difference.

CONCLUSION

Large-pore PP and co-PVDF-meshes showed comparable good results in the intra-abdominal position, with a reduced inflammatory tissue reaction for co-PVDF. Large pore meshes should be considered an alternative for the development of intraperitoneal onlay meshes.

Evaluation of implant/host tissue interactions following intraperitoneal implantation of porcine dermal collagen prosthesis in the rat

An ideal prosthesis for ventral hernia repair should minimize development of postoperative adhesions. This study evaluates adhesion formation following intraperitoneal implantation of acellular porcine dermal collagen (PDC) and polypropylene (PP) mesh in 16 rats. Implant placement alternated left/right. Sacrifice (4 or 12 weeks) was randomized. Methods included adhesion grading (extent, severity, required dissection method) and histological evaluation. At 4 weeks, 7 of 8 PDC specimens and 0 of 8 PP implants were adhesion-free; results were identical at 12 weeks. Four-week adhesions were less developed than 12-week adhesions. Histology showed mononuclear cell foreign body reaction and disorganized collagen deposition for PPs compared to infiltration with neovascular channels and qualitatively less intense foreign body reaction for PDCs. PDC exhibits fewer adhesions and more favorable cellular response than PP in the rat.

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.

Polypropylene in the intra-abdominal position: influence of pore size and surface area

BACKGROUND

Polypropylene is a material widely used in surgery. Because of its association with formation of enterocutaneous fistulae and adhesions, direct contact between mesh and intestine is avoided. The following study was designed to investigate the adhesive potential of different polypropylene meshes when placed in direct contact with intestine.

MATERIAL AND METHODS

In an established experimental model, a total of 45 chinchilla rabbits underwent laparoscopic placement of meshes with different pore size (Group I: monofilament PP 0.6 mm, Group II: monofilament PP 2.5 mm, Group III: multifilament PP 4.0 mm) with the Intra-Peritoneal-Onlay-Mesh Technique (IPOM). The degree of adhesion formation was measured after 7, 21, and 90 days, evaluated by an adhesion score, quantified by computer-assisted planimetry, followed by histological and morphometric investigation of the perifilamental granuloma formation.

RESULTS

The heavyweight, small porous polypropylene meshes (PP 0.6) showed significantly stronger adhesion formation at all intervals of investigation compared with the lightweight meshes with a pore size >2.5 mm. Between the two different lightweight mesh variations, there was no significant difference. Granuloma formation was lowest in large-pore-size monofilament meshes (PP 2.5).

CONCLUSION

The IPOM rabbit model is suitable for investigation of biomaterials in the intra-abdominal position. Our results show that the adhesive potential is significantly influenced by the pore size. However, the extent of the foreign-body reaction seems also to be influenced by the filament structure, respectively, the surface area, favoring monofilament material.