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

In-vitro Characterization of a Hernia Mesh Featuring a Nanostructured Coating

Abdominal hernia repair is a frequently performed surgical procedure worldwide. Currently, the use of polypropylene (PP) surgical meshes for the repair of abdominal hernias constitutes the primary surgical approach, being widely accepted as superior to primary suture repair. Surgical meshes act as a reinforcement for the weakened or damaged tissues and support tissue restoration. However, implanted meshes could suffer from poor integration with the surrounding tissues. In this context, the present study describes the preliminary evaluation of a PCL-Gel-based nanofibrous coating as an element to develop a multicomponent hernia mesh device (meshPCL-Gel) that could overcome this limitation thanks to the presence of a nanostructured biomimetic substrate for enhanced cell attachment and new tissue formation. Through the electrospinning technique, a commercial PP hernia mesh was coated with a nanofibrous membrane from a polycaprolactone (PCL) and gelatin (Gel) blend (PCL-Gel). Resulting PCL-Gel nanofibers were homogeneous and defect-free, with an average diameter of 0.15 ± 0.04 μm. The presence of Gel decreased PCL hydrophobicity, so that membranes average water contact angle dropped from 138.9 ± 1.1° (PCL) to 99.9 ± 21.6°, while it slightly influenced mechanical properties, which remained comparable to those of PCL (E = 15.7 ± 2.7 MPa, σ R = 7.7 ± 0.6 ε R = 118.8 ± 13.2%). Hydrolytic and enzymatic degradation was conducted on PCL-Gel up to 28 days, with maximum weight losses around 20 and 40%, respectively. The meshPCL-Gel device was obtained with few simple steps, with no influences on the original mechanical properties of the bare mesh, and good stability under physiological conditions. The biocompatibility of meshPCL-Gel was assessed by culturing BJ human fibroblasts on the device, up to 7 days. After 24 h, cells adhered to the nanofibrous substrate, and after 72 h their metabolic activity was about 70% with respect to control cells. The absence of detectable lactate dehydrogenase in the culture medium indicated that no necrosis induction occurred. Hence, the developed nanostructured coating provided the meshPCL-Gel device with chemical and topographical cues similar to the native extracellular matrix ones, that could be exploited for enhancing the biological response and, consequently, mesh integration, in abdominal wall hernia repair.

Comparison of coated meshes for intraperitoneal placement in animal studies: a systematic review and meta-analysis

PURPOSE

Laparoscopic intraperitoneal onlay mesh in hernia repair can result in adhesions leading to intestinal obstruction and fistulation. The aim of this systematic review is to compare the effects of mesh coatings reducing the tissue-to-mesh adhesion in animal studies.

METHODS

Pubmed and Embase were systematically searched. Animal experiments comparing intraperitoneally placed meshes with coatings were eligible for inclusion. Only studies with comparable follow-up, measurements, and species were included for data pooling and subsequent meta-analysis.

RESULTS

A total of 131 articles met inclusion criteria, with four studies integrated into one comparison and five studies integrated into another comparison. Compared to uncoated polypropylene (PP) mesh, PP mesh coated with hyaluronic acid/carboxymethyl cellulose (HA/CMC) showed significantly reduced adhesion formation at follow-up of 4 weeks measured with adhesion score of extent (random effects model, mean difference,-  0.96, 95% CI - 1.32 to - 0.61, P < 0.001, I² = 23%; fixed effects model, mean difference,- 0.94, 95% CI - 1.25 to - 0.63, P < 0.001, I² = 23%). Compared to PP mesh, polyester mesh coated with collagen (PC mesh) showed no significant difference at follow-up of 4 weeks regarding percentage of adhesion-area on a mesh, using random effects model (mean difference - 11.69, 95% CI - 44.14 to 20.76, P = 0.48, I² = 92%). However, this result differed using fixed effects model (mean difference - 25.55, 95% CI - 33.70 to - 7.40, P < 0.001, I² = 92%).

CONCLUSION

HA/CMC coating reduces adhesion formation to PP mesh effectively at a follow-up of 4 weeks, while the anti-adhesive properties of PC mesh are inclusive comparing all study data.

Biological Scaffolds for Abdominal Wall Repair: Future in Clinical Application?

Millions of abdominal wall repair procedures are performed each year for primary and incisional hernias both in the European Union and in the United States with extremely high costs. Synthetic meshes approved for augmenting abdominal wall repair provide adequate mechanical support but have significant drawbacks (seroma formation, adhesion to viscera, stiffness of abdominal wall, and infection). Biologic scaffolds (i.e., derived from naturally occurring materials) represent an alternative to synthetic surgical meshes and are less sensitive to infection. Among biologic scaffolds, extracellular matrix scaffolds promote stem/progenitor cell recruitment in models of tissue remodeling and, in the specific application of abdominal wall repair, have enough mechanical strength to support the repair. However, many concerns remain about the use of these scaffolds in the clinic due to their higher cost of production compared with synthetic meshes, despite having the same recurrence rate. The present review aims to highlight the pros and cons of using biologic scaffolds as surgical devices for abdominal wall repair and present possible improvements to widen their use in clinical practice.

Mesh materials and hernia repair

Hernia incidence has been observed since ancient time. Advancement in the medical textile industry came up with the variety of mesh materials to repair hernia, but none of them are without complications including recurrence of hernia. Therefore individuals once developed with the hernia could not lead a healthy and comfortable life. This drawn attention of surgeons, patients, researchers and industry to know the exact mechanism behind its development, complications and recurrence. Recent investigations highlighted the role of genetic factors and connective tissue disorders being the reason for the development of hernia apart from the abnormal pressure that is known to develop during other disease conditions. This review discusses different mesh materials, their advantages and disadvantages and their biological response after its implantation.

Parietex™ Composite mesh versus DynaMesh®-IPOM for laparoscopic incisional and ventral hernia repair: a retrospective cohort study

INTRODUCTION Laparoscopic incisional and ventral hernia repair (LIVHR) is widely accepted and safe but the type of mesh used is still debated. We retrospectively compared postoperative outcomes with two different meshes commonly used in LIVHR. METHODS This is a retrospective study of patients who underwent incisional hernia repair between January 2008 and December 2010. Two meshes were used: Parietex™ Composite (Covidien, New Haven, CT, USA) and the DynaMesh®-IPOM (FEG Textiltechnik mbH, Aachen, Germany). The two groups were compared with respect to recurrence rates, incidence of seroma and intestinal obstruction. RESULTS Among the 88 patients who underwent LIVHR, 75 patients (85.2%) presented with primary incisional hernia, 10 (11.4%) presented with a first recurrence and 3 (3.4%) presented with a second recurrence. Median follow-up was 53.6 months (range 40-61 months). 12.9% of patients had recurrence in the Parietex™ Composite mesh group (n=62) in comparison to 3.8% in the DynaMesh®-IPOM mesh group (n=26; P=0.20). DynaMesh®-IPOM was associated with a significantly higher incidence of intestinal obstruction secondary to adhesions (11.5% vs. 0%, P=0.006) and lower incidence of seroma and haematoma formation compared to Parietex™ composite mesh group (0% vs. 6.4% of patients; P=0.185). CONCLUSIONS LIVHR is a safe and feasible technique. Dynamesh®-IPOM is associated with a significantly higher incidence of adhesion related bowel obstruction, albeit with a lower incidence of recurrence, seroma and haematoma formation compared with Parietex™ Composite mesh. However, there is a need for further well-designed, multicentre randomised controlled studies to investigate the use of these meshes.

The effect of methylprednisolone and tenoxicam on the protection of damage of the nerve physiomorphology caused by prolene mesh

INTRODUCTION

Aim was to investigate the effect of methylprednisolone and tenoxicam on the protection of damage of the nerve physiomorphology caused by prolene mesh used in hernia repair.

METHODS

Fifty male Wistar-albino rats weighing 250-350 gr, were randomly divided into 5 groups. Sciatic nerve was dissected in all rats after performing EMG on basal neural transport. In group 1, only sciatic nerve manipulation was performed. Other groups received a monofilament polypropylene cuff around the sciatic nerve. No additional procedure was performed in group 2. In group 3, 2 mg/kg single dose methylprednisolone was injected around the nerve and mesh. In group 4 and 5, 0.5 mg/kg/day methylprednisolone and 1 mg/kg tenoxicam was injected around the nerve and mesh for 4 weeks, respectively. Neural transport was evaluated by electromyography 4 weeks later and compared with pre-procedural values. Then the rats were sacrificed and, sciatic nerves including 1 cm around the mesh were excised. Inflammation and fibrosis were scored histopathologically.

RESULTS

While basal latency was similar, postoperative latency was significantly different among groups. Latency was significantly longer in group 2 than the group 1. It was significantly shorter in group 3 when compared to group 2 (p = 0.007). Preoperative and postoperative amplitudes were similar among groups. Denervation was significantly different among groups (p < 0.05). Denervation was higher in group 2 than group 1. It was similar to group 2 in study groups. Inflammation and fibrosis was significantly different among groups (p < 0.05). Inflammation and fibrosis scores were significantly higher in group 2 than group 1. The highest inflammation and fibrosis scores were detected in repetitive drug administrated groups. Although it wasn't statistically significant, inflammation was lower in single dose steroid administrated group than group 2. Similarly, the highest fibrosis scores were detected in repetitive drug administrated groups. Single dose steroid administration didn't increase fibrosis when compared to group 2.

CONCLUSIONS

Prolene mesh used in hernia repair caused increased inflammation and fibrosis and effected latency and denervation negatively. Single dose methylprednisolone administration decreased nerve damage and inflammation. On the other hand, daily administration of methylprednisolone and tenoxicam for 4 weeks caused increased inflammation and fibrosis and wasn't affective on protection of nerve physiomorphology.

Molecular weight-modulated electrospun poly(ε-caprolactone) membranes for postoperative adhesion prevention

Electrospun PCL membranes with various molecular weights behave distinctively for the prevention of surgery induced-adhesions, which finally helped acquire well-suited candidates for anti-adhesion biomaterial films.

Assessment of adhesion formation after laparoscopic intraperitoneal implantation of Dynamesh IPOM mesh

INTRODUCTION

Formation of adhesions after laparoscopic hernia repair using the intra-peritoneal onlay mesh (IPOM) procedure can lead to intestinal obstruction or mesh erosion into intestinal lumen. The aims of this study included: measurement of adhesion formation with Dynamesh IPOM after laparoscopic intraperitoneal implantation, and assessment of the occurrence of isolated adhesions at the fastening sites of slowly absorbable sutures.

MATERIAL AND METHODS

Twelve healthy pigs underwent laparoscopic implantation of 2 Dynamesh IPOM mesh fragments each, one was fastened with PDSII, and the other with Maxon sutures. An assessment of adhesion formation was carried out after 6 weeks and included an evaluation of surface area, hardness according to the Zhulke scale, and index values. The occurrence of isolated adhesions at slowly absorbable suture fixation points was also analyzed.

RESULTS

Adhesions were noted in 83.3% of Dynamesh IPOM meshes. Adhesions covered on average 37.7% of the mesh surface with mean hardness 1.46 and index value 78.8. In groups fixed with PDS in comparison to Maxon sutures adhesions covered mean 31.6% vs. 42.5% (p = 0.62) of the mesh surface, mean hardness was 1.67 vs.1.25 (p = 0.34) and index 85.42 vs. 72.02 (p = 0.95).

CONCLUSIONS

The Dynamesh IPOM mesh, in spite of its anti-adhesive layer of PVDF, does not prevent the formation of adhesions. Adhesion hardness, surface area, and index values of the Dynamesh IPOM mesh are close to the mean values of these parameters for other commercially available 2-layer meshes. Slowly absorbable sutures used for fastening did not increase the risk of adhesion formation.

Inflammatory reaction and neotissue maturation in the early host tissue incorporation of polypropylene prostheses

PURPOSE

The use prosthetic materials for the surgical repair of abdominal wall defects has become almost standard practice. This study was designed to assess the expression of different growth factors (VEGF/TGF-β1) and macrophages during the early host tissue incorporation of several polypropylene lightweight (PP-LW)-including one partially absorbable-and heavyweight (PP-HW) prosthetic meshes.

METHODS

Ventral defects were created in the anterior abdominal wall of New Zealand rabbits and repaired by fixing PP-LW meshes of different pore size and a low porosity PP-HW mesh to the edges of the defect. Following killing 14 days after implant, specimens were taken to examine TGF-β1/VEGF gene and protein expression by qRT-PCR and immunohistochemistry. The macrophage response was also assessed.

RESULTS

All the materials showed good host tissue incorporation, with a more severe inflammatory reaction and greater numbers of macrophages recorded in the partially absorbable LW implants. Relative amounts of VEGF mRNA were significantly lower for the LW partially absorbable implants compared with the remaining LW meshes. Protein expression of VEGF showed undetectable or minimum staining in the different groups. TGF-β1 mRNA levels were also lower in the partially absorbable group compared with one of PP-LW type of mesh. Gene expression patterns were consistent with the TGF-β1 protein levels detected.

CONCLUSIONS

The results suggest that VEGF and TGF-β1 expression were independent of mesh pore size. The expression of both growth factors and the macrophage response were correlated with the presence of biodegradable material in the mesh. The presence of absorbable material in the LW mesh gave rise to a more intense inflammatory reaction and the reduced synthesis of growth factors known to contribute to neotissue maturation.

Comparative evaluation of adhesions to intraperitoneally placed fixation materials: a laparoscopic study in rats: adhesions to fixation materials

After laparoscopic ventral hernia repair, the nature of the adhesions to fixation materials or to mesh had not been clarified. We examined adhesion formation specific to the fixation material in rats. We designed an experimental laparoscopy setup, and placed four intraperitoneal fixation materials on the peritoneum of rats without a mesh graft. Another group of researchers documented the incidence and intensity of postoperative adhesion formation. The adhesion scores for the nickel-titanium anchor were significantly greater than those for polylactic acid (p = 0.004), a titanium tacker (p < 0.0001), and fibrin glue (p < 0.0001). No adhesions occurred in the fibrin glue group. Fibrin glue is the preferred fixation material because it produced no postoperative adhesions. The nickel-titanium anchor produced heavy adhesions but may be applicable for recurrent hernia cases and in patients with thin abdominal walls.

A review of the composition, characteristics, and effectiveness of barrier mesh prostheses utilized for laparoscopic ventral hernia repair

BACKGROUND

The objective of this review was to provide an overview of the components that comprise each of the eight barrier mesh prostheses commonly utilized for LVHR and to review the current literature related to the characteristics and effectiveness of these materials to guide the general surgeon in selecting the most appropriate material for LVHR.

METHODS

Composite prostheses with permanent barriers (Bard™ Composix™ E/X, Bard™ Composix™ L/P, and DUALMESH(®) Biomaterial) were compared to composite prostheses with absorbable barriers (C-QUR™ Mesh, PROCEED™ Surgical Mesh, Bard™ Sepramesh™ IP Composite, Parietex™ Composite, and PHYSIOMESH™) using scanning electron microscopy and a review of the current preclinical and clinical literature.

RESULTS

Clinical studies and preclinical animal models have attempted to determine the adhesion characteristics and effectiveness of barrier mesh prostheses available for ventral hernia repair applications. However, it is difficult to make any definitive statements about the adhesion characteristics and effectiveness of these materials because all meshes were not included in all studies and likewise not compared under identical conditions. Overall, Parietex™ Composite and DUALMESH(®) Biomaterial were cited most frequently for improvement of adhesion characteristics, followed closely by Bard™ Sepramesh™ IP Composite and C-QUR™ Mesh. Bard™ Composix™, PROCEED™ Surgical Mesh, and uncoated polypropylene were cited most frequently as having the most tenacious and extensive adhesions.

CONCLUSIONS

Differences observed between the various barrier prostheses are likely attributable to the chemical composition of the barrier or the conditions required for resorption and metabolism of the barrier components. It is likely that the components of these barriers incite a wide range of inflammatory responses resulting in the range of adhesion coverage and tenacity observed in the preclinical and clinical studies reviewed. Clinical trials are needed to more appropriately define the clinical effectiveness of these barriers.

Fabrication and characterization of porous EH scaffolds and EH-PEG bilayers

Biomaterials made from synthetic polymers are becoming more pervasive in the medical field. Synthetic polymers are particularly advantageous as their chemical and mechanical properties can be easily tailored to a specific application. This work characterizes polymer scaffolds derived from the cyclic acetal monomer 5-ethyl-5-(hydroxymethyl)-β,β-dimethyl-1,3-dioxane-2-ethanol diacrylate (EHD). Both porous scaffolds and bilayer scaffolds based upon the EHD monomer were fabricated, and the resulting scaffolds' degradation and mechanical properties were studied. The results showed that by modifying the architecture of an EH scaffold, either by adding a porous network or a poly(ethylene glycol) (PEG) coating, the degradation and Young's modulus of the biomaterial can be significant altered. However, results also indicated that these architectural modifications can be accomplished without a significant loss in the flexural strength of the scaffold. Therefore, we suggest that porous EH scaffolds, and particularly porous EH-PEG bilayers, may be especially useful in dynamic tissue environments due to their advantageous architectural and mechanical properties.

Impact of Heavy Polypropylene Mesh and Composite Light Polypropylene and Polyglactin 910 on the Inflammatory Response

The aim of the study was to analyze the acute inflammatory response after implantation of a heavyweight mesh of polypropylene (PP) compared with a composite mesh of light PP and polyglactin 910 (PG) in patients undergoing inguinal hernioplasty. A total of 30 male patients with inguinal hernia were included in the study and divided into 2 groups (PP and PP-PG) according to the mesh used. Changes of leukocytes, cytokines, growth factors, and acute phase proteins were evaluated in the sera. Leukocytes and acute phase proteins were significantly increased postoperatively in both groups, and the values were slightly higher in the PP group. Cytokine levels were significantly increased postoperatively in both groups; a slight increase was observed in the PP-PG group, especially for the proinflammatory cytokine. Growth factors decreased significantly in both groups immediately after surgery. The authors found that the use of the mesh is a stimulator of inflammatory response, and the 2 types of mesh induce a similar inflammatory response.

Management of giant ventral hernia by polypropylene mesh and host tissue barrier: trial of simplification

BACKGROUND

Surgical management of giant ventral hernias is a surgical challenge due to limited abdominal cavity. This study evaluates management of giant ventral hernias using polypropylene mesh and host tissue barrier after suitable preoperative preparation.

METHODS

In the period from January 2005 and January 2007, 35 patients with giant ventral hernias underwent hernia repair. After careful preoperative preparation, repair was done using polypropylene mesh. The mesh was separated from the viscera by a small part of the hernia sac and the greater omentum.

RESULTS

The average age of the patients was 52. Twenty patients had post-operative incisional and 15 had para-umbilical hernias. The mean hernia defect size was 16.8 cm. Mean body mass index was 33. Follow up ranged from 18-36 months. No patient required ventilation after operation. Recurrent seroma, which responded to repeated aspiration, was experienced in 4 patients. Minor wound infection was observed in 5 patients. Small hernia recurrence occurred in one patient.

CONCLUSION

The use of polypropylene and host tissue barrier after suitable preoperative preparation is relatively simple, safe, and reliable surgical solution to the problem of giant ventral hernia.

KEYWORDS

Hernia repair; Giant ventral hernia; Polypropylene mesh.

Skeletal muscle tissue engineering approaches to abdominal wall hernia repair

Abdominal wall hernias resulting from prior incisions are a common surgical complication affecting hundreds of thousands of Americans each year. The negative consequences associated with abdominal hernias may be considerable, including pain, bowel incarceration, vascular disruption, organ loss, and death. Current clinical approaches for the treatment of abdominal wall hernias focus on the implantation of permanent biomaterial meshes or acellular xenografts. However, these approaches are not infrequently associated with postoperative infections, chronic sinuses, or small bowel obstruction. Furthermore, the most critical complication, hernia recurrence, has been well described and may occur in a large percentage of patients. Despite many advances in repair techniques, wound healing and skeletal muscle regeneration is limited in many cases, resulting in a decrease in abdominal wall tissue function and contributing to the high hernia recurrence rate. This review will give an overview of skeletal muscle anatomy, skeletal muscle regeneration, and herniation mechanisms, as well as discuss the current and future clinical solutions for abdominal wall hernia repair.

Polypropylene meshes to prevent abdominal herniation. Can stable coatings prevent adhesions in the long term?

Abdominal surgery is associated with a significant risk for incisional herniation. Hernia repair is routinely performed by implantation of synthetic meshes. Such meshes may cause serious adhesions between the implanted material and organs leading to intestinal obstruction or enterocutaneous fistulas. This study compares three knitted meshes for their capacity to prevent adhesion formation in an in vivo study. The meshes evaluated are polypropylene (Prolene), polypropylene coated with oxygenated regenerated cellulose-in principle-a biodegradable biomaterial (Proceed, and Prolene coated with a nondegradable copolymer of the hydrophilic building block N-vinyl pyrrolidone (NVP) and the hydrophobic building block n-butylmethacrylate (BMA). The meshes were implanted in the abdomen of rats (follow-up 7 or 30 days). After 7 days, the formation of adhesions decreased in the order: Prolene > NVP/BMA-coated Prolene > Proceed; after 30 days, this order changed into: Proceed > Prolene > NVP/BMA-coated Prolene. Both at 7 and at 30 days, Proceed was the only mesh surrounded by macrophage cells that contained foreign materials, presumably degradation products of the (biodegradable) surface coating. The data indicate that long-term protection of implanted meshes against excessive adhesions may be achieved through stable biocompatible hydrogel surface coatings.

Effects of two different meshes used in hernia repair on nerve transport

BACKGROUND

We aimed to investigate the effects of two different types of mesh used in hernia repair on nerve transport and neural injury.

STUDY DESIGN

Forty-five Wistar-albino rats were randomly allocated to three groups. Basal neural transport on the index of the left sciatic nerve was performed in all groups before surgery. In the control group, only sciatic nerve manipulation was performed. Other groups received a cuff around the index sciatic nerve. The second group received a monofilament polypropylene and the third group received a polytetrafluoroethylene mesh. Effects of entrapment on neural transport were evaluated by electromyography on the 28th day. Tissue samples from sciatic nerves were taken for evaluation of nerve injury.

RESULTS

There was no significant difference between basal latency and amplitudes (p=0.609 and p=0.152, respectively). But latency was significantly different 4 weeks after the operation (p < 0.0001). At post hoc evaluation, entrapment groups had longer latency times compared with those in the control group (p=0.006 and p < 0.0001, respectively). But the increase in latency between entrapment arms was similar on the 28th day (p=0.601). Both initial and late term amplitudes were similar (p=0.364 and 0.913, respectively). Histologic evaluation by Masson's trichrome staining revealed high fibrosis scores and increased collagen deposits, especially in the polypropylene group (p < 0.0001), and increased inflammation in the polytetrafluoroethylene group (p < 0.001).

CONCLUSIONS

Our results showed that the two most commonly used meshes in tension-free hernia surgery have different effects on nerve physiology and morphology. We concluded that alterations in nerve physiomorphology are from the properties of the mesh and may be the source of postoperative pain in hernia surgery.

Prosthetic material in ventral hernia repair: how do I choose?

Several factors must be considered in deciding which mesh to use for a ventral hernia repair. Open hernia repairs with no exposure of mesh to viscera can be performed with unprotected synthetic mesh, preferably a "lightweight" option. For open repair with high risk for fascial dehiscence and visceral exposure to mesh, and for open underlay repair and laparoscopic underlay repair, recommendations call for a tissue-separating mesh that prevents ingrowth of intra-abdominal contents into the mesh. Although no long-term data are available about biologic (acellular collagen scaffold) meshes, these may have good results when used in contaminated or well-drained infected fields, and do best when used according to the principles of a high-quality synthetic mesh repair (wide mesh overlap, frequent fixation points). Evidence is still insufficient to support the use of biologic materials for primary hernia repair.

EH Networks as a scaffold for skeletal muscle regeneration in abdominal wall hernia repair

Incisional hernias are a common clinical problem occurring in up to 10% of all patients undergoing abdominal procedures. Primary closure, synthetic biomaterials, as well as xenografts and allografts have been used in hernia defect repair. Despite these approaches, the incidence of hernia recurrence ranges from 32% to 63%. To address this high recurrence rate, we propose an incisional hernia treatment that utilizes a functional biomaterial developed for skeletal muscle regeneration. In particular, we have developed a cyclic acetal biomaterial (EH network) based on 5-ethyl-5-(hydroxymethyl)-beta,beta-dimethyl-1,3-dioxane-2-ethanol diacrylate. Initial tests of the scaffold's mechanical properties indicate that the complex modulus of the EH network decreased after a significant increase in initiator concentration. Subsequent studies indicate that EH networks promote myoblastic cell attachment and proliferation as well as delivers functional insulin-like growth factor-1 to an in vitro population of skeletal myoblasts. This work establishes that an EH network, a degradable cyclic acetal biomaterial, can function as a scaffold for skeletal muscle engineering.

Mesh-related infections after pelvic organ prolapse repair surgery

The use of vaginal meshes has been an advance in the surgical management of women with pelvic organ prolapse. We reviewed the literature to synthesize the evidence regarding the infectious complications related to this new type of foreign body. We searched PubMed, current contents, and references of initially identified relevant articles and extracted data regarding the incidence, clinical manifestation, and management of vaginal mesh-related infections. The incidence of mesh-related infections and erosion ranged from 0 to 8%, and 0 to 33%, respectively, in the published studies. Various factors influence the development of vaginal mesh-related infectious complications such as the kind of biomedical material (e.g. filament structure, pore size) of the mesh, the type of procedure, the preventive measures taken, and the age and underlying comorbidity of the treated women. Non-specific pelvic pain, persistent vaginal discharge or bleeding, dyspareunia, and urinary or faecal incontinence are the most common manifestation of vaginal mesh-related infection. Clinical examination may reveal induration of the vaginal incision, vaginal granulation tissue, draining sinus tracts, and prosthesis erosion or rejection. Various pathogens have been implicated, including Gram-positive and Gram-negative aerobic and anaerobic bacteria. The management of mesh-related infections in women who underwent pelvic organ reconstruction is combined surgical and medical treatment. Although the use of vaginal meshes has become a new effective method of pelvic organ prolapse surgery clinicians should be aware of the various post-operative complications, including mesh-related infections.

Hyaluronic Acid/Carboxymethylcellulose Membrane Barrier versus Taurolidine for the Prevention of Adhesions to Polypropylene Mesh

BACKGROUND

A hyaluronic acid/carboxymethylcellulose (HA/CMC) membrane is an effective measure to prevent polypropylene mesh induced adhesions. We hypothesized that taurolidine 2% solution might be a cost-effective alternative to decrease adhesion formation.

MATERIALS AND METHODS

Twenty-four rats were randomized into three groups: mesh alone (group 1), mesh + taurolidine 2% (group 2), and mesh + HA/CMC (group 3). Polypropylene mesh (4 cm2) was used to repair surgically induced anterior abdominal wall defects. Taurolidine 2%or a HA/CMC membrane was used as an antiadhesive measure. The animals were sacrificed 6 weeks after the operation, and adhesions to the prosthetic material were evaluated with digital image analysis.

RESULTS

Group 1 (mesh alone) had the highest adhesion ratio (58.5 +/- 4.8%) compared with groups 2 and 3 (p < 0.05). The differences between groups 2 (mesh + taurolidine 2%; adhesion ratio 42.9 +/- 1.6%) and 3 (mesh + HA/CMC; adhesion ratio 40.3 +/- 3.0%) were not significant (p > 0.05).

CONCLUSIONS

The animals of both treatment groups (2 and 3) had lower adhesion ratios compared with the controls (group 1). In particular, the HA/CMC membrane did not present with a superior antiadhesive effect compared with taurolidine. Therefore, taurolidine is a cost-effective alternative to HA/CMC membranes when a polypropylene mesh is used in direct contact with the abdominal viscera.

Collagen-coated vs noncoated low-weight polypropylene meshes in a sheep model for vaginal surgery. A pilot study

The aims of this study were dual. First, to evaluate the feasibility of a sheep model as an animal model for vaginal surgery with meshes. Second, to compare host response to two low-weight polypropylene (PP) meshes, a noncoated (Soft Prolene, Gynecare, Ethicon) and a coated mesh with an absorbable hydrophilic film (Ugytex, Sofradim). Thirty-six 20 x 20 mm polypropylene meshes (18 coated and 18 noncoated) were surgically implanted by the vaginal route in 12 adult ewes. Meshes were implanted in the anterior (n=12) and the posterior vaginal compartments (n=24). Animals were killed 1 (n=6) and 12 (n=6) weeks after surgery. Postimplantation evaluation included macroscopical examination, histological and immunohistochemical analysis and histomorphometrical measures of the distance between the meshes and the vaginal epithelium. The experimental procedure was feasible in all cases. Vaginal erosions were observed twice as frequently with the noncoated-PP meshes (6/18, 33.3%) as with the coated-PP meshes (3/18, 16.7%), even if that difference was not significant (p=0.4). However, no differences were observed between the two meshes in terms of shrinkage, tissue ingrowth, inflammatory response, and position of the mesh in the vaginal wall. The mechanism involved in the reduction of vaginal erosion could be due to the lesser adhesion of the coated mesh on the vaginal wound during the early postoperative period.