Incisional hernia: challenge of re-operations after mesh repair

Background and aims The widespread use of meshes for the repair of incisional hernia is currently followed by an increasing number of re-operations. The incidence of incisional hernia recurrence after mesh repair varies between 3 and 32%. The problem of mesh failure and options for another surgical intervention seem rather unattended. Methods We present our experience of 77 re-operations after previous mesh repair that were performed between 1995 and 2004 out of a total of 1,070 operations for incisional hernia. The retrospective analysis focused on recurrence in relation to location, material of the previous mesh repair and the surgical procedure to resolve the problem. Results The locations of the preceding meshes were epifascial as onlays (n=23), retromuscular as sublays (n=46), within the defect as inlays (n=6) or intraperitoneally (n=2). The direction of the incision was vertical medial (n=41) or horizontal crossing the linea semilunaris (n=36). Recurrences after median incisional hernia mesh repair mainly occurred at the cranial border of the mesh subxiphoidal. Except for two patients, all recurrences manifested at the margin of the enclosed mesh. Conclusions Re-operation after previous mesh repair is a surgical challenge. The type of revision procedure has to consider the position and material of the previous mesh. In our clinic recurrences, heavyweight polypropylene meshes were mostly treated with mesh exchange and lightweight polypropylene meshes could be treated by extension with a second mesh. In contrast to suture techniques, deficient mesh repairs are more evidently related to technical problems.     

Tensile properties of commonly used prolapse meshes

Introduction and hypothesis  To improve our understanding of the differences in commonly used synthetic prolapse meshes, we compared four newer generation meshes to Gynecare PS™ using a tensile testing protocol. We hypothesize that the newer meshes have inferior biomechanical properties. Methods  Meshes were loaded to failure (n = 5 per group) generating load–elongation curves from which the stiffness, the load at failure, and the relative elongation were determined. Additional mesh samples (n = 3) underwent a cyclic loading protocol to measure permanent elongation in response to subfailure loading. Results  With the exception of Popmesh, which displayed uniform stiffness, other meshes were characterized by a bilinear behavior. Newer meshes were 70–90% less stiff than Gynecare™ (p < 0.05) and more readily deformed in response to uniaxial and cyclical loading (p < 0.001). Conclusion  Relative to Gynecare™, the newer generation of prolapse meshes were significantly less stiff, with irreversible deformation at significantly lower loads.     

In vivo study of meshes implanted over the inguinal ring and external iliac vessels in uncastrated pigs

Background: The effects of placing a prosthesis directly on the internal inguinal ring and external iliac vessels in inguinal hernia repair are unknown. We compared tissue responses to five prostheses implanted in this position in uncastrated male pigs. Methods: Three types of polypropylene and two types of expanded polytetrafluoroethylene (ePTFE) mesh were implanted in 20 pigs (n= 8 for each prosthesis type). Specimens of the implants and surrounding tissue were obtained 30 and 90 days after implantation and assessed histologically. Results: The polypropylene implants had more adhesions, more surface area covered by adhesions, and more tenacious adhesions than did the ePTFE implants. Perivascular cuffing was observed in eight polypropylene and one ePTFE specimen; ossification, necrosis, and testicular venous congestion were seen in polypropylene specimens. Conclusions: Abnormal healing processes after implantation of polypropylene mesh may increase complications of the transabdominal preperitoneal and total extraperitoneal approaches in laparoscopic inguinal hernia repair, whereas the minimal response to ePTFE meshes may make them safer for use in the preperitoneal space. Received: 2 April 1997/Accepted: 8 August 1997     

Mesh repair for postoperative wound dehiscence in the presence of infection: is absorbable mesh safer than non-absorbable mesh?

Objective In patients with postoperative wound dehiscence in the presence of infection, extensive visceral oedema often necessitates mechanical containment of bowel. Prosthetic mesh is often used for this purpose. The aim of the present study was to assess the safety of the use of non-absorbable and absorbable meshes for this purpose. Method All patients that had undergone mesh repair of abdominal wound dehiscence between January 1988 and January 1998 in the presence of intra-abdominal infection were included in a retrospective cohort study. All surviving patients had physical follow-up in February 2001. Result Eighteen patients were included in the study. Meshes consisted of polyglactin (n = 6), polypropylene (n = 8), polyester (n = 1), or a combination of a polypropylene mesh with a polyglactin mesh on the visceral side (n = 3). All patients developed complications, consisting mainly of mesh infection (77%), intra-abdominal abscess (17%), enterocutaneous fistula (17%), or mesh migration through the bowel (11%). Mesh removal was necessary in eight patients (44%). Within four months postoperatively, six patients (33%) had died because of progressive abdominal sepsis. The incidence of progressive abdominal sepsis was significantly higher in the group with absorbable polyglactin mesh than in the group with nonabsorbable mesh (67 vs. 11%, p = 0.02) After a mean follow-up of 49 months, 63% of the surviving patients had developed incisional hernia. Absorbable meshes did not yield better outcomes than nonabsorbable meshes in terms of complications and mortality rate. Conclusion Synthetic graft placement in the presence of intra-abdominal infection has a high risk of complications, regardless of whether absorbable (polyglactin) or non-absorbable mesh material (polypropylene or polyester) is used, and should be avoided if possible.     

The new 4DDome prosthesis: an original light and partially absorbable composite mesh for hernia repair

Introduction The use of non-absorbable meshes for the repair of inguinal hernias has become standard; however, these meshes have been associated with complications including long-term postoperative pain. To this end, a new partially absorbable composite mesh has been developed, and the aim of this study was to investigate its efficacy in animal and human trials. Materials and methods Sixty male Wistar rats were used to evaluate the behavior of the newly designed composite mesh. Composite meshes were implanted in the extra-peritoneal plane for 2, 4 and 8 weeks and compared to a standard polypropylene mesh. Forty patients with symptomatic inguinal hernias were treated using a new 4DDome designed prosthesis. Follow-up was by clinical and ultrasound examination at 1, 6 and 12 months. Results The animal study demonstrated that the inflammatory reaction associated with the new composite mesh was significantly lower than a standard polypropylene mesh, characterized by a lower macrophage infiltrate (P < 0.001). The mesh did not shrink over the 8-week period, unlike the polypropylene mesh (P < 0.05). The human study showed that there were three minor postoperative complications, no recurrences and the mesh was well tolerated. Follow-up with serial ultrasound showed that at 10 days and 1 month the dome was clearly visible in position; however, by 6 months it had flattened out, been partially absorbed and become incorporated into the repair. Conclusion These experimental and clinical studies have validated the concept of the new 4DDome composite mesh. It was well tolerated and was associated with good short-term results. The combination of the dome shape and the new composite mesh means that less polypropylene is required and represents a significant advance in anterior hernia repair.     

Biomechanical effects of polyglecaprone fibers in a polypropylene mesh after abdominal and rectovaginal implantation in a rabbit

Introduction and hypothesis

To investigate the biomechanical effects of polyglecaprone fibers in lightweight meshes implanted into the vaginal and abdominal wall of parous rabbits.

Methods

New Zealand White rabbits (n?=?24) were implanted with polypropylene meshes (32?g/m²), with (Prolift plus M, n?=?12) or without (Prolift minus M, n?=?12) polyglecaprone fibers. Following implantation in the posterior vaginal and abdominal wall, local side effects were evaluated and explants underwent uniaxial tensiometry after 120 and 180?days.

Results

The vaginal extrusion rate was at least 50?%, coinciding with a minimum of 20?% of contraction. There were no measurable effects of the addition of polyglecaprone on tensiometric strength and compliance in abdominal explants.

Conclusions

The addition of polyglecaprone fibers did not compromise the biomechanical properties nor did it prevent vaginal extrusion and contraction. The latter as well as some other limitations preclude the rabbit vagina to be a suitable model for biomechanical testing.     

Bacteriological analysis of meshes removed for complications after surgical management of urinary incontinence or pelvic organ prolapse

The aim of this study is to examine the role of bacterial infection in complications following surgical management of urinary incontinence and genital prolapse using meshes. There were sixteen prostheses removed. Eight were monofilament polypropylene-knitted meshes, one was a silicone-coated polypropylene mesh, another was a collagen-coated polypropylene mesh, four were silicone-coated polyester meshes and two were polyester meshes. The most frequent cause for removal was symptomatic vaginal erosion (62%). Cultures were performed under aerobic, anaerobic and enrichment conditions. Infection was multimicrobial for 31% of meshes. When only one bacteria was found, it was Proteus mirabilis in 25% of cases. Forty-three per cent of bacterial quantifications were under 10³ colony-forming units per millilitre. Bacterial contamination was found in all meshes, quantification was often low, and therefore, its exact role is not yet clear.     

Trocar-guided total tension-free vaginal mesh repair of post-hysterectomy vaginal vault prolapse

Introduction and hypothesis  

The objective of this study was to report 1 year anatomical and functional outcomes of trocar-guided total tension-free vaginal mesh (Prolift™) repair for post-hysterectomy vaginal vault prolapse with one continuous piece of polypropylene mesh.     

Randomized trial of porcine dermal sling (Pelvicol<Superscript>™</Superscript> implant) vs. Tension-free Vaginal Tape (TVT) in the Surgical treatment of stress incontinence: a questionnaire-based study

 The objective of this study was to compare porcine dermal sling (Pelvicol^™ implant, Bard) with tension-free vaginal tape (TVT) in the surgical treatment of stress incontinence. One hundred and forty-two women with genuine stress incontinence (GSI) were randomly assigned to either Pelvicol^™ implant pubovaginal sling (n=74) or TVT (n=68). They were followed up at a minimum of 6 months (range 6–24 months), with a median follow-up of 12 months. The majority (n=109) of procedures were carried out in a day surgery unit. The median operation time was 35 minutes (range 15–60) in the TVT group and 30 minutes (range 20–80) in the Pelvicol^™ implant group; 81% of the TVT group and 77% of the Pelvicol^™ implant group were able to void urine within 24 hours, and had insignificant residual bladder volumes. The prevalence of postoperative symptomatic voiding dysfunction was 3.4% after TVT and 1.4% after Pelvicol^™ implant. Nine percent of the TVT group developed de novo urge incontinence and 6% of the Pelvicol^™ implant group had de novo urge incontinence 6 months after the procedure. Postoperative evaluation was done at the outpatient department, and a postal questionnaire was also completed to determine subjective continence status. The patient-determined cure rate was 85% in the TVT group and 89% in the Pelvicol^™ implant group. The Pelvicol^™ implant sling had a comparable patient- determined success rate with TVT and should be considered in the surgical treatment of women with genuine stress incontinence. Received: 15 January 2002 / Accepted: 1 July 2002     

Comparison of biomaterials in the early postoperative period

Background: Laparoscopic hernia repair necessitates the use of biocompatible materials. A prospective, double-blind study was conducted to compare two different polypropylene meshes. Methods: The study included 40 men with primary inguinal hernia undergoing transabdominal preperitoneal polypropylene mesh repair. In 20 of these men, a monofile, heavy-weight, rigid mesh was implanted (group A), and in the remaining 20 men, a smooth, heavy-weight variant of polypropylene mesh was implanted (group B). Complications, pain development, inability to work, physical conditions, testicular volume, and blood circulation were documented. Results: Reconvalescence in group A was slower than in group B. In group A, the postoperative values of the visual scales for pain development were higher; inability to work was 7.3 days longer; urologic disorders were worse; activities of everyday life were more reduced; and SF-36 data showed a significant reduction of physical problems (p < 0.05). Conclusions: The polypropylene mesh variant seems to be more compatible with the human organism than conventional mesh. Not only the material, but also the structure seems to influence the comfort of the mesh.     

Experimental Comparison of Monofile Light and Heavy Polypropylene Meshes: Less Weight Does Not Mean Less Biological Response

Background Mesh implantation is a standard procedure in hernia repair. It provides low recurrence rate but increases complication rate due to foreign-body reaction induced by alloplastic materials in surrounding tissues. It is believed that biocompatibility of meshes may be improved by reducing their weight per meter squared (m²) and altering the implant structure. Aim The aim of this study was to evaluate the effect of weight and structure as determinants of mesh biocompatibility. Method Thirty-six Wistar rats were studied. In 12 animals, conventional polypropylene (heavy) meshes (HM) were implanted; in other 12, material-reduced (light) microporous polypropylene meshes (LM); and the remaining 12 served as a sham-operated control group. Meshes were explanted after 21 and 90 days (6 animals per group). All samples were examined by light and electron microscopies. Integration of meshes in surrounding tissue, inflammatory response, fibrotic reactions, and structural changes were recorded. Quantification of the inflammatory response was achieved by CD-68 marking of macrophages and counting their number per surface unit. Results After 21 days, there was no significant difference in thickness of surrounding connective tissue between meshes in all groups studied. After 90 days, thickness of connective tissue decreased in both groups, and fibrotic reaction in the mesh bed was significantly less in the HM group. Total amount of macrophages per millimeter squared (mm²) decreased with time in HM and LM samples but was significantly lower in the HM group on day 21 (43.5%) and day 90 (46.7%). Conclusion This study found worse biocompatibility of LM compared with HM. Thus, the amount of implanted mesh was not the main determinant of biocompatibility (expressed as successful incorporation and diminished foreign-body reaction) but the size of the pores.     

Polypropylene meshes coated with a polysaccharide based bioadhesive for intra-abdominal mesh fixation in a rabbit model

Background

In this study, we evaluate a new bioadhesive for intra-abdominal onlay mesh fixation of a polypropylene–polyvinylchloride graft.

Methods

Three pieces of a commercially available polypropylene/polyvinylfluoride mesh, each 3 × 3 cm in size, and three pieces of the same mesh coated with a polysaccharide bioadhesive were fixated to the surface of the anterior abdominal wall of 30 New Zealand white rabbits. The fixation was performed either by using four transabdominal Prolene^® 4/0 sutures, four spiral tacks (Protack 5 mm Tyco), or cyanoacrylate glue (Glubran^® GEM, Viareggio, Italy). Each mesh position and the according kind of fixation were randomized before implantation. The animals were sacrificed 12 weeks postoperatively. After determining the extent of intra-abdominal adhesions, the meshes were excised en bloc with the anterior abdominal wall for tensile strength measurements and histological analysis.

Results

All meshes coated with the bioadhesive adhered to the intact peritoneum without extra fixation. Irrespective of the fixation technique coated meshes led to more and stronger adhesions. Mesh shrinkage by scarring was increased in coated meshes fixed with glue and low in uncoated meshes fixed with tacks. Testing the tensile strength, coated meshes fixed with transfascial sutures achieved the best results (16.14 ± 6.1 N), whereas coated meshes fixed with glue showed the lowest strength (10.39 ± 4.81 N). The foreign body reaction was considerably more distinctive using coated mesh. The mesh ingrowth was not influenced by this reaction.

Conclusions

All meshes coated with the new bioadhesive were self-adhesive in that way; they stayed in position when attached to the peritoneum. Although this may facilitate intra-operative mesh fixation, the bioadhesive displayed several disadvantages, such as stronger adhesions and an increased shrinkage of the implant. The tensile strength was not influenced by the use of the bioadhesive. At present, we see no major advantage for polysaccharide bioadhesive applied in this study.     

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.     

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.     

Laparoscopic evaluation of abdominal adhesions with different prosthetic meshes in rabbits.

BACKGROUND: The use of prosthetic materials to reinforce the abdominal wall is associated with a low index of recurrence; however, intraperitoneal placement of a foreign body may lead to adhesions. The present investigation was designed to determine adhesion formation with commercially available meshes implanted laparoscopically in rabbits. METHODS: Three different meshes were implanted laparoscopically in 24 rabbits: polypropylene (mesh A), polypropylene and sodium hyaluronate-carboxymethylcellulose (mesh B), and polypropylene and expanded polytetrafluoroethylene (mesh C). Sites of implantation for each mesh (the left lower quadrant, right lower quadrant, and lower midline) were randomly determined so that every rabbit had all 3 meshes implanted. All animals underwent diagnostic laparoscopy after 28 days to grade adhesions and histological analysis of inflammation. RESULTS: Adhesions were noticed in 46 of the 72 meshes implanted (64%). The number of adhesions was higher for mesh C (87.5%) compared with meshes A (62.5%) and B (41.6%). The severity of adhesions was also higher for mesh C (grade I in 14, II in 6, and III in 1) compared with mesh A (grade I in 10, II in 4, and III in 1 case) and B (all of them grade II). Histological inflammatory reaction was classified as mild in 23 cases of mesh A, 15 of mesh B, and 23 of mesh C. A moderate reaction was found in 1 case of mesh A, 4 cases of mesh B, and 1 case of mesh C. Severe reaction was induced in 5 cases of mesh B. Mesh B induced a higher inflammatory reaction compared with the other meshes. CONCLUSIONS: All meshes induced adhesions of different grades. Mesh B had fewer adhesions and more intense inflammation them did the others.     

Biocompatibility of bacterial contaminated prosthetic meshes and porcine dermal collagen used to repair abdominal wall defects

Background and aims A contaminated or infected surgical site is considered a contraindication for the use of the nonabsorbable alloplastic materials employed to repair abdominal wall defects. Therefore, the biocompatibility of new prosthetic materials was investigated. Materials and methods Meshes measuring 1.5×1.5 cm made of conventional and titanium-coated polypropylene, polyglycol, or porcine dermal collagen were implanted under the abdominal wall of 96 rats (eight groups of 12 animals each) employing the inlay technique. Implantation of all four materials was performed both under semisterile conditions and bacterial contamination of the mesh. The meshes were explanted after 28 days. Results All the materials implanted under semisterile conditions were incorporated into the abdominal wall with only few intraabdominal adhesions (mean adhesion scores: 1.0, 1.2, 1.0, 0.8 points, respectively, not significant). With the porcine dermal collagen, proliferation rate and the proportion of inflammatory cells were statistically lower (p<0.01). In the bacterial contamination group, all meshes were associated with a suppurating infection and strong adhesions between the bowel and mesh, which were most prominent in the case of dermal collagen (mean adhesion scores: 1.6, 1.7, 1.7, and 1.9 points, respectively, not significant). In this group, two animals died of peritonitis. In comparison with the other materials, the proliferation rate was significantly elevated (p=0.03). No significant differences were seen between the other materials employed. Conclusion Irrespective of the material employed, implantation of alloplastic meshes in an abdominal wall contaminated with bacteria, is associated with suppurating infections, in particular in the case of the membrane-like porcine dermal collagen. Nonabsorbable alloplastic meshes and dermal skin grafts should therefore not be used to repair infected abdominal wall defects.     

Mesh complications after prosthetic reinforcement of hiatal closure: a 28-case series

Background  Primary laparoscopic hiatal hernia repair is associated with up to a 42% recurrence rate. This has lead to the use of mesh for crural repair, which has resulted in an improved recurrence rate (0–24%). However, mesh complications have been observed. Methods  We compiled two cases, and our senior author contacted other experienced esophageal surgeons who provided 26 additional cases with mesh-related complications. Care was taken to retrieve technical operative details concerning mesh size and shape and implantation technique used. Results  Twenty-six patients underwent laparoscopic and two patients open surgery for large hiatal hernia (n = 28). Twenty-five patients had a concomitant Nissen fundoplication, two a Toupet fundoplication, and one a Watson fundoplication. Mesh types placed were polypropylene (n = 8), polytetrafluoroethylene (PTFE) (n = 12), biological mesh (n = 7), and dual mesh (n = 1). Presenting symptoms associated with mesh complications were dysphagia (n = 22), heartburn (n = 10), chest pain (n = 14), fever (n = 1), epigastric pain (n = 2), and weight loss (n = 4). Main reoperative findings were intraluminal mesh erosion (n = 17), esophageal stenosis (n = 6), and dense fibrosis (n = 5). Six patients required esophagectomy, two patients had partial gastrectomy, and 1 patient had total gastrectomy. Five patients did not require surgery. In this group one patient had mesh removal by endoscopy. There was no immediate postoperative mortality, however one patient has severe gastroparesis and five patients are dependent on tube feeding. Two patients died 3 months postoperatively of unknown cause. There is no apparent relationship between mesh type and configuration with the complications encountered. Conclusion  Complications related to synthetic mesh placement at the esophageal hiatus are more common than previously reported. Multicenter prospective studies are needed to determine the best method and type of mesh for implantation.     

Long-term follow-up of persistent vaginal polypropylene mesh exposure for transvaginally placed mesh procedures

Introduction and hypothesis

The surgical treatment of a cystocele via the vaginal route may require the placement of a synthetic mesh below the bladder. However, the placement of a synthetic mesh via the vaginal route can be associated with specific complications, such as vaginal mesh exposure. There is a lack of data concerning the long-term follow-up of asymptomatic persistent vaginal polypropylene mesh exposure.

Methods

This was a retrospective case series of nine patients presenting with persistent vaginal mesh exposure following the placement of a macroporous monofilament polypropylene mesh for cystocele treatment. Expectant management has been proposed since the patients were asymptomatic.

Results

The median follow-up duration was 121?months [interquartile range (IQR) 119–132]. The median surface area of vaginal mesh exposure (1?cm²; IQR 1–1) did not change significantly during the follow-up. No pelvic or perineal abscess occurred during the follow-up. Only one of them was sexually active; she complained of dyspareunia at the last follow-up, but refused renewed surgery since she had sexual intercourse on only a small number of occasions per year. Clinical examination using the International Continence Society Pelvic Organ Prolapse Quantification system: Ba ?3 to ?2 (n?=?7; 88?%), Ba ?1 (n?=?1; 12?%), Ba 0 or greater (n?=?0).

Conclusions

Persistent asymptomatic vaginal polypropylene mesh exposure is associated with few complications at long-term follow-up.     

Long-term foreign-body reaction to preperitoneal polypropylene mesh in the pig

Summary The aim of the study is to establish the long-term foreign-body reaction to a polypropylene mesh used for inguinal hernia repair in a pig model. Twenty-two Surpipro^® meshes were implanted in 22 preperitoneal inguinal areas in 11 female 10-week-old Yorkshire and Dutch landway swine. The prosthetic mesh was implanted using a laparoscopic transperitoneal technique. At 1, 2, 3, 4, 6, 12 and 26 weeks, the animals were sacreificed and the number of foreign-body giant-cells at the mesh-tissue interface was counted. The mean numbers of giant-cells (SD) after 1, 2, 3, 4, 6, 12 and 26 weeks were: 0.9 (2.4), 7.3 (5.4), 19 (8.2), 15.2 (7.9), 15.9 (6.9), 14.1 (5.6), and 8.2 (4.7). The mean number of giant-cells at 12 weeks was significantly lower than at 3 weeks. The mean number of giant-cells at 26 weeks was significantly lower than at 3, 4, 6, and 12 weeks. We conclude that the foreign-body giant-cell reaction to polypropylene mesh increases until the third week after implantation. Thereafter, it gradually decreases, and at six months it persists at half the maximal level at 3 weeks.     

Biomechanical effects of the inclusion of holes to facilitate the integration in monofilament polypropylene meshes: an experimental study

ObjectiveTo evaluate the biomechanical properties of a type of monofilament polypropylene mesh used to repair vaginal prolapse, as well as the effects of the inclusion of standard size orifices, called “helper orifices,” on the interface resistance in the receiving area.Material and methodsForty female Wistar rats, 3 month-old, received an implant of monofilament polypropylene mesh, measuring 24 x 11 mm with no orifices, on left side of the abdominal wall (block 1). On the right side, a similar mesh with two circular orifices (6 mm diameter) was implanted (block 2). The rats were euthanized 90 days later and their abdominal walls were removed and divided into two blocks. The biomechanical study used a precision tensiometer in which the mesh was uniaxially tensioned until it was loosened from the tissue interface. In order to determine the tissue adherence and elasticity in each group, the following variables were analyzed: maximum load; deflection at maximum load; work to maximum load; stiffness as well as load, deflection and work at detachment the mesh.ResultsWith the exception of stiffness, all the other variables showed statistical differences between the groups, considering that they were increased in meshes with orifices (p < 0.001). The inclusion of standard size orifices reduced 30% of the mesh weigth.ConclusionBesides reducing the weight and amount of material, the inclusion of standard size orifices in the monofilament macroporous polypropylene mesh improved the elasticity and adherence to the tissues when implanted in the interface of the abdominal wall in adult female rats.