Does expanded polytetrafluoroethylene mesh really shrink after laparoscopic ventral hernia repair?

Background

The shrinkage of mesh has been cited as a possible explanation for hernia recurrence. Expanded polytetrafluoroethylene (ePTFE) is unique in that it can be visualized on computed tomography (CT). Some animal studies have shown a greater than 40% rate of contraction of ePTFE; however, very few human studies have been performed.

Study design

A total of 815 laparoscopic incisional/ventral hernia (LIVH) repairs were performed by a single surgical group. DualMesh Plus (ePTFE) (WL Gore &; Associates, Newark, DE) was placed in the majority of these patients using both transfascial sutures and tack fixation. Fifty-eight patients had postoperative CTs of the abdomen and pelvis with ePTFE and known transverse diameter of the implanted mesh. The prosthesis was measured on the CT using the AquariusNet software program (TeraRecon, San Mateo, CA), which outlines the mesh and calculates the total length. Data were collected regarding the original mesh size, known linear dimension of mesh, seroma formation, and time interval since mesh implantation in months.

Results

The mean shrinkage rate was 6.7%. The duration of implantation ranged from 6?weeks to 78?months, with a median of 15?months. Seroma was seen in 8.6% (5) of patients. No relationship was identified between the percentage of shrinkage and the original mesh size (P?=?0.78), duration of time implanted (P?=?0.57), or seroma formation (P?=?0.074). In 27.5% (16) of patients, no shrinkage of mesh was identified. Of the patients who did experience mesh shrinkage, the range of shrinkage was 2.6?C25%.

Conclusions

Our results are markedly different from animal studies and show that ePTFE has minimal shrinkage after LIVH repair. The use of transfascial sutures in addition to tack fixation may have an implication on the mesh contraction rates.     

Prospective evaluation of adhesion formation and shrinkage of intra-abdominal prosthetics in a rabbit model

Laparoscopic ventral hernia repair requires an intraperitoneal prosthetic; however, these materials are not without consequences. We evaluated host reaction to intraperitoneal placement of various prosthetics and the functional outcomes in an animal model. Mesh (n = 15 per mesh type) was implanted on intact peritoneum in New Zealand white rabbits. The mesh types included ePTFE (DualMesh), ePTFE and polypropylene (Composix), polypropylene and oxidized regenerated cellulose (Proceed), and polypropylene (Marlex). Adhesion formation was evaluated at 1, 4, 8, and 16 weeks using 2-mm mini-laparoscopy. Adhesion area, adhesion tenacity, prosthetic shrinkage, and compliance were evaluated after mesh explantation at 16 weeks. DualMesh had significantly less adhesions than Proceed, Composix, or Marlex at 1, 4, 8, and 16 weeks (P < 0.0001). Marlex had significantly more adhesions than other meshes at each time point (P < 0.0001). There were no statistically significant differences in adhesions between Proceed and Composix meshes. After mesh explantation, the mean area of adhesions for Proceed (4.6%) was less than for Marlex (21.7%; P = 0.001). The adhesions to Marlex were statistically more tenacious than the DualMesh and Composix groups. Overall prosthetic shrinkage was statistically greater for DualMesh (34.7%) than for the remaining mesh types (P < 0.01). Mesh compliance was similar between the groups. Prosthetic materials demonstrate a wide variety of characteristics when placed inside the abdomen. Marlex formed more adhesions with greater tenacity than the other mesh types. DualMesh resulted in minimal adhesions, but it shrank more than the other mesh types. Each prosthetic generates a varied host reaction. Better understanding of these reactions can allow a suitable prosthetic to be chosen for a given patient in clinical practice.     

A lightweight polypropylene mesh (TiMesh) for laparoscopic intraperitoneal repair of abdominal wall hernias

BACKGROUND: Despite numerous experimental studies, conducted most often with the open small-animal model, the ideal structure for a mesh with maximum biocompatibility in the intraabdominal region has yet to be found. To date, few experimental models have been concerned with the laparoscopic intraabdominal implantation of meshes. Numerous experimental and clinical studies appear to have identified expanded polytetrafluoroethylene (ePTFE), in the form of DualMesh, as the gold standard. Since publications have reported fistula formation and marked adhesions to be associated with the use of polypropylene meshes, only few studies have investigated meshes made of this material. It is known, however, that a reduction in the amount of material and an increase in pore size results in better mesh biocompatibility. METHODS: Six pigs each underwent laparoscopic intraabdominal placement of either a TiMesh or a DualMesh, both of which were prepared for implantation in standardized fashion. After 87 +/- 2 days, the pigs were killed, and postmortem laparoscopy was performed, followed by the removal of the tissue embedding the mesh for assessment of adhesions and shrinkage, and for histologic workup. The specimens were processed both histologically and immunohistochemically. RESULTS: In all but one case, the greater omentum adhered, usually over discrete areas, to the mesh. In every case the omentum was separable from the mesh surface only by sharp dissection. With the titanium-coated polypropylene meshes, the average total adhesion area was only 0.085, as compared with 0.25 for the GoreTex meshes (p = 0.055). The GoreTex meshes showed an average shrinkage to almost half of the original surface area (median, 0.435). The average shrinkage of the TiMesh, was to 0.18 of the original area (p = 0.006), which thus was significantly smaller. Determination of the partial volume of the inflammatory cells showed significantly lower median figures for the TiMesh (p = 0.009). Measurements of the proliferation marker Ki67 showed significantly higher values for ePTFE than for TiMesh (p = 0.011). The apoptosis index was significantly higher for the ePTFE membranes (p = 0.002). CONCLUSIONS: Titanium-coated polypropylene mesh (TiMesh) is clearly superior to the DualMesh in terms of biocompatibility, and is thus suitable for the laparoscopic intraperitoneal repair of abdominal wall and incisional hernias.     

Adhesion formation of a polyvinylidenfluoride/polypropylene mesh for intra-abdominal placement in a rodent animal model

Background  Effective laparoscopic ventral herniorrhaphy mandates the use of an intraperitoneal mesh. Visceral adhesions and shrinkage of prosthetics may complicate repairs. The aim of this study was to compare adhesion formation, mesh shrinkage and tissue ingrowth after intra-abdominal placement of a novel two-component monofilament mesh structure made of polypropylene (PP) and polyvinylidenfluoride (PVDF) with current alternatives. Materials and methods  Forty Sprague-Dawley rats were used in this study. Mesh samples were fixed as intra-abdominal only mesh at the right lateral abdominal wall. The study groups were: PVDF+PP (polypropylene parietally and polyvinylidenfluoride viscerally), PP+Col (polypropylene with a collagenoxidized film), ePTFE (smooth surface viscerally and a textured surface parietally), and PP (a pure polypropylene mesh serving as control). The meshes were explanted after 30 days. Adhesions were scored as a percentage of explanted biomaterials’ affected surface area; prosthetic shrinkage was calculated. Foreign-body reaction to mesh materials was measured by investigating the amount of inflammatory infiltrate and fibrotic tissue formation. Results  In terms of adhesion score, the pure PP mesh showed the highest values followed by the ePTFE, PVDF+PP, and PP+Col meshes. Quantitative assessment of adhesion area revealed a significantly higher value of the pure PP mesh sample (62.0 ± 22.1%) compared with the PP+Col (26.8 ± 12.1%) and the PVDF+PP mesh (34.6 ± 8.2%). Percentage of shrinkage showed a significantly higher value of the ePTFE mesh (52.4 ± 13.9%) compared with all other mesh modifications (PP+Col 19.8 ± 13.9%, PVDF+PP 19.9 ± 7.0%, and PP 26.8 ± 9.5%). Inflammatory infiltrate was significantly reduced in the PVDF+PP mesh group compared with all other mesh samples. Conclusion  The use of the novel two-component monofilament mesh structure made of polypropylene and polyvinylidenfluoride was found to be favorable regarding adhesion formation and mesh shrinkage compared to conventional mesh materials used for intra-abdominal placement.     

The use of sterilised polyester mosquito net mesh for inguinal hernia repair in Ghana

Background  The use of alloplastic mesh is now commonplace in hernia repair. However, in developing countries, cheaper alternatives to commercial mesh are required due to the high associated cost. Whilst nylon mosquito net mesh has been trialled previously, this study aimed to assess the use of polyester mosquito net mesh in tension-free inguinal hernia repair in Ghana. Methods  All patients undergoing inguinal hernia repair during the 5-day ‘Operation Hernia’ mission in 2007 were eligible for the study. A piece of sterilised 10 × 15-cm 100% polyester mosquito net mesh, manufactured and donated by Scotmas Limited, was implanted for all tension-free hernia repairs. The surgeons’ ease of handling and incidence of complications at 6 weeks and 6 months were assessed. Results  Ninety-five patients underwent inguinal hernia repair using a total of 106 polyester mosquito net meshes. The mean (range) age of patients was 44.3 (15–78) years. Seventy-two (76%) were repaired using local anaesthesia. At 6 weeks and 6 months, a total of seven (7%) patients suffered wound complications (five haematomas, two wound infections). Ease of practical handling improved after the first 2–5 cases. The cost of an individual 10 × 15-cm mesh was estimated at US$0.0072–0.014, and the cost of sterilisation and packaging was US$1.46 per mesh. Conclusions  Polyester mosquito net mesh represents a cost-effective alternative to commercial meshes in developing countries, with a relatively low rate of early complications and similar short-term recurrence rates. The use of local anaesthesia may enhance this further. An erratum to this article can be found at     

Strategies to minimize adhesions to intraperitoneally placed mesh in laparoscopic ventral hernia repair

Introduction:

Adhesions to mesh/tacks in laparoscopic ventral hernia repair are often cited as reasons not to adopt its evidence-based superiority over conventional open methods. This pilot study assessed the occurrence of adhesions to full-sized Polypropylene and Gore-tex DualMesh Plus meshes and the possibility for adhesion prevention using fibrin sealant.

Methods:

Two 10-cm to 15-cm pieces of mesh were placed and fixed laparoscopically in pigs (25kg to 55kg). Group I: 2 animals with Polypropylene mesh on one side and DualMesh on other side. Group II: 2 animals with DualMesh on each side with fibrin sealant applied to the periphery of mesh and staples to one side. Group III: 1 animal with 2 pieces of Polypropylene mesh with fibrin sealant applied to the entire mesh. All animals underwent laparoscopy 3 months later to assess the extent of adhesions, and full-thickness specimens were removed for histological evaluation.

Results:

More Polypropylene mesh was involved in adhesions than DualMesh. However, with the DualMesh involved in adhesions, more of the surface area was involved in forming adhesions than with Polypropylene mesh. None of the implanted DualMesh had visceral adhesions, while 2 out of 3 Polypropylene meshes had adhesions to both the liver and spleen but none to the bowel. Implanted Polypropylene mesh with fibrin sealant had no adhesions. DualMesh had shrunk more significantly than Polypropylene mesh. Histological evaluation showed absence of acute inflammatory response, significantly more chronic inflammatory response to DualMesh compared to Polypropylene and complete mesothelialization with both meshes. There was extensive collagen deposition between Polypropylene mesh fibers, while fibrosis occurred on both sides of DualMesh with synovial metaplasia over its peritoneal surface akin to encapsulation.

Conclusions:

DualMesh caused fewer omental and visceral adhesions than Polypropylene mesh did. Fibrin sealant eliminated adhesions to DualMesh and prevented adhesions to Polypropylene mesh when applied over the entire surface. These results support our current use of DualMesh and fibrin sealant in LVHR.     

Critical evaluation of a novel DualMesh repair for large hiatal hernias

Background  The use of mesh for laparoscopic repair of large hiatal hernias may reduce recurrence rates in comparison to primary suture repair. However, there is a potential risk of mesh-related oesophageal complications due to prosthesis erosion. The aim of this study was to critically evaluate a novel mesh (DualMesh) repair of hiatal hernias with particular reference to intraluminal erosion. Method  Medical records of 19 patients who underwent laparoscopic hiatal hernia repair with DualMesh reinforcement of the crural closure were reviewed from a prospectively collected database. Quality of life and symptom analysis was performed using quality of life in reflux and dyspepsia (QOLRAD) questionnaires pre- and postoperatively after 6 weeks, 6 months, 1 year and 2 years. Barium studies were performed on patients pre-operatively and two years postoperatively to assess hernia recurrence. After 2 years, oesophagogastric endoscopy was performed to assess signs of erosion. Results  Mean patient age was 70.5 years (range 49–85 years). Two years after hiatal hernia repair, there was significant improvement in quality-of-life scores (QOLRAD: p < 0.001). Follow-up barium studies performed at 31.3 months (range 29–40 months) after surgery showed moderate recurrent hernias (>4 cm) in 1/14 patients (7%). Endoscopies performed at 34.4 months (range 28–41 months) after surgery did not show any signs of prosthetic erosion. Conclusion  Laparoscopic reinforcement of primary hiatal closure with DualMesh leads to a durable repair in patients with large hiatal hernias. Long-term endoscopic follow-up did not show any signs of mesh erosion after prosthetic reinforcement of the crural repair.     

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.     

Comparative evaluation of adhesion formation, strength of ingrowth, and textile properties of prosthetic meshes after long-term intra-abdominal implantation in a rabbit

BACKGROUND: Effective laparoscopic ventral herniorrhaphy usually mandates the use of an intraperitoneal prosthetic. Visceral adhesions and changes in textile characteristics of prosthetics may complicate repairs, especially long-term. The aim of this study was to compare the adhesion formation, tissue ingrowth, and textile characteristics one year after intra-abdominal placement of the commonly used prosthetic meshes. MATERIALS AND METHODS: Forty (4 x 4 cm) meshes were sutured using absorbable suture to an intact peritoneum in 20 New Zealand white rabbits. The study groups included: polypropylene (PP) [Marlex; C.R. Bard Inc, Cranston, NJ], expanded polytetrafluoroethylene (ePTFE) [DualMesh; WL Gore, Flagstaff, AZ], ePTFE and PP (ePTFE/PP) [Composix, C.R. Bard Inc], reduced weight PP and oxidized regenerated cellulose (rPP/C) [Proceed; Ethicon, Inc, Somerville, NJ]. The meshes were explanted after one year. Adhesions were scored as a percentage of explanted biomaterials' affected surface area. Prosthetic shrinkage was calculated. The strength of incorporation and mesh compliance were evaluated using differential variable reluctance transducers. Mesh ingrowth was measured as the load necessary to distract the mesh/tissue complex. Mesh compliance was calculated as the change in linear displacement of the sensors due to applied load. The groups were compared using Student's t-test and Fisher's exact test. RESULTS: ePTFE had significantly less adhesions (0%) than both ePTFE/PP (40%) and PP (80%) groups (P < 0.001). The mean area of adhesions for the rPP/C (10%) and the ePTFE/PP (14%) groups was less than that for the PP group (40%) (P = 0.02). Prosthetic shrinkage was greatest in the ePTFE (32%) group than in any other group (P = 0.001). There were no differences in mesh incorporation between the groups. At explantation, mesh compliance in the ePTFE group was superior to other meshes (P < 0.0001). The rPP/C mesh induced the smallest change in the compliance of the tissue adjacent to the mesh (P = 0.0001). CONCLUSIONS: Prosthetic materials demonstrate a wide variety of characteristics. Although exposed PP formed the most adhesions, up to 40% of the other PP-based meshes formed adhesions despite protective barriers. The ePTFE mesh did not induce adhesions and was the most compliant, however, this prosthetic's contraction was greatest. Reduced weight polypropylene (rPP/C) mesh induced the smallest change in the adjacent tissue pliability/compliance. Understanding of the long-term effects of various prosthetic materials is important to ensure an adequate hernia repair while minimizing postoperative morbidity and patient discomfort.     

Re-operation due to severe late-onset persisting groin pain following anterior inguinal hernia repair with mesh

Objectives  Mild pain lasting for a few days is common following mesh inguinal hernia repair. In some patients however, severe groin pain may appear months or even years postoperatively. The aim of this study was to report our experience of late-onset persisting severe postoperative groin pain occurring years after mesh hernioplasty. Methods  In a 9-year period, 1,633 patients (1,073 men), median age 63 years (range 19–88), underwent mesh groin hernia repair. Between 1.5 and 4 years postoperatively, six patients (0.35%) presented with severe chronic groin pain unrelieved by conservative measures and surgical exploration was essential. The patients’ records were retrospectively reviewed for the purpose of this study. Results  Ilioinguinal nerve entrapment was detected in four patients. The meshes appeared to be indistinguishable from the nerve and were removed along with the stuck nerve. New meshes were properly inserted. Mesh fixation on the periostium of the pubic tubercle by a staple was found in the other two patients. The staples were removed from the periostium in both patients. Neither hernia recurrence nor chronic groin pain was persisting in all six patients during a follow-up of 6–44 months postoperatively. Conclusion  From the results of this study, it appears that ilioinguinal nerve entrapment and/or mesh fixation on the periostium of the pubic tubercle are the causes of late-onset severe chronic pain after inguinal mesh hernioplasty. Mesh removal, along with the stuck ilioinguinal nerve and staple detachment from the periostium, are the gold-standard techniques if conservative measures fail to reduce pain.     

Feasibility and outcome after laparoscopic ventral hernia repair using Proceed mesh

Background  There are many different meshes available for laparoscopic repair of ventral hernias. A relatively new product is the Proceed mesh with a bioresorbable layer against the bowels and a polypropylene layer against the abdominal wall. There are, however, no human data available. The aim of this study was to evaluate the feasibility and outcome after laparoscopic ventral hernia repair using the Proceed mesh in humans. Methods  Patients presenting for laparoscopic ventral hernia repair in our department from September 2004 to October 2006 were included in the study. All patients had a standard laparoscopic ventral hernia repair using the Proceed mesh secured with tackers with a double crown technique. Patients were discharged according to standard discharge criteria, and follow-up was performed with a search in the national patient database and with manual search in the patients’ files. Results  Our study included 49 patients with a median age of 64 years (range 30–89) and body mass index of 27.8 (19.4–50.5). The dimensions of the mesh varied from 4 × 4 cm to 30 × 40 cm (median 15 × 15 cm). One patient developed an uncomplicated wound infection and none of the 49 patients developed mesh infections or postoperative seroma requiring surgical intervention. Thus, there were no mesh-related complications. During the follow-up period of 17 months (3–27), we have not seen any postoperative recurrences. The median length of stay was 1 day (range 0–63), and there was no mortality. Conclusion  Laparoscopic ventral hernia repair in humans using the Proceed mesh is feasible and has a low complication rate even in obese patients or those with pulmonary disease.     

Prospective histologic evaluation of intra-abdominal prosthetics four months after implantation in a rabbit model

Background

Placement of an intraperitoneal prosthetic is required for laparoscopic ventral hernia repair. The biocompatibility of these prosthetics determines the host’s inflammatory response, scar plate formation, tissue ingrowth, and subsequent mesh performance, including prosthetic compliance and prevention of hernia recurrence. We evaluated the host response to intraperitoneal placement of several prosthetics currently used in clinical practice.

Methods

A 4-cm × 4-cm piece of mesh was implanted on intact peritoneum in New Zealand white rabbits. The mesh types included expanded polytetrafluoroethylene (ePTFE) (DualMesh^®), ePTFE and polypropylene (Composix^®, heavyweight polypropylene), polypropylene and oxidized regenerated cellulose (Proceed^®, midweight polypropylene), and polypropylene (Marlex^®, heavyweight polypropylene). At four months, standard hematoxylin and eosin and Milligan’s trichrome stains of the mesh-tissue interaction were analyzed by three observers blinded to the mesh types. Each specimen was evaluated for scar plate formation, inflammatory response, and tissue ingrowth. Each of these three categories was graded on a standard scale of 1–4 (1 = normal tissue and 4 = severe inflammatory response). The scores were analyzed using Wilcoxon rank sum test with p < 0.05 as significant.

Results

Ten samples of each mesh type were evaluated. There was no difference in tissue incorporation between the groups. The mean scar plate formation was greater in the heavyweight polypropylene meshes than for DualMesh (p = 0.04). With Proceed, the reduction in scar plate formation compared with that for Composix and Marlex approached statistical significance (p = 0.07). The mean number of inflammatory cells was greater around the ePTFE when compared with the midweight polypropylene (p = 0.02) but equal to the other meshes.

Conclusions

The four prosthetic materials evaluated in this study demonstrate comparable host biocompatibility as evidenced by the tissue ingrowth. Scar plate formation around DualMesh was significantly less than that around Composix and Marlex. Interestingly, more inflammatory cells were noted surrounding the DualMesh which was equal to that of the heavyweight meshes. Proceed, a midweight polypropylene mesh, has the potential for improved patient tolerance compared to heavyweight polypropylene meshes based on its favorable histologic findings.     

A lightweight,partially absorbable mesh (Ultrapro) for endoscopic hernia repair: experimental biocompatibility results obtained with a porcine model

Background A meticulous surgical technique, a mesh of adequate dimensions, and use of a mesh with good biocompatibility properties are decisively important for minimizing the development of recurrences after endoscopic hernia repair surgery. Mesh “shrinkage” is a function of the mesh’s biocompatibility, that is, the properties of the mesh. Large-pore, lightweight polypropylene meshes possess the best biocompatibility, and the newly developed meshes meet these requirements. Methods Using a totally extraperitoneal technique in an experimental animal model, 10 domestic pigs were implanted with a lightweight, large-pore polypropylene mesh containing an absorbable component consisting of poliglecaprone (Ultrapro). After a period of 91 days, diagnostic laparoscopy followed by explantation of the specimens for macroscopic, histologic, and immunohistochemical evaluation was performed. Results The mean mesh shrinkage was a mere 1.9%. The partial volume of the inflammatory cells was a low 15.8%. The markers of cell turnover, namely Ki67 and the apoptosis index, were, at 5.8 and 2.1, respectively, also very low. The extracellular matrix showed a low value of transforming growth factor-beta (TGF-beta) (50.8). The mean value of collagen 1 was 136.9. Conclusions As a result of its good biocompatibility and elastic properties, the lightweight, large-pore Ultrapo mesh showed only a very slight tendency to “shrink.” This renders it extremely well suited for clinical use in hernia repair surgery, and its minimal shrinkage characteristic should help in achieving low complication and recurrence rates.     

Shrinking of polypropylene mesh in vivo: an experimental study in dogs.

OBJECTIVE: To assess the extent of shrinkage of meshes used for hernia repair. DESIGN: Experimental study in dogs. SETTING: University hospital, Germany and University Research Centre, Moscow. ANIMALS: 10 dogs had monofilament polypropylene meshes that weighed 95 g/m2 (Marlex) or multifilament reduced polypropylene meshes combined with polyglactin 910 that weighed 55 g/m2 (Soft Hernia Mesh) implanted for either 3 or 6 months. MAIN OUTCOME MEASURES: Histological appearance and radiological assessment of the position and area of the mesh. RESULTS: After 4 weeks the area of mesh in the monofilament group was reduced from to 139 (11) to 75 (8) cm2 (54%) and that of the multifilament from 116 (18) to 77 (20) cm2 (66%). The multifilament mesh with the reduced amount of polypropylene showed less inflammatory response and less shrinkage. The mesh did not seem to have moved. CONCLUSION: Meshes that contain a lot of polypropylene shrink to about 30%-50% of their original size after 4 weeks, requiring an overlap of at least 3 cm if implanted subfascially. Reduction in the polypropylene content decreases both the inflammatory response and the shrinkage. Meshes with big pores are less likely to fold and improve compatibility.     

Minimal adhesions to ePTFE mesh after laparoscopic ventral incisional hernia repair: reoperative findings in 65 cases.

OBJECTIVES: Laparoscopic ventral incisional hernia repair involves intraabdominal placement of a synthetic mesh, and the possibility of formation of severe visceral adhesions to the prosthesis is a principal concern. Little clinical information based on reoperative findings is available about adhesions to biomaterials placed intraabdominally. We conducted a multiinstitutional study of adhesions to implanted expanded polytetrafluoroethylene (ePTFE) mesh at reoperation in patients who had previously undergone laparoscopic incisional hernia repair done with the same mesh implantation technique. METHODS: Nine surgeons retrospectively assessed the severity of adhesions to ePTFE mesh at reoperation in 65 patients. For each case, adhesions were assigned a score of 0 to 3, with 0 indicating no adhesions and 3 severe adhesions. RESULTS: The mean time from mesh implantation to reoperation was 420 days (range, 2 to 1739 days). No adhesions were observed in 15 cases. Forty-four cases received an adhesion score of 1, and 6 cases a score of 2; no scores of 3 were assigned. Thus, 59 patients (91%) had either no or filmy, avascular adhesions. No enterotomies occurred during adhesiolysis. CONCLUSIONS: In this large series of reoperations after laparoscopic incisional hernia repair, no or minimal formation of adhesions to implanted ePTFE mesh was observed in 91% of cases, and no severe cohesive adhesions were found. Comparative analyses of newer materials based on clinical reoperative findings are warranted to assess the safety of intraabdominally placed meshes.     

Minimal adhesions to ePTFE mesh after laparoscopic ventral incisional hernia repair: reoperative findings in 65 cases

BACKGROUND AND OBJECTIVES: Laparoscopic ventral incisional hernia repair involves intraabdominal placement of a synthetic mesh, and the possibility of formation of severe visceral adhesions to the prosthesis is a principal concern. Little clinical information based on reoperative findings is available about adhesions to biomaterials placed intraabdominally. We conducted a multi-institutional study of adhesions to implanted expanded polytetrafluoroethylene (ePTFE) mesh at reoperation in patients who had previously undergone laparoscopic incisional hernia repair done with the same mesh implantation technique. METHODS: Nine surgeons retrospectively assessed the severity of adhesions to ePTFE mesh at reoperation in 65 patients. For each case, adhesions were assigned a score of 0 to 3, with 0 indicating no adhesions and 3 severe adhesions. RESULTS: The mean time from mesh implantation to reoperation was 420 days (range, 2-1 739 days). No adhesions were observed in 15 cases. Forty-four cases received an adhesion score of 1, and 6 cases a score of 2; no scores of 3 were assigned. Thus, 59 patients (91 %) had either no or filmy, avascular adhesions. No enterotomies occurred during adhesiolysis. CONCLUSIONS: In this large series of reoperations after laparoscopic incisional hernia repair, no or minimal formation of adhesions to implanted ePTFE mesh was observed in 91 % of cases, and no severe cohesive adhesions were found. Comparative analyses of newer materials based on clinical reoperative findings are warranted to assess the safety of intraabdominally placed meshes.     

Does the additional application of a polylactide film (SurgiWrap) to a lightweight mesh (TiMesh) reduce adhesions after laparoscopic intraperitoneal implantation procedures? Experimental results obtained with the laparoscopic porcine model

Background  Intraperitoneal repair of incisional hernias using a mesh makes particular demands on the material used. In addition to good integration of the mesh on the parietal side, adhesions to the visceral peritoneum must be avoided. Large-pore, light-weight meshes induce fewer adhesions than heavy-weight polypropylene meshes. Although numerous adhesion-barrier substances for use in combination with a polypropylene mesh have been tested already, mostly in open small animal models, unequivocal benefits have been identified to date in only a few of the experiments. Methods  Using the laparoscopic intraperitoneal onlay mesh technique, six pigs were implanted with either a lightweight polypropylene mesh (TiMesh light) or TiMesh plus an adhesion-barrier film made of polylactide (SurgiWrap). After 3 months, the animals underwent a postmortem laparoscopy, and specimens were obtained for planimetric and histologic investigations. Results  No adhesions to intestinal structures were found in any of the animals. Adhesions between the greater omentum and the mesh did not differ significantly between the TiMesh (32%) and SurgiWrap (33.5%) groups. The shrinkage of the mesh’s surface area was comparable between the two groups (18% vs. 21%). Histology showed pronounced inflammatory reaction and bridging of scar tissue between the filaments with the use of SurgiWrap versus TiMesh light without film. However, immunohistochemical investigations examining the partial volume of the inflammatory cells, the proliferation marker Ki67, and the apoptotic index at the interface of the filaments all failed to show any significant differences. Conclusion  To avoid adhesions, it is essential that the acute and chronic inflammatory reaction to the implanted material be as small as possible. This requirement is met specifically by the lightweight polypropylene mesh TiMesh light. The additional application of a slowly absorbable adhesion-barrier film made of polylactide (SurgiWrap) does not appear to confer any further benefit.     

Deep prosthesis infection in incisional hernia repair: predictive factors and clinical outcome.

OBJECTIVE: To evaluate the incidence of prosthetic infection in incisional hernia repairs, to determine whether there are any factors associated with prosthetic infection and to describe the clinical outcome. DESIGN: Retrospective clinical study. SETTING: Teaching hospital, Germany. SUBJECTS: 121 consecutive patients who underwent incisional hernia repair in our department from December 1994 to December 1999. INTERVENTION: Hernia repair by implantation of an alloplastic prosthesis by the Stoppa-Rives technique. MAIN OUTCOME MEASURES: Postoperative deep prosthetic infection and associated factors. RESULTS: All 121 patients had the mesh implanted in the subfascial plane, 77 had a polypropylene mesh (Prolene) (64%), 7 had a polyester mesh (Mersilene) (6%), and 37 patients had a expanded polytetrafluoroethylene patch (ePTFE, Gore-Tex) (31%). Postoperatively the mesh became infected in 8 patients (7%), a mean of 4.5 months (range 0.5-16) after hernia repair. All three infected ePTFE patches had to be removed whereas drainage was sufficient treatment for the infected polypropylene and polyester meshes. CONCLUSION: Once a mesh infection is verified adequate drainage seems to be sufficient for polypropylene and polyester meshes but ePTFE patches should be removed.     

Laparoscopic parastomal hernia repair using a nonslit mesh technique

Background The management of parastomal hernia is associated with high morbidity and recurrence rates (20–70%). This study investigated a novel laparoscopic approach and evaluated its outcomes. Methods A consecutive multi-institutional series of patients undergoing parastomal hernia repair between 2001 and 2005 were analyzed retrospectively. Laparoscopy was used with modification of the open Sugarbaker technique. A nonslit expanded polytetrafluoroethylene (ePTFE) mesh was placed to provide 5-cm overlay coverage of the stoma and defect. Transfascial sutures secured the mesh, allowing the stoma to exit from the lateral edge. Five advanced laparoscopic surgeons performed all the procedures. The primary outcome measure was hernia recurrence. Results A total of 25 patients with a mean age of 60 years and a body mass index of 29 kg/m² underwent surgery. Six of these patients had undergone previous mesh stoma revisions. The mean size of the hernia defect was 64 cm², and the mean size of the mesh was 365 cm². There were no conversions to open surgery. The overall postoperative morbidity was 23%, and the mean hospital length of stay was 3.3 days. One patient died of pulmonary complications; one patient had a trocar-site infection; and one patient had a mesh infection requiring mesh removal. During a median follow-up period of 19 months (range, 2–38 months), 4% (1/25) of the patients experienced recurrence. Conclusion On the basis of this large case series, the laparoscopic nonslit mesh technique for the repair of parastomal hernias seems to be a promising approach for the reduction of hernia recurrence in experienced hands. Presented at the Plenary Session of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) 2006 Annual Meeting, Dallas, Texas, April 2006