Elastic TPU Mesh as Abdominal Wall Inlay Significantly Reduces Defect Size in a Minipig Model

ABSTRACT

Background: The open abdomen with mesh implantation, followed by early reoperation with fascial closure, is a modern surgical approach in difficult clinical situations such as severe abdominal sepsis. As early fascial closure is not possible in many cases, mesh-mediated fascial traction is helpful for conditioning of a minimized ventral hernia after open abdomen. The aim of this study was to evaluate the clinical utilization of an innovative elastic thermoplastic polyurethane mesh (TPU) as an abdominal wall inlay in a minipig model. Methods: Ten minipigs were divided in two groups, either receiving an elastic TPU mesh or a nonelastic polyvinylidene fluoride (PVDF) mesh in inlay position of the abdominal wall. After 8 weeks, mesh expansion and abdominal wall defect size were measured. Finally, pigs were euthanized and abdominal walls were explanted for histological and immunohistochemical assessment. Results: Eight weeks after abdominal wall replacement, transversal diameter of the fascial defect in the TPU group was significantly smaller than in the PVDF group (4.5 cm vs. 7.4 cm; p = 0.047). Immunhistochemical analysis showed increased Ki67 positive cells (p = 0.003) and a higher number of apoptotic cells (p = 0.047) after abdominal wall replacement with a TPU mesh. Collagen type I/III ratio was increased in the PVDF group (p = 0.011). Conclusion: Implantation of an elastic TPU mesh as abdominal wall inlay is a promising approach to reduce the size of the ventral hernia after open abdomen by mesh-mediated traction. However, this effect was associated with a slightly increased foreign body reaction in comparison to the nonelastic PVDF.     

Polyvinylidene fluoride: a suitable mesh material for laparoscopic incisional and parastomal hernia repair!

Background

Today, the laparoscopic approach is a standard procedure for the repair of incisional hernias. However, the direct contact of visceral organs with mesh material is a major issue.

Patients and methods

This prospective observational study presents the data of 344 patients treated for incisional and parastomal hernias with a new mesh made of polyvinylidene fluoride (PVDF; Dynamesh IPOM^®) between May 2004 and January 2008 with a minimum follow-up of 6 months. The median follow-up of 297 patients after incisional hernias totaled 24 months and 20 months for 47 patients with parastomal hernias. Incisional hernias were repaired using an IPOM technique. For parastomal hernias, a recently described sandwich technique was used with two meshes implanted in an intraperitoneal onlay position.

Results

The recurrence rate for incisional hernias was 2/297 = 0.6% and 1/47 = 2% for parastomal hernias. Three patients developed a secondary infection after surgical revision or puncture of a seroma. One patient had a bowel fistula through the mesh, with an abscess in the hernia sac. In all cases, the infection healed and the mesh could be preserved. No long-term mesh-related complications have been observed.

Conclusion

The laparoscopic repair of incisional and parastomal hernias with meshes made of PVDF (Dynamesh IPOM^®) revealed low recurrence and, overall, low complication rates. Especially in cases of infection, the material proved to be resistant without clinical signs of persistent bacterial contamination. Mesh-related complications did not occur during the follow-up.     

Comparison of Long-Term Biocompability of PVDF and PP Meshes

ABSTRACT

Background: Abdominal hernia repair is the most frequently performed operation in surgery. Mesh repair in hernia surgery has become an integral component. Although meshes made of PVDF are already in clinical use, so far no data of long-term biocompability are available. Methods: In this study a PVDF mesh was compared to a polypropylene mesh with regard to its long-term biocompatibility. A total of 28 rats were randomized to two groups. Mesh material was implanted subcutaneously; animals were euthanized seven days and six months postoperatively. The quantity of inflammatory tissue response was characterized by measuring the diameter of the foreign body granuloma. Furthermore quality of cellular immune response (T-lymphocytes, macrophages, and neutrophils), and inflammation (COX-2) was analyzed by immunohistochemistry. Furthermore the collagen type I/III ratio was determined. Results: Macrophages, T-lymphocytes, neutrophiles, and COX-2 declined significantly up to six months postoperatively in comparison to day 7 for both PVDF and PP meshes, and in both groups the collagen ratio increased significantly in the course of time. PVDF meshes showed a foreign body granuloma size significantly reduced compared to PP (7 days: 20 ± 2 μm vs. 27 ± 2 μm; 6 months 15 ± 2 μm vs. 22 ± 3 μm; p < .001). However no significant differences were found analyzing cellular response six months postoperatively. Conclusions: Our current data suggest that even in the long-term course after six months and despite a higher effective surface of the PVDF samples it showed a smaller foreign body granuloma than with PP whereas the cellular response was similar.     

Parastomal hernia repair with a 3-D mesh device and additional flat mesh repair of the abdominal wall

Purpose

Parastomal hernias (PSHs) have been a major clinical problem. The aim of this study was to evaluate a new method of PSH repair in combination with an additional flat mesh reinforcement of the abdominal wall.

Methods

In a pilot case series, seven patients suffering from complex PSHs (≥5 cm diameter and/or recurrence) underwent surgery and were treated by intraperitoneal onlay technique (IPOM) with a synthetic 3-D funnel-shaped mesh implant. The demographics, perioperative, and follow-up data are presented in this report.

Results

The surgical strategy varied between purely laparoscopic (n = 1), laparoscopically assisted (hybrid n = 3), or open techniques (n = 3) using original or suture-reconstructed mesh devices. The funnel mesh implantations in IPOM technique were combined with attached flat meshes in the appropriate position of the abdominal wall. No procedure-related complications occurred. The mean length of hospital stay was 12 days and the mean operating time was 171 min. No recurrence of PSH or incisional hernias was observed during a mean follow-up period of 12.3 months (range from 7 to 22).

Conclusion

The use of a 3-D mesh implant has so far shown to be a promising option in the treatment of primary and recurrent PSHs. Its use proved to be reasonable in both laparoscopic and open IPOM technique. PSHs were preferably repaired using the original, unmodified implant, but when we also found it safe to incise, place and then suture the mesh around the pre-existing ostomy.     

Mesh contraction: in vivo documentation of changes in apparent surface area utilizing meshes visible on magnetic resonance imaging in the rabbit abdominal wall model

Introduction and hypothesis

Our aim was to analyze the apparent contraction of meshes in vivo after abdominal wall reconstruction and evaluate histological and biomechanical properties after explantation.

Methods

Nine New Zealand female rabbits underwent repair of two full-thickness 25 × 30-mm midline defects in the upper and lower parts of the abdomen. These were primarily overlaid by 35 × 40-mm implants of a polyvinylidene fluoride (PVDF) DynaMesh (n?=?6) or polypropylene meshes Ultrapro (n?=?6) and Marlex (n?=?6). Edges of the meshes were secured with iron(II,III) oxide (Fe₃O₄)-loaded PVDF sutures. Magnetic resonance images (MRIs) were taken at days 2, 30 and 90 after implantation. The perimeter of the mesh was traced using a 3D spline curve. The apparent surface area or the area within the PVDF sutures was compared with the initial size using the one-sample t test. A two-way repeat analysis of variance (ANOVA) was used to compare the apparent surface area over time and between groups.

Results

PVDF meshes and sutures with Fe₃O₄ could be well visualized on MRI. DynaMesh and Marlex each had a 17 % decrease in apparent surface area by day 2 (p?<?0.001 and p?=?0.001), respectively, which persisted after day 90. Whereas there was a decrease in apparent surface area in Ultrapro, it did not reach significance until day 90 (p?=?0.01). Overall, the apparent surface area decreased 21 % in all meshes by day 90. No differences in histological or biomechanical properties were observed at day 90.

Conclusions

There was a reduction in the apparent surface area between implantation and day 2, indicating that most mesh deformation occurs prior to tissue in-growth.     

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 20×20 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.     

What do we know about titanized polypropylene meshes? An evidence-based review of the literature

Purpose

Despite the vast selection of brands available, nearly all synthetic meshes for hernia surgery continue to use one or other of three basic materials: polypropylene, polyester and ePTFE. These are used in combination with each other or with a range of additional materials such as titanium, omega 3, monocryl, PVDF and hyaluronate. This systematic review of all experimental and clinical studies is aimed at investigating whether titanized meshes confer advantages over other synthetic meshes in hernia surgery.

Materials and methods

A search of the medical literature from 2002 to 2012, as indexed by Medline, was performed, using the PubMed search engine (http://www.pubmed.gov). The search terms were: hernia mesh, titanium coating, lightweight mesh, TiMesh, mesh complications. All papers were graded according to the Oxford hierarchy of evidence.

Results

Patients operated on with the Lichtenstein technique performed using the lightweight titanium-coated mesh have a shorter convalescence than those with the heavy-weight mesh Prolene. For inguinal hernias operated on with the TAPP technique and using a lightweight titanium-coated mesh in comparison to a heavy-weight Prolene mesh, the early postoperative convalescence seems to improve. Titanized meshes do exhibit a negative effect on sperm motility 1 year after a TEP operation, but not after 3 years. The laparoscopic IPOM technique with a titanium-coated polypropylene mesh was associated with less postoperative pain in the short term, lower analgesic consumption and a quicker return to everyday activities compared with the Parietex composite mesh.

Conclusion

In clinical studies, the titanium-coated polypropylene mesh shows in inguinal hernia repair certain benefits compared with the use of older heavy-weight meshes.     

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.     

Comparative analysis of histopathologic responses to implanted porcine biologic meshes

Objectives

Biologic mesh (BM) prostheses are increasingly utilized for hernia repairs. Modern BMs are not only derived from different tissue sources, but also undergo various proprietary processing steps—factors that likely impact host tissue responses and mesh performance. We aimed to compare histopathologic responses to various BMs after implantation in a mouse model.

Materials and methods

Five-mm samples of non-crosslinked [Strattice (ST)], and intentionally crosslinked [CollaMend (CM), Permacol (PC)] porcine-derived biologic meshes were implanted subcutaneously in C57BL/6 mice. 1, 4, 8, and 12 weeks post-implantation, meshes were assessed for inflammation, foreign body reaction (FBR), neocellularization, and collagen deposition using H&E and trichrome stains.

Results

All meshes induced early polymorphonuclear cell infiltration (highest in CM; lowest in ST) that resolved by 4 weeks. ST was associated with extensive macrophage presence at 12 weeks. Foreign body response was not seen in the ST group, but was present abundantly in the CM and PC groups, highest at 8 weeks. New peripheral collagen deposition was seen only in the ST group at 12 weeks. Collagen organization was highest in the ST group as well. Both CM and PC groups were associated with fibrous encapsulation and no evidence of integration or remodeling.

Conclusions

Inflammation appears to be a common component of integration of all biologic meshes studied. Pronounced inflammatory responses as well as profound FBR likely lead to observed encapsulation and poor host integration of the crosslinked BMs. Overall, ST was associated with the lowest foreign body response and the highest degree of new collagen deposition and organization. These features may be key predictors for improved mesh performance during hernia repair.     

Transgastric placement of biologic mesh to the anterior abdominal wall

Background

Incisional hernia repairs have a risk of wound complications that may be decreased using a natural orifice transluminal endoscopic surgery (NOTES) approach. The aim of this study was to determine the feasibility and safety of transgastric mesh placement to the anterior abdominal wall in a porcine model as a precursor to future studies of NOTES ventral hernia repair.

Methods

The procedure was done under sterile conditions with a double lumen endoscope using a plastic overtube. The endoscope was placed in the stomach preloaded with an overtube. Entrance of the endoscope and overtube into the peritoneal cavity was performed with the percutaneous endoscopic gastrostomy (PEG) technique. A 13 × 15 cm Surgisis^® Gold? mesh with four corner sutures was delivered through the overtube. Transfascial suture passer and endoscopic grasper were used to externalize the sutures and attach the mesh to the anterior abdominal wall. The gastrotomy was closed with a transabdominal gastropexy. The pigs were sacrificed at 2 weeks.

Results

Mesh placement was performed in five pigs. Operative time was 215 min (standard deviation, SD 99 min). The most difficult portion of the procedure involved manipulating the gastric overtube, likely exposing the mesh to bacteria in the stomach. Culture-positive abscesses were present at the mesh in 3/5 animals. The mesh appeared intact in 4/5 animals; one of the infected meshes had delamination of 50% of the mesh. Adhesions to the mesh surface varied from 2% to 100%. At 2 weeks, median mesh size was 116 cm² (range 96–166 cm²) and median contraction was 41% (range 15–51%). Histologic evaluations demonstrated marked inflammation and fibrosis progressing into the mesh material.

Conclusions

Totally endoscopic transgastric delivery and fixation of a biologic mesh to the anterior abdominal wall is feasible. Challenges remain in designing systems for mesh delivery that exclude gastric content. Once these problems can be surmounted NOTES ventral hernia repair may become an option in man.     

Laparoscopic intraperitoneal mesh fixation with fibrin sealant (Tisseel<Superscript>®</Superscript>) vs. titanium tacks: a randomised controlled experimental study in pigs

Background

The main reason for hospital stay after laparoscopic ventral hernia repair (LVHR) is probably pain, which also causes a lengthening of the patient’s time to assume normal daily activities and work. It is likely that titanium tacks may be the main contributing factor to early (and maybe chronic) pain after LVHR. Therefore, non-invasive and patient-friendly mesh fixation methods must be considered. The present study was designed to investigate the technical applicability, safety and effect of Tisseel^® for intraperitoneal mesh fixation.

Methods

Nine 40-kg Danish Landrace female pigs had two pieces of MotifMESH^® and two pieces of Proceed^® mesh fixed in the intraperitoneal position by a laparoscopic technique. The two pieces of the same mesh were fixed with fibrin glue (Tisseel) and titanium tacks, respectively. All pigs were euthanised on the 30th postoperative day and the mesh–tissue samples were tested for strength of ingrowth (peel test), adhesion formation, mesh shrinkage and examined for histological alterations.

Results

No meshes were displaced from their initial position at autopsy, but we observed two cases of mesh folding that could have resulted in hernia recurrence in real patients. There were no significant differences in the strength of ingrowth between different mesh types or fixation methods, measured as peel work per area of mesh (J/m²) and peak force per width of mesh (N_max/cm). The Proceed mesh shrank by 11% compared to 4% for the MotifMESH mesh (p =  0.002). There was no difference in the grade of adhesions (%) between fixation methods (p = 0.794) or different mesh types (p = 0.296). In the same fashion, there was no difference in the strength of adhesions (grades 0–4) between the two fixation methods or different mesh types (p>0.5, χ² test). There was no significant difference in the formation of fibrosis or inflammation between the different meshes or fixation methods. All samples showed significant foreign-body reaction with giant cells.

Conclusion

Our results suggest that the laparoscopic fixation of an intraperitoneal mesh with Tisseel is safe and technically feasible in a pig model. There is still no evidence that fibrin-sealing alone is appropriate for intraperitoneal mesh fixation in hernia repair, but the technique might become an alternative or supplement to mechanical mesh fixation. Until then, further experimental research in animal hernia models with larger meshes is needed, especially with a focus on mesh folding and displacement.

     

Long-lasting bioresorbable poly(lactic acid) (PLA<Subscript>94</Subscript>) mesh: a new approach for soft tissue reinforcement based on an experimental pilot study

The purpose of this study was to evaluate host response and soft-tissue regeneration after poly(lactic acid) (PLA) mesh implantation in a rat model, in comparison with light-weight polypropylene (PPL) and poly(glycolic acid) (PGA) meshes. Full-thickeness abdominal wall defects were created in 45 Wistar rats and reconstructed with 15 PLA₉₄, 15 PPL and 15 PGA meshes. Animals were killed on days 7, 30 and 90 to evaluate the presence of adhesions and changes in tensile strength of the implants. Histolopathology and immunohistochemistry were performed to evaluate the collagen deposition and the inflammatory response. Statistics were done using unpaired Student’s t-test, Mann–Whitney rank sum test, Student–Newman–Keuls test and Bonferroni (Dunn) t-test. The inflammatory response induced by the PLA mesh implantation was significantly milder than after PPL mesh. In PLA, vascularity and collagen organization was significantly higher than in PPL and PGA at 30 and 90 days, and collagen composition score was significantly higher than in PPL at 7 and 30 days. In PLA, shrinkage was significantly lower than in PPL and PGA at 7 and 30 days. Elongation at break and tensile strength were comparable between PLA and PPL over the 90-day period. The PLA mesh induces a milder inflammatory response, more orderly collagen deposition than PPL, and preserved comparable tensile strength after 90 days.     

Novel technique of overlaying a poly-l-lactic acid nanosheet for adhesion prophylaxis and fixation of intraperitoneal onlay polypropylene mesh in a rabbit model

Background

One problem with polypropylene mesh (PPM) used to repair abdominal wall hernias is dense adhesions to the visceral surface. The authors developed the biocompatible poly-l-lactic acid (PLLA) nanosheet (thickness?Methods The PLLA nanosheet was fabricated by the spin-coating method and peeling technique with polyvinyl alcohol (PVA) as a supporting film. Two 1.5-cm-square pieces of mesh were implanted on each peritoneal side of the midline incision. The mesh was fixed to the peritoneum with a suture and then overlaid with a 4-cm-square piece of Seprafilm or nanosheet. To examine the fixative property, mesh was overlaid with Seprafilm or nanosheet without a fixed suture. After 4?weeks, mesh adhesion, inflammatory reaction, fixation, and dislocation of mesh were evaluated.

Results

Nanosheet-overlaid meshes were flexible and fit over the peritoneum. Adhesion was observed in 10% of the nanosheet-overlaid meshes and in 50% of the Seprafilm-overlaid meshes. The adhesion tenacity grade was significantly lower with the nanosheet-overlaid meshes (0.1?±?0.1) than with the Seprafilm-overlaid meshes (1.0?±?0.4) (p?=?0.029), and the percentage of the adhesion area also was lower with the nanosheet-overlaid meshes (1.0?±?1.0% vs 8.5?±?3.2%; p?=?0.037). The mean inflammatory cell counts were lower with the nanosheet-overlaid meshes (p?=?0.0023). Regarding the fixative property, 37.5% of the nanosheet-overlaid meshes were fixated on the peritoneum, but no Seprafilm-overlaid mesh was fixated.

Conclusion

Overlaying of a PLLA nanosheet was effective for adhesion prophylaxis of intraperitoneal mesh. It also may have a possible beneficial effect on fixation of mesh.     

Hernienchirurgie: Wachstumsverhalten humaner Fibroblasten auf alloplastischen Kunststoffnetzen

Background

The biocompatibility of meshes in hernia surgery seems to be influenced markedly by the amount of the selected material and its structure. Fibroblasts play a major key role during the process of mesh incorporation. This study was performed to investigate differences in cell morphology and proliferation of human fibroblasts cultured on different polypropylene meshes.

Methods

In the present in vitro study the cellular response of human fibroblasts was investigated by scanning electron microscopy (SEM), comparing three different polypropylene meshes: a newly constructed low-weight and microporous mesh (NK1), a low-weight and macroporous mesh with absorbable polyglactin filaments (Vypro), and a heavy-weight and microporous mesh (BiomeshP1). Human fibroblasts (1,5·10⁵ cells) were incubated with the meshes (each 12 mm²) for 6 hours, 5 days, 2, 4, 6, and 12 weeks. Computer-assisted morphometry of the fibroblast/mesh surface ratio served to reflect the biological cell response.

Results

The Vypro mesh showed the significantly highest fibroblast density during the first 6 weeks, but cell growth was nearly exclusively limited to the polyglactin filaments. At 3 months, after reabsorption of the polyglactin, the fibroblast-coated polypropylene mesh surface was only 50% compared to NK1 and BiomeshP1. The morphologic aspect of the fibroblasts on the BiomeshP1 mesh was much more degenerative and unphysiological, compared to NK1 and Vypro, with isolated, single cells instead of a broad, connective growth. The BiomeshP1 showed a significantly higher fibroblast proliferation around the nodes of the mesh compared to the straight filaments. On the NK1 mesh fibroblasts exclusively proliferated on the filaments but not on the pressed mesh surface.

Conclusions

The polymer surface and structure appears to be of major importance for the biocompatibility of meshes: human fibroblasts preferably grow on low-weight meshes, thin filaments, and mesh nodes. Heavy-weight meshes induce degenerative cell reactions. Polyglactin seems to further improve cell proliferation whereas a pressed mesh surface without pores hinders fibroblast growth.     

A propensity-score matched analysis of ventral-TAPP vs. laparoscopic IPOM for small and mid-sized ventral hernias. Comparison of perioperative data,surgical outcome and cost-effectiveness

Purpose

Laparoscopic techniques have been used and refined in hernia surgery for several years. The aim of this study was to compare an established method such as laparoscopic intra-peritoneal onlay mesh repair (lap. IPOM) with ventral Transabdominal Preperitoneal Patch Plasty (ventral-TAPP) in abdominal wall hernia repair.

Methods

Patient-related data of 180 laparoscopic ventral hernia repairs between June 2014 and August 2020 were extracted from our prospectively maintained database. Of these patients, 34 underwent ventral-TAPP and 146 lap. IPOM. After excluding hernias with a defect size > 5 cm and obtaining balanced groups with propensity-score matching, a comparative analysis was performed in terms perioperative data, surgical outcomes and cost-effectiveness.

Results

Propensity-score matching suggested 27 patients in each of the two cohorts. The statistical evaluation showed that intake of opiates was significantly higher in the lap. IPOM group compared to ventral-TAPP patients (p = 0.001). The Visual Analogue Scale (VAS) score after lap. IPOM repair was significantly higher at movement (p = 0.008) and at rest (p = 0.023). Also, maximum subjective pain during hospital stay was significantly higher in the lap. IPOM group compared to ventral-TAPP patients (p = 0.004). No hernia recurrence was detected in either group. The material costs of ventral-TAPP procedure (34.37 ± 0.47 €) were significantly lower than those of the lap. IPOM group (742.57 ± 128.44 € p = 0.001). The mean operation time was 65.19 ± 26.43 min in the lap. IPOM group and 58.65 ± 18.43 min in the ventral-TAPP cohort. Additionally, the length of hospital stay in the lap. IPOM cohort was significantly longer (p = 0.043).

Conclusion

Ventral-TAPP procedures represent an alternative technique to lap. IPOM repair to reduce the risk of complications related to intra-peritoneal position of mesh and fixating devices. In addition, our study showed that postoperative pain level, material costs and hospital stay of the ventral-TAPP cohort are significantly lower compared to lap. IPOM patients.

     

Evaluation of a fully absorbable poly-4-hydroxybutyrate/absorbable barrier composite mesh in a porcine model of ventral hernia repair

Background

The objective of this study was to evaluate the mechanical and histological properties of a fully absorbable poly-4-hydroxybutyrate/absorbable barrier composite mesh (Phasix? ST) compared to partially absorbable (Ventralight? ST), fully absorbable (Phasix?), and biologically derived (Strattice?) meshes in a porcine model of ventral hernia repair.

Methods

Bilateral abdominal surgical defects were created in twenty-four Yucatan pigs, repaired with intraperitoneal (Phasix? ST, Ventralight? ST) or retromuscular (Phasix?, Strattice?) mesh, and evaluated at 12 and 24 weeks (n = 6 mesh/group/time point).

Results

Prior to implantation, Strattice? demonstrated significantly higher (p < 0.001) strength (636.6 ± 192.1 N) compared to Ventralight? ST (324.3 ± 37.1 N), Phasix? ST (206.9 ± 11.3 N), and Phasix? (200.6 ± 25.2 N). At 12 and 24 weeks, mesh/repair strength was significantly greater than NAW (p < 0.01 in all cases), and no significant changes in strength were observed for any meshes between 12 and 24 weeks (p > 0.05). Phasix? mesh/repair strength was significantly greater than Strattice? (p < 0.001) at 12 and 24 weeks, and Ventralight? ST mesh/repair strength was significantly greater than Phasix? ST mesh (p < 0.05) at 24 weeks. At 12 and 24 weeks, Phasix? ST and Ventralight? ST were associated with mild inflammation and minimal–mild fibrosis/neovascularization, with no significant differences between groups. At both time points, Phasix? was associated with minimal–mild inflammation/fibrosis and mild neovascularization. Strattice? was associated with minimal inflammation/fibrosis, with minimal neovascularization at 12 weeks, which increased to mild by 24 weeks. Strattice? exhibited significantly less neovascularization than Phasix? at 12 weeks and significantly greater inflammation at 24 weeks due to remodeling.

Conclusions

Phasix? ST demonstrated mechanical and histological properties comparable to partially absorbable (Ventralight? ST) and fully resorbable (Phasix?) meshes at 12 and 24 weeks in this model. Data also suggest that fully absorbable meshes with longer-term resorption profiles may provide improved mechanical and histological properties compared to biologically derived scaffolds.

     

Concomitant Bariatric Surgery with Laparoscopic Intra-peritoneal Onlay Mesh Repair for Recurrent Ventral Hernias in Morbidly Obese Patients: an Evolving Standard of Care

Background and Aims

Repair of recurrent ventral hernias (RVHs) has a high failure rate more so in the presence of obesity. The chronic increase in intra-abdominal pressure (IAP) associated with obesity might, in part, be an important implicating factor that needs to be addressed in these patients. Laparoscopic ventral hernia repair (LVHR) done with concomitant bariatric surgery in morbidly obese patients with RVHs may avoid multiple failures.We report our preliminary experience in treating RVHs in morbidly obese patients with laparoscopic intra-peritoneal onlay mesh (IPOM) repair and concomitant bariatric surgery.

Methods

A retrospective review of all patients with a RVH who underwent concomitant bariatric surgery and laparoscopic IPOM repair at our institution from 2009 to 2013 was performed. Demographic, operative, postoperative, and follow-up data were collected.

Results

There were 23 patients included in the study. The mean BMI was 43.24. Fifteen patients had a previous open mesh repair, and eight had a laparoscopic IPOM repair. The patients had a median of 2 previous repairs (range 1–5 repairs). A laparoscopic sleeve gastrectomy was performed in 22 patients, and a laparoscopic Roux-en-Y gastric bypass was performed in one. The mean operating time was 112 min (65–220 min). The mean hospital stay was 3.3 days (2–8 days). A seroma was noted in four patients. No mesh infection or recurrence was noted at a median follow-up of 3.3 years (9 months to 5.5 years).

Conclusion

Laparoscopic IPOM repair done with concomitant bariatric surgery in morbidly obese patients with RVHs seems promising with a low rate of early recurrence.

     

Magnetic Resonance–Visible Meshes for Laparoscopic Ventral Hernia Repair

Methods:Ten patients were surgically treated with intraperitoneally positioned superparamagnetic flat meshes. A magnetic resonance investigation with a qualified protocol was performed on postoperative day 1 and at 3 months postoperatively to assess mesh appearance and demarcation. The total magnetic resonance–visible mesh surface area of each implant was calculated and compared with the original physical mesh size to evaluate potential reduction of the functional mesh surfaces.Results:We were able to show a precise mesh demarcation, as well as accurate assessment of the surrounding tissue, in all 10 cases. We documented a significant decrease in the magnetic resonance–visualized total mesh surface area after release of the pneumoperitoneum compared with the original mesh size (mean, 190 cm² vs 225 cm²; mean reduction of mesh area, 35 cm²; P < .001). At 3 months postoperatively, a further reduction of the surface area due to significant mesh shrinkage could be observed (mean, 182 cm² vs 190 cm²; mean reduction of mesh area, 8 cm²; P < .001).Conclusion:The new method of combining magnetic resonance imaging and meshes that provide enhanced signal capacity through direct integration of iron particles into the polyvinylidene fluoride base material allows for detailed mesh depiction and quantification of structural changes. In addition to a significant early postoperative decrease in effective mesh surface area, a further considerable reduction in size occurred within 3 months after implantation.     

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.