Prevention of adhesions to polypropylene mesh

BACKGROUND: Polypropylene mesh used to repair abdominal wall hernias routinely induces dense adhesions if there is direct contact between the mesh and the viscera. Adhesions may lead later to difficult reoperation, intestinal obstruction, or enteric fistula. STUDY DESIGN: A 2.5-cm square defect was surgically created in the rat abdominal wall and replaced with: 1) polypropylene mesh, 2) Sepramesh (SM), or 3) SM plus Seprafilm. Each group included 20 animals. Adhesion area as a percent of the mesh surface was subjectively quantitated by means of laparoscopy and at sacrifice. Evaluations varied from 7 to 28 days after mesh placement. Tissues were harvested at intervals for scanning electron microscopy. RESULTS: Adhesions were complete by day 7, with no change in area thereafter. Adhesion-free mesh surfaces were found on scanning electron microscopy to be carpeted with mesothelial cells from day 5 on. Polypropylene mesh alone induced adhesions in all rats (20/20). The mean area involved was 92%. With SM, 9 of 20 were adhesion-free. The mean area was 15%. When Seprafilm was added to SM, minimal adhesions developed in 5 of 20 rats, the mean area being 2%. Four of the five were single point omental attachments. CONCLUSIONS: 1) Sepramesh alone reduces polypropylene mesh adhesions by roughly three-quarters. 2) Sepramesh plus Seprafilm nearly eliminates such visceral adhesions. 3) Mesothelial cell coverage of polypropylene mesh confers adhesion resistance.     

Seprafilm reduces adhesions to polypropylene mesh

BACKGROUND: Adhesions to polypropylene mesh used for abdominal wall hernia repair may eventuate in intestinal obstruction or enterocutaneous fistula. A Seprafilm Bioresorbable Membrane translucent adhesion barrier has been shown to inhibit adhesions. This investigation was designed to determine if Seprafilm alters abdominal visceral adhesions to polypropylene mesh. METHODS: A 2.5-cm square abdominal muscle peritoneal defect was created and corrected with polypropylene mesh. Mesh alone was used in 17 rats. In another 17, the Seprafilm membrane was applied between the viscera and the mesh. Five animals had the bioresorbable membrane placed in the subcutaneous space and between the mesh and the viscera. Laparoscopy was performed 7, 14, and 28 days later to evaluate adhesions as a percentage of mesh surface involved. RESULTS: Polypropylene mesh alone was associated with adhesions in every rat. The average area involved was 90%, the minimum was 75%. Adhesions were present within 24 hours and progressed up to 7 days with no change thereafter. When the Seprafilm barrier was used, the mean area involved was 50%. In 16 such rats, the area involved was smaller than any control animal. No adhesions formed in 5 animals. Scanning electron microscopy demonstrated a mesothelial cell layer covering the mesh after 4 weeks. CONCLUSIONS: The use of the Seprafilm adhesion barrier resulted in a significant reduction of adhesion formation to polypropylene mesh (P <.001).     

Peritoneal effects of prosthetic meshes used to repair abdominal wall defects: monitoring adhesions by sequential laparoscopy

BACKGROUND: The prosthetic materials currently used to repair abdominal wall defects sometimes have to be placed in contact with the visceral peritoneum. This interface is often a site of complications such as intestinal obstruction or fistulas due to adhesions. The aim of this study was to follow the process of adhesion formation in several prosthetic materials by sequential laparoscopy. MATERIAL AND METHODS: Defects (7 x 5 cm) were created in the abdominal wall of 30 New Zealand White rabbits and repaired using Surgipro polypropylene mesh (PP), Ultrapro monocryl-prolene mesh (UP), Dual Mesh expanded polytetrafluoroethylene (ePTFE), Composix (PP-ePTFE), Parietex Composite (polyester with collagen-polyethylene glycol-glycerol coating [PO-gl]), or PL-PU99 (PP-polyurethane) patches fixed to the edges of the defect by running polypropylene suture. Adhesions to the implants were laparoscopically determined at 3, 7, and 14 days after surgery. RESULTS: Percentage adhesion scores were significantly lower for ePTFE, PP-ePTFE, PO-gl, and PP-PU, compared to PP or UP. No differences were observed in adhesion scores recorded at 3, 7, and 14 days postimplant. Reticular prostheses were infiltrated by disorganized scar tissue with fibers concentric to the mesh filaments. In contrast, ePTFE implants were encapsulated by organized tissue, with fibers running parallel to the surface of biomaterial. All three composites achieved good recipient tissue integration and a homogeneous, organized, and well-vascularized neoperitoneum. CONCLUSION: At 14 days postimplant, laminar prostheses and composites showed similar results in terms of adhesion formation and integration within host tissue. Our findings suggest that both the composite prostheses and the laminar ePTFE performed very well in terms of reduced adhesion formation at the peritoneal interface.     

Trehalose solution protects mesothelium and reduces bowel adhesions

Background

Preventing interbowel adhesions still remains a challenge. Peritoneal mesothelial damage can induce postoperative adhesions. Our study evaluated the effects of 3% trehalose solution on mesothelial protection and adhesion prevention. Also, we compared this novel solution with Seprafilm regarding efficacy.

Methods

Mesothelial damage was induced on the cultured human mesothelial cell (Met-5A) and rabbit cecum-serosal surface by air-drying for 60 min, and trehalose solution was applied. Cell integrity was tested by measuring lactate dehydrogenase, and serosal-morphologic changes were analyzed using scanning electron microscopy. Intra-abdominal adhesions were induced in rabbits by the combination of abrasion and air-drying procedures. Animals were divided into four groups: control, 3% trehalose solution, Seprafilm, and 3% trehalose solution with Seprafilm. Adhesions were evaluated blindly 7 d later.

Results

Lactate dehydrogenase release from the Met-5A cells was reduced dose-dependently by trehalose (P < 0.05). Morphologic studies clearly showed that mesothelial cells on the serosal surface were kept intact by 3% trehalose solution. In a rabbit adhesion model, 3% trehalose solution reduced adhesions between bowel and bowel or bowel and surrounding structures (P < 0.01 versus control and Seprafilm). Seprafilm reduced adhesions between abdominal wall and underlying viscera (P < 0.01 versus control and 3% trehalose solution). Three-percent trehalose solution with Seprafilm showed additive effects of adhesion prevention, reducing adhesion formation at the previously mentioned sites.

Conclusions

Three-percent trehalose solution protects mesothelial cells and leads to reduced adhesions between bowel and bowel or bowel and surrounding structures. This effect seems to be resulted from the characteristics of the solution covering most areas that potentially develop adhesions.     

Mesh fixation devices and formation of intraperitoneal adhesions

Purpose: To investigate the effect of mesh fixation devices on the formation of intra-abdominal adhesions. Materials and Methods: Fourteen New Zealand rabbits were used. In seven animals, nickel-titanium (nitinol) anchors (group 1) and titanium tacks (group 2) were applied by laparoscopy on the right and left sides of the abdomen, respectively. In the remaining seven rabbits, the same devices were applied on prosthetic meshes (groups 3 and 4, respectively). On day 30, the rabbits were sacrificed and macroscopic adhesion scoring was performed. All the specimens were assessed by scanning electron microscopy (SEM). Results: All parameters of adhesion except extension were significantly higher in group 4 than group 3 (P < 0.05). Comparisons of group 1 vs. group 2 were not statistically significant (P > 0.05). All the comparisons between a nonmesh group and a mesh group resulted in significant differences. SEM results revealed that the mesothelial cell layer and connective tissue intensively covered the tacks in group 2 whereas no similar findings were observed in group 1. Comparable appearances were encountered in groups 3 and 4. Conclusion: The nitinol anchor is associated with an acceptable level of adhesion formation and its intraperitoneal use can be considered safe in this regard.     

Effective prevention of adhesions with hyaluronate

HYPOTHESIS: Hyaluronate sodium in the form of a bioresorbant membrane reduces the development of intra-abdominal adhesions frequently found after implantation of synthetic mesh in the context of surgical hernia repair. DESIGN: The effect of hyaluronate on the formation of adhesions was evaluated when applied laparoscopically as a bioresorbant membrane to protect the peritoneal surface of a synthetic mesh. SETTING: Experimental animal model. INTERVENTIONS: A peritoneal defect 5 cm in diameter was bilaterally created in the abdominal wall of each of 9 pigs by laparoscopy. A polypropylene mesh was fixed with clips onto these defects on both sides. In each of the animals, only on one side, the synthetic mesh was also covered by a hyaluronate membrane. MAIN OUTCOME MEASURES: The incidence and severity of adhesions (grade 0-4, where 0 indicates no adhesion; 1, filmy avascular adhesions; 2, vascular adhesions; 3, cordlike fibrous adhesions; and 4, plain fibrous adhesions) were determined after 45 days, comparing treated and untreated sides by autopsy results and histological features. RESULTS: Adhesions, mainly grades 3 and 4, occurred in 7 of the 9 animals in those meshes not covered by hyaluronate; 2 untreated animals did not develop adhesions. On the other hand, only 1 of the 9 animals developed adhesions (grade 2) at the mesh concealed by the hyaluronate membrane. CONCLUSIONS: The bioresorbant hyaluronate membrane significantly reduced the formation of peritoneal adhesions (1-sided sign test, P<.05) induced by the insertion of a polypropylene mesh, when compared with the contralateral implants not protected by hyaluronate. Thus, hyaluronate membranes are efficient for reducing the incidence of peritoneal adhesions.     

Assessment of adhesion formation to intra-abdominal polypropylene mesh and polytetrafluoroethylene mesh

BACKGROUND: The development of intra-abdominal adhesions, bowel obstruction, and enterocutaneous fistulas are potentially severe complications related to the intraperitoneal placement of prosthetic biomaterials. The purpose of this study was to determine the natural history of adhesion formation to polypropylene mesh and two types of polytetrafluoroethylene (ePTFE) mesh when placed intraperitoneally in a rabbit model that simulates laparoscopic ventral hernia repair. MATERIALS AND METHODS: Thirty New Zealand white rabbits were used for this study. A 10-cm midline incision was performed for intra-abdominal access and a 2 cm x 2 cm piece of mesh (n = 60) was sewn to an intact peritoneum on each side of the midline. Two types of ePTFE mesh (Dual Mesh and modified Dual Mesh, W.L. Gore & Assoc., Flagstaff, AZ) and polypropylene mesh were compared. The rate of adhesion formation was evaluated by direct visualization using microlaparoscopy (2-mm endoscope/trocar) at 7 days, 3 weeks, 9 weeks, and 16 weeks after mesh implantation. Adhesions to the prosthetic mesh were scored for extent (%) using the Modified Diamond Scale (0 = 0%, 1 50%). At necropsy the mesh was excised en bloc with the anterior abdominal wall for histological evaluation of mesothelial layer growth. RESULTS: The mean adhesion score for the polypropylene mesh was significantly greater (P < 0.05) than Dual Mesh at 9 weeks and 16 weeks and modified Dual Mesh at 7 days, 9 weeks, and 16 weeks. Fifty-five percent (n = 11) of the polypropylene mesh had adhesions to small intestine or omentum at necropsy compared to 30% (n = 6) of the Dual Mesh and 20% (n = 4) of the modified Dual Mesh. There was a significantly greater percentage (P < 0.003) of ePTFE mesh mesothelialized at explant (modified Dual Mesh 44.2%; Dual Mesh 55.8%) compared to the polypropylene mesh (12.9%). CONCLUSIONS: Serial microlaparoscopic evaluation of intraperitoneally implanted polypropylene mesh and ePTFE mesh in a rabbit model revealed a progression of adhesions to polypropylene mesh over a 16 week period. The pore size of mesh is critical in the development and maintenance of abdominal adhesions and tissue ingrowth. The macroporous polypropylene mesh promoted adhesion formation, while the microporous nature of the visceral side of the ePTFE served as a barrier to adhesions.     

Adhesions and adhesiolysis: the role of laparoscopy.

BACKGROUND: Adhesions commonly result from abdominal and pelvic surgical procedures and may result in intestinal obstruction, infertility, chronic pain, or complicate subsequent operations. Laparoscopy produces less peritoneal trauma than does conventional laparotomy and may result in decreased adhesion formation. We present a review of the available data on laparoscopy and adhesion formation, as well as laparoscopic adhesiolysis. We also review current adjuvant techniques that may be used by practicing laparoscopists to prevent adhesion formation. DATABASE: A Medline search using "adhesions," "adhesiolysis," and "laparoscopy" as key words was performed for English-language articles. Further references were obtained through cross-referencing the bibliography cited in each work. DISCUSSION: The majority of studies indicate that laparoscopy may reduce postoperative adhesion formation relative to laparotomy. However, laparoscopy by itself does not appear to eliminate adhesions completely. A variety of adjuvant materials are available to surgeons, and the most recent investigation has demonstrated significant potential for intraperitoneal barriers. Newer technologies continue to evolve and should result in clinically relevant reductions in adhesion formation.     

Effects of seprafilm on peritoneal fibrinolytic system

BACKGROUND: There is a high incidence of adhesions after ventral hernia repair with polypropylene mesh. The purpose of the present study was to evaluate the efficacy of Seprafilm in the prevention of adhesion formation and effect on peritoneal fibrinolytic activity. METHODS: An incisional hernia model was created in rats. In the experimental group Seprafilm was placed between polypropylene mesh and abdominal organs. On the 14th day adhesions were evaluated and tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), plasminogen activator inhibitor (PAI) type 1 and 2 were measured in peritoneal biopsy specimens. Results: Adhesions were significantly reduced in the Seprafilm group (P = 0.002). Nevertheless, there were no difference between the two groups in levels of tPA, PAI-1 and PAI-2. However, the levels of uPA were significantly decreased in the Seprafilm group. CONCLUSIONS: The adhesion preventive effect of Seprafilm is not directly related in peritoneal fibrinolytic activity. Instead, the physical properties (barrier, hydroflotation and sliconizing effect) of the membrane are primarily responsible for adhesion prevention.     

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.     

Preliminary assessment of postoperative adhesion formation after laser-assisted mesh fixation to the peritoneal surface

OBJECTIVE: This study evaluated the incidence and persistence of adhesions following intraperitoneal onlay mesh fixation with tissue soldering in an experimental model. METHODS: Anesthetized New Zealand white rabbits (n = 21), weighing 2.8-3.2 kg, underwent laparotomy. Controls (group 1 [n = 3]) had 2 x 2 cm Mersilene (Ethicon, Somerville, New Jersey) polyester mesh segments fixed to the peritoneum with staples (USSC, Norwalk, Connecticut). Group 2 (n = 7) rabbits had Mersilene mesh affixed by melting 55% collagen solder using a prototype laser (1.43 micro, 2.5 W CW, 4 mm spot size, 60 degrees C set temperature) over mesh. Group 3 (n = 6) rabbits had Vicryl (Ethicon, Somerville, New Jersey) polyglactin mesh embedded in 60% collagen solder placed onto the peritoneum and fixed with identical laser parameters as group 2. Group 4 (n = 5) rabbits had 55% collagen solder placed and Mersilene pressed into it after melting. Four segments were placed in each experimental animal. Animals were euthanized at 2, 4, or 6 weeks. Adhesions were graded (0 = none; I = filmy adhesions; II = omental; III = bowel adhesions gently lysed; IV = dense adhesions requiring sharp dissection). RESULTS: Grade III adhesions were observed in both control and group 4 animals at 2 weeks, persisting in group 4 animals at 6 weeks, but having lysed in controls at 6 weeks. No adhesions were present in group 3 specimens at any interval. Grade I adhesions were present in group 2 at 2 weeks at exposed mesh areas, and declined in frequency at 6 weeks. Evidence of reabsorption of the polyglactin mesh-solder composite was apparent in the group 3 specimens at 4 weeks, and complete resorption had occurred by 6 weeks postoperatively. DISCUSSION: Laser-assisted solder fixation caused minimal adhesion formation when mesh was covered by solder. Adhesions were observed if Mersilene mesh material was exposed to the abdominal contents. Vicryl mesh-solder composites reabsorbed without inflammation, scarring, or adhesions at the sites of mesh fixation. CONCLUSION: Further development of this technology is warranted.     

Bioabsorbable membrane prevents adhesions to polypropylene mesh in rats

Summary Most of mesh materials used in the repair of ventral hernias lead to considerable adhesion formation. In this study we evaluated the effects of a bioabsorbable membrane composed of carboxymethylcellulose and hyaluronic acid (HA membrane) on adhesion formation in the presence of a polypropylene mesh used to repair an incisional hernia model in rats. We repaired the defects either primarily or by polypropylene mesh. The abdominal surface of the repairs were then covered by a piece of HA membrane in randomly selected groups. The presence and grade of adhesions to the repair or mesh were recorded on the 8th day. Tissue specimens were analyzed for the extent of mesothelial and collagenous tissue growth and the degree of inflammation. Dense adhesions developed on all of the defects repaired by polypropylene mesh alone. The HA membrane decreased adhesions significantly when used as a supplement over the mesh (p < 0.01). Histopathologically, the HA membrane further retarded mesothelial growth over the mesh, and decreased vascular proliferation, inflammatory cell infiltration (p < 0.01) and collagen content of the wound (p < 0.05). In our rat model, the HA membrane prevented most of the adhesions that would be expected to occur on the mesh. It decreased the local infiltration of white cells and neovascularization. The HA membrane seemed to be a suitable physical barrier in rats against adhesion formation without compromising the wound healing. However, these findings need to be confirmed in humans.     

Adhesions after intraperitoneal mesh repair in pigs: Prolene" vs. Vypro"

BACKGROUND: Newly developed meshes with low weight and large pores such as Vypro (Ethicon, Norderstedt) were exactly adapted to the physiology of the human abdominal wall and proved to reduce chronic inflammatory processes. It was hypothesized that the reduced inflammatory response to a Vypro mesh would lead to reduced adhesion formation following intraperitoneal implantation in comparison with a Prolene mesh (Ethicon). MATERIALS AND METHODS: To test this hypothesis, 20 25-kg pigs underwent resection of a 10 x 10-cm section of the full-thickness anterior abdominal wall, excluding subcutaneous and cutaneous surface. The fascial defect was repaired using a 20 x 20-cm piece of either Vypro or Prolene mesh, which was sutured in inlay position with 4-0 Prolene single sutures at the edges. The main endpoint was the presence and degree of intra-abdominal adhesions to the mesh after 3 months. The amount of adhesions was calculated as a percentage of the mesh square and classified into four grades. RESULTS: There were no significant differences in the amount and grade of adhesions between the groups. Adhesions were less intensive in the Vypro group, but this difference was not significant. Dense adhesions between the liver and the mesh and small-bowel obstruction were observed only in the Prolene group. CONCLUSIONS: From the results of this study, Prolene and Vypro meshes cannot be recommended for intraperitoneal placement in hernia surgery because of their adhesion potential and risk of bowel obstruction.     

Prevention of adhesion to prosthetic mesh: comparison of different barriers using an incisional hernia model

OBJECTIVE: To assess whether use of antiadhesive liquids or coatings could prevent adhesion formation to prosthetic mesh. SUMMARY BACKGROUND DATA: Incisional hernia repair frequently involves the use of prosthetic mesh. However, concern exists about development of adhesions between viscera and the mesh, predisposing to intestinal obstruction or enterocutaneous fistulas. METHODS: In 91 rats, a defect in the muscular abdominal wall was created, and mesh was fixed intraperitoneally to cover the defect. Rats were divided in five groups: polypropylene mesh only (control group), addition of Sepracoat or Icodextrin solution to polypropylene mesh, Sepramesh (polypropylene mesh with Seprafilm coating), and Parietex composite mesh (polyester mesh with collagen coating). Seven and 30 days postoperatively, adhesions were assessed and wound healing was studied by microscopy. RESULTS: Intraperitoneal placement of polypropylene mesh was followed by bowel adhesions to the mesh in 50% of the cases. A mean of 74% of the mesh surface was covered by adhesions after 7 days, and 48% after 30 days. Administration of Sepracoat or Icodextrin solution had no influence on adhesion formation. Coated meshes (Sepramesh and Parietex composite mesh) had no bowel adhesions. Sepramesh was associated with a significant reduction of the mesh surface covered by adhesions after 7 and 30 days. Infection was more prevalent with Parietex composite mesh, with concurrent increased mesh surface covered by adhesions after 30 days (78%). CONCLUSIONS: Sepramesh significantly reduced mesh surface covered by adhesions and prevented bowel adhesion to the mesh. Parietex composite mesh prevented bowel adhesions as well but increased infection rates in the current model.     

Postimplantation host tissue response and biodegradation of biologic versus polymer meshes implanted in an intraperitoneal position

Background

This study compared the in vitro and in vivo behaviors at the peritoneal interface of a new polymer material (Bio-A) and of two biologic non-cross-linked materials (Tutomesh [Tuto] and Strattice [St]), all biodegradable.

Methods

Omentum mesothelial cells from rabbits were seeded onto the three prosthetic materials tested. At 1, 4, 8, 16, and 24 h after implantation, mesothelial cover was performed using a scanning electron microscope (SEM). In the in vivo study, 3 × 3 cm mesh fragments were placed on the parietal peritoneum of the same rabbits and fixed at the four corners with individual stitches. The implants were randomized such that six fragments of each material were implanted in nine animals (2 per animal). Adhesion formation was quantified by sequential laparoscopy and image analysis 3, 7, and 14 days after implantation. The animals were killed at 90 days, and the meshes were subjected to microscopy and immunohistochemistry.

Results

The in vitro mesothelial cover was significantly greater for St than for Bio-A at each time point. The percentage of cover for St was also higher than for Tuto 16 and 24 h after seeding and higher for Tuto than for Bio-A at all time points. Compared with the biologic meshes, significantly higher adhesion percentages were recorded for Bio-A. At 90 days after implantation, differences in absorption measured as percentage of reduction in mesh thickness were detected among all the meshes. The least absorbed was St. The neoperitoneum thickness was significantly greater for the biologic meshes than for the polymer mesh, although this variable also differed significantly between St and Tuto. Macrophage counts were higher for Bio-A than for the biologic meshes.

Conclusions

Greater mesothelial cover was observed in vitro for St. In vivo, adhesion formation and the macrophage response induced by Bio-A were greater than those elicited by the biologic materials. Bio-A and Tuto showed substantial biodegradation compared with St.     

Novel and simple method for isolating autologous mesothelial cells from the tunica vaginalis

OBJECTIVE: To report the development of a new method of isolating autologous mesothelial cells from the tunica vaginalis that are easily obtained and generally free from the effects of abdominal cancer, and to investigate whether transplanting these mesothelial cells is effective in preventing postoperative adhesions. MATERIALS AND METHODS: The tunica vaginalis was resected from male Lewis rats, and mesothelial cells were collected by enzymatic disaggregation. To investigate the efficacy of mesothelial cells in preventing adhesion, harvested cells were transplanted into a rat intestinal hernia adhesion model. RESULTS: Cells isolated from the tunica vaginalis were homogenous, polygonal when confluent, expressed cytokeratin and vimentin, and the cell surface was covered with microvilli, which is the characteristic appearance of endogenous mesothelial cells. The transplantation of autologous mesothelial cell sheets reduced peritoneal adhesion. CONCLUSION: We developed a new method of obtaining autologous mesothelial cells from the tunica vaginalis. These cells may provide a valuable option for treating patients at risk of postoperative adhesions.     

Efficiency of 4% icodextrin in preventing adhesions to spiral tacks used to fix intraperitoneal prostheses

BACKGROUND/AIMS: This study was designed to evaluate the extent of adhesion formation to prostheses fixed with spiral tacks and to establish whether the use of Ringer's lactate or icodextrin could prevent these adhesions. METHODS: 24 New Zealand white rabbits weighing around 3,000 g were implanted with a 7 x 5 cm patch of ePTFE (DualMesh) through a midline laparotomy. The prosthesis was fixed to the intact peritoneum using spiral tacks. Three study groups were established according to whether the animals were: implanted with ePTFE fixed with spiral tacks or implanted with ePTFE fixed with spiral tacks and simultaneously administered Ringer's lactate or 4% icodextrin in the peritoneal cavity. Adhesion formation and prosthetic behavior at the prosthesis/peritoneal interface were evaluated and quantified by sequential laparoscopy performed at 3, 7 and 14 days. RESULTS: Adhesions generally formed on the tacks and were classified as the fully integrated type. No significant differences were observed in terms of the extent of adhesions or of neoperitoneal thickness between control animals and those receiving Ringer's lactate or icodextrin. CONCLUSIONS: (a) Prosthesis-fixing tacks induced adhesions; (b) the use of substances such as icodextrin or Ringer's lactate does not seem to diminish adhesion formation, and (c) the use of icodextrin offered no benefits over that of Ringer's lactate solution.     

Application of Polycaprolactone as an Anti‐Adhesion Biomaterial Film

Adhesions are unavoidable consequences of surgery and other trauma. How to prevent the adhesions remains a big issue in healthcare system. The objective of this study is to test the efficacy of polycaprolactone (PCL) films as physical barriers in reducing postoperative intra‐abdominal adhesions in the rat cecum‐abdominal wall model. PCL is quite cheap compared with the agents recently used in the market. The fabrication method is also very easy to perform. Scanning electron microscope (SEM) showed multiple pores over upper and bottom surfaces but too small to permit cells to migrate from one surface onto another surface. Those pores were proven to be not interconnected. The PCL film did not show any evidence of cytotoxic effects as it did not induce any significant increase in cytoplasmic lactate dehydrogenase release from the NIH3T3 cells that it came in contact with. In animal studies, the PCL films led to fewer adhesions than Seprafilm in rat adhesion model. PCL films were efficacious in reducing postoperative intra‐abdominal adhesion formation in rat cecum‐abdominal wall models.     

Peritoneal regeneration induced by an acellular bovine pericardial patch in the repair of abdominal wall defects

BACKGROUND: This study was to evaluate the feasibility of using an acellular bovine pericardium fixed with genipin (AGP) to repair an abdominal wall defect created in a rat model. MATERIALS AND METHODS: The glutaraldehyde-fixed acellular pericardium (AGA), the genipin-fixed cellular pericardium (GP), and a commercially available polypropylene mesh were used as controls. RESULTS: Gross examination at 3-month post-operatively revealed that dense adhesions to the visceral organs were observed for the polypropylene mesh and the AGA patch, while a filmy to dense adhesion was seen for the GP patch. In contrast, no adhesion to the visceral organs was observed for the AGP patch. Histologically, inflammatory cells were found mainly surrounding the GP patch. In contrast, host cells (inflammatory cells, fibroblasts, and neo-capillaries) were able to infiltrate into the AGA and AGP patches. Unlike the AGA patch, the AGP patch retrieved at 1-month post-operatively became well integrated with the host tissue near the suture line. Additionally, there were some mesothelial cells, identified by the van Gieson stain, observed on the AGP patch. At 3-month post-operatively, a neo-peritoneum was observed on the AGP patch. The neo-peritoneum consisted of organized vascularized connective tissues covered by an intact layer of mesothelial cells. The calcium contents of the polypropylene mesh and the AGA patch increased significantly at 3-month post-operatively, while those of the GP and AGP patches stayed minimal throughout the entire course of the study. CONCLUSIONS: The results obtained in the study revealed that the AGP patch effectively repaired abdominal wall defects in rats and successfully prevented the formation of post-surgical abdominal adhesions.