Tenacity Of Adhesions Research Articles

META Score: An International Consensus Scoring System on Mesh-Tissue Adhesions.

Currently, the lack of consensus on postoperative mesh-tissue adhesion scoring leads to incomparable scientific results. The aim of this study was to develop an adhesion score recognized by experts in the field of hernia surgery. Authors of three or more previously published articles on both mesh-tissue adhesion scores and postoperative adhesions were marked as experts. They were queried on seven items using a modified Delphi method. The items concerned the utility of adhesion scoring models, the appropriateness of macroscopic and microscopic variables, the range and use of composite scores or subscores, adhesion-related complications and follow-up length. This study comprised two questionnaire-based rounds and one consensus meeting. The first round was completed by 23 experts (82%), the second round by 18 experts (64%). Of those 18 experts, ten were able to participate in the final consensus meeting and all approved the final proposal. From a total of 158 items, consensus was reached on 90 items. The amount of mesh surface covered with adhesions, tenacity and thickness of adhesions and organ involvement was concluded to be a minimal set of variables to be communicated separately in each future study on mesh adhesions. The MEsh Tissue Adhesion scoring system is the first consensus-based scoring system with a wide backing of renowned experts and can be used to assess mesh-related adhesions. By including this minimal set of variables in future research interstudy comparability and objectivity can be increased and eventually linked to clinically relevant outcomes.

Zwitterionic amino acid-based Poly(ester urea)s suppress adhesion formation in a rat intra-abdominal cecal abrasion model

Hernia repair outcomes have improved with more robust material options for surgeons and optimized surgical techniques. However, ventral hernia repairs remain challenging with an inherent risk of post-surgical adhesions in the peritoneal space which can occur regardless of interventional material or its surgical placement. Herein, amino acid-based poly(ester urea)s (PEUs) with varied amount of an allyl ether side chains were modified post polymerization modification with the zwitterionic sulfnate group (3-((3-((3-mercaptopropanoyl)oxy)propyl) dimethylammonio)propane-1-sulfonate) to promote anti-adhesive properties. These alloc-PEUs were processed using roll-to-roll fabrication methods to afford films that were amenable to surface functionalization via a zwitterion-thiol. Functional group availability on the surface was confirmed via fluorescence microscopy, x-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance (QCM) measurements. Zwitterionic treated PEUs exhibited reduced fibrinogen adsorption in vitro when compared to unfunctionalized control polymer. A rat intrabdominal cecal abrasion adhesion model was used to assess the extent and tenacity of adhesion formation in the presence of the PEUs. The 10% alloc-PEU zwitterion functionalized material was found to reduce the extent and tenacity of adhesions when compared to adhesion controls and the unfunctionalized PEU controls.

EW-7197, an oral transforming growth factor β type I receptor kinase inhibitor, for preventing peritoneal adhesion formation in a rat model

BackgroundEW-7197 is an oral transforming growth factor β type I receptor kinase inhibitor currently undergoing phase I clinical trials for cancer treatment in the United States. This study evaluates whether EW-7197 prevents peritoneal adhesion formation in a rat model. MethodsForty-eight female Wistar rats underwent peritoneal adhesion induction by the creation of peritoneal ischemic buttons and were randomly divided into 4 groups of 12 each. The control group received 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction. The 10 mg and 20 mg groups received 10 or 20 mg/kg EW-7197 phosphate dissolved in 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction. The rebound group received 20 mg/kg EW-7197 phosphate dissolved in 0.3 mL vehicle by oral gavage once daily for 7 days after adhesion induction followed by 0.3 mL vehicle only by gavage once daily for an additional 21 days. After the respective treatments were completed, the animals were euthanized. ResultsAll rats survived until the end of the study without complications. EW-7197 reduced the incidence, quality, and tenacity of peritoneal adhesions in a dose-dependent manner. Fibrosis and collagen production were reduced in EW-7197–treated peritoneal ischemic buttons. Transforming growth factor β/Smad2/3 signaling and mesothelial-to-mesenchymal transition were inhibited in EW-7197–treated peritoneal ischemic buttons. Discontinuation of EW-7197 was not associated with rebound effects. ConclusionEW-7197 prevented peritoneal adhesion formation potentially via inhibition of transforming growth factor β1/Smad2/3–induced mesothelial-to-mesenchymal transition in a rat model.

A randomized controlled experimental study of the efficacy of platelet-rich plasma and hyaluronic acid for the prevention of adhesion formation in a rat uterine horn model.

Platelet-rich plasma (PRP) has been known to possess an efficacy in tissue regeneration. The aim of this study was to determine the role of PRP on post-operative adhesion formation in an experimental rat study. Thirty Sprague-Dawley rats were randomly divided into control, hyaluronic acid, and PRP treatment groups and operated on for uterine horn adhesion modeling. Blood was collected to produce a PRP with platelet counts of 688×10(3)/μL, and 1ml of either hyaluronic acid gel or PRP was administered over the standard lesions, while the control group received no medication. The evaluation of post-operative adhesions was done on the 30th post-operative day. The location, extent, type, and tenacity of adhesions as well as total adhesion scores, tissue inflammation, fibrosis and transforming growth factor-1beta (TGF-1β) expressions were evaluated. The total adhesion score was significantly lower in the PRP group (3.2±1.5) compared with the hyaluronic acid (5.0±1.3) and control (8.1±1.7) groups. The extent of the adhesions was significantly lower in the PRP group. There was no significant difference in the type and tenacity of adhesions between the hyaluronic acid and the PRP group. The level of inflammation was significantly higher in the control group than the others, while there was no difference between the PRP and hyaluronic acid groups. TGF-1β expression was significantly lesser in the PRP group than the control and hyaluronic acid groups. PRP is more effective than hyaluronic acid treatment in preventing post-operative adhesion formation in an experimental rat uterine horn adhesion model.

The use of Vicryl mesh in a porcine model to assess its safety as an adjunct to posterior fascial closure during retromuscular mesh placement.

Posterior component separation has become a common approach to complex abdominal wall reconstructions. This technique includes creation of an extraperitoneal retromuscular space for subsequent large synthetic mesh reinforcement. In certain cases, when complete restoration of "posterior" layer is precluded by significant tissue loss/damage, one proposed strategy is to replace the posterior fascia with an absorbable synthetic polyglactin (Vicryl) mesh. However, the safety of this strategy to prevent mesh-related visceral complication is unknown. Herein, we aimed to characterize mesh-viscera adhesion profiles and host tissue response of synthetic mesh either exposed directly to the viscera, or protected with Vicryl mesh. Using adult Yorkshire pigs, 5×5cm pieces of mesh were secured to the intact peritoneum in each of the four quadrants (n=6 pigs, 24 mesh samples). The study groups were Vicryl (V), Marlex (M), Softmesh (S), Marlex+Vicryl construct (MV), Softmesh+Vicryl construct (SV). The self-made composite meshes were then implanted with the Vicryl side facing the exposed viscera. The pigs were survived for 60days. At necropsy, grossly, the extent and tenacity of visceral adhesions were evaluated using established scales. Histologically, all specimens for fibrous encapsulation on the visceral surface of the mesh were reviewed by an experienced pathologist blind to meshes used. At necropsy, all Vicryl meshes were completely resorbed. The mean adhesion and tenacity scores for M and MV were 1.8 and 1.1 (P>0.05), 2.0 and 1.5 (P>0.05), respectively; while the mean adhesion extent scores and tenacity scores for S and SV were 2.0 and 1.2 (P>0.05), 2.0 and 1.7 (P>0.05). No significant difference in adhesion extent and tenacity was observed between Synthetic and Vicryl composite mesh groups. Histologically, Marlex+Vicryl mesh and Softmesh+Vicryl mesh constructs had thicker fibrous capsules than the corresponding unprotected Marlex and Soft mesh implants. Furthermore, visceral adhesions in the composite groups were noted to be to the fibrous capsule and not synthetic mesh itself. Utilization of the absorbable polyglactin (Vicryl) mesh as a separating layer between a synthetic mesh and intestines, did not reduce adhesions across various mesh types and composites. Histologically, however, a thick fibrous capsule replaced the Vicryl mesh and may be an important layer to prevent intestinal erosion into retromuscular synthetic meshes.

Histological and adhesiogenic characterization of the Zenapro Hybrid Hernia Repair Device

BackgroundA major clinical problem relating to hernia repair is the formation of intra-abdominal, post-surgical adhesions when mesh products are used to reinforce the abdominal wall. To achieve better outcomes, more technologically-advanced products designed to achieve permanence of repair while eliminating serious complications such as adhesion formation are needed. This study was designed to assess the histological remodeling and adhesiogenic properties of the Zenapro™ Hybrid Hernia Repair Device as compared to uncoated and coated polypropylene. Materials and MethodsZenapro™, Prolene® and Ventralight® ST Mesh were implanted to repair full-thickness abdominal wall defects in rabbits and rats and were allowed to survive for various lengths of time. Animals were euthanized, the implants were identified, and the extent and tenacity of adhesions were evaluated. Tissue samples were collected and evaluated for inflammation, integration of the mesh with the abdominal wall, and collagen deposition. ResultsA significant difference was found in the extent of adhesions in the Prolene group as compared to the Zenapro group (p = 0.021) and the Ventralight ST group (p = 0.04) in the rat study. The tenacity of the adhesions in the Prolene mesh group trended higher than in the other groups but failed to reach statistical significance. Histological evaluation demonstrated that collagen accumulation was greatest for the Zenapro implants as compared to either the Ventralight ST or Prolene samples. At the conclusion of 6-months in the rabbit model, the Zenapro sites showed signs of a thicker repair composed of more organized mature collagen than was seen in the Ventralight ST samples. Neither device was found to elicit any sort of detrimental inflammatory tissue reaction. ConclusionA combination hernia device composed of a complete extracellular matrix with a synthetic mesh can result in enhanced tissue ingrowth and neovascularization while maintaining high tensile strength and mitigating adhesiogenic effects.

Prevention of abdominal adhesions and healing skin after peritoniectomy using low level laser

Adhesions commonly occur after abdominal surgery and can cause bowel obstruction, chronic abdominal pain, and infertility. Their prevention remains a challenge. To evaluate the effects of the application of low-level lasers on the prevention of adhesions and scarring of the skin after peritoniectomia. Twenty-four New Zealand breed male rabbits, approximately 2 months of age, were randomly divided into 3 groups (n = 8): GC-control group not subjected to laser, GL1-group with laser application at a dose of 0.2 J, and GL2-group with laser application at a dose of 3.6 J. All animals received a longitudinal midline incision and a bilateral resection of the peritoneal fragment, measuring 3 × 1 cm(2) . The animals received a laser treatment of one application every 24 hours, beginning at the time of surgery and lasting for a period of 4 days. After 14 days post-surgery, the animals were killed and adhesion formation was evaluated qualitatively and quantitatively by means of a laparotomy shaped inverted "U", which allowed for the verification of the broad wall of the abdominal cavity and organs. Differences were considered significant at P < 0.05. The adhesion formation was observed in 100% of the rabbits from groups GC and GL1, as compared to 37.5% of the rabbits from group GL2 (P < 0.01). The evaluation of the vascularization and tenacity of adhesions among the groups showed no significant difference. In groups CG and GL1, 72% and 83% of adhesions were verified between visceras, respectively whereas in GL2 occurred among abdominal wall. The tensile strength of the skin between the groups was not significant (P = 0.3106). The resistance of abdominal wall segments without skin he resistance of skin segments between groups GL2 and GC were higher than in GL1 (P = 0.01). Low-level LASER is effective in preventing intra-abdominal adhesions in rabbits without compromising strength and healing of the abdominal wall.

Combined Application of Acellular Bovine Pericardium and Hyaluronic Acid in Prevention of Postoperative Pericardial Adhesion

An experiment was designed to find the suitable acellular bovine pericardium (ABP) patch in pericardial cavity reconstruction and to evaluate the effect of sodium hyaluronic acid (NaHA) on inflammatory reaction in prevention of pericardial adhesions. The pericardial adhesion model was established in 20 rabbits, weighing from 3.2 to 3.6 kg. Groups were classified as follows: Group A (n = 5), the control group, the pericardium was directly closed; Group B (n = 5), 0.15% glutaraldehyde-treated ABP (low cross-link degree); Group C, 0.3% glutaraldehyde-treated ABP (middle cross-link degree); Group D, 0.15% glutaraldehyde-treated ABP + NaHA solution. Blood samples were collected at 6 h, 24 h, 3 days, and 5 days, to assay postoperative inflammatory reaction. The tenacity and severity of adhesions were evaluated 2 months after operation, by macroscopic and microscopic examinations, and Q-PCR (real-time quantitative polymerase chain reaction) test was used to quantitatively analyze the associated genes with adhesion. Pericardium regeneration was demonstrated by immunohistochemical technique to identify mesothelial cells. In Group D, the serum concentration of tumor necrosis factor-α (TNF-α) was significantly lower in the early postoperative period, and the mean adhesion score (adhesion between the epicardium and ABP) was significantly lower compared with the control group (Groups D vs. A: 0.20 ± 0.45 vs. 2.00 ± 0.71, P = 0.009*). The signs of degradation of the ABPs were observed 2 months postoperation in Groups D and B. Immunohistochemically, the positive cytokeratin AE1 staining results demonstrated the relatively total regeneration of the pericardium in Group D. Signs of regeneration were observed in Group D. Compared with the control group, the level of TGF-β2 in Group D was significantly lower (0.00132 ± 0.00114, P = 0.022*). The TGF-β3 level was statistically significant, being highest in Group D (0.00805 ± 0.00136, P = 0.029*). The mean quantity of Smad6 in Group D was also lower than the other groups. Low cross-link degree ABP may be an efficient physical block between the epicardium and the sternum and also an ideal scaffold for pericardial tissue regeneration, whereas combined use with NaHA may significantly reduce postoperative pericardial adhesions. The signal transduction pathway of transforming growth factor-β (TGF-β) and Smad6 may play a key role in the formation of pericardial adhesion.

To perform operative procedures in an optimized local atmosphere: Can it reduce post-operative adhesion formation?

BackgroundAdhesion formation is a major problem following abdominal surgery as it creates a considerable economic burden in addition to an increased risk for complications. In the present study, an effort was made to reduce post-operative adhesion formation by creating an artificial atmosphere within and around the abdominal cavity during an open surgical procedure. Methods82 Wistar male rats (Clr:WI) (200 gr, 7 weeks) were randomized into two groups. The abdominal cavity of the control group was exposed to the normal atmosphere of the operating-theatre during surgery (21% O2, 21 °C, 40–47% relative humidity (RH)), while the abdominal cavity of the study group was exposed to an artificial atmosphere during surgery (3–6% O2, >75% CO2, 95–100% RH, 37 °C). Adhesion induction consisted of a laparotomy along linea-alba, four lesions in the anterior abdominal-wall, blood from the tail vein dripped inside the abdominal cavity and exposure to the atmosphere around the wound by use of self-retaining retractors. In addition, a liquid-sample for quantitative bacteriologic cultivation and bacterial load (CFU/ml) calculation was taken just before closure. After 3 weeks the abdominal cavity was scored for the extent, tenacity and severity of adhesions before the rats were euthanized. The two-sample-Wilcoxon-rank-sum test was used in the analysis. ResultsHighly significant differences in postoperative total adhesion score, extent-, severity- and tenacity-score were found (P < 0.01). No differences were found between the two groups regarding mean bacterial load (P > 0.05). ConclusionsThe rats exposed to the warmed and humidified artificial atmosphere consisting of more than 75% carbon dioxide and 3–4% oxygen during surgery had more severe and more post-operative adhesions compared to the rats that were exposed to the ambient air during surgery.

Duodenum Clamping Trauma Induces Significant Postoperative Intraperitoneal Adhesions on a Rat Model

ObjectiveThe purpose of this study was to investigate the histological and morphological changes in the first two postoperative weeks on a rat intraperitoneal adhesion model induced by duodenum clamping trauma.MethodThe rat model of postoperative intraperitoneal adhesions was established in 48 male Wistar rats by laparotomy, followed by the duodenum clamping trauma. Rats were sacrificed respectively on 1st, 3rd, 5th, 7th and 14th day after the operation. The control rats were sacrificed immediately after the operation (0 day). Then the intraperitoneal adhesions were assessed macroscopically. Histopathology and immunohistochemistry were performed to evaluate the fibrosis, inflammatory responses, neovascularization, and cells infiltration in adhesion tissues. In addition, the changes of the mesothelium covering the surgical sites were examined by scanning electron microscopy.ResultsOur study revealed that duodenum clamping trauma induced by mosquito hemostat can result in significant postoperative intraperitoneal adhesions formation. The extent and tenacity of intraperitoneal adhesions reached their peaks on 3rd and 5th days, respectively. Histopathological examination showed that all rats developed inflammatory responses at the clamped sites of duodenum, which was most prominent on 1st day; the scores of fibrosis and vascular proliferation increased slowly from 3rd to 5th day. Myofibroblasts proliferated significantly in the adhesion tissues from 3rd day, which were examined by immunohistochemical method. And the mesothelium covering the surgical sites and the adhesion tissues healed on 7th day.ConclusionThis study suggests that clamping trauma to the duodenum can result in significant postoperative intraperitoneal adhesions formation, which represents an ideal rat model for intraperitoneal adhesions research and prevention. And myofibroblasts may play an important role in the forming process of intraperitoneal adhesions.

Halofuginone infused keratin hydrogel attenuates adhesions in a rodent cecal abrasion model

BackgroundPostoperative adhesion formation continues to be a significant surgical complication, and methods for preventing abdominopelvic adhesions remain limited. Halofuginone (HF) is a type-1 collagen synthesis inhibitor and may enhance the effects of a physical barrier in preventing adhesion formation. We evaluated the effectiveness of a HF infused keratin hydrogel on preventing adhesions in a rat cecal abrasion model. Material and methodsLaparotomy and standardized cecal abrasion was performed on 58 retired-breeder Sprague Dawley female rats to induce intra-abdominal adhesions. Rats were randomized to: no treatment; Interceed absorbable adhesion barrier; keratin hydrogel alone; or keratin hydrogel infused with 22 μg/mL of HF. Necropsies were performed at postop d-14 to assess the extent and tenacity of adhesions and grade histologic inflammation and fibrosis using a standard scoring system. Serum, liver, kidneys, and lungs were harvested to evaluate tissue HF concentrations. Protein and drug elution curves were generated to assess the release of HF from the hydrogel. ResultsTreatment with Keratin-HF hydrogel resulted in significantly fewer abdominal adhesions than any other treatment, and significantly less dense adhesions compared with Interceed or keratin hydrogel alone. Subset histologic analysis did not reveal qualitative differences. HF was undetectable in serum and kidneys, and detected at negligible concentrations in liver and lungs. Keratin-HF hydrogel drug release in phosphate-buffered solution (PBS) was sustained over 7 d and correlated with keratin protein degradation. ConclusionsKeratin-HF hydrogel is a novel therapeutic agent that may provide a better method for preventing the development of postoperative adhesions using a combined physical barrier and pharmacologic approached.

Polytetrafluoroethylene Membrane (Gore Preclude Vessel Guard) for Vessel Protection During Anterior Lumbar Surgery

The effects of implanting a polytetrafluoroethylene (PTFE) membrane (Gore Preclude Vessel Guard, WL Gore and Associates, Flagstaff, AZ) during anterior lumbar surgery were studied in a pig model. We investigated whether placement of a PTFE membrane between the great vessels and anterior surface of the lumbar spine would minimize adhesions. Anterior lumbar procedures continue to increase, as do revision operations. Anterior approaches remain challenging, however, because of the considerable risk of vascular injury. The risk is especially high with revision procedures because of the presence of adhesions that can hinder visualization and mobilization of vessels. Use of an anti-adhesion barrier may decrease the rate of vascular complications associated with revision surgery. Three spinal levels in 3 pigs were subjected to either discectomy, creation of a hole in the disc, or disc exposure only. In 5 of the 9 levels, a PTFE membrane was then implanted over the disc; the other 4 levels were controls. Spine segments were obtained 12 weeks later, and the tenacity of adhesions (scale of 0 to 4) and percentage of disc space covered by adhesions were assessed. The specimens were also studied histologically. Mean values for adhesion tenacity were 2.75 for control spinal levels and 0.4 for levels with a PTFE membrane (P=0.008). Mean values for adhesion coverage were 81% for control disc spaces and 15% for spaces with a PTFE membrane (P=0.008). Histologic studies showed minimal adhesions, lack of an inflammatory reaction, and vascularized connective tissue between PTFE membranes and the vena cava. In a pig model, implantation of a PTFE membrane during anterior lumbar surgery decreased the tenacity and amount of adhesions observed at necropsy. Studies of the efficacy and safety of the PTFE membrane in clinical anterior lumbar surgery are warranted.

Efficacy of melatonin and hyaluronate/carboxymethylcellulose membrane in preventing adhesion reformation following adhesiolysis in a rat uterine model

To evaluate the efficacy of hyaluronate/carboxymethylcellulose (HA/CMC) membrane and melatonin separately and in combination in reducing adhesion reformation following adhesiolysis of surgically induced adhesions in a rat uterine horn adhesion model. A randomized, prospective study was carried out in a university animal laboratory. Ninety-eight female Sprague-Dawley albino rats were operated on. Following infliction of standard lesions, all the animals underwent second operations after one week. In all the animals, there were dense and vascular adhesions only between the uterine horns. These adhesions were lysed. Following the completion of adhesiolysis, the animals were randomized before closure of the abdomen to one of four groups (melatonin, HA/CMC membrane, combination of melatonin and HA/CMC membrane, control group). Seven days after the second surgery, the third operations were carried out and adhesions were scored. The main outcome measures were type, tenacity, and extent of adhesions. Total adhesion scores were determined. Adhesion scores in the melatonin and HA/CMC membrane groups were similar, and significantly lower than those in the control group (P < 0.001). Adhesion scores in the combination group were lower than those in the other three groups (P < 0.001). Melatonin and HA/CMC membrane are both effective separately in preventing adhesion reformation following adhesiolysis, but in combination they are significantly more beneficial.

Prevention of postoperative pericardial adhesions in children with hypoplastic left heart syndrome

Reoperations for congenital cardiac defects are associated with an increased surgical risk due to adhesions. We compared the capability of a polytetrafluoroethylene (PTFE) membrane, synthetic polyethyleneglycol hydrogel (PEG), and a combination of them to prevent postoperative pericardial adhesions in patients with hypoplastic left heart syndrome (HLHS). Eighteen consecutive patients with HLHS were included. At the end of the Norwood I operation the cranial and the caudal half of the heart of each patient was randomized to receive a PTFE membrane, a synthetic PEG, a combination of them, or no treatment (control). Tenacity and density of adhesions, epicardial visibility, and adhesions between the heart and the sternum were analyzed semiquantitatively at a subsequent bidirectional Glenn operation. The PTFE membrane significantly decreased adhesion formation between the heart and the sternum (P<0.001). However, the PTFE membrane, with or without synthetic PEG, impaired epicardial visibility (P<0.05) when compared to synthetic PEG or controls. Synthetic PEG alone did not significantly reduce the formation of pericardial adhesions. Tenacity and density of adhesions were not affected by any of the treatment modalities. The PTFE membrane significantly decreases postoperative adhesions between the heart and the sternum, but impairs epicardial visibility. Synthetic PEG does not prevent formation of pericardial adhesions.

Assessment of Processed Porcine Extracellular Matrix as a Protective Barrier in a Rabbit Nerve Wrap Model

Nerve wrapping can improve outcomes by protecting nerves in a scarred tissue bed. Autologous tissue wraps have shown good results, but there are limitations associated with harvesting and availability. Extracellular matrix (ECM) derived from porcine small intestinal submucosa offers an attractive off-the-shelf option. This study evaluated this material as a nerve wrap. The sciatic nerves of 18 New Zealand rabbits were exposed and then wrapped, while the contralateral side served as sham control. Presence and quality of adhesions, motor conduction velocity (MCV), and histology were evaluated at 1, 2, and 6 months ( N = 6 animals per time point). The quality, extent, tenacity, and overall impression of adhesions were not different from control at any time point ( P = 0.18 to 0.99). MCV was also not statistically different from control (1 month, P = 0.35; 2 months, P = 0.20; 6 months, P = 0.83). Histology demonstrated that wrapped nerves were healthy in terms of myelination, density, and vascularity compared with controls. Vascularization and incorporation of the ECM material could be visualized at explants. All assessments supported the feasibility and safety of this material as a nerve wrap. Its ability to function as a protective barrier has strong implications for clinical use in trauma and/or recurrent compression neuropathies.

Effect of biomaterial design criteria on the performance of surgical meshes for abdominal hernia repair: a pre-clinical evaluation in a chronic rat model

Despite the recognized advantage of surgical meshes in abdominal hernia repair, reports of long term complications after implantation are increasing. 25 chronic hernia rats underwent incisional repair (n = 5/mesh group) with compressed poly(tetra-fluoro-ethylene) (cPTFE), expanded poly(tetra-fluoro-ethylene) (ePTFE), polypropylene (PP), poly(ethylene-terephtalate) + collagen (PET + C), and porcine intestinal submucosa (SIS). At 30 days, the extent and strength of intra-abdominal adhesions was evaluated, along with tissue-mesh integration, material shrinkage, and inflammatory response. The extent and tenacity of adhesions were reduced in PET + C and SIS, while tissue contraction was largely reduced in the presence of cPTFE. The tissue integration was not affected by composition or material construction. The host tissue response was elevated and arrested in a chronic imflammatory phase in the presence of PET + C and SIS, and resolved in the case of cPTFE. The different composition and material construction did not affect significantly the overall performance of the evaluated surgical meshes, apart from PP.

Cyanoacrylate Glue for Intra-abdominal Mesh Fixation of Polypropylene-Polyvinylidene Fluoride Meshes in a Rabbit Model

Cyanoacrylate glues are tissue adhesive with high adherent and hemostatic properties. The aim of this study was to evaluate the efficacy of cyanoacrylates glue for polypropylene-polyvinylidene fluoride (PP-PVDF) intraperitoneal onlay mesh (IPOM) fixation in a rabbit model. In 40 New Zealand white rabbits, three pieces (3×3cm) of a PP-PVDF mesh (n=120) were fixed in IPOM technique on both sides of a midline laparotomy. For mesh fixation we used spiral tacks, nonabsorbable sutures, or cyanoacrylate glue in a randomized manner. All animals were killed after 12 wk. The prosthetic materials were excised en bloc with the anterior abdominal wall for evaluation of the tensile strength and histologic analysis. Results are presented as mean and standard deviation. Meshes fixed with glue showed a significantly higher tenacity of adhesions (2.75±0.97) compared with those with tacks (2.44±0.97 sutures versus 1.91±0.92 tacks). The percentage of adhesions in the glue group was comparable to the suture group (36.50% ± 27.60% glue, 37.62% ± 27.36% suture). The tensile strength of stapled and sutured meshes was significantly higher than the tensile strength glued mesh (14.15±0.97N suture versus 14.84±0.74 stapler versus 9.64±0.78N glue). Mesh shrinkage was irrespective of the fixation technique. The inflammation reaction was more pronounced in the glue group. Although cyanoacrylate glue showed a considerable cellular ingrowth in this rabbit model, sutures and tacks proved to be superior for IPOM fixation of PP-PVDF meshes in terms of tensile strength.

Reduction in postlaminectomy epidural adhesions in sheep using a fibrin sealant‐based medicated adhesion barrier

Epidural adhesion formation is believed to be a central governing factor in the prevalence of pain after spinal surgery and is regarded as being the primary instigator of neural tethering, leading to complications during revision surgery. In this study, we assess the effectiveness and safety of fibrin sealant supplemented with tributyrin, termed Medicated Adhesion Barrier (MAB), as an alternative means of reducing the incidence of posterior spinal epidural adhesion formation. Laminectomy defects in sheep were treated with MAB, fibrin sealant alone, ADCONGel, or remained untreated. At 12 weeks postoperatively, the extent of fibrosis and epidural adhesion formation was evaluated using magnetic resonance imaging (MRI), peel-off testing, and histological examination. Initial invitro analysis revealed that tributyrin was retained in fibrin gel in a time-dependent manner and was an effective inhibitor of fibroblast proliferation. Treatment of sheep with MAB significantly reduced both the prevalence (p < 0.05) and tenacity (p < 0.05) of epidural adhesions. The effectiveness of MAB in preventing epidural adhesions was found to be comparable with that of ADCONGel. No adverse events were reported after the use of MAB. The MAB preparation seems to be an effective resorbable barrier for the prevention of epidural adhesions.

Human Peritoneal Membrane Controls Adhesion Formation and Host Tissue Response Following Intra-Abdominal Placement in a Porcine Model

Even with the advent of bioresorbable barriers, complications due to visceral adhesions following surgery continue to occur. The use of a homologous adhesive barrier such as human peritoneal membrane (HPM) could prevent adhesions formation and enhance wound healing. This study evaluates HPM as an effective adhesive barrier in a porcine model simulating a ventral hernia procedure. Through a midline laparotomy, meshes (10 cmx10 cm) were sewn onto the intact peritoneum of a pig, on each side of a midline incision in superior and inferior positions (4 randomized meshes/pig, n=9 pigs). The pigs were survived for 90 d. The meshes used were: HPM, compressed polytetrafluoro-ethylene (cPTFE), cPTFE+HPM, and polyester-collagen composite (PX). Exploratory laparoscopy was performed at 30 and 90 d to evaluate the extent of visceral adhesions. At necropsy, the extent and tenacity of visceral adhesions as well as material-abdominal wall integration were evaluated. Finally, host tissue response was assessed through scoring of inflammation, foreign body reaction, and mesothelialization. HPM and PX led to the least extent and tenacity of visceral adhesions compared to cPTFE and cPTFE+HPM, but integrated less strongly within the adjacent abdominal wall. PX displayed the most robust foreign body reaction among all prosthetic materials, while HPM scored similarly to the native peritoneum. The extent of mesothelialization was similar throughout the materials tested. The HPM barrier which promotes long-term peritoneal remodeling could diminish postsurgical intraperitoneal adhesions following hernia repair.

Human Peritoneal Membrane Reduces the Formation of Intra-Abdominal Adhesions in Ventral Hernia Repair: Experimental Study in a Chronic Hernia Rat Model

Adhesions leading to intestinal obstructions and fistulae are severe complications related to the intraperitoneal placement of synthetic meshes. This study evaluated the efficacy of human peritoneal membrane (HPM) in a chronic hernia repair rat model as an anti-adhesive solution for preventing the development of intra-abdominal adhesions. The mechanical properties of HPM and human fascia lata (HFL) were evaluated prior to in vivo implantation. Twenty rats underwent midline laparotomy, which led to the development of chronic hernias 28 d later. Then, animals underwent incisional hernia repair in an underlay fashion (n=5/mesh group) with compressed poly(tetra-fluoro-ethylene) (cPTFE), onto which HPM or HFL were affixed pre-repair, along with two additional controls. The extent and tenacity of intra-abdominal adhesions were determined through qualitative gross evaluations and quantitative tensiometry at 30 d post-repair. The host tissue response was evaluated histologically. In hydrated state, the elastic properties of HPM were superior to HFL. Repairs with HPM had significantly less surface area covered by adhesions, with significantly lower tenacity compared with all other groups. Furthermore, intra-abdominal adhesions developed in the presence of HPM were associated with omentum only, and were distributed around the perimeter of the exposed cPTFE. HPM served as an active tissue remodeling template, replacing the traditional foreign body encapsulation with an anatomically and physiologically superior outcome. HPM significantly reduces the extent and tenacity of intra-abdominal adhesion formation, and represents a bioprosthetic template that encourages structural and functional neo peritonealization.