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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. [ABSTRACT FROM AUTHOR]

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Introduction. The purpose of this study was to analyse the value of 3-dimensional computed tomography cholangiography (3D-ERC) compared to conventional retrograde cholangiography in the preoperative diagnosis of hilar cholangiocarcinoma (HC) with special regard to the resection margin status (R0/R1). Patients and Methods. All hepatic resections performed between January 2011 and November 2013 in patients with HC at the Department of General, Visceral and Transplant Surgery of the RWTH Aachen University Hospital were analysed. All patients underwent an ERC and contrast-enhanced multiphase CT scan or a 3D-ERC. Results. The patient collective was divided into two groups (group ERC: n=17 and group 3D-ERC: n=16). There were no statistically significant differences between the two groups with regard to patient characteristics or intraoperative data. Curative liver resection with R0 status was reached in 88% of patients in group ERC and 87% of patients in group 3D-ERC (p=1.00). We could not observe any differences with regard to postoperative complications, hospital stay, and mortality rate between both groups. Conclusion. Based on our findings, preoperative imaging with 3D-ERC has no benefit for operative planning and R0 resection status. It cannot replace the exploration by an experienced surgeon in a centre for hepatobiliary surgery. [ABSTRACT FROM AUTHOR]

Introduction: Anastomotic leakage still remains a major complication in general surgery. Beside general risk factors, the ideal method of anastomotic technique has not been found until now. The aim of the present study was to analyze wound healing in suture-free small intestine anastomoses using fibrin glue with and without mesh-reinforcement. Methods: Laparotomy and four different types of small bowel anastomoses were performed in 32 chinchilla rabbits. Standard hand-sewn anastomoses (CG), suture-free glued anastomoses (FG) with and without mesh reinforcement using two different types of meshes [Vicryl-mesh (VM) and Surgisis (SM)]. Animals were sacrificed after 5 and 21 days. Bursting pressure, collagen type I/III ratio, and matrix-metalloproteinase 2, 9, and 13 were analyzed. Results: None of the animals died due to an anastomotic leakage. All animals in the long term group with Surgisis mesh died due to a mechanical bowel obstruction based on a distinctive stenosis of the anastomosis. The bursting pressures did significantly differed in animals with fibrin glue alone compared to animals with Vicryl-mesh reinforcement ( p < 0.05). Histological examination revealed statistically significant differences ( p < 0.05) in the values for MMP-2 (VM < SM), MMP-9 (VM < CG), and MMP-13 (CG < SM, VM < FG, and VM < SM). However, collagen type I/III ratios were not significantly different between groups. Conclusions: Our results suggest that a mesh reinforced glued anastomosis is technically feasible. Furthermore, mesh-reinforcement using VM increased the integrity and simplified the technique of suture-free anastomoses. [ABSTRACT FROM AUTHOR]

To reduce infection rates after mesh implantation antibiotic-coated meshes were designed. The aim of the study was to analyze biocompatibility and in vitro efficiency of a modified gentamicin-supplemented polyvinylidenfluoride mesh. Twenty rats were randomized to two groups (PVDF group and Genta group). Mesh material was implanted subcutaneously. Blood samples were taken to determine the gentamicin serum concentration. Seven and 90 days after mesh implantation, animals were euthanized. The inflammatory tissue response was characterized by analyzing the foreign body granuloma. Cellular immune response was analyzed by immunohistochemical investigations. The collagen type I/III ratio was estimated by crosspolarization microscopy. In vitro agar diffusion test, suspension test, and gentamicin release were characterized. Agar diffusion and suspension test showed efficient antibiotic effects of the mesh in vitro. Serum concentrations of gentamicin showed a peak value 1 h postoperatively with a decline within the next day. The total size of the granuloma was significantly smaller in the Genta group compared to the PVDF group at both points of time. Except of a short period of increased expression of CD68 in the Genta group after 7 days, no further difference was found analyzing cellular immune response. The collagen type I/III ratio was widely constant analyzing the two mesh types without significant differences comparing both mesh materials. A significantly decreased foreign body granuloma formation compared to the pure PVDF mesh group was found. In vitro analysis showed efficient antibiotic effects of the Gentamicin supplementation compared to the pure PVDF mesh. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Mesh implants are frequently used in congenital diaphragmatic hernia. This experimental study aimed to examine the influence of different materials on the diaphragmatic movement over time as well as their mechanical qualities after 4 months. Ultrapro®, Surgisis®, and Proceed ® were implanted onto a diaphragmatic defect in growing rabbits. Diaphragmatic mobility was determined at three time points. At 4 months, defect shrinkage and mechanical properties were measured. The break strength decreased for Ultrapro® and Surgisis®, but did not change relevantly for Proceed®. Ultrapro® (32.46 N/cm) and Proceed® (31.75 N/cm) showed a four-fold higher resistance to tearing than Surgisis® (8.31 N/cm). The elasticity of Ultrapro® showed no significant difference compared to Surgisis® (p = 0.75). Proceed®, on the other hand, was more than twice as elastic as Ultrapro® or Surgisis ® (p = 0.015). Ultrapro® had a higher spring rate (6.48 N/mm) compared to Surgisis® (3.82 N/mm) or Proceed ® (5.23 N/mm). Observing the standardized movement rates of the diaphragm for each mesh group over time the only statistical differences were seen for the Proceed® group. On account of its material qualities Ultrapro® was found to be the most suitable mesh material for demanding locations in our model. [ABSTRACT FROM AUTHOR]

Background: Mesh reinforcement in hiatal hernia repair becomes more frequent but is charged by complications such as erosion or stenosis of the oesophagus. These complications are accompanied by an intense inflammatory infiltrate around the polymer fibres. To characterize this effect, the response to polypropylene fibres in the absence of tension was examined. Methods: In rats, polypropylene sutures (USP size 1, 3-0 and 7-0) were placed in the subcutis of the abdominal wall without knot or tension. On postoperative days 3, 7 and 21, specimens were excised. The expressions of c-myc, β-catenin, Notch3, COX-2, CD68 and Ki-67 were measured by immunohistochemistry. Results: In the absence of tension, sutures were surrounded by a foreign body granuloma with an inflammatory infiltrate not encircling the fibre but forming almost symmetric comet-tail-like infiltrates on opposite sides. The expression of c-myc, β-catenin, Notch3, COX-2, CD68 and Ki-67 was significantly reduced over time in the comet tail, but not in the granuloma. Conclusions: Even in tension-free conditions, surgical sutures cause a foreign body response with infiltrates of inflammatory cells. This reaction is shaped like a comet tail, and its extension depends on the diameter of the used fibre. Therefore, for reduction of perifilamental infiltrates, not only absence of tension is required, but also a small-sized fibre textile. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Currently, absorbable meshes are used as temporary closure in case of laparostoma. Unfortunately the multifilament polyglycolic acid (PG) meshes with small pores reveal little elasticity acting rather as a fluid barrier than permitting drainage of intra-abdominal fluids. Therefore, a new mesh was constructed of absorbable polydioxanon monofilaments (PDS) with increased porosity and longer degradation time. Material and Methods: For evaluation of the tissue response the new PDS mesh was implanted as abdominal wall replacement in each five rats for 7, 21, or 90 days, respectively, and compared to a PG mesh. Histological analysis included HE staining with measurement of the size of the granuloma and immunoshistochemistry for TUNEL, Ki67, TNF-R2, MMP-2, YB1, FVIII, gas6, AXL. Parameters for neovascularization and nerve ingrowth were analyzed. Results: The inflammatory and fibrotic tissue reaction is attenuated with PDS in comparison to PG, e.g., the size of the granuloma was smaller with less cell turnover, and less remodeling as represented by, e.g., reduction of apoptosis, expression of MMP-2, or TNF-R2. The number of ingrowing nerves and vessels explored via AXL, gas6, and factor VIII was increased in the PDS mesh. Conclusion: The results from the present investigation showed that a mesh can be constructed of monofilament PDS that induce significant less inflammatory and fibrotic reaction, however permits fluid drainage and preserves elasticity. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the gas-dependent effects of pneumoperitoneum on wound healing distant from the abdomen. Dorsal skin incisions were performed in 54 male Sprague–Dawley rats. A CO2 or a helium pneumoperitoneum of 3 mmHg was maintained before, with an overall duration of 30 min (each n = 18). Rats in the control group received laparotomy only ( n = 18). Animals were killed after 5 and 10 days. The infiltration of macrophages (CD 68), expression of matrix metalloproteinase 13 (MMP-13) and collagen I/III ratios were analysed in the dorsal skin wounds. Both after 5 and 10 days, infiltration of macrophages and expression of MMP-13 were greatest after helium pneumoperitoneum. After 5 days, collagen I/III ratio was significantly increased in the helium group. After 10 days, collagen I/III ratio was lowest in the CO2 group. Our results suggest beneficial effects on systemic wound healing for helium pneumoperitoneum as compared to CO2. [ABSTRACT FROM AUTHOR]

Usually an abdominal wall hernia is regarded as a mechanical problem with a local defect which has to be closed by technical means. Despite the introduction of several therapeutic improvements, recurrent hernias still appear in 10-15%. Therefore, reasons for a recurrence are discussed in a more fundamental way. It is assumed that a failure mainly depends on the quality of the repair. Correspondingly, in principle, the close causal relationship between the technical component and its failure during time is reflected by an s-shaped outcome curve. In contrast, the configuration of the outcome curve changes markedly if a breakdown is caused by numerous components. Then, the superposition of all incidence curves inevitably leads to a linear decline of the outcome curve without any s-shaped deformation. Regarding outcome curves after hernia repair, the cumulative incidences for recurrences of both incisional and inguinal hernia show a linear rise over years. Considering the configuration of outcome curves of patients with hernia disease, it may therefore be insufficient to explain a recurrence just by a failing technical repair. Rather, biological reasons should be suspected, such as a defective wound healing with impaired scarring process. Recent molecular-biological findings provide increasing evidence of underlying biochemical alterations in patients with recurrent hernia. Until predicting markers to identify patients with an impaired wound healing are available and considering the formation of insufficient scar as the underlying disease, the consequences for every surgical repair should be a supplementary reinforcement with nonabsorbable alloplastic nets as flat meshes with an extensive overlap.