Maternal cytokine status may prime the metabolic profile and increase risk of obesity in children.

BACKGROUND: The maternal inflammation status during pregnancy has been associated with metabolic imprinting and obesity development in the child. However, the influence of the maternal Th2 cytokines, interleukin-4 (IL4), IL5 and IL13, has not been studied so far. METHODS: We investigated the relationship between maternal innate (IL6, IL8, IL10 and tumor necrosis factor-α (TNFa)) and adaptive (interferon-γ, IL4, IL5 and IL13) blood cytokine levels at 34 weeks of gestation and children's overweight development until the age of 3 years in 407 children of the German longitudinal LINA (Lifestyle and Environmental Factors and their Influence on Newborns Allergy risk) cohort. Children's body weight and height were measured during the annual clinical visits or acquired from questionnaires. Body mass index (BMI) Z-scores were calculated according to the WHO reference data to adjust for child's age and gender. Cytokine secretion was stimulated with phytohemagglutinin or lipopolysaccharide and measured by cytometric bead assay. Furthermore, we assessed metabolic parameter in blood of 318 children at age 1 using the AbsoluteIDQ p180 Kit (Biocrates LIFE Science AG). RESULTS: Applying logistic regression models, we found that an increase of maternal IL4 and IL13 was associated with a decreased risk for overweight development in 1- and 2-year-old children. This effect was consistent up to the age of 3 years for IL13 and mainly concerns children without maternal history of atopy. Children's acylcarnitine concentrations at 1 year were positively correlated with maternal IL13 levels and inversely associated with the BMI Z-score at age 1. CONCLUSIONS: We were able to show for the first time that the maternal Th2 status may be linked inversely to early childhood overweight development accompanied by an altered metabolic profile of the fetus. However, our data do not support a direct mediating role of acylcarnitines on maternal IL13-induced weight development.

Pancreatogastrostomy Versus Pancreatojejunostomy for RECOnstruction After PANCreatoduodenectomy (RECOPANC, DRKS 00000767): Perioperative and Long-term Results of a Multicenter Randomized Controlled Trial.

OBJECTIVES: To assess pancreatic fistula rate and secondary endpoints after pancreatogastrostomy (PG) versus pancreatojejunostomy (PJ) for reconstruction in pancreatoduodenectomy in the setting of a multicenter randomized controlled trial. BACKGROUND: PJ and PG are established methods for reconstruction in pancreatoduodenectomy. Recent prospective trials suggest superiority of the PG regarding perioperative complications. METHODS: A multicenter prospective randomized controlled trial comparing PG with PJ was conducted involving 14 German high-volume academic centers for pancreatic surgery. The primary endpoint was clinically relevant postoperative pancreatic fistula. Secondary endpoints comprised perioperative outcome and pancreatic function and quality of life measured at 6 and 12 months of follow-up. RESULTS: From May 2011 to December 2012, 440 patients were randomized, and 320 were included in the intention-to-treat analysis. There was no significant difference in the rate of grade B/C fistula after PG versus PJ (20% vs 22%, P = 0.617). The overall incidence of grade B/C fistula was 21%, and the in-hospital mortality was 6%. Multivariate analysis of the primary endpoint disclosed soft pancreatic texture (odds ratio: 2.1, P = 0.016) as the only independent risk factor. Compared with PJ, PG was associated with an increased rate of grade A/B bleeding events, perioperative stroke, less enzyme supplementation at 6 months, and improved results in some quality of life parameters. CONCLUSIONS: The rate of grade B/C fistula after PG versus PJ was not different. There were more postoperative bleeding events with PG. Perioperative morbidity and mortality of pancreatoduodenectomy seem to be underestimated, even in the high-volume center setting.

Influence of intraoperative radiotherapy (IORT) on perioperative outcome after surgical resection of rectal cancer.

BACKGROUND: Intraoperative radiotherapy (IORT) for locally advanced or recurrent rectal cancer as an integral part of multimodal treatment might be an option to reduce local cancer recurrence. The aim of the present study was to determine the influence of IORT on the postoperative outcome and complications rates in the treatment of patients with adenocarcinoma of the rectum in comparison to patients with rectum resection only. METHODS: A total of 162 patients underwent operation for International Union against Cancer stage III/IV rectal cancer or recurrent rectal cancer at our surgical department between 2004 and 2012. They were divided into two groups depending on whether they received IORT or not. General patient details, tumor, and operation details, as well as perioperative major and minor complications, were registered and compared. RESULTS: Of the 162 patients treated for stage III/IV rectal cancer, 52 underwent rectal resection followed by IORT. Complication rates were similar in the two groups. Operative time was significantly longer in the IORT group (248 ± 84 vs 177 ± 68 min; p < 0.001). No significant differences were found concerning anastomotic leakage rate, hospital stay, or wound infection rate. CONCLUSIONS: Intraoperative radiotherapy appears to be a safe treatment option in patients with locally advanced or recurrent rectal cancer with acceptable complication rates. The effect on local recurrence rate has to be estimated in long-term follow-up.

Impact of pressure and gas type on adhesion formation and biomaterial integration in laparoscopy.

BACKGROUND: Laparoscopic mesh repair of inguinal and incisional hernias has been widely adopted. Nevertheless, knowledge about the impact of pneumoperitoneum on mesh integration is rare. The present study investigates pressure and gas-dependent effects of pneumoperitoneum on adhesion formation and biomaterial integration in a standardized animal model. METHODS: Laparoscopic intraperitoneal onlay mesh implantation (IPOM) was performed in 32 female chinchilla rabbits using CO(2) or helium for pneumoperitoneum. Intra-abdominal pressures were 3 or 6 mmHg. Animals were killed after 21 days, and the abdominal wall was explanted for subsequent histopathological examinations. Adhesions were assessed qualitatively with a scoring system, and the adhesion surface was analyzed semiquantitatively by planimetry. Infiltration of macrophages (CD68), expression of matrix metalloproteinase 13 (MMP-13), and cell proliferation (Ki67) were analyzed at the mesh to host interface by immunohistochemistry. The collagen type I/III ratio was analyzed by cross-polarization microscopy to determine the quality of mesh integration. RESULTS: After 21 days, perifilamental infiltration with macrophages (CD68) and percentage of proliferating cells (Ki67) were highest after 6 mmHg of CO(2) pneumoperitoneum. The extent of adhesions, as well as the expression of MMP-13 and the collagen type I/III ratio, were similar between groups. CONCLUSIONS: Our experiments showed no pressure or gas-dependent alterations of adhesion formation and only minor effects on biomaterial integration. Altogether, there is no evidence for a clinically negative effect of CO(2) pneumoperitoneum.

Haemorrhoids - a collagen disease?

OBJECTIVE: The cause of haemorrhoidal disease is unknown, epidemiological data and histopathological findings support the hypothesis that reduced connective tissue stability is associated with the incidence of haemorrhoids. Therefore the aim of this study was to analyse the quantity and quality of collagen formation in the corpus cavernosum recti in patients with III°/IV° haemorrhoids in comparison with persons without haemorrhoids. METHOD: Haemorrhoidectomy specimens of 31 patients with III°/IV° haemorrhoids were examined. The specimens of 20 persons who died a natural death and who had no haemorrhoidal disease served as the controls. The amount of collagen was estimated photometrically by calculating the collagen/protein ratio. The collagen I/III ratio served as parameter for the quality of collagen formation and was calculated using cross polarization spectroscopy. RESULTS: Patients with haemorrhoids had a significantly reduced collagen/protein ratio (42.2 ± 16.2µg/mg vs 72.5±31.0µg/mg; P= 0.02) and a significantly reduced collagen I/III ratio (2.0±0.1 vs 4.6±0.3; P<0.001) compared with persons without haemorrhoidal disease. There was no correlation with patients' age or gender. CONCLUSIONS: There is a fundamental disorder of collagen metabolism in patients with haemorrhoidal disease. It remains unclear whether this is due to exogenous or endogenous influences.

The Gist of literature on pediatric GIST: review of clinical presentation.

AIM/BACKGROUND: To provide a review of existing literature on pediatric GIST with focus on clinical presentation. METHODS: A MEDLINE search was conducted in July 2007 to give an overview on literature concerning pediatric gastrointestinal stromal tumors (GISTs) with a focus on clinical presentation, using keywords "gastrointestinal stromal tumor" and one of the following "young/boy/girl/child/children/pediatric." Two of the authors sorted the resulting abstracts by relevance for a review on clinical aspects of pediatric GIST if they were in English language, not explicitly only reporting of adults and describing clinical features of patients. RESULTS: One hundred and six articles were found, 43 of which were excluded because they did not match the criteria mentioned above. We found 97 patients in the articles meeting our criteria, of which 38 cases had to be excluded, because of lacking clinical data, negative staining for CD117 or syndromal occurrence. This left 59 patients for analysis of clinical symptoms in the presentation of nonsyndromal CD117-positive GIST in children. DISCUSSION: Clinical feature most frequent was anemia in 86.4% (n=51) symptomatic either through acute or subacute bleeding. There was no palpable tumor in 88.1% (n=52), no abdominal pain in 84.7% (n=50), and no vomiting in 88.1% (n=52). Girls tend to show more high-grade tumors and existing case reports show a 2.7-fold higher incidence in females. Altogether epithelioid cell tumors are most frequent, although in boys spindle-cell tumors are reported more often. On the basis of National Institute of Health criteria (6) tumors were low grade in 22% (n=13), medium grade in 37.3% (n=22), and high grade in 35.6% (n=21). There were more high-grade tumors in girls than in boys (40.5% vs. 28.6%). Local excision was the operation most often performed, but details of surgery were missing in most cases. CONCLUSIONS: Pediatric GIST is a rare but considerable diagnosis in chronic anemia, which is the most frequent clinical finding with this tumor entity. Recent review articles focus on histopathologic criteria but omit clinical features and course of disease. In nonsyndromal CD117-positive GIST, girls tend to show more high-grade tumors and existing literature on pediatric GIST shows a 2.7-fold higher incidence in females. Altogether epithelioid cell tumors are most frequent, although in boys spindle-cell tumors are reported more often. Together with known differences in molecular changes and local as well as systemic tumor behavior this strongly suggests that pediatric GIST represents a different entity than adult GIST. After establishment of clear-cut pathologic features in the past, reports on preoperative diagnostic findings, long-term follow-up, and therapy have to be emphasized to clarify the relationship of these entities.

[Risk factors for anastomotic leakage after colorectal surgery]. / Risikofaktoren für das Auftreten postoperativer Anastomoseninsuffizienzen nach kolorektalen Resektionen.

BACKGROUND: Despite improved surgical techniques, anastomotic leakage is still a serious complication in colorectal surgery, resulting in increased morbidity and mortality. This study was initiated to investigate those clinical risk factors which may influence the onset of anastomotic wound-healing complications. METHODS: The postoperative courses were assessed in 400 consecutive patients who underwent colonic or rectal resection. Possible clinical risk factors were investigated by unvariate and multivariate analysis. RESULTS: 23 patients developed an anastomotic leakage (5.8 %). 10 patients could be treated conservatively, 13 had a second operation. In the multivariate analysis significant risk factors were perioperative radiotherapy (OR = 3.76 [95 % CI 1.03-13.7]), blood transfusion (OR = 2.98 [95 % CI 1.18-7.54]), alcohol consumption (OR = 2.94 [95 % CI 1.06-8.17]), and steroid medication (OR = 3.91 [95 % CI 1.17-13.07]). CONCLUSION: The clinically most important risk factors for leakage were radiotherapy and blood transfusion. Further analyses with a focus on the extracellular matrix, including other clinical factors may be valuable in identifying targets for improvement.

Biomechanical analyses of mesh fixation in TAPP and TEP hernia repair.

BACKGROUND: Reliable laparoscopic fixation of meshes prior to their fibrous incorporation is intended to minimize recurrences following transabdominal preperitoneal hernia repair (TAPP) and totally extraperitoneal repair (TEP) repair of inguinal hernias. However, suture-, tack- and staple-based fixation systems are associated with postoperative chronic inguinal pain. Initial fixation with fibrin sealant offers an atraumatic alternative, but there is little data demonstrating directly whether fibrin-based mesh adhesion provides adequate biomechanical stability for repair of inguinal hernia by TAPP and TEP. METHODS: Using a newly developed, standardized simulation model for abdominal wall hernias, sublay repairs were performed with six different types of commercially available hernia mesh. The biomechanical stability achieved, and the protection afforded by the mesh-hernia overlap, were compared for three different techniques: nonfixation, point-by-point suture fixation, and fibrin sealant fixation. RESULTS: Mesh dislocation from the repaired hernia defect was consistently seen with nonfixation. This was reliably prevented with all six mesh types when fixed using either sutures or fibrin sealant. The highest stress resistance across the whole abdominal wall was found following superficial fixation with fibrin sealant across the mesh types. There was a highly statistically significant improvement in fixation stability with fibrin sealant versus fixation using eight single sutures (p = 0.008), as assessed by the range of achievable peak pressure stress up to 200 mmHg. CONCLUSIONS: To ensure long-term freedom from recurrence, intraoperative mesh-hernia overlap must be retained. This can be achieved with fibrin sealant up to the incorporation of the mesh - without trauma and with biomechanical stability.

Gas-related impact of pneumoperitoneum on systemic wound healing.

INTRODUCTION: The aim of the present study was to investigate the gas-dependent effects of pneumoperitoneum on wound healing distant from the abdomen. MATERIALS AND METHODS: Dorsal skin incisions were performed in 54 male Sprague-Dawley rats. A CO(2) 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. RESULTS: 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 CO(2) group. CONCLUSION: Our results suggest beneficial effects on systemic wound healing for helium pneumoperitoneum as compared to CO(2).

Analysis of c-myc, PAI-1 and uPAR in patients with incisional hernias.

BACKGROUND: Disturbed wound healing leading to alterations in collagen composition has been thought to play a key role in the pathogenesis of incisional hernia formation. The aim of the present study was to further characterise the scarring process in such patients. METHODS: Mature skin scars from patients with either primary or recurrent incisional hernias were compared to mature abdominal skin scars from patients without hernias. The distribution of collagen types I and III was analysed using crosspolarisation microscopy. Expression of c-myc--a parameter for cell differentiation and proliferation--and of PAI-1 and uPAR--parameters of the proteolytic cascade in wound healing--were determined by immunohistochemistry. RESULTS: In agreement with previous studies, decreased collagen I/III ratios were found in patients with incisional hernias. In these patients, c-myc levels were significantly elevated whereas plasminogen activator inhibitor-1 (PAI-1) and urokinase-plasminogen activator receptor (uPAR) levels were only slightly increased. In contrast to controls, a significant correlation between c-myc, PAI-1 and uPAR expression and collagen I/III ratios was found in patients with incisional hernias. CONCLUSION: The differential correlation of collagen types and expression of c-myc, PAI-1 and uPAR within the scar tissue might represent a causal factor in incisional hernia formation.

Fibrin sealant for mesh fixation in Lichtenstein repair: biomechanical analysis of different techniques.

BACKGROUND: Mesh fixation using sealants is becoming increasingly popular in hernia surgery. Fibrin sealant is an atraumatic alternative to suture or stapler fixation and is currently the most frequently used sealant. There are currently no biomechanical data available for evaluation of the quality of adhesion achieved with fibrin sealant during Lichtenstein hernia repair. METHODS: Five different suture and sealant techniques were evaluated and compared during simulated Lichtenstein hernia repair in an established, standardised biomechanical model for abdominal wall hernias. RESULTS: Significantly greater stability was achieved with fibrin sealant fixation of meshes than with point-by-point suture fixation. Fibrin adhesion protected meshes from dislocation at least as well as suture fixation with additional running-suture closure of the hernia orifice. Fibrin mesh fixation combined with additional support from running-suture hernia closure was significantly (P < or = 0.002) superior to all other methods. CONCLUSIONS: On the basis of these favourable biomechanical properties, mesh fixation using fibrin sealant can be recommended for use in onlay repair of transinguinal hernias.

[Video-assisted retroperitoneal debridement : Minimally invasive treatment and long-term results for necrotizing pancreatitis]. / Videoassistiertes retroperitoneales Débridement : Minimalinvasive Therapie und Langzeitverlauf bei nekrotisierender Pankreatitis.

BACKGROUND: Among patients with necrotizing pancreatitis 15-20% develop infected necrosis, which entails mortality rates of up to 20%. Particularly driven by the results of the Dutch Pancreatitis Study Group there has been a paradigm change from open necrosectomy to step-up treatment with initial percutaneous and/or endoscopic drainage followed, if necessary, by minimally invasive retroperitoneal debridement. AIM OF THE STUDY: Description of case series in which patients underwent video-assisted retroperitoneal debridement (VARD) including follow-up focused on quality of life. METHODS: Systematic cohort study including all patients who underwent a VARD procedure at the Department of General, Visceral and Transplantation Surgery at Aachen University Hospital from 2011 to 2015. Quality of life was recorded using the EORTC QLQ-C 30 questionnaire and compared to a representative sample of the German general population. RESULTS: The VARD procedure was performed in 9 cases, although in 1 case conversion to an open approach due to an acute bleeding was necessary. There was no 30-day and 60-day mortality following VARD. During the postoperative stay no patient required specific treatment for surgical complications. In particular, no enterocutaneous fistula or organ perforation was observed. Regarding the quality of life score there was no significant difference concerning the global health status, compared to the sample from the general population. DISCUSSION: Our data reinforce that a step-up approach in patients with necrotizing pancreatitis is a feasible and safe treatment procedure. For the first time, we could demonstrate satisfactory results in a long-term follow-up including QOL.

Improved abdominal wall wound healing by helium pneumoperitoneum.

BACKGROUND: Despite widespread use of the endoscopic technique in the treatment of inguinal and incisional hernias, knowledge about its impact on abdominal wall wound healing is rare. Questions remain regarding the risk of port-site hernias and hernia recurrence. The current study investigated the gas-dependent effects of pneumoperitoneum on laparotomy wound healing. METHODS: Laparotomy was performed in 54 male Sprague-Dawley rats. A carbon dioxide (n = 18) or helium (n = 18) pneumoperitoneum of 3 mmHg was maintained before and after laparotomy, with an overall duration of 30 min. The rats in the control group (n = 18) received no pneumoperitoneum. The animals were killed after 5 and 10 days, and the abdominal wall was explanted for subsequent histopathologic examinations of the laparotomy wound. The granuloma formation in hematoxylin and eosin-stained sections was analyzed. Infiltration of macrophages (CD68) and expression of matrix metalloproteinases (MMP-8 and MMP-13) were examined by immunohistochemistry. The collagen type 1 to type 3 ratio was investigated by cross-polarization microscopy after Sirius Red staining. RESULTS: After 5 and 10 days, the percentages of CD68-positive cells, granuloma formation, and expression of MMP-8 did not differ between the groups. In contrast, after both 5 and 10 days, the expression of MMP-13 and the collagen 1 to 3 ratio were significantly higher after helium pneumoperitoneum than in the control animals. CONCLUSION: The results suggest that helium pneumoperitoneum may ameliorate wound healing within the abdominal wall and could therefore represent a beneficial gas for endoscopic hernia repair.

Laparoscopy and collagen metabolism.

The collagens represent a vital component within the wound healing process and physiological scar formation. Therefore, analysing the influence of new operative procedures on collagen metabolism is of great surgical interest. As the endoscopic technique has, nowadays, become routinely applied for diverse abdominal diseases worldwide, we present a review of literature facing its impact on collagen biology.

Modification of collagen formation using supplemented mesh materials.

BACKGROUND: Formation of recurrent inguinal and incisional hernia shows an underlying defect in the wound healing process. Even following mesh repair an altered collagen formation and insufficient mesh integration has been found as main reason for recurrences. Therefore the development of bioactive mesh materials to achieve a local modification of the scar formation to improve patients outcome is advisable. METHODS: Thirty-six male Wistar rats were used within this study. A Mersilene (R) mesh sample was implanted after midline skin incision and subcutaneous preparation. Before implantation mesh samples were incubated for 30 minutes with either one of the following agents: doxycycline, TGF-beta 3, zinc-hydrogeneaspartate, ascorbic acid, hyaluronic acid. Incubation with a physiologic 0.9 % NaCl solution served as control. Seven and 90 days after mesh implantation 3 animals from each group (n = 6) were sacrificed for morphological observations. Collagen quantity and quality was analyzed measuring the collagen/protein as well as the collagen type I/III ratio. RESULTS: Following an implantation interval of 90 days supplementation with doxycycline (39.3 +/- 7.0 microg/mg) and hyaluronic acid (34.4 +/- 5.8 microg/mg) were found to have a significantly increased collagen/protein ratio compared to implantation of the pure Mersilene (R) mesh samples (28.3 +/- 1.9 microg/mg). Furthermore, an overall increase of the collagen type I/III ratio was found in all groups indicating scar maturation over time. However, no significant differences were found after 7 and 90 days of implantation comparing collagen type I/III ratio of supplemented mesh samples and control group. CONCLUSIONS: In summary, we found an influence of supplemented mesh materials on collagen deposition. However, the investigated bioactive agents with reported influence on wound healing were not associated with an improved quality in scar formation.

Risk factors related to recurrence in inguinal hernia repair: a retrospective analysis.

The aim of this study was to analyze and evaluate the long-term recurrence rate and risk factors for inguinal hernia recurrence in patients treated by the Shouldice suture repair. A total of 293 hernias treated by Shouldice suture technique in 1992 were studied retrospectively. After a 10-year follow-up, 15 potential risk factors for recurrence were assessed in 142 patients undergoing 171 Shouldice repairs. Recurrent hernias showed a significantly higher (22.0%) recurrence rate than primary inguinal hernias (7.7%). Furthermore, an age of more than 50 years, smoking, and the presence of two or more similarly affected relatives were found to be independent risk factors for recurrence. The present study underlines the importance of patient-related risk factors for the development of a recurrent inguinal hernia. Patients at risk should preoperatively be identified in order to improve treatment by, for example, the application of mesh techniques.

Incisional intercostal hernia after a nephrectomy.

The aim of the present case report is to present the diagnostic and therapeutic challenge of intercostal incisional hernia. We report on a female patient with leftsided intercostal incisional hernia between the eleventh and twelfth rib due to preceding lumbar incision for tumor nephrectomy. Because of its infrequence, diagnosis was established late although simple clinical examination and ultrasound investigation displayed the hernia. At laparotomy, a 5x5 cm(2) fascial defect with a colonic sliding hernia was found. Hernia repair using permanent mesh reinforcement in the retromuscular position is described. Abdominal incisional hernia in the intercostal region is rare and therefore easily overlooked. As with other incisional hernias, the hernia repair using mesh implantation in the retromuscular region is technically feasible and represents the treatment of choice.

Biomaterial-dependent MMP-2 expression in fibroblasts from patients with recurrent incisional hernias.

With regard to the pathogenesis of recurrent incisional hernia, an impaired connective tissue quality leading to an aberrant scarring process has been proposed. For the matrix metalloproteinase (MMP-2) a pathogenetic involvement in direct inguinal hernia development is reported. With mesh implantation as the gold standard treatment for incisional hernias, the aim of the present study was to investigate the MMP-2 expression in patients with recurrent incisional hernias with and without mesh-materials. In primary fibroblast cultures obtained from skin scars in patients with and without recurrent incisional hernias, MMP-2 synthesis and gene expression were investigated. Furthermore, MMP-2 synthesis and gene expression of fibroblasts were compared after incubation with two different mesh materials: polypropylene and absorbable polyglactin filaments. MMP-2 enzyme activity was determined by semiquantitative zymography and mRNA synthesis by quantitative RT-PCR. Both MMP-2 enzyme activity and mRNA expression were similar in hernia and control fibroblasts in vitro. In control fibroblasts mesh incubation did not significantly affect MMP-2 expression, whereas polypropylene mesh contact of fibroblasts from patients with recurrent incisional hernias led to a major decrease of MMP-2 activity and of mRNA expression. In the absence of biomaterials fibroblasts from recurrent incisional hernia, patients have no alterations of their MMP-2 synthesis compared to control fibroblasts, whereas a specific response was found after biomaterial contact hereby indicating differences in fibroblast phenotype.

Intraabdominal adhesion formation of polypropylene mesh. Influence of coverage of omentum and polyglactin.

BACKGROUND: Adhesions after intraabdominal surgical procedures are related to high morbidity and mortality. Biomaterials, particularly those made of polypropylene, in the intraabdominal position have to be considered as pathophysiological cofactor in a multifactorial process of adhesion formation. To investigate the adhesive potential induced by the biomaterial, an animal model was performed. In addition, the influence of coverage by omentum or a polyglactin barrier was investigated. METHODS: In, 18 Chinchilla rabbits the biomaterial was placed laparoscopically using the intraperitoneal onlay mesh technique. Using this model, a polypropylene-polyglactin mesh compound (PPMC) was used with three different implantation techniques: group 1, PPMC implantation without coverage (PPMC): group 2, PPMC implantation with additional omentum coverage (PPMC-O): and group 3, PPMC implantation with coverage of an absorbable polyglactin mesh (PPMC-V). The degree of adhesion formation was measured 90 days after implantation by computer-assisted planimetry. Morphometric examination followed the explantation analyzing the amount of foreign body response. RESULTS: We found a significant reduction of adhesion formation for the PPMC and PPMC-O groups compared to the PPMC-V group, in which dense adhesions were found. Morphometric investigations of the perifilamental granulomas of the pure (PPMC) group revealed a typical foreign body reaction with a mild to moderate fibrosis around all mesh fibers. However, tissue specimens of the PPMC-O and PPMC-V groups indicated a similar inflammatory reaction but significantly increased connective tissue formation around the polymer fibers compared to the pure PPMC group. CONCLUSION: The intraabdominal placement of a pure PPMC shows a neoperitonealization and perifilamental collagenous ingrowth with almost no adhesions. Coverage with omentum (PPMC-O) or polyglactin mesh (PPMC-V) resulted in a significant increase in inflammation and perifilamentary connective tissue formation.

Influence of pneumoperitoneum on small bowel anastomoses: a histological analysis in the rat model.

Laparoscopic techniques are increasingly applied for the treatment of diverse gastrointestinal diseases. With regard to reports of a pronounced decrease of intra-abdominal blood flow with increasing intra-abdominal pressure, the present study investigates the impact of pressure and gas type on ischemia in small bowel anastomoses in the rat model. Laparotomy and ileoileal anastomosis were performed in 39 male Sprague-Dawley rats. A CO2 or helium pneumoperitoneum of 3 mm Hg or of 6 mm Hg was maintained before and after anastomoses. Rats in the control group received no pneumoperitoneum. Animals were sacrificed after 5 d, and the anastomotic region was explanted for subsequent histopathological examinations. In hematoxylin and eosin (HE)-stained sections, the Chiu score, villi configuration, and number of goblet cells were analyzed. Proliferation (Ki67) and expression of a matrix metalloproteinase (MMP-8) were examined by immunohistochemistry. Mucosal damage according to the scoring system by Chiu, the number of goblet cells, the villus length, the proliferation (Ki67), and the submucosal expression of MMP-8 was similar in all groups. Our results suggest that within a certain range of pressures and time, laparoscopic assisted surgery using CO2 pneumoperitoneum can be performed safely. Helium gas offers no advantages over CO2.