Marcel Binnebösel

Biomechanical analyses of mesh fixation in TAPP and TEP hernia repair

BackgroundReliable 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.MethodsUsing 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.ResultsMesh 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.ConclusionsTo 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.

Are collagens the culprits in the development of incisional and inguinal hernia disease

Incidence curves for the development of inguinal hernia disease and recurrences thereof exhibit a linear rise over the years and therefore suggest multi-factorial underlying causes. Several studies have revealed marked changes in the abundance and composition of interstitial collagens in patients with (recurrent) hernia diseases, adult groin hernia and incisional hernia. These observations led to the hypothesis that hernia formation and the recurrence of incisional hernia may be explained by disordered tissue renewal and by abnormal wound healing, respectively. Interstitial collagens, owing to their long half-lives and biomechanical strength, are most likely critical components of the biological system of tissue remodelling. An overview of the literature is provided, and the consequences for surgical practice are discussed.

Simvastatin Reduces Endotoxin-Induced Acute Lung Injury by Decreasing Neutrophil Recruitment and Radical Formation

Introduction Treatment of acute lung injury (ALI) remains an unsolved problem in intensive care medicine. As simvastatin exerts protective effects in inflammatory diseases we explored its effects on development of ALI and due to the importance of neutrophils in ALI also on neutrophil effector functions. Methods C57Bl/6 mice were exposed to aerosolized LPS (500 µg/ml) for 30 min. The count of alveolar, interstitial, and intravasal neutrophils were assessed 4 h later by flow cytometry. Lung permeability changes were assessed by FITC-dextran clearance and albumin content in the BAL fluid. In vitro, we analyzed the effect of simvastatin on neutrophil adhesion, degranulation, apoptosis, and formation of reactive oxygen species. To monitor effects of simvastatin on bacterial clearance we performed phagocytosis and bacterial killing studies in vitro as well as sepsis experiments in mice. Results Simvastatin treatment before and after onset of ALI reduces neutrophil influx into the lung as well as lung permeability indicating the protective role of simvastatin in ALI. Moreover, simvastatin reduces the formation of ROS species and adhesion of neutrophils without affecting apoptosis, bacterial phagocytosis and bacterial clearance. Conclusion Simvastatin reduces recruitment and activation of neutrophils hereby protecting from LPS-induced ALI. Our results imply a potential role for statins in the management of ALI.

Mesh biocompatibility: effects of cellular inflammation and tissue remodelling.

Mesh biocompatibility is basically determined by the foreign body reaction (FBR). In contrast to physiological wound healing and scar formation, the FBR at the host-tissue/biomaterial interface is present for the lifetime of the medical device. The cellular interactions at the mesh/tissue interface proceed over time ending up in a chronic inflammatory process. The time course of the FBR has been studied extensively and consists of three crucial steps that are protein absorption, cell recruitment and, finally, fibrotic encapsulation and extracellular matrix formation. Each of these steps involves a complex cascade of immune modulators including soluble mediators and various cell types. Recent research has focused on the cellular and molecular interactions of the distinct phases of the FBR offering a new basis for therapeutical strategies. The highly dynamic process of the FBR is considerably influenced by the biomaterial composition. Modifications of the type of polymer, the material weight, the filament structure and the pore size are realized and have substantial effects on the in vivo biocompatibility. Moreover, modern mesh technology aims to utilize the available implants as carrier systems for bioactive drugs. Studies in animal models account for the efficiency of these drugs that aim to reduce mesh-related infections or to minimize FBR by influencing inflammation or extracellular matrix remodelling. A thorough understanding of the molecular mechanisms of FBR provides a sophisticated background for the development of new biomaterials at least as carrier systems for bioactive reagents to reduce inflammation and to improve clinical outcome.

A civilian perspective on ballistic trauma and gunshot injuries

BackgroundGun violence is on the rise in some European countries, however most of the literature on gunshot injuries pertains to military weaponry and is difficult to apply to civilians, due to dissimilarities in wound contamination and wounding potential of firearms and ammunition. Gunshot injuries in civilians have more focal injury patterns and should be considered distinct entities.MethodsA search of the National Library of Medicine and the National Institutes of Health MEDLINE database was performed using PubMed.ResultsCraniocerebral gunshot injuries are often lethal, especially after suicide attempts. The treatment of non space consuming haematomas and the indications for invasive pressure measurement are controversial. Civilian gunshot injuries to the torso mostly intend to kill; however for those patients who do not die at the scene and are hemodynamically stable, insertion of a chest tube is usually the only required procedure for the majority of penetrating chest injuries. In penetrating abdominal injuries there is a trend towards non-operative care, provided that the patient is hemodynamically stable. Spinal gunshots can also often be treated without operation. Gunshot injuries of the extremities are rarely life-threatening but can be associated with severe morbidity.With the exception of craniocerebral, bowel, articular, or severe soft tissue injury, the use of antibiotics is controversial and may depend on the surgeons preference.ConclusionThe treatment strategy for patients with gunshot injuries to the torso mostly depends on the hemodynamic status of the patient. Whereas hemodynamically unstable patients require immediate operative measures like thoracotomy or laparotomy, hemodynamically stable patients might be treated with minor surgical procedures (e.g. chest tube) or even conservatively.

Comparison of Long-Term Biocompability of PVDF and PP Meshes

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

Operative outcome of colon interposition in the treatment of esophageal cancer: A 20-year experience

BACKGROUND In patients with esophageal cancer and a history of gastric surgery, colonic interposition is the treatment of choice. Our aim was to review our experience with this technique and to identify possible predictors of the clinical outcome. METHODS Between 1986 and 2006, 43 patients underwent esophageal reconstruction accomplished by colon interposition in our surgical department. Data from these patients were collected consecutively and reviewed retrospectively. RESULTS Colon interposition was performed isoperistaltically in 15 patients and was performed in 28 patients anisoperistaltically. In 18 patients, the right colon was used for interposition, whereas in 25 patients, the left colon was used. The mean survival time was 23+/-29 months. Artificial ventilation more than 24h, tumor differentiation grade III, the presence of major complications, and the presence of multivisceral resection had a significant negative influence on the operative outcome of colon interposition for esophageal replacement. CONCLUSION Colon interposition for esophageal replacement provides a satisfactory operative outcome with high complication rates. Therefore, it should be reserved as a treatment of second choice for cases in which the stomach is not available.

Macrophage and T-lymphocyte infiltrates in human peritoneal adhesions indicate a chronic inflammatory disease.

BackgroundPeritoneal adhesions are common and lead to significant clinical morbidity and mortality. Besides various individual factors, notably the inflammatory response to peritoneal defects affects adhesion formation. The aim of this study was to investigate whether there is inflammatory activity even in persistent adhesions.MethodsTissue specimens of 40 patients suffering peritoneal adhesions were prospectively collected. Expression profiles of seven parameters as potential mediators in cellular immune response, cell differentiation, and wound healing were analyzed (macrophages [CD68], B-lymphocytes [CD20] and T-lymphocytes [CD45], cyclo-oxygenase-2 [COX-2], Notch-3, β-catenin, and c-myc). Furthermore, clinical details and co-morbidities were recorded.ResultsInfiltrates of mononuclear round cells were found in all adhesion specimens irrespective of the maturity. Immunohistochemical analysis identified mononuclear round cells as macrophages (CD68) and as T-lymphocytes (CD45). Expression of CD68 was significantly elevated in adhesion tissue with an age <12 months. Positive expression of CD45, COX-2, Notch-3, β-catenin, and c-myc, was observed even in long-lasting adhesions.ConclusionsA persistent inflammatory process has to be considered, even in mature adhesions. Macrophages may play an important role in triggering adhesions, whereas T-cells and the Notch-3/β-catenin complex signaling pathway may play a crucial role in maintaining adhesions. These findings indicate that adhesions should not be regarded simply as an adynamic result of an operative trauma but rather may be grasped as a permanent process in remodeled tissue.

[Acute appendicitis. Modern diagnostics--surgical ultrasound].

Acute appendicitis is one of the most common acute surgical conditions of the abdomen. Nevertheless, the indications for appendectomy are associated with a high preoperative rate of false diagnoses. Although the rate of unnecessary appendectomies is comparatively high (20-30%) it is considered acceptable because the rate of perforated appendices is 7-30%. With good availability and lack of radiation exposure, ultrasound is the slice imaging modality of first choice. The sensitivity of ultrasonic detection of appendicitis lies between 55 and 98% and the specificity between 78 and 100%. Computed tomography (CT) has a significantly higher sensitivity for detecting acute appendicitis compared to ultrasound both in infancy and adulthood but the specificity shows no significant differences. CT is, therefore, the imaging modality of choice in cases of relevant differential diagnosis that cannot be visualized adequately or inconclusively by sonography especially in obese and critically ill patients. Comparison of ultrasound and magnet resonance imaging (MRI) revealed a significant advantage for MRI regarding accuracy, sensitivity and negative predictive value. In contrast, specificity and positive predictive value showed no significant differences. Currently MRI is only an alternative imaging modality to ultrasound in cases of undetermined and inconclusive ultrasonic findings especially in childhood and pregnancy. The value of ultrasound in the diagnosis of acute appendicitis is increasing and, particularly in the hands of experienced investigators, is an important imaging modality which delivers important and decision-making findings. Nevertheless, the final decision for appendectomy depends on the findings of the physical examination.

Biocompatibility of prosthetic meshes in abdominal surgery

Surgical meshes today represent a group of implants mainly used for hernia repair. Modern hernia surgery is no longer imaginable without the application of these special biomaterials leading to millions of implantations each year worldwide. Because clinical trials are insufficient to evaluate the distinct effects of modified mesh materials in regard to tissue biocompatibility and functionality, a basic understanding of the physicochemical properties of mesh materials, as well as the underlying cause for hernia formation, is essential for a rational selection of the most appropriate device. The most important properties of meshes were found to be the type of filament, tensile strength, and experimental data, which indicate that particularly the meshs porosity is of outstanding importance.