The late appearance ofincisional hernias several years after laparotomy and the high recurrence rates after operation strongly imply the presence of a disorder of the connective tissue, although a specific defect in patients with incisional hernias has not yet been identified. In the present study we used both immunohistochemistry and Western blot analysis to evaluate the ratio of collagen I and III and the expression of the metalloproteinases (MMP) 1 and 13 in the fascia of patients with incisional or recurrent incisional hernias. Samples of healthy skin or stable skin scar in patients without hernias served as controls. Altogether, our data indicated a significantly decreased ratio of collagen I/III in the fascia of patients with incisional hernias and recurrent incisional hernias. Furthermore, in these patients the expression of MMP-1 was decreased compared to the controls, whereas MMP-13 could not be detected in any fascia sample, with or without hernias present. For the first time, our results give evidence of the existence of a possible collagen disorder in these patients. The decreased ratio ofcollagen I/III is explainable due to a relative increase of collagen type III, which is known to be characterized by thin fibril diameters and lowered mechanical strength. The altered collagen ratio might be the result of the decreased activity of MMP-1, whereas the absent MMP-13 expression did not seem to modify the scar formation. Thus, our data indicate the presence of collagen metabolic disorders in patients with incisional hernias and recurrent incisional hernias. Furthermore, these results might explain the poor results of a mesh-free hernia repair, which again builds up scar tissue of inadequate collagen composition and strength.

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.

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.

The marked reduction in recurrence rates following reinforcement of the abdominal wall by meshes in incisional hernia has promoted their increasingly widespread use. The primary suture in technique failed more than half of the cases; therefore, the closure method needs to be changed and improved, particularly with regard to a possibly underlying defect in collagen metabolism. After more than 100 years of mesh development they are mainly placed in a sublay or onlay position, ePTFE, polyester and polypropylene are preferred. In any case the mesh has to overlap the defect sufficiently because of wound contraction. On the basis of our experience and reports in the literature, the advantages and disadvantages of various mesh techniques and mesh materials are discussed. However, because long-term studies are missing, the relevance of the cumulative risk for long-term complications such as mesh migration and fistula formation, the extent of patient complaints or the potential risk of a persistent foreign-body reaction cannot yet be ascertained. Nevertheless, because there are no surgical alternatives, meshes represent an improvement in hernia surgery that cannot be overestimated.

Pneumatosis cystoides intestinalis (PCI), a condition involving submucosal or subserosal gas-containing cysts of the wall of the gastrointestinal tract, is a rare entity. It is mostly diagnosed between the third and fifth decades of life without a clear sexual predominance. Different aetiopathogenetic factors are under discussion, the most probable being a bacteriologic cause (Clostridium perfringens) in combination with minimal leaks in the mucosal barrier. There are no pathognomonic symptoms; the clinical picture ranges from incidental findings to haematochezia. Diagnosis is based on plain abdominal film and X-ray following barium enema. Methods of treatment in symptomatic cases are oxygen and antibiotic (metronidazole) therapies and, in severe cases, resection of the diseased part of the intestine.