Incisional hernia is the most frequently seen long term complication in surgery causing much morbidity and even mortality in patients. Despite studies on the optimal closing technique for laparotomies, the risk for incisional hernia after midline incision remains about 5-20 %. Major risk factors for incisional hernia after a laparotomy, like obesity, steroid use, malnutrition, smoking and connective tissue disorders, are known. Despite this knowledge, there has not yet been developed a sufficient method for prevention. One specific group of high risk patients are patients with an abdominal aortic aneurysm (AAA). The relationship between aortic aneurysm and other abdominal wall hernias, like inguinal hernias, has been reported. Retrospective and prospective studies have shown an average risk for incisional hernia after AAA repair of 31.6 %. Another high risk group is the group of obese patients. Patients with a BMI of more than 27 have a high risk of developing an incisional hernia after midline incision with an incidence of 22% after 12 months. Considering only 50 % of incisional hernia will be clinically evident in the first 12 months, the total incidence will be above 30%. This high risk group of patients with obesitas and aneurysmatic disease can benefit most from prevention. Some small studies have been performed to evaluate the usefulness and safety of primary laparotomy wound closure with the aid of prosthetic mesh. These studies show a very low risk for incisional hernias and a low infection rate, even when used in contaminated wounds such as colostomal surgery. However, there has not been performed an adequate randomized controlled trial to study the prevention of incisional hernias. Our hypothesis is that incisional hernia prevention with use of prosthetic mesh after laparotomy is effective in patients with aortic aneurysm and in obese patients with a BMI of more than 27.

Inclusion Criteria:

• Every elective midline laparotomy for patients with Abdominal Aortic Aneurysm and patients with a BMI of more than 27.
• Signed informed consent

Exclusion Criteria:

• Age < 18 years
• Emergency procedure
• Inclusion in other trials
• Aortic reconstruction for obstructive disease
• Life expectancy less than 24 months
• Pregnant women