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 %. It has been established that implementing a mesh reduces recurrence of the incisional hernia but still the results of repair are often disappointing. Incisional hernias can become increasingly complex due to complicated abdominal wall defects caused by a disturbed anatomy, fistulas, burst abdomen, wound and mesh infections. In these cases it is not save to repair the incisional hernia by means of a synthetic mesh and other augmentation tools need to be implemented.

In the recent years the use of biological meshes has been gaining popularity. Recent reports of the use of collagen-based prosthesis have suggested that they support new vessel growth, do not excite a significant foreign body reaction, form fewer adhesions, are well incorporated into host tissues with minimal wound contraction, and can be used in grossly contaminated wounds with fewer infective complications. Biologic meshes are harvested from a source tissue and processed for medical use but they vary widely in their processing methods. They include tissues of human or animal origins, both chemically cross-linked and non cross-linked processes, and submucosal, pericardial, or dermal tissue sources. Current studies investigating the effectiveness of these meshes are small and have short periods of follow-up. These shortcomings can be explained to high cost of the meshes and unclear indication when to use a biological mesh.

The aim of this study is investigate the short and long term effects of the Permacol© biological mesh. Also the investigators will be inquiring why a biologic mesh was used, what is the true indication to use a biological mesh.

Inclusion Criteria:

• Signed informed consent
• Complicated abdominal wall hernia repair
• Permacol© mesh implantation

Exclusion Criteria:

• No signed informed consent
• Operation other than Complicated abdominal wall hernia repair
• Implant other than Permacol© mesh implantation

The design of the trial will be a cross sectional cohort study. We will be gathering information from all the centers in the Netherlands who have used the Permacol© mesh in the past to treat complicated abdominal wall defects. Patients will be asked to return to the hospitals outpatient clinic. A total of around 70 patients will be included into the study.