The following statement(s) is/are true concerning abdominal incisional hernias

a. Large incisional hernias are associated with a high recurrence rate when closed primarily

b. A large potential space remains anterior to the abdominal wall closure in most patients indicating a need for postoperative wound drainage

 c. The use of prosthetic mesh can often be avoided by employing relaxing incisions in the anterior fascia parallel to the midline

d. Incisional hernias are frequently associated with a tissue deficit either due to chronic retraction and scarring or the result of tissue necrosis from either infection or tension at the initial closure

Repair of an incisional hernia can be difficult with several factors making these hernias particularly challenging. First, incisional hernias are often related to a postoperative wound infection, in which case associated fascitis or muscle necrosis may result in loss of tissue. Second, a previous abdominal wall closure under tension or with a technique that resulted in tension on particular sutures may lead to a multifenestrated region of the musculoaponeurotic abdominal wall near or slightly back from its margin. Third, chronic retraction of the abdominal wall muscles result in a larger defect. Fourth, a large potential space remains anterior to the abdominal wall closure in the subcutaneous area; postoperative fluid accumulation in this space contributes to the wound infection rate of 5%. Any such potential space should have operatively placed drains.

The key to successful repair involves sufficient dissection and exposure of the true musculoaponeurotic edge and exclusion of adjacent musculoaponeurotic defects and avoidance of closing the wound under tension. Large defects greater than 3 to 4 cm in diameter are seldom able to be closed without excessive tension. The use of relaxing incisions decreases tension and may be particularly useful in midline hernias and therefore may avoid the need for prosthetic mesh.