What is an incisional hernia and how can it be treated?

In response to a question on healthshare.com.au

A hernia is where the internal parts of the body - such as the fat or the intestines inside the abdominal cavity (belly) - protrude through a gap or weakness in the muscles over them. The weakness can be natural, for example at the umbilicus (belly button) or in the groin; or it can be acquired as a result of an injury or a surgical incision.

An incisional hernia is a hernia that protrudes through a previous surgical incision. When a surgical incision heals the normal tissues are replaced by scar tissue. The scar does not have the same structural properties as the muscular and fibrous tissue it replaces, and the scar can weaken or stretch over time. Often this stretching is uneven, leaving gaps through which the fat or intestines can protrude.

Any abdominal incision can develop a hernia over time. Some things increase the risk of this happening: wound infections; emergency surgery; abdominal swelling causing excess tension on the stitches used to close the muscles; straining or lifting, particularly early after surgery.

Most incisional hernias should be repaired surgically to prevent them from enlarging or causing a bowel obstruction. Repair can be open or laparoscopic, although not all surgeons offer laparoscopic hernia surgery.

In most cases the weakness is not stitched together, but instead a piece of mesh is used to cover the hernia. The mesh can be made of plastic (polypropylene, polyester and PTFE are the commonest materials) or collagen from a biological source. Most meshes are designed to remain permanently within the body, although for some situations it is appropriate to use meshes that break down or are replaced by scar tissue. The mesh can be glued, tacked or stitched in place.