What is a hernia?

A hernia is an abnormal protrusion through the abdominal wall.  The protrusion contains a cavity (the hernial sac) which can be empty or it can fill with abdominal contents such as bowel. Typically hernias are more evident when standing or straining (eg coughing, heavy lifting, digging) as this forces bowel into the sac.  

Hernias usually develop over time for no obvious reason, although in some people there may be an inborn weakness in the abdominal wall.  They can occur in the scar from previous surgery. Occasionally a strenuous activity such as moving furniture will cause a lump to appear suddenly.  Hernias may occur at any age and are more common in men than women.

There are many types of hernia:

  • Inguinal hernia – this is the commonest type of hernia and results in a lump in the groin.
  • Umbilical hernia – these are usually quite small and it is rare for any bowel to get into the sac
  • Incisional hernia – a surgical scar can become weak and a bulge develops usually within a year or two of surgery
  • Femoral hernia – this is a groin hernia sometimes difficult to distinguish from an inguinal hernia with the lump slightly lower in the groin.
  • Parastomal hernia – here there is a hernia around a stoma (eg colostomy or ileostomy) which can make it difficult to manage the stoma


Hernias may simply present as a bulge that enlarges with standing or coughing.  A large hernia will give a dragging sensation.  Pain is not typical unless something is getting stuck in the sac. There is a danger that bowel can get caught within the sac, thereby causing a bowel obstruction or pain due to strangulation of the blood supply to that part of the bowel.  It is generally recommended, therefore, that hernias be repaired to prevent such complications arising.

Some early groin hernias can start with before a lump is evident – but a commoner cause of groin pain is a strain from strenuous activity.


Clinical examination is usually all that is required to make the diagnosis of a hernia. Where there is doubt an ultrasound scan is often performed; however the results have to be interpreted carefully as ultrasound can over diagnose hernias that are not clinically important. For large abdominal hernias a CT scan can be useful to plan surgery.


Almost all hernias need surgery as they tend to enlarge over time. The essence of surgery is to close the defect in the abdominal wall and reinforce the area with mesh to prevent recurrence. Hernia surgery can be performed as an ‘open’ operation with a cut in the skin over the hernia or as a laparoscopic (keyhole) operation depending on a number of factors.


In general hernia repair is straight forward, often performed as a day case (you are admitted and discharge the same day) All surgical procedures have potential complications and hernia repair is no different.

Recurrence – all hernias have a recurrence rate and this is to some extent dependent on which kind of hernia you have.  The recurrence rate following repair with a mesh is usually less than 2%.

Chronic discomfort in the groin – this can effect up to 10% of patients and is slightly more common in open hernia repairs.

Bruising – surgery can result in bruising or blood in the tissues of the groin.

Infection – this is rare in hernia repairs as it is a clean procedure and antibiotics are given to minimize the risk of skin organisms infecting the mesh.

Numbness – sometimes the small nerves to the groin can be damaged in any hernia repair and this might result in a small area of numbness which usually gets better over time.