What is a Hernia?

What is a Hernia? When any part of the body protrudes through a normal or abnormal defect it is said to herniate. We usually apply this term to the abdominal wall structures or abdominal wall contents. However the term can be applied to other parts of the body.


External hernias of the abdominal wall usually present as a swelling noticed by the patient or detected routinely on examination by a doctor. This swelling may come and go.  It often protrudes when the person is standing up or straining. The hernia may disappear at night when lying down or when it is pushed in.  The lump may be permanently irreducible.

There may be discomfort or pain present.

The lump detected is made up of contents from within the abdomen, which are out of their normal place. This may consist of fat, omental fat, small or large bowel and other organs, such as bladder, ovary or rarely even appendix.

Apart from inconvenience and discomfort hernias are important because they tend to enlarge and develop complications.



There are some basic terms, which are important in describing hernias.

Reducible – the hernia disappears back into the abdomen temporarily.
Irreducible – the hernia cannot be pushed back into the abdomen.
Incarcerated – the hernia contents have become trapped, irreducible and painful. This term suggesting that the hernia is becoming dangerous.
Obstructed – the bowel in the sac is blocked but is not dead. There is usually pain and vomiting and there may be an inability to pass flatus.  That is a bowel obstruction.
Strangulated – the hernia has had its blood supply clamped off and the contents such as bowel or fat are in the process of dying. Urgent surgical correction is required for this.


Some patients may have a hernia present for years and not have too much trouble. On the other hand some patients do not even know they have a hernia and suddenly present with one of the complications such as strangulation. That is why any patient who presents with abdominal symptoms such as pain or vomiting should have all their hernia sites thoroughly checked.

Many years ago, hernia surgery like other forms of surgery, was dangerous and there were significant complications to surgery. Included in this, there was a high rate of recurrence of the hernia following surgery. This meant that patients often deferred surgery, but it also meant there was a higher rate of significant complications such as strangulation and bowel obstruction.

The materials which we used to repair hernias years ago were not as strong and were more subject to the risk of infection. Now most of these problems have been overcome. Thus surgery is usually advised for all but the most minor of hernias. This should take into account of course the patient’s general health, age etc.

  • In the past, the hospital stay was many days. Now most patients can be treated as a day case.
  • In the past, extreme care regarding mobility and work was required. Now early mobility and return to work are encouraged.
  • In the past, there was a high recurrence rate following hernia surgery. Now the recurrence rate in specialist’s hands is low.

Then there were the complications and risks of general anaesthesia – now these risks are minimal but still need to be considered, even for healthy patients. The procedure is now carried out under local anaesthesia and sedation with mesh reinforcement – the “tension free” technique which allows early mobilisation, low recurrence rate, early return to normal activity and minimal after effects of the anaesthetic.

We recommend the tension free technique, popularised by Dr Lichenstein of the Lichenstein Hernia Centre and used exclusively in England’s largest Hernia Clinic, The British Hernia Centre.