A hernia occurs when an internal part of the body pushes through a weakness in the muscle or surrounding tissue wall.

Your muscles are usually strong and tight enough to keep your intestines and organs in place, but a hernia can develop if there are any weak spots.

What is an inguinal hernia?

An inguinal (pronounced "ingwanal") hernia is the most common type of hernia. The hernia can appear as a swelling or lump in your groin, or as an enlarged scrotum (the pouch containing the testicles). The swelling may be painful.

The lump will often appear when you are lifting something and disappear when you lie down.

What causes an inguinal hernia?

An inguinal hernia usually occurs when fatty tissue or a part of your bowel, such as the intestine, pokes through into your groin at the top of your inner thigh.

It pushes through a weak spot in the surrounding muscle wall (the abdominal wall) into the inguinal canal. The inguinal canal is a channel through which blood vessels to the testicles pass in men and through which the round ligament (the ligament surrounding the womb) passes in women.

Inguinal hernias occur mainly in men. Most are thought to be due to ageing. This is because as you get older, the muscles surrounding your abdomen (tummy) can become weaker.

Inguinal hernias can sometimes appear suddenly due to strain on the abdomen, such as straining on the toilet if you have constipation or carrying and pushing heavy loads. They have also been linked to having a persistent, heavy cough.

When is surgery needed?

Inguinal hernias can be repaired using surgery to push the bulge back into place and strengthen the weakness in the abdominal wall.

The operation will only usually be recommended if you have a hernia that causes severe or persistent symptoms, or if any serious complications develop.

Complications that can develop as a result of an inguinal hernia include:

• obstruction – where a section of the bowel becomes stuck in the inguinal canal, causing nausea, vomiting and stomach pain, as well as a painful lump in the groin
• strangulation – where a section of bowel becomes trapped and its blood supply is cut off; this requires emergency surgery within hours to release the trapped tissue and restore its blood supply so it does not die

Surgery will get rid of the hernia and prevent any serious complications, although there is a chance of it returning after the operation.

What happens during surgery?

There are two ways that an inguinal hernia repair can be performed:

• open surgery – where one cut is made to allow the surgeon to push the lump back into the abdomen
• keyhole (laparoscopic) surgery – a less invasive but more difficult technique where several smaller cuts are made, allowing the surgeon to use various special instruments to repair the hernia

There are advantages and disadvantages to both methods. The type of surgery you have will depend on which method suits you and your surgeon’s experience.

You should be able to go home the same day or the day after surgery. It's important to follow the hospital's instructions on how to look after yourself. This includes eating a good diet to avoid constipation, caring for the wound and not straining yourself too soon.

Most people make a full recovery from inguinal hernia repair within six weeks, although many people are able to return to driving, work and light activities within two weeks.

Read more about how an inguinal hernia repair is performed and recovering from an inguinal hernia repair.

Are there any risks from the operation?

An inguinal hernia repair is a routine operation with very few risks. However, up to 1 in every 10 hernias will recur at some point after surgery, with around 1 in every 50 recurring within two years.

Other potential complications of inguinal hernia repair include:

• blood or fluid building up in the space left by the hernia (this will usually get better without treatment)
• painful swelling and bruising of the testicles or base of the penis in men
• pain and numbness in the groin area caused by a nerve being damaged or trapped during surgery

Complications are more likely if you are over 50 or you have another illness, such as heart disease or breathing problems.