Introduction and Definitions

A hernia is – a protrusion of a viscous out of a containing cavity. i.e. it is when a structure passes through another thing and ends up somewhere it shouldn’t be.
  • Irreducible – the hernia can’t be pushed back to where its supposed to be
  • Incarcerated – the contents of the hernia sac are stuck inside it by adhesions
  • Obstructed – the contents of the bowel is prevented from passing along the bowel as an obstruction has occurred as a result of the hernia
  • Strangulated – ischaemia of the tissue inside the hernia occurs. This patient will become toxic and requires urgent surgery. Strangulation can lead to herniation! Note that with a strangulated hernia, it is possible to push the strangulation back inside where it has come from, and thus give the appearance of a successful reduction, but in actual fact, you have not de-strangulated the hernia.

The three signs of bowel obstruction:

  • Distension
  • Vomiting
  • Absolute constipation – (no wind or faeces)

Checking for hernias

Abdominal hernias can be found in the following places (indicated on diagram). They are most common in the inguinal region.

Inguinal

These are more common in men, and are more common than femoral hernias.
To understand inguinal hernias, we have to know a little bit about the inguinal canal. We find the inguinal canal, just above the medial half of the inguinal ligament. The inguinal ligament goes from the anterior superior iliac spine, to the pubic tubercle. The inguinal canal ahs the deep inguinal ring at its lateral side, and the external inguinal ring at its medial side. The inguinal canal is the canal between these two rings. In men, the rings and the canal are larger, hence the fact that inguinal hernias are more common in men. The contents of the canal are the genitofemoral nerve, and the spermatic cord (round ligament in women).

 

Indirect inguinal hernias – these come through the deep inguinal ring, and if large enough, out of the superficial inguinal ring. To reduce these, you have to go from medial to lateral. You will see this above and medial to the pubic tubercle – if it is large enough to have come out of the superficial ring. These account for 80% of inguinal hernias. They can strangulate – and usually at the deep inguinal ring as this is narrow.
If the hernia is really big it can descend into the scrotum and the labia majora.
Direct inguinal hernias – these come into the inguinal canal through a defect in the posterior wall of the canal. These are easier to reduce – they should just pop straight back in! these account for 20% of inguinal hernias. They are generally easy to reduce and do not strangulate.

As this fantastic diagram demonstrates, you can see the deep inguinal ring is located ½ way along the inguinal ligament, 1 ½ cm above this midpoint. The superficial ring is just about above the pubic tubercle.

Differentiating direct and indirect hernias – this is loved by examiners, but is actually of no clinical use as the repair for both is the same – you should reduce the hernia, then occlude the internal inguinal canal with 2 fingers. Ask the patient to cough. If it pops out, then is direct, if it stays in then its indirect!
Don’t forget the acronyms for remembering what stuff is around here! – NAVEL – (or NAVY)
  • N – Nerve
  • A – artery
  • V – vein
  • E – empty space
  • L – lymphatics

Femoral

These tend to occur more in females. They tend to be irreducible and strangulate.  These go down the femoral canal (not the inguinal canal). They are usually found below and lateral to the inguinal ligament – this is the opposite of inguinal hernias! However, remember they can present above the inguinal ligament as well – but when they do, they will point along the femoral canal, and down the leg, as opposed to towards the groin (like inguinal ones do). Repair is recommended for these hernias.
 

Paraumbilical hernias

These are found just above or just below the umbilicus. Omentum or bowel can herniated through them. Surgery involves repair of the rectus sheath. Risk factors involve obesity and ascites.

Epigastric hernias

These pass through the linea alba above the umbilicus.

Inscisional hernias

These appear along lines of previous incision due to surgery. They occur in up to 11-20% of cases of surgery. Below you can see a diagram of incisional scars.

Spigelian Hernias

These occur at the lateral edge of the rectus sheath, below and lateral to the umbilicus.
 
Note that other hernias can occur all over the abdomen – the ones described are just the main types.
Irreducable hernia – often you may be asked to reduce a hernia. They can often be present for a long time, but still suddenly become painful. It is important to try and reduce it yourself, because you can prevent strangulation (which can be a surgical emergency due to necrosis). You should perceiver when trying to reduce – especially with obstruction – remember it can prevent surgery!
Reducing a hernia – requires lots of practice! The patients themselves are often experts. Generally they tend to use the flat of the hand, and push with the hand of the opposite side.

Repairing an inguinal hernia

This is usually done with a mesh technique. The patient should be advised to lose weight and stop smoking before the operation. In these procedures, a synthetic mesh is used to re-enforce the posterior inguinal canal wall. The same technique is used regardless of if it is a direct or an indirect hernia. The recurrence rate is less than 2%.
It is a very common operation – >100 000 per year in the UK. Often now it is performed as a day case under local anaesthetic, and this is useful because it helps to reduce the cost to the NHS. Laparoscopic techniques are also available and are just as successful, but they aren’t recommended as standard techniques.
Patients can return to work, including manual labour and driving after 2 weeks if they feel comfortable. Older practice used to advice 4 weeks rest.

Reducing a hernia

Can be an OSCE skill!
  • Get a chaperone
  • Wash hands
  • Introduce to patient – explain what you are going to do, get consent etc.
  • Get hands + gloves
  • Ask the patient if they are having any pain anywhere
  • Ask them to stand up and expose themselves
  • Cough – whether you can see a bulge or not, ask them t cough. You might then see one even if you couldn’t see it to begin with.
  • Feel – if you can see a bulge, put your hand on it, and get them to cough. You should feel it bulge when they cough.
  • Still not felt anything? – then you should you feel around a bit! Remember where the deep inguinal ring is – ½ way along the inguinal ligament – just above it. Just below the inguinal ligament in this place is the femoral pulse. Identify the pubic tubercle to help you identify what type of hernia (direct, indirect, femoral). You might also want to check the scrotum for inguinal scrotal hernia.
  • Try reducing the hernia – along with the info you have got from the site of the hernia, this should help you tell what type it is.
  • Wash your hands and report your findings!
Other bits of info:
  • Lymph nodes of greater than 1cm in this region are pathological and should not be ignored
  • Note the distribution of pubic hair in men – is it distributed as it is in females? Are the testicles looking shrunken?

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