Hernias

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Hernias are defined as an abnormal protrusion of either tissue or organ e.g. bowel, from the normal area they are located in. There is a wide array of different types of hernias that patients may develop, with the most common hernia occurring in the groin. There are a number of risk factors that can increase the chance of hernias developing, these includes obesity, pregnancy, smoking, chronic lung conditions (COPD) and previous surgery. The anatomy of the hernia is dependent on the type of hernia. As hernias can occur at many sites management will be dependent on the symptoms, size of the hernia and location of the hernia.

Doctor holding hernia icon
Hernias are defined as an abnormal protrusion of either tissue or organ

Hernias are defined as an abnormal protrusion of either tissue or organ e.g. bowel, from the normal area they are located in. There is a wide array of different types of hernias that patients may develop, with the most common hernia occurring in the groin. There are a number of risk factors that can increase the chance of hernias developing, these includes obesity, pregnancy, smoking, chronic lung conditions (COPD) and previous surgery. The anatomy of the hernia is dependent on the type of hernia. As hernias can occur at many sites management will be dependent on the symptoms, size of the hernia and location of the hernia.

Different locations of abdominal wall hernias
Types of hernia include: Incisional, Umbilical, Direct Inguinal, Indirect Inguinal, Femoral and Epigastric

The Anatomy of the Abdominal Wall

Before discussing the different types of hernia, a brief understanding of the anatomy of the abdominal wall is required.

The abdominal cavity is enclosed in layers of muscles that wrap around from the back to enclose the anterior abdominal muscles (rectus abdominus). These muscles play an important role in breathing, structural support and posture, as well as hold the abdominal content within the abdominal cavity.

Anatomy of the abdominal wall showing the different muscular layers
Anatomy of the abdominal wall

These muscles can become over stretched for example in obesity, which interferes with the muscle integrity and results in weakness in its structure.

Abdominal Wall Hernia

The two most common types of abdominal wall hernia are umbilical hernias and epigastric hernias

Abdominal wall hernias are a result of herniation through a natural small defect; umbilical hernias occur around or through the umbilicus (belly button) and are seen in young infants. In comparison an epigastric hernia occurs above the umbilicus in the midline.

Umbilical hernia containing a loop of small bowel
Umbilical hernias occur around or through the umbilicus (belly button) and are seen in young infants

Abdominal wall hernias (umbilical) can be seen in conditions that cause increased intra-abdominal pressure for example in obesity, pregnancy or in conditions that result in ascites (excess fluid accumulation in the abdominal cavity e.g. liver failure).

Umbilical hernias are treated surgical by open surgery in infants and the timing will be dependent on the severity of the condition. Epigastric hernias on the other hand can be managed conservatively if they are small, or by surgical closure if large.

These muscles can become over stretched for example in obesity, which interferes with the muscle integrity and results in weakness in its structure.

Groin Hernia (Inguinal and Femoral)

A groin hernia comes in two forms, either an inguinal hernia or femoral hernia. Of which inguinal hernias are the most common.

Groin hernia containing bowel loop
A groin hernia comes in two forms, either an inguinal hernia or femoral hernia

The anatomy of the inguinal hernia is related to the inguinal canal, this is important during embryological development and remains patent in adulthood. However it is a natural canal that abdominal content/tissue may herniate through, this is referred to an indirect inguinal hernia. In addition there is a natural weak area of the abdominal wall related to the inguinal canal through which abdominal content/tissue can herniate and this is referred to a direct hernia. The inguinal canal is larger in males than females, and therefore indirect inguinal hernias are more prevalent in males.

To differentiate between the two types of inguinal hernia clinical examination is performed and the knowledge of the inguinal canal and Hesselbach’s triangle are needed to distinguish between the two types.

Patients may experience a bulge in their abdominal wall (direct inguinal hernia) just above the groin crease when sneezing, coughing or straining, as these activities increase intra-abdominal pressure and thereby make the hernia more prominent. Sometimes in males the hernia may be noticed by an enlargement in the scrotum which is a result of a herniation through the inguinal canal that is connected to the testicles.

Management can be conservative with the use of supportive clothing; however surgery is often offered if the hernia is large, or present in the absence of increased intra-abdominal pressure. Inguinal hernias that contain bowel tissue can become strangulated or blocked off resulting in bowel obstruction which requires urgent emergency surgery.

Inguinal hernias are repaired depending on the underlying anatomical cause and can be done by either open or laparoscopic surgery.

In comparison femoral hernias are more common in females due to the wider pelvis which facilitates childbirth. Abdominal content or tissue can herniate underneath the inguinal ligament appearing as a bulge in the upper groin region (below the groin crease). Unlike inguinal hernias, femoral hernias that contain bowel loops can commonly become strangulated and require urgent emergency surgery. Due to the potential risks associated with femoral hernias, surgical management is the gold standard of treatment.

Signs of severe causes of groin hernias include severe pain, vomiting, not opening bowels/inability to pass wind and in cases where the tissue blood supply is strangulated the patient may notice a black lump, or develop signs if infection and urgent hospital admission is needed.

Hiatus Hernia

A hiatus hernia is a specific type of hernia that involves an organ within the abdominal cavity typically the stomach, protruding through the diaphragm and into the thoracic cavity. Patients can experience a myriad of symptoms including chest pain, indigestion/heartburn, and difficulty in swallowing and an acidic taste in the mouth. It can also result in gastric oesophageal reflux disease (GORD).

Comparison between hiatus hernia and a healthy stomach
A hiatus hernia involves an organ within the abdominal cavity typically the stomach, protruding through the diaphragm and into the thoracic cavity

The anatomy at the junction between the lower oesophagus and stomach (gastro-oesophageal junction) is important to ensure the food and digestive enzymes don’t reflux back up into the oesophagus and is assisted by the diaphragm through which the oesophagus passes and joins the stomach.

Following a detailed history and examination, radiological investigations are performed to assist in diagnosis and can include the use of a chest x-ray, CT scan and endoscopy (OGD). There are two main types of hiatus hernias, a rolling or sliding hiatus hernia. In a sliding hiatus hernia, the stomach moves up through the opening of the diaphragm, whereas a rolling hiatus hernia is when the stomach moves up through a defect of the diaphragm.

The 3 types of hiatal hernia – Type 1 (sliding), type 2 (Rolling) and Type 3 (mixed)
The different types of hiatal hernia

Management can be divided into conservative and surgical. Conservative management includes life style modifications for example weight loss or adjusting eating habits. Medical management may include proton pump inhibitors (e.g. Ondasetron) or a H2 receptor antagonist (e.g. Ranitidine) which reduces gastric acid pH thereby reducing the symptoms experienced.

However if this fails to work or the hiatus hernia is large then surgery is needed. This can be done via an open or laparoscopic approach (Nissen fundoplication), however a laparoscopic surgery is the preferred choice.

Treatment of a hiatus hernia via laparoscopic Nissen Fundoplication surgery
Plication of the stomach to form a functional sphincter replacing the dysfunctional lower esophageal sphincter

Incisional Hernia

These occur following surgery, and are a result of weakness that is made when the abdominal wall has been incised to allow an operation to occur. It is more common following open surgery rather than keyhole (laparoscopic) surgery. It is most common in surgery requiring a midline incision of the abdominal wall (Laparotomy). They usually develop as a result of incomplete healing of the abdominal wall. Precipitating factors include the type of operation, post-operative infection (wound or chest), age, diabetes, smoking, steroids, and early return to physical activity prior to having the wound fully healed.

Incisional hernias usually develop several months post-surgery and can initially be felt/seen as a lump at the surgical site following a sneeze/cough. This is because the weakness at the incisional site is unable to maintain the integrity of the abdominal wall when there is increased intra-abdominal pressure (during sneezing, coughing, straining).

Conditions such as post-operative infections, diabetes, the use of steroids for chronic conditions (COPD, rheumatoid arthritis, and inflammatory bowel) and smoking all impair/delay healing. Therefore hernias are more commonly seen in these patients.

Management is dependent on the extent of the incisional hernia, however commonly these are managed surgically with either a mesh or non-mesh repair which can be done laparoscopically or via an open approach. Conservative management is reserved for very small incisional hernias, or in patients where the risk of a further operation outweighs the benefits.