11.14 Hernia
A hernia is when internal organs or tissues bulge through an inappropriate opening. Common types of hernias are inguinal hernias, hiatal hernias, and ventral hernias[1],[2],[3],[4],[5]:
- Inguinal hernias occur in the inguinal canal. The inguinal canal is a passageway that contains the spermatic cord and blood vessels in men and the round ligaments in women. See Figure 11.36[6] for an image of the small bowel herniating through the inguinal canal of a male.
- Hiatal hernias are when part of the stomach bulges through the diaphragmatic opening. This opening of the diaphragm is also known as the esophageal hiatus as the esophagus passes through this opening on its way to the stomach. See Figure 11.37[7] for an illustration of a hiatal hernia.
- Ventral hernias are hernias that occur in the wall of the abdomen and are neither inguinal nor hiatal in origin. See Figure 11.38[8] for an illustration of a ventral hernia in a child.
All types of hernias can be present at birth (i.e., congenital) or acquired over time, but they are most likely to be acquired. Risk factors for hernias depend on the specific type of hernia. See Table 11. 14 for a comparison of risk factors for inguinal, hiatal, and ventral hernias.[9],[10],[11],[12],[13]
Table 11.14. Hernia Risk Factors
| Inguinal Hernia | Ventral Hernia | Hiatal Hernia |
|---|---|---|
| Family history | Previous surgical procedures (leads to an incisional hernia or a hernia at the site of an incision) | Previous surgery |
| History of connective tissue disorders such as Ehlers-Danlos or Marfan syndrome | Trauma to abdominal wall | Trauma to abdominal wall |
| Increased intra-abdominal pressure (obesity, coughing, lifting of heavy objects, staining with bowel movements) | Stress to abdominal wall (obesity or frequent weight loss and gain) | Increased intra-abdominal pressure (obesity, pregnancy, straining with bowel movements, COPD) |
| Not linked to age, but much more common in males | Not linked to age | Older age |
| No genetic link | No genetic link | Genetic link |
Hernias can be further described as reducible or incarcerated. A reducible hernia means that the hernia and its contents can be pushed back into their normal anatomical space. An incarcerated hernia means that the hernia cannot be reduced. This can lead to a strangulated hernia, or when the hernia undergoes a reduction in oxygen supply due to reduced blood flow. This is considered a medical emergency that requires urgent surgical intervention.[14],[15],[16],[17],[18]
View a supplementary YouTube video[19] on hernias and hernia repair: Repairing a hernia with surgery.
Pathophysiology
Hernias usually occur when there is a combination of increased pressure, as well as an area of weakened tissue or musculature. The increase in pressure causes the organ or tissue to push through the weakened area.[20],[21],[22],[23],[24]
An inguinal hernia occurs when there is a weakened area in the oblique or transversalis muscles and abdominal organ