Direct vs. indirect inguinal hernias
The inguinal canal travels through the abdominal wall and is a passageway from the abdomen to the genitals. People have two inguinal canals, one on each side of the lower abdomen.
The abdomen is defined as the area between the chest and hips. The lower abdominal wall is the inguinal region, more commonly known as the groin.
Often what bulges is body fat or part of the small intestine, which comes through a weakened part of the lower abdominal wall.
Here are some key points about hernias. More detail and supporting information is in the main article.
- Symptoms of both include groin pain, which can be severe.
- Direct inguinal hernias are often caused by age-related stress and weakened muscles in the inguinal canal.
- Indirect inguinal hernias are caused by a persistent opening that does not close during fetal development.
- The only way to repair an inguinal hernia is through surgery.
What is an inguinal hernia?
There are two types of inguinal hernias:
- Direct: Develops over time due to straining and is caused by weakness in the abdominal muscles. Most common in adult males and rare in children.
- Indirect: Caused by a defect in the abdominal wall that will typically have been present since birth. Most common in children, it affects up to 5 percent of newborns and up to 30 percent of premature babies. Often, it is discovered in the first year of life but can remain undetected until adulthood.
Inguinal hernias are up to 10 times more more common in men than women and one in four men will develop a hernia at some point in their life.
Symptoms of an inguinal hernia include pain, burning, or aching in the groin.
Symptoms can develop gradually or start suddenly. Sometimes a person is unaware of any symptoms, and the inguinal hernia is detected during a physical examination.
However, a person will often have symptoms, which can include:
- groin pain
- a bulge that comes and goes
- burning or aching sensation in the groin
- heavy or dragging sensation in the groin, especially at the end of a day or after prolonged activity
- swollen or enlarged scrotum in boys and men
Activities that cause strain on the abdomen can also make the bulge increase. These include:
- lifting objects
- straining for any reasons
- crying in infants
Symptoms may be hard to detect, especially if the hernia is not severe or large.
The cause of an inguinal hernia will depend on whether it is direct or indirect.
These usually occur in adult males. Aging and stress or strain can weaken the muscles around the inguinal canal. Previous surgery in the lower abdomen can also weaken the muscles there.
It is much less common for females to develop a direct hernia. This is because the round ligament of the uterus within the inguinal canal acts as an additional barrier alongside the muscle. The inguinal canal is also smaller in females.
Indirect hernias affect up to 30 percent of premature babies.
While a fetus is still in the womb, there is an internal opening to the inguinal canal, but this usually closes before birth.
When the inguinal canal opening fails to close completely by the time of birth, this allows a portion of fat or intestine to slip through and cause an indirect hernia.
In females, the ovaries and other parts of the reproductive system can slide through the opening and cause a hernia.
Indirect hernias are the most common type of inguinal hernia. Although they occur in both sexes, they are more more common in males than females.
- heavy lifting
- constipation and strain with bowel movements
- being overweight
There are several main ways that a doctor can see if a person has an inguinal hernia. These are:
The doctor will examine the individual, often asking them to stand and cough or strain, as this is the time when a bulge is most likely to occur.
Specially trained technicians will perform imaging tests, including X-rays, either in a doctor's office, an outpatient center, or a hospital.
A specialist, known as a radiologist, then interprets the images. Anesthesia is not usually needed.
The tests used to diagnose a hernia include X-rays and ultrasounds.
The tests include:
- Abdominal X-ray: An X-ray machine is positioned over the abdominal area and a small amount of radiation is used to take a picture.
- Computerized tomography (CT) scan: A person either drinks a solution, or a special dye, known as contrast medium, is injected into a vein. This helps to see blood vessels and blood flow on the X-ray.
- Ultrasound: A device known as a transducer bounces painless sound waves off organs and body parts to build up an image.
Inguinal hernia surgery is the most common general surgical procedure in developing and industrialized countries, with around 2 in every 1,000 people undergoing the operation every year.
Surgery does not always have to be immediate, but if an inguinal hernia is discovered, it must be monitored closely by a doctor to see if the symptoms get worse. If the tissue of the hernia becomes trapped or incarcerated, then surgery will be more urgent.
The two main types of surgery are:
- Open hernia repair: This is usually done under general anesthesia. A cut is made in the groin and the fat and intestines are moved back into the abdomen. Often, synthetic mesh will be placed over the weak area to prevent it reoccurring.
- Laparoscopic hernia repair: Usually done under general anesthesia, small cuts are made and a laparoscope, a thin tube with a camera on the end, is inserted. Using the camera images as a guide, the repair procedure is done.
Most people recover more quickly from laparoscopic hernia repair than open hernia repair, but in both cases complications are rare.
Intense activity and heavy lifting are not recommended for several weeks and pain medication is often prescribed.
Hernias can reoccur after being repaired, so it is important for patients to follow their doctor's aftercare instructions and advice to reduce the risk of reoccurrence.