Ultrasound For Inguinal Hernia: Does Ultrasound Accurately Detect Hernia?

If you talk to general surgeons worldwide, they will tell you that inguinal hernias are among the most common surgical procedures they perform. That’s because over 20 million inguinal hernias are surgically repaired globally each year, and close to half of these are done in the United States.

While this post isn’t primarily about the prevalence of inguinal hernias, knowing that it is a relatively common condition informs our key question:

How do doctors diagnose inguinal hernias before a surgeon proceeds to operate on them?

Ultrasound for inguinal hernia is a key procedure in diagnosis. It usually follows a physical examination confirming the presence of an inguinal hernia or one that does not detect it, but the symptoms suggest it could be present.

To give you a complete picture of inguinal ultrasound, I’ll be answering these core questions in this post:

What exactly is an inguinal hernia? What are the types of inguinal hernia? Can an ultrasound detect a hernia? And … What type of ultrasound for inguinal hernia?

Let’s start with the most basic of these questions.

Inguinal refers to “the area of the groin” or “related to the groin”.

A hernia is a health condition in which a part of an organ bulges out of the cavity wall containing it.

As such, an inguinal hernia is one that’s situated in the groin area.

An inguinal hernia occurs when the abdominal tissue pushes through the wall of the lower abdomen. It presents as a bulging mass in the groin area.

Of all abdominal hernias, inguinal hernias are the most common, accounting for 75% of all abdominal wall hernia cases.

Regarding their cause, inguinal hernias can be congenital, but their risk also comes with muscle degeneration during aging.

Sex is also a factor, with more men than women being at a higher risk of developing inguinal hernias. In fact, inguinal hernia risk among men is 27%, against only 3% among women.

Men are more susceptible to inguinal hernias because the muscles of the abdominal wall open consistently to allow the passage of testicular vessels and spermatic cords.

It’s worth noting that an inguinal hernia is sometimes called a groin hernia. However, it is not the only type of hernia that can develop in the groin area. Femoral hernias also develop in the groin area.

But as a difference, inguinal hernias protrude from the intestines through or into the inguinal canal. Femoral hernias protrude from the intestine through the femoral canal and appear more on the thigh area.

There are also different types of inguinal hernias.

There are two types of inguinal hernias: indirect inguinal hernia and direct inguinal hernia. Both types occur in the inguinal canal that runs down the pelvic area into the sex organs.
Experts differentiate the two types by the mode of herniation or protrusion.

Indirect inguinal hernia describes the protrusion of abdominal tissue that starts from the inguinal ring and enters the inguinal canal at the top. It passes through the canal and exits or fails to exit the superficial ring.

The bulging of a lateral hernia is often associated with a birth defect where the inguinal canal fails to close completely during fetal development.

A direct inguinal hernia bulges straight through the lower abdominal wall at the region known as Hesselbach’s triangle. This region is considered weak and susceptible to herniation.

Medial hernias are common in adults, following the progressive weakening of the abdominal wall muscles and consistently exerted pressure on the wall.

Compared to each other, experts report these key differences between indirect and direct inguinal hernias:

The difference between the two types of inguinal hernias is also factored in when performing inguinal hernia ultrasound. I’ll tell you how that happens a bit later in the article after answering the question, can ultrasound see hernia?

Yes. An ultrasound can detect an inguinal hernia and even help know what type of hernia it is.

In fact, the US National Institutes of Health (NIH) confirms that ultrasound imaging has become the most convenient procedure in diagnosing inguinal hernia. This is because it has the benefits of ease in portability and being non-invasive since it does not involve any form of radiation.

Research also shows that inguinal ultrasound has a high positive predictive value in determining whether a hernia should be operated on. One such study reported a 90.9% correct prediction that inguinal hernia in 175 patients required surgery.

The 9.1% difference was due to a higher body mass index. As you may already know, ultrasound waves have weaker penetration where there’s dense fat tissue, and that could make hernia detection less effective.

Also, compared to imaging ultrasound alternatives for inguinal hernia diagnosis like MRI and CT scan, ultrasound is only second to MRI in sensitivity and specificity. Regardless, it is preferred for being non-invasive and more accessible in terms of cost.

Here’s how ultrasound compares to CT scan and MRI in detecting inguinal hernia.

As you’ll read in the following section, differences in the way ultrasound detects hernia can also be created by the type of ultrasound.

An abdominal ultrasound is used to detect inguinal hernia. This considering inguinal hernias protrude through the abdominal wall. The sonographer performs the abdominal ultrasound while the patient is in the supine position.

In an inguinal hernia diagnosis, an abdominal ultrasound follows a physical examination of the groin areas.

It is recommended that ultrasound imaging for inguinal hernia be dynamic, involving postural changes that allow for a more precise diagnosis.

A key postural aspect in inguinal hernia diagnosis is the Valsalva maneuver.

The maneuver entails the application of forceful exhaling with a closed mount to exact pressure on the abdominal wall while the sonographer maneuvers the probe. The maneuver will especially accentuate a reduced hernia when in the resting position.

The sonographer may want to repeat the ultrasound while the patient is in the standing position. This is especially recommended when inguinal hernia signs are present, but the ultrasound in a supine position does not reveal a hernia. Such signs include a bulge in the groin area and pain when lifting or coughing.

In the standing position, more pressure is applied in the groin area and can help reveal small hernias.

From the perspective of the type of ultrasound machine for inguinal hernia, a linear transducer with a scanning frequency of 10MHz is good enough to detect an inguinal hernia. That’s because the structures of the inguinal region are superficial.

However, for patients with a high body mass index, an ultrasound transducer with a lower scanning frequency (≤7MHz), like the DRSONO Tri-scan Max, is recommended. This allows deeper penetration through body fat tissue.

Diagnosing inguinal hernia takes essentially the same procedure for women as for men. In women, as in men, an inguinal hernia can be detected by physical examination or palpitation while performing the Valsalva maneuver.

However, while inguinal hernias may present in an obvious bulge in men, this may not be the case in women due to their differentiated anatomy. That often means women, more than men, may require an ultrasound to diagnose an inguinal hernia.

For the same reason of differentiated anatomy, doctors need to perform a different ultrasound probe maneuver when diagnosing inguinal hernial in women.

Here’s how.

This video demonstrates how to perform a hernia ultrasound for both inguinal and femoral hernias. It will give you a general idea of how to perform an inguinal ultrasound on women and men.

It’s also worth noting the difference between indirect inguinal hernia ultrasound and direct inguinal hernia ultrasound when diagnosing inguinal hernia.

You place the transducer where the inferior epigastric artery branches from the iliac artery, then rotate along the inguinal ligament so the medial area is inferior. In that position, an indirect inguinal hernia will present bulging anteriorly from the branching point.

Like in indirect inguinal hernia ultrasound, place the ultrasound probe to the front of the branching of the inferior epigastric artery and longitudinal to the inguinal canal when performing a direct inguinal hernia ultrasound.

Different from indirect hernia ultrasound, however, you should move the probe medially to detect direct hernia because it protrudes medially to the inferior epigastric artery.

The risk factors for inguinal hernia include being male, older age, premature birth, pregnancy, chronic cough, obesity and overweight, systematic connective tissue disorders, low BMI, cystic fibrosis, and patent processus vaginalis. Others include daily lifting of heavy weights and standing for long hours. Studies have also confirmed that inguinal hernias can be genetic and run in the family line.

While the presence of an inguinal hernia is the most common cause of a lump in the groin area, it can be mistaken for other conditions such as lipoma, hematoma, and gynecological conditions in women. An undescended testicle may also be taken for an inguinal hernia in newborn males. Proper clinical diagnosis is the best option for confirming an inguinal hernia.

Inguinal hernia is a relatively common condition affecting both children and adults and is most common in men.

Physical assessment can detect inguinal hernias. However, ultrasound is considered a gold standard in confirming diagnosis, determining the type of inguinal hernia, and deciding whether it requires repair surgery.

While other imaging procedures like MRI and CT scan can detect hernia, ultrasound is widely recommended because it is non-invasive and more accessible.

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