Abdominal Hernias

Hernia repairs are among the most common procedures performed by general surgeons. More than 1 million of these interventions are performed each year in the United States alone.1

A hernia is an abnormal protrusion of an organ or part of an organ through the connective tissue or the wall of the cavity in which it is normally enclosed.2 This weakness in the connective tissue allows the contents of one area of the body to move into another area.

Hernias may occur in a variety of locations. Hiatal hernias occur when the stomach pushes into the thorax. The bladder herniating into the vagina is a cystocele. The rectum herniating into the vagina is a rectocele. Herniated intervertebral discs are common. These occur when the nucleus pulposus pushes through the ligament that normally contains it.

This article focuses on abdominal hernias. These typically involve the bowel or omentum pushing through a defect or weakness in the abdominal wall.

In addition to location, it is important to note characteristics of a hernia. The ability or inability to reduce a hernia sac is an important piece of information. If the hernia sac can be pushed back into place with manual manipulation, it is called a reducible hernia. A hernia that cannot be reduced through manual manipulation is called an irreducible or incarcerated hernia. It requires surgical intervention. In a strangulated hernia, the blood supply to the tissue within the hernia sac has been cut off secondary to pressure from the surrounding tissue. If not corrected, the situation can lead to necrosis.3

Direct and Indirect Inguinal Hernias

The inguinal canal is a passage through the inferior aspect of the abdominal wall. This passage begins at the internal inguinal ring and ends at the external inguinal ring. Under normal conditions in a boy or man, the inguinal canal contains the spermatic cord and the ilioinguinal nerve. The spermatic cord includes the testicular artery and the vas deferens, as well as a several other arteries and nerves.4

Groin hernias account for 75% of abdominal wall hernias. Indirect inguinal hernias account for 60% of inguinal hernias.5 An indirect hernia occurs when the processus vaginalis remains intact. This is a part of the peritoneum that travels down with the testis into the scrotum. Under normal conditions, this tissue is obliterated once the testes have completed their dissent. These comprise almost all hernias up through adolescence. They are far more common in boys and men than in girls and women.2

In the case of an inguinal hernia, the hernia sac passes from the internal ring through the inguinal canal and into the scrotum through the external ring.

Direct inguinal hernias occur secondary to wear-and-tear issues. Chronic cough, heavy lifting and repeated straining are all risk factors for a direct inguinal hernia. These may be thought of as an acquired hernia, in contrast to indirect inguinal hernias, which are congenital. Rather than passing through the internal ring of the inguinal canal, a direct inguinal hernia passes through a weakened area of fascia in the posterior inguinal canal. This area of fascia is known as Hesselbach's triangle. The hernia sac then continues along the inguinal canal, passing out through the external ring and into the scrotum.5

Inguinal Hernias: Presentation and Diagnosis

Because inguinal hernia is the most common type of hernia, it is one that all practitioners should be familiar with. Patients with an inguinal hernia often have few symptoms. The most common presentation for an inguinal hernia is a dull abdominal ache or a visible bulge in the scrotum. A patient might notice a bulge that has been growing.

As the hernia gets larger, patients usually develop an aching pain. Patients may be able to manually reduce their own hernias, thereby relieving symptoms. Lying supine tends to relieve the patient's symptoms and reduce the hernia.3 A patient with inguinal hernia may also complain of pain with straining. Some patients report acute pain following strenuous activity, but this is rare.6 Frequently, the patient has no symptoms all, and the problem is picked up on a routine physical exam.

The physical examination should begin with the patient standing and naked. If there is an obvious bulge, you should see it move when the patient coughs. You should also be able to feel it move with soft pressure. If no bulge is obvious, the practitioner may place a finger up into the scrotal skin to detect the external inguinal ring. As the patient coughs, a mass pushing against the finger confirms the diagnosis of a hernia.7 In women, both valsalva observation and invagination of the labia to find the external ring are unreliable. Men are 25 times more likely than women to have groin hernias.2

When a physical exam is inconclusive, imaging may be required to diagnosis a hernia. An ultrasound is the least invasive type of imaging, but it can give false positives and, in a thin patient, false negatives. A CT or MRI may be more accurate in making the diagnosis. Imaging may also be helpful in narrowing the differential by excluding other possible causes of abdominal pain.6

 Inguinal Hernias: Treatment

Treatment for inguinal hernias falls into two categories: surgical repair or watchful waiting. In a symptomatic patient, the decision is relatively easy. Repair of a hernia is usually advised if it is causing anything other than mild symptoms. In patients who are asymptomatic or have only minimal symptoms, the answer is not so clear.

In a study published in 2006, Fitzgibbons and colleagues randomized 720 men with minimally symptomatic inguinal hernias into two groups. Three hundred sixty-four men were assigned to the watchful waiting group and 356 men underwent surgical repair. The study sought to determine whether or not watchful waiting is a reasonable treatment for people who have minimal symptoms with an inguinal hernia. Twenty-three percent of patients assigned to the watchful waiting group did cross over and have surgical repairs secondary to increased symptoms; this resulted in few complications. The incarceration rate was 1.8 per 1,000 patient years.

The conclusion of the study was that watchful waiting in a man with an inguinal hernia and minimal symptoms is a reasonable treatment. Hernia complication rates are low, and delaying surgery did not affect patient outcomes.8

Femoral Hernias

Femoral hernias account for only about 10% of groin hernias,1 but they are much more likely to incarcerate or strangulate due the narrow path they are forced to travel through. Complication rates for femoral hernias have been reported in as much as 40% of cases. Femoral hernias are 10 times more likely in women.5

Femoral Hernia: Presentation and Diagnosis

Patients with femoral hernias often first present for care after incarceration has occurred. Prior to incarceration or obstruction, symptoms are often mild or nonexistent. The patient may complain of colicky abdominal pain or other abdominal discomfort, but typically not discomfort in the groin or femoral area. A mass is often found below the inguinal ligament. This creates a bulge on the upper medial thigh. On rare occasions, the hernia sac presents over the inguinal ligament, making it difficult to differentiate it from an inguinal hernia on physical exam.3

Femoral Hernias: Treatment

Due to the high rate of complications, the consensus is that all femoral hernias should be surgically repaired. If the hernia has incarcerated, it is particularly important for the surgeon to inspect the bowel for possible injury.

Umbilical Hernias

Umbilical hernias are more common in women than men. Risk factors include multiparty, difficult labor, obesity and large intra-abdominal tumors. These hernias tend to pass through tight rings, leading to frequent issues with incarceration and strangulation. 3 In children, these are usually congenital defects. In adults, up to 90% of cases are acquired.1Umbilical Hernia: Presentation and Diagnosis

Patients with an umbilical hernia often present with a slow-growing, soft abdominal mass. These are relatively asymptomatic but may cause a dull ache or dragging sensation. In a child, the mass is often obvious to the parent or the pediatrician.

Umbilical Hernia: Treatment

In an adult, surgical repair of an umbilical hernia is usually recommended. In children younger than 2 years, a watchful waiting approach is generally taken because 80% of defects heal on their own. If the hernia is not healed by the age of 2, the hernia should be surgically repaired before age 5.1

Epigastric Hernia

Epigastric hernias occur secondary to a defect in the linea alba. These are two to three times more likely in men than in women, and they occur in 1% to 5% of the population. Although, these hernias may be tender and symptomatic, they rarely strangulate or even involve the bowel.1

Epigastric Hernia: Presentation and Diagnosis

The chief complaint associated with epigastric hernia is usually a painful nodule in the upper midline.1 A patient may present with epigastric pain described as mild and superficial to deep and severe, radiating to the back. The patient may also experience nausea and vomiting.

The mass is usually palpable and can be exaggerated with a valsalva or cough. Imaging such as ultrasound or computed tomography may be needed to confirm diagnosis, especially in an obese patient.3

Epigastric Hernia: Treatment

As with many other abdominal hernias, surgical repair is the recommended treatment. Rates of incarceration and complication are low, but as time passes the hernia sac will likely continue to enlarge. In addition, patients often find epigastric hernias to be uncomfortable and unsightly and prefer to have them repaired.1

Incisional Hernias

Approximately 10% of all hernia repairs in the United States are performed to treat incisional hernias. An incisional hernia is an abdominal wall gap, with or without a bulge, that is perceptible on physical exam or imaging study up to 1 year after the index operation. The hernia rate associated with midline laparotomy incision is between 3% and 20%.1

Incisional Hernia: Treatment

Surgical repair of the defect is the recommended treatment. Recurrence rates after repair are directly correlated to the size of the initial defect. Recurrence rates range from 2% for small defects to almost 50% for large defects.1

Other issues

Abdominal hernias are now the second most common cause of small bowel obstruction.9 It is therefore important that all members of the medical community have a clear understanding of what hernias are, why they occur, and the risks associated with them. A patient who presents with an obvious bulge in the scrotum, upper thigh, umbilical or epigastric area should be evaluated for a hernia. A patient who complains of a vague, dull ache in the scrotum or abdomen that is relieved by a supine position should be evaluated for a hernia. A patient with signs and symptoms of a bowel obstruction also should be evaluated for a hernia.

Brian Wallace is a practicing surgical physician assistant and creator of Physician Assistant Exam Review, a podcast and prep program  for physician assistants who are taking the PANCE or the PANRE.  You can find out more at www.physicianassistantexamreview.com.


1. Souba et al. Open Hernia Repair.  ACS Surgery, Principles and Practice 2005. Webmd Prof Pub; 2005: 603,619, 621

2. Beauchamp et al. Hernias. In: Sabiston Textbook of Surgery. The Biological Basis of Modern Surgical Practice. WB Saunders Company; 2008: 1155,1516.

3. Deveney KE. Hernias & Other Lesions of the Abdominal Wall. In: Doherty GM, ed. CURRENT Diagnosis & Treatment: Surgery. 13th ed. New York: McGraw-Hill; 2010.

4. Moore KL, Agur AM. Abdomen. In: Essential Clinical Anatomy. 2002: 138.

5. Byars D. Hernias in Adults. In: Tintinalli JE et al, eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York: McGraw-Hill; 2011.

6. Sherman V, et al. Inguinal Hernias. In: Brunicardi F, et al, eds. Schwartz's Principles of Surgery. 9th ed. New York: McGraw-Hill; 2010.

7. Lowry SF, et al. Groin Hernias and Masses, and Abdominal Hernias. In: Learning Surgery. The Surgery Clerkship Manual. Springer; 2005: 486.

8. Fitzgibbons RJ, et al. Watchful waiting vs repair of inguinal hernia in minimally symptomatic men: a randomized clinical trial. JAMA. 2006;295(3):285-292.

9. Ott DJ. Gastrointestinal Tract. In: Chen MM, et al, eds. Basic Radiology. 2nd ed. New York: McGraw-Hill; 2011.





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