Inguinal Hernias

Mohammad K. Jamal

Eric J. DeMaria

Mr. Jones is a 72-year-old man who presented to the emergency department with complaints of abdominal pain, nausea, vomiting, and poor appetite during the preceding 2 days. His last bowel movement was 3 days ago. His medical history was significant for recently diagnosed hypertension, myocardial infarction 4 years ago, and a stab wound to the abdomen. When questioned about the stab wound, he indicated that an exploratory laparotomy with small-bowel resection was performed. He smoked one to two packs of cigarettes a day for 50 years but quit just this year. His medications include occasional nifedipine, nitroglycerin, and occasional antibiotics for seasonal bronchitis.

A physical examination reveals the following vital signs: temperature, 37.2°C; blood pressure, 140/85 mm Hg; pulse, 100 beats per minute; and respiratory rate, 24 breaths per minute. The head and neck examination produces normal findings, the chest examination reveals mild wheezes in both lower lung fields, and cardiovascular examination shows mild tachycardia. Mr. Jones is moderately obese, and his abdomen is distended and diffusely tender. There is no guarding or rebound detected. A few high-pitched bowel sounds are discernible. The prostate gland is slightly enlarged and firm and has no irregularities. The stool examination reveals traces of occult blood. Pedal pulses are intact.

What is the working diagnosis on the basis of these findings?

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Bowel obstruction is the likely diagnosis.

What further tests confirm the diagnosis?

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Tests that can confirm this diagnosis are discussed in Chapter 10.

A radiographic series for diagnosis of acute abdominal pain is ordered along with blood tests. Radiographs of the abdomen reveal multiple loops of small bowel with air and fluid levels; the colon is free of gas. The chest radiograph does not show free air under the diaphragm but does indicate some mild streaking in both lower lung fields. The following are results of laboratory tests: sodium, 145 mEq per L; chloride, 95 mEq per L; potassium, 3.2 mEq per L; bicarbonate, 17 mEq per L; hematocrit, 48%; amylase, 50 mIU per mL; and white blood cell count, 14,000 per mL with 10% bands. Urinalysis is unremarkable except for a specific gravity of 1.035. The electrocardiogram shows sinus tachycardia without signs of ischemia.

Mr. Jones is admitted to the surgical service. A nasogastric tube is inserted, and normal saline with potassium replacement is administered intravenously after the urine output is confirmed. He is allowed nothing by mouth. Repeat radiographs are ordered for the next day. The admitting diagnosis is small-bowel obstruction, most likely the result of adhesions arising from the previous abdominal exploration. During the admitting physical examination, a firm, painful swelling is noted in Mr. Jones’s right groin, midway between the testicle and the symphysis pubis. The penis, testicles, and scrotum are otherwise normal, as is the skin over the mass.

What is the diagnosis?

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The patient has an incarcerated inguinal hernia that is causing small-bowel obstruction. There is a possibility of strangulated bowel.

What are the most common causes of small-bowel obstruction?

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In patients of all ages, the most common cause of small-bowel obstruction is adhesive bands, followed by groin hernias and small-bowel tumors. These three conditions account for 80% of bowel obstructions. Groin hernia is the leading cause in children, and diverticulitis and colorectal carcinoma are the common causes in the elderly. Incisional and groin hernias are easily detected during a physical examination and must be sought in all cases of bowel obstruction.

What are other significant history and laboratory findings?

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Smoking and chronic bronchitis may predispose patients to development of groin hernias because of frequent coughing and straining. Smokers may actually develop a defect in collagen that increases the risk of both new and recurrent herniation. Occult blood in the stool may indicate a problem with the bowel mucosa. The occult blood may be explained by a tumor or ischemic necrosis from strangulation. Although in the past all patients with hernias were evaluated for large-bowel tumors because hernia was believed to result from increased intraabdominal pressure from the narrowed bowel lumen, the association between hernia and large-bowel tumors has never been proven.

What is a hernia?

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A hernia is a defect in a wall through which contents normally contained by that wall may protrude. In a groin hernia, abdominal contents may protrude through a congenital defect. This is best exemplified by an indirect hernia, in which abdominal contents protrude through an enlarged internal ring and a patent processus vaginalis. Groin hernias may also develop over time because of thinning of the abdominal wall itself. For example, a direct inguinal hernia results when the transversalis fascia (the inguinal floor in the region of Hesselbach’s triangle) has thinned, allowing abdominal contents to protrude. A hernia typically has three components: (a) neck, (b) body (or sac), and (c) contents.

What are some of the etiologic factors contributing to the development of groin hernias?

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Groin hernias are generally related to congenital variations in the inguinal anatomy and the fatigue of the abdominal wall supporting structures over time, “the chronic stress and injury theory.” Furthermore, the presence of a patent processus vaginalis has been considered the sine qua non of indirect inguinal hernias. Several conditions that increase intraabdominal pressure (e.g., obesity, ascites, constipation, chronic obstructive pulmonary disease, urinary retention, pregnancy) may contribute to the development of abdominal wall hernias.

What are the symptoms of a hernia?

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A hernia is often asymptomatic and can be found only on physical examination when the patient is asked to strain or cough, actions that force abdominal contents through the defect. Patients who have large defects may have abdominal contents in the sac at all times but may have no symptoms. Some patients complain of a dull ache or intermittent pain and notice periodic bulging. Small defects can produce a constricting ring around protruding contents and when swelling increases, can become very painful and lead to ischemia. The hernia contents occasionally become necrotic.

What are some of the important anatomic landmarks to be considered when examining a patient with groin hernia?

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The important anatomic landmarks in the groin can be remembered as boundaries of a canal and triangle.

The femoral canal is the site of occurrence of a femoral hernia and is bounded by the external iliac vein laterally, inguinal ligament superiorly, Cooper’s ligament posteriorly, and iliopubic tract medially.

The Hesselbach triangle is the site of a direct inguinal hernia and is bounded by the inferior epigastric artery, inguinal ligament, and the rectus sheath. Direct inguinal hernias are typically located medial to whereas indirect inguinal hernias are lateral to the inferior epigastric vessels.

How should a patient with a hernia be examined?

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The patient should be standing, if possible, facing the seated examiner. Often, the protruding bulge can be seen above or below the inguinal ligament, which passes between the anterior superior iliac spine and the symphysis pubis. The internal ring lies midway along this line. Femoral hernias are usually felt below this line, but a large bulge may appear to be above the line.

If the hernia is not readily apparent, the examiner should ask the patient to indicate where the bulge was. Palpation of the inguinal canal while the patient strains may reproduce the bulge. The physician can best produce a Valsalva effect by asking the patient to bear down as during a bowel movement. Using the index finger of the gloved hand, the physician should invaginate the upper scrotal skin and follow the testicular cord (vessels and vas deferens) up into the canal. Attention must be directed at palpating the inguinal floor and the external inguinal ring. Indirect hernias may be felt protruding through this ring, and a weak floor can sometimes be palpated lateral to this ring. When both protrusions are felt simultaneously, the hernia is called a pantaloon type.

Can the three types of hernia (direct, indirect, and femoral) be accurately differentiated during a physical examination?

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Femoral hernias are differentiated from inguinal hernias on physical examination because the bulge of a femoral hernia is below the inguinal ligament and medial to the femoral pulsation. However, reliable differentiation between a direct and an indirect inguinal hernia can be done only at surgery because the distinction is based on the relation of the epigastric vessels to the defect. Direct hernias lie medial to these vessels, whereas indirect hernias originate lateral to the vessels. The location of the hernia in relation to the epigastric vessels and the size of the opening are important determinants of the type of repair needed and the propensity for recurrence.

The size of the hernia orifice is classified as follows