Brief Summary of Inguinal Hernia

Introduction

A hernia occurs when all or part of a viscus protrudes from a normal location in the body. Most hernias are protrusions of part of the abdominal viscus through the abdominal wall. Although many kinds of abdominal hernias are possible, inguinal hernias are most common.
With an inguinal hernia, the large or small intestine, omentum, or bladder protrudes into the inguinal canal. Hernias can be reducible, incarcerated, or strangulated.

Pathophysiology
In males, during the 7th month of gestation, the testes normally descend into the scrotum, preceded by the peritoneal sac. If the sac closes improperly, it leaves an opening through which the intestine can slip. In either sex, a hernia can result from weak abdominal muscles or increased intra-abdominal pressure. An inguinal hernia may be indirect or direct.

Indirect inguinal hernia
An indirect inguinal hernia, the more common hernia, results from weakness in the fascial margin of the internal inguinal ring. This type of hernia enters the inguinal canal through the internal inguinal ring and emerges through the external inguinal ring. The hernia extends down the inguinal canal into the scrotum or labia.
An indirect inguinal hernia may develop at any age, is three times more common in males, and is especially prevalent in infants younger than age 1.

Direct inguinal herniaA direct inguinal hernia results from a weakness in the fascial floor of the inguinal canal. Portions of the bowel or omentum protrude through the floor of the inguinal canal to emerge through the external ring extending above the inguinal ligament. Instead of entering the canal through the internal ring, the hernia passes through the posterior inguinal wall, protrudes directly through the fascia transversalis of the canal (in an area known as Hesselbach’s triangle), and comes out at the external ring.

Signs and symptoms
Inguinal hernia usually causes a lump over the herniated area when the patient stands or strains. The lump disappears when the patient is in a supine position. Tension on the herniated contents may cause a sharp, steady pain in the groin, which fades when the hernia is reduced.
Strangulation produces severe pain and may lead to partial or complete bowel obstruction and even intestinal necrosis. Partial bowel obstruction may cause anorexia, vomiting, pain and tenderness in the groin, an irreducible mass, and diminished bowel sounds. Complete obstruction may cause shock, high fever, absent bowel sounds, and bloody stools. In an infant, it’s common for an inguinal hernia to coexist with an undescended testis or a hydrocele.

Diagnosis
In a patient with a large hernia, physical examination reveals an obvious swelling or lump in the inguinal area. In a patient with a small hernia, the affected area may simply appear full. Palpation of the inguinal area while the patient is performing Valsalva’s maneuver confirms the diagnosis.
To detect a hernia in a male patient, the patient is asked to stand with his ipsilateral leg slightly flexed and his weight resting on the other leg. The examiner inserts an index finger into the lower part of the scrotum and invaginates the scrotal skin so the finger advances through the external inguinal ring to the internal ring (1 ½? to 2? [4 to 5 cm] through the inguinal canal). The patient is then told to cough. If the examiner feels pressure against the fingertip, an indirect hernia exists; if pressure is felt against the side of the finger, a direct hernia exists.
A patient history of sharp or “catching” pain when lifting or straining may help confirm the diagnosis. A suspected bowel obstruction requires X-rays and a white blood cell count (which may be elevated).

Treatment
If the hernia is reducible, the pain may be temporarily relieved by pushing the hernia back into place. A truss may keep the abdominal contents from protruding into the hernial sac, although it won’t cure the hernia. This device is especially beneficial for an elderly or a debilitated patient for whom surgery is potentially hazardous.

Herniorrhaphy
Herniorrhaphy, the treatment of choice, returns the contents of the hernial sac to the abdominal cavity and closes the opening. This procedure is commonly performed laparoscopically under local anesthesia as an outpatient procedure.

Hernioplasty
Another effective surgical procedure is hernioplasty, which reinforces the weakened area with steel mesh, fascia, or wire. Complications include urine retention, wound infection, hydrocele formation, and scrotal edema.

Bowel resection
A strangulated or necrotic hernia necessitates bowel resection. Rarely, an extensive resection may require temporary colostomy. In either case, resection lengthens postoperative recovery and requires an antibiotic, parenteral fluid, and electrolyte replacement.