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Abdominal Hernia Reduction
When a patient is seen in the emergency department (ED) with a suspected abdominal hernia, the emergency clinician should consider three issues: (1) Is a palpable mass truly a hernia? (2) Is the hernia easily reducible or incarcerated? (3) Is the vascular supply to the bowel strangulated? A patient with an easily reducible hernia can be discharged safely for outpatient follow-up and elective repair, whereas an acutely incarcerated and strangulated hernia is a surgical emergency. Some seemingly incarcerated hernias can be reduced by careful manipulation in the ED. A patient seen in the ED with a chronically incarcerated hernia without obstruction or significant changes in symptoms is not necessarily a surgical emergency. Any patient with symptoms of bowel obstruction should also be evaluated for the possible presence of an abdominal hernia ( Fig. 44.1 ).
A, This patient was admitted with the diagnosis of bowel obstruction. B, It was not until the physician carefully examined the groin area that an incarcerated inguinal hernia was found. Symptoms of the obstruction, the impressive radiographic findings, and an incomplete physical examination led to initial failure to diagnose the obvious hernia.
Hernias in the groin area have been the subject of medical diagnosis and treatment as long ago as 1550 bc . Throughout history, treatment of this condition has been the focus of ongoing discussion and debate. This chapter addresses abdominal and groin hernias, both of which are amenable to diagnosis and potential manual reduction in the ED.
Background
A hernia is defined as: a protrusion of any viscus from its normal cavity through an abnormal opening. Abdominal hernias are characterized by protrusion of intraabdominal contents (usually bowel or omentum) through an abnormal defect in the abdominal wall musculature. Hernias can develop along a congenital tract that fails to close (e.g., indirect inguinal or umbilical hernias), or along an area of weakness in the muscular and fascial layers (e.g., direct inguinal, ventral, or incisional hernias). This weakness may be the result of aging and the accompanying loss of tissue elasticity, increased intraabdominal pressure, failure of proper healing, or trauma involving the abdominal wall. It is estimated that hernias develop in 5% of men and 2% of women, and that 75% of them occur in the groin. In children and young adults the majority of hernias are indirect inguinal hernias of congenital origin, whereas most direct hernias are acquired and become more common as a patient ages. In patients with abdominal surgery, incisional hernias can occur in up to 20% of cases.
Classification
One of the first priorities for an emergency clinician is to determine whether a suspected hernia is reducible, incarcerated, or strangulated. A reducible hernia is one whose contents can be returned through the fascial defect back into the abdominal cavity without surgical intervention. Patients often have large reducible hernias for years and are able to reduce them easily, but such hernias can also become strangulated or incarcerated. An incarcerated hernia is one whose contents are not reducible without surgical intervention. These hernias often have associated swelling of the hernia sac contents. A strangulated hernia is an incarcerated hernia whose blood supply to the herniated structures is compromised. Hernias with a small neck are more likely to become incarcerated or strangulated. A strangulated hernia is a surgical emergency because tissue ischemia and necrosis will result if adequate blood flow is not restored.
A primary ventral hernia of the abdominal wall may be umbilical, epigastric, or spigelian, depending on its location. An incisional hernia is found along or near a previous surgical scar. An inguinal hernia is found within the inguinal triangle, which is formed by the inguinal ligament on the inferior side, the inferior epigastric artery on the superior lateral side, and the lateral edge of the rectus abdominis muscle on the medial side. Direct and indirect inguinal hernias occur superior to the inguinal ligament, whereas a femoral hernia is located inferior to the inguinal ligament. A spigelian hernia (lateral ventral hernia) is located in the abdominal wall just lateral to the rectus abdominis muscle.
Indirect Inguinal Hernia
An indirect inguinal hernia passes through the internal (deep) inguinal ring and into the inguinal canal ( Fig. 44.2 ). It is located lateral to the inferior epigastric vessels. During fetal development, the processus vaginalis allows descent of the testes into the scrotum. Failure of this to close before birth can lead to a hernia or hydrocele.
An indirect inguinal hernia is the most common type of hernia. These occur more frequently in males and are commonly diagnosed in children and young adults. Approximately 5% of full-term infants and 30% of preterm infants will have an inguinal hernia. Incarceration occurs more commonly in patients younger than 1 year, and 30% of hernias in children younger than 3 months become incarcerated. When an incarcerated inguinal hernia is successfully reduced in a child, surgical repair within 24 to 48 hours should be considered because of the risk for recurrent incarceration. When an inguinal hernia is diagnosed, even without incarceration or strangulation, it is important to make a referral for elective repair. Asymptomatic and painless inguinal hernias can progress to cause symptoms over time if they are not surgically repaired, although watchful waiting may also be appropriate in some patients. Clinical studies demonstrate increased morbidity with emergency versus elective repair of inguinal hernias.
Direct Inguinal Hernia
A direct inguinal hernia comes directly through the muscular and fascial wall of the abdomen. It is located medial to the inferior epigastric vessels within the inguinal triangle ( Fig. 44.3 ). These can be differentiated from indirect inguinal hernias as direct hernias do not travel along the inguinal canal.
A direct inguinal hernia is the second most common groin hernia. It is an acquired weakening of the myofascial wall caused by aging and the repetitive stress of increased abdominal pressure. This hernia carries a lower risk for incarceration because the hernia orifice is typically wide.
Pantaloon Hernia
A pantaloon hernia is a combination of direct and indirect hernias. This variation of an inguinal hernia is difficult to diagnose in the ED, is difficult to achieve sustained reduction using standard manual techniques, and is often discovered during surgical exploration.
Femoral Hernia
A femoral hernia occurs inferior to the inguinal ligament through a defect in the transversalis fascia. Abdominal contents protrude into the potential space medial to the femoral vein and lateral to the lacunar ligament in the femoral canal, and appear as a medial thigh mass below the area where direct and indirect hernias are typically identified ( Fig. 44.4 ). A small fascial defect leading to constriction by the inguinal ligament means that this hernia becomes incarcerated in up to 45% of cases. A femoral hernia is relatively uncommon, occurs more frequently in women, and is an uncommon condition in children.
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