• Clinical science

Abdominal hernias

Summary

Abdominal hernias are defined as the abnormal protrusion of intra-abdominal contents through congenital/acquired areas of weakness in the abdominal wall. The four categories of anatomically-classified abdominal hernias include the following: ventral hernias (e.g., epigastric, umbilical, incisional hernias), groin hernias (inguinal and femoral hernias), pelvic hernias (obturator, sciatic, and perineal hernias), and flank/lumbar hernias. Groin hernias are discussed in more detail in their respective learning cards. Inguinal, incisional, and umbilical hernias are the most common types of hernias. Persistently raised intra-abdominal pressure (e.g., due to ascites, pregnancy, intra-abdominal tumors, chronic cough, etc.) increases the risk of developing an abdominal hernia. Uncomplicated hernias are asymptomatic, nontender, and completely reducible with an expansile cough impulse. Complicated hernias include incarcerated, obstructed, and strangulated hernias and are characterized by tenderness, irreducibility, features of bowel obstruction, and an absent cough impulse. Abdominal hernias are often diagnosed on clinical examination. Imaging (e.g., ultrasound, CT scan) is used to confirm the diagnosis and evaluate the contents of the hernia. Complicated hernias and those with a narrow neck (e.g., femoral hernia, obturator hernia, paraumbilical hernia) should be surgically repaired (primary repair/mesh repair). Congenital umbilical hernias typically close spontaneously by 5 years of age, have a wide neck, and a low risk of complications; surgical intervention is rarely necessary.

Classification

Ventral hernias

Groin hernias

Pelvic hernias (rare)

Flank hernias

References:[1][2][2][3][4][5][6][7]

Clinical features

Reducible hernia

  • Hernial contents completely return to the abdominal cavity through the abdominal wall defect on lying down or upon application of mild external pressure.
    • Most reducible hernias manifest as an asymptomatic nontender mass.
      • Increases on straining (e.g., sitting up from a recumbent position)
      • Decreases completely on lying down
    • Visible cough impulse present: expansion of the hernia when the patient is asked to cough
    • Edges of the fascial defect are palpable
    • Bowel sounds may be heard over the mass (if the hernial content is bowel)

Irreducible/incarcerated hernia

  • Hernial contents become adhered to the hernial sac and cannot be reduced into the abdominal cavity.
    • Irreducible nontender mass
    • Visible cough impulse present
    • May decrease partially on lying down
    • Increased risk of obstruction and strangulation

Obstructed hernia

  • The abdominal wall defect acts as a tourniquet around the hernial contents, causing edema and distension of the hernial contents.

Strangulated hernia

  • Ischemia and necrosis of the hernial contents due to compromised vascular supply
    • Acute pain at the site of the hernia
    • Features of bowel obstruction (if the hernial content is bowel)
    • Signs of strangulation
    • Toxic appearance, fever, signs of sepsis
    • May lead to intestinal gangrene
    • Fatal if left untreated

The smaller the hernial orifice, the higher the risk of incarceration!

References:[8][9][1][10]

Diagnostics

  • Usually a clinical diagnosis
  • Imaging: indicated if the diagnosis is unclear and/or to identify contents of the hernial sac (e.g., loops of bowel)
    • Ultrasound: especially useful to identify ventral hernias (e.g., epigastric, Spigelian, incisional, or umbilical hernia)
    • IV and oral contrast enhanced CT scan: useful for suspected hernias that may be difficult to identify on physical examination (e.g., lumbar, obturator, perineal or sciatic hernia)
    • Findings: abdominal wall defect with/without protrusion of intra-abdominal contents through it
    • Abdominal x-ray
      • Indicated if an obstructed and/or strangulated hernia is suspected
      • Findings: features of bowel obstruction
        • Dilated bowel loops proximal to obstruction
        • Collapsed bowel loops distal to obstruction
        • Multiple air-fluid levels within dilated bowel loops

References:[1]

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

Treatment

  • Surgical hernia repair is recommended for the management of most abdominal hernias.
    • Surgery: open or laparoscopic tension-free closure of the abdominal wall defect with/without a mesh
    • Elective surgery is indicated in reducible and incarcerated hernias.
    • Emergency surgery is indicated in obstructed or strangulated hernias.
  • Conservative management (observation) is indicated in:
    • Congenital umbilical hernia in children < 5 years of age
    • Asymptomatic wide-necked hernias in patients with high operative risk: A truss or corset may be considered in these patients to decrease the risk of obstruction and strangulation.

Incisional hernia

  • Definition: Herniation of intra-abdominal contents through an abdominal wall defect created during a previous abdominal surgery.
  • Incidence: ∼15% of patients who have undergone abdominal surgery develop incisional hernias.
  • Risk factors
    • Upper midline laparotomy incisions (highest risk)
    • Wound dehiscence
    • Postoperative wound infection
    • Poor wound healing
    • Emergency abdominal surgeries
  • Clinical features
    • Most (∼ 75%) incisional hernias occur within 3 years of surgery
    • Mass/protrusion at the site of the incisional scar which increases with coughing/straining
    • Edges of the hernial defect can be palpated on reducing the hernia
  • Treatment
    • Conservative management is indicated in:
      • Asymptomatic incisional hernias, with a wide neck;
      • Patients who are at a high anesthetic risk (advanced age, multiple comorbidities)
    • Surgery is indicated in symptomatic/complicated hernias or those with a narrow neck.
      • Small incisional hernias (< 3 cm defect): primary repair
      • Larger incisional hernias: hernioplasty (mesh repair)

References:[11][12][13][1][14][15]

Umbilical hernia

Congenital umbilical hernia

Acquired umbilical hernia

(Paraumbilical hernia)

Epidemiology
  • Accounts for ∼ 5% of all adult abdominal hernias
Site of hernial defect
  • Umbilical orifice
  • Adjacent to the umbilical orifice (superior/inferior/lateral)
Etiology
  • Patent umbilical orifice
  • Acquired abdominal wall defect
Risk factors
  • Persistently raised intra-abdominal pressure
Clinical features
  • Mass protruding through the umbilicus
  • Mass increases on crying/coughing/straining; reduced in size on lying down
  • Hernia can be completely reduced (unless incarcerated)
  • Mass protruding adjacent to the umbilical orifice pushing the umbilicus into a crescent shape
  • Fascial defect is small

Risk of developing complications

(Incarceration/obstruction/strangulation)

  • Low
  • High
Treatment
  • Conservative: ∼ 90% will spontaneously close by 5 years of age
  • Surgery (rarely necessary)
    • Large umbilical hernias (defect > 2 cm or protuberant hernias)
    • No evidence of spontaneous closure by 5 years of age
    • Incarcerated, obstructed, or strangulated umbilical hernias
  • Surgery (primary repair/mesh plasty): all paraumbilical hernias
Differential diagnosis

References:[1][16][17][18]

last updated 09/01/2019
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