• Clinical science

Inguinal hernia

Summary

An inguinal hernia is an abnormal protrusion of intra-abdominal contents either through the deep inguinal ring (indirect inguinal hernia; lateral to the inferior epigastric artery) or through the weakened posterior wall of the inguinal canal (direct inguinal hernia; medial to the epigastric artery). Inguinal hernias are often asymptomatic, presenting as a painless swelling in the groin. Pain and features of intestinal obstruction are signs of a complicated inguinal hernia (obstructed/strangulated hernia). Diagnosis is mainly based on clinical findings. Surgical repair is the definitive treatment. Elective open/laparoscopic mesh repair of the inguinal hernia is the standard of care for uncomplicated inguinal hernias. Emergency surgery which may include resection of gangrenous bowel is indicated in patients with complicated inguinal hernias.

Epidemiology

References:[1][2]

Epidemiological data refers to the US, unless otherwise specified.

Anatomy

Inguinal canal

Hesselbach triangle borders

References:[3]

Pathophysiology

Direct inguinal hernia

Indirect inguinal hernia

'MD': medial = direct

References:[1][2][4][3]

Clinical features

  • Visible, palpable groin protrusion or bulge
  • Inguinal pain (does not have to correlate with the size of the hernia)
  • Increase of symptoms during physical activity (walking or standing, coughing, sneezing, abdominal pressure)
  • Indirect inguinal hernia may be associated with a communicating hydrocele
  • Palpation of the inguinal canal
    1. With the patient standing, palpate from the scrotal skin towards the superficial (external) inguinal ring.
    2. Ask the patient to cough or strain and bear down (Valsalva maneuver).
  • For other possible symptoms, see “Complications” below.

References:[2]

Diagnostics

Inguinal hernia diagnosis is typically established based on medical history and physical exam findings!

  • Ultrasound
    • Imaging test of choice
    • Visualization of the hernial orifice and hernial contents may be possible.
  • CT/MRT: to distinguish from differential diagnoses in ambiguous cases

References:[2]

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

Treatment

Indications for surgery

  • Complicated hernia (see “Complications” below)
  • Uncomplicated hernia + moderate symptoms:
    • Inguinal pain associated with exertion
    • Daily activities are limited due to pain
    • Manual reduction is not possible
  • Uncomplicated hernia + mild symptoms: elective hernia repair

Open vs. laparoscopic hernia repair

Surgical management

  • Main idea: reinforcement of the posterior wall of the inguinal canal with synthetic mesh or primary tissue approximation
    • Mesh vs. nonmesh repair: Mesh is preferred because of decreased recurrence rates and postoperative pain. It is contraindicated in the case of inguinal infection or contamination.
  • Most common surgical procedures
  • Recurrence after surgical intervention is 0.5–15% depending on the surgical procedure (see “Therapy” above).

Risks of surgery

References:[5][6][7][1]

Complications

References:[2][5]

We list the most important complications. The selection is not exhaustive.

Special patient groups

Inguinal hernia in infants

References:[8][9]