• Clinical science
  • Clinician

Inguinal hernia

Summary

An inguinal hernia (IH) is an abnormal protrusion of intraabdominal contents through the inguinal canal. IH is one of two different types of groin hernias (in addition to the less common femoral hernia), and can be further subdivided based on anatomic location: an indirect inguinal hernia protrudes lateral to the inferior epigastric vessels through the deep inguinal ring, whereas a direct inguinal hernia protrudes medial to the inferior epigastric vessels through a defect in the posterior wall of the inguinal canal. An uncomplicated inguinal hernia typically manifests as a mass in the groin with or without pain (inguinodynia). Incarceration, obstruction, and strangulation of hernial contents are collectively referred to as complicated inguinal hernia. IH is a clinical diagnosis. Imaging, preferably with ultrasound, is indicated if the clinical diagnosis is uncertain. Surgery is the only definitive management of IH and can be performed as an open surgery or laparoscopically. A strangulated inguinal hernia is a surgical emergency. In patients with an incarcerated hernia with/without bowel obstruction, manual reduction of the hernia may be considered as a temporizing measure before surgery. Conservative management may be considered in a select group of patients with small, uncomplicated inguinal hernia.

Definition

Epidemiology

Epidemiological data refers to the US, unless otherwise specified.

Anatomy

Inguinal canal

Hesselbach triangle borders

References:[3]

Pathophysiology

Direct inguinal hernia

Indirect inguinal hernia

"The DIRECT path leads through the MiDdle, the INDIRECT path goes beLow." (DIRECT hernias lie MeDial and INDIRECT hernias lie Lateral to the inferior epigastric vessels)

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

Clinical features

Uncomplicated inguinal hernia [5][6][7]

  • Typically manifests as an ill-defined mass in the inguinal region with the following features:
    • Increases in size on coughing or straining
    • Decreases in size on lying supine
    • Inguinal pain (inguinodynia) or vague inguinal discomfort that increases with physical activity; can also be painless
  • Inguinodynia with no palpable groin mass is typically the only manifestation of an occult inguinal hernia. [8]
  • Physical examination
    • Ask the patient to perform a Valsalva maneuver and observe for an expansile cough impulse in the inguinal region.
    • Palpate the inguinal canal
      • Invaginate the scrotal skin toward the superficial inguinal ring with the index or little finger.
      • Ask the patient to perform a Valsalva maneuver.
      • A bulge palpable on the fingertip confirms the diagnosis of an inguinal hernia.
    • Hernia is completely reducible

Complicated inguinal hernia [9][6][7]

Manual reduction of inguinal hernia should not be attempted if there are any signs of strangulation!

Diagnostics

Inguinal hernia is typically a clinical diagnosis. Imaging is useful if the clinical diagnosis is in doubt. All patients should be evaluated for risk factors for an acquired inguinal hernia.

Imaging [5][10]

Emergency surgery should not be delayed for imaging in unstable patients with signs of strangulation or bowel obstruction. [5]

Laboratory studies [15]

The following tests should be obtained in patients with strangulated inguinal hernia or incarcerated inguinal hernia with bowel obstruction for supportive diagnostic evidence and to assess for complications. [18]

  • CBC
  • Blood glucose
  • Serum electrolytes
  • BMP
  • Serum lactate

Differential diagnoses

Groin or scrotal mass [6][7]

A groin bulge with an expansile cough impulse above the inguinal ligament is diagnostic of an inguinal hernia. A femoral hernia typically manifests as a groin bulge below the inguinal ligament and lateral to the pubic tubercle. [7]

Inguinodynia [6]

The differential diagnoses listed here are not exhaustive.

Treatment

Surgical repair of the hernial defect is the only definitive treatment of inguinal hernia. The management of direct inguinal hernia and indirect inguinal hernia does not differ.

Approach [5][6]

Complicated inguinal hernia [7][15]

Acute management

Strangulated inguinal hernia and incarcerated inguinal hernia with mechanical bowel obstruction are surgical emergencies.

Manual reduction of inguinal hernia [21][19]

  • Indication: : Consider as a temporizing measure before surgery in patients with incarcerated hernia with/without bowel obstruction.
  • Contraindication: strangulated inguinal hernia
  • Successful hernia reduction: Observe the patient for 12–24 hours.
    • Symptoms improve: Schedule an elective hernia repair as early as possible.
    • Symptoms worsen: Immediate surgical consult to evaluate for reduction en masse. [22]
  • Unsuccessful hernia reduction: urgent surgery (see “Surgical procedures” below)

Manual reduction of hernial contents is contraindicated if there are signs of a strangulated hernia, as necrotic bowel or omentum can be pushed into the abdominal cavity, potentially leading to serious complications including peritonitis. [21]

Incarcerated inguinal hernia causing bowel obstruction (without evidence of strangulation) is not a contraindication for manual reduction of hernial contents. [19]

Uncomplicated inguinal hernia

Elective surgery [5][23][24]

  • Indications
    • Significant inguinodynia limiting daily activities.
    • Female patients
    • Worsening of symptoms during watchful waiting.
    • Patient prefers surgery to watchful waiting.
  • Procedures: See “Surgical procedures” below.

Conservative management (watchful waiting) [5][15]

  • Indications [23]
    • Asymptomatic or minimally symptomatic, completely reducible hernia in a male patient
    • Uncomplicated inguinal hernia in patients unfit for surgery or anesthesia
  • Contraindications [5]
  • General recommendations [5]
    • Consider the use of a truss.
    • Advice against lifting heavy weights.
    • Advice to return to hospital if symptoms worsen. [5]
    • Evaluate and treat potential risk factors of hernia.

Surgical procedures

Once the hernial contents are reduced (i.e., returned to the abdominal cavity), the goal of hernia surgery is to reinforce the posterior wall of the inguinal canal with a synthetic mesh or through primary tissue approximation. Emergency surgery is associated with an increased risk of complications; elective surgery is preferred when it is an option.

Hernioplasty (mesh repair)

Herniorrhaphy (non-mesh repair)

  • Definition: open surgical repair of a hernial defect using autologous tissue
  • Indication: Consider in patients at high risk of surgical site infection. [20][7]
  • Options: Shouldice repair
    • A pure tissue repair that involves a multilayer imbricated repair of the posterior wall of the inguinal canal with a continuous running suture technique. [7]
    • Preferred procedure when hernioplasty is not feasible
    • Has a lower recurrence rate than other non-mesh repairs
  • Important consideration: Herniorrhaphy is associated with a greater risk of recurrence than hernioplasty. [25]

Management checklist

Complicated inguinal hernia

Uncomplicated inguinal hernia

  • Consider imaging for inguinal hernia if clinical diagnosis is unclear
  • Surgical consult for elective surgery or consideration for watchful waiting

Complications

Preoperative complications [5]

Postoperative complications [5]

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

Special patient groups

Inguinal hernia in infants

References:[27][28]

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last updated 11/24/2020
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