Inguinal Hernia


Inguinal Hernia, Scrotal Hernia, Indirect Inguinal Hernia, Indirect Hernia, Direct Inguinal Hernia

  • Epidemiology
  1. Most common Hernia type
    1. Accounts for 75% of all Hernias
    2. Accounts for 96% Groin Hernias (other 4% are femoral)
    3. Results in 600,000 Inguinal Hernia repairs annually in U.S.
  2. Bilateral in 20% of cases
  3. Gender predisposition: Male by 9 to 1 ratio
  4. Peak age: 40-59 years old
  5. Lifetime risk of Inguinal Herniation: 10%
  6. Children account for 5% of Inguinal Hernia cases
    1. See Inguinal Hernia in Children
  • Risk Factors
  1. Men
    1. Hiatal Hernia (2 fold increased Inguinal Hernia risk)
    2. Normal weight (lower risk in obese men)
  2. Women
    1. Tall height
    2. Chronic Cough
    3. Umbilical Hernia
    4. Older age
  • Types
  1. Background: Anatomy
    1. See Hesselbach's Triangle
    2. See Inguinal Canal
  2. Indirect Inguinal Hernia (most common in men and women)
    1. Course
      1. Hernia sac passes outside Hesselbach's Triangle
      2. Herniates via Inguinal Canal
        1. Enters through Internal Inguinal Ring (Lateral to inferior epigastric artery)
        2. See Inguinal Canal for anatomic course
        3. Canal carries spermatic cord in men and round ligament in women
      3. May result in Scrotal Hernia in males
      4. More commonly on right in males (due to right Testicle migration lags the left in development)
    2. Pathophysiology
      1. Nonobliterated processus vaginalis (congenital)
      2. Internal abdominal ring weakened fascia
      3. Decreased muscular tone
      4. Increased abdominal pressure
  3. Direct Inguinal Hernia
    1. Hernia sac passes within Hesselbach's Triangle (medial inguinal fossa)
    2. Breaches posterior inguinal wall
    3. Hernia develops medial to inferior epigastric vessels
    4. Pathophysiology
      1. Usually occurs in males
      2. Congenital weakness of medial inguinal fossa musculature in some cases
      3. Acquired deficiency in transversus abdominis muscle
  • Symptoms
  1. Often asymptomatic (especially in direct Hernias)
  2. Groin Pain or (dull sensation)
    1. Intensity varies from mild to severe
    2. Burning or ache may be present
    3. Increased pain with valsalva (coughing, straining, lifting)
  3. Bulging, localized fullness or heaviness in the groin
    1. Progressively larger over time
    2. Increased with upright position and valsalva
    3. Decreased when supine
  • Signs
  1. See Inguinal Canal Exam (for males)
  2. Palpable defect or swelling may be present
    1. Indirect Hernia may bulge at Internal Inguinal Ring
      1. Look for bulge site at mid-inguinal ligament
    2. Direct Hernia may bulge at External Inguinal Ring
      1. Look for bulge site at pubic tubercle
      2. Occurs just above inguinal ligament
      3. Seen medial and inferior to Indirect Hernia bulge
  3. Distinguishing indirect and direct Hernias difficult
    1. Experienced clinicians are incorrect in 30% of cases
    2. Indirect Inguinal Hernia palpation difficult in women
    3. Inguinal Hernias difficult to palpate in children
  • Differential Diagnosis
  1. See Groin Pain
  2. See Scrotal Pain
  3. See Groin Swelling
  4. Athletic Pubalgia (Sports Hernia)
    1. Seen in high intensity athletes
    2. Hernia symptoms with no inguinal bulge on examination
    3. Pain reproduced with hip adduction against resistance
  5. Adductor Strain
  6. Osteitis Pubis
    1. Pain at Symphysis Pubis
  7. Testicular Torsion
    1. Especially in young males with unilateral Scrotal Pain
  • Imaging
  1. Indications: Imaging is not required in most cases of Inguinal Hernia
    1. Distinguish from other causes of Groin Pain (e.g. Sports Hernia, Hydrocele)
    2. Post-operative pain
  2. Modalities
    1. Inguinal Ultrasound (excellent first-line study)
    2. CT Pelvis
      1. Distinguishes inguinal from Femoral Hernias
    3. MRI Pelvis
      1. Consider in Sports Hernia evaluation
  1. Technique: Ultrasound in various patient positions
    1. Supine
    2. Upright
    3. Valsalva Maneuver
  2. Efficacy
    1. High Test Sensitivity: >90%
    2. High Test Specificity: 82-86%
      1. Distinguish Incarcerated Hernia from firm mass
  • Management
  1. Small, first, incidental or minimally symptomatic Hernia
    1. Observation is reasonable
    2. Incarceration rate in 2 years is 0.3%
    3. Fitzgibbons (2006) JAMA 295(3):285-92 +PMID:16418463 [PubMed]
  2. Large or recurrent Hernias
    1. See Herniorrhaphy
    2. Repair is recommended within one month of diagnosis
  • Complications
  1. Incarcerated Hernia
    1. Painless entrapment of bowel (contrast with the pain and local inflammation of a Strangulated Hernia)
    2. Risk of Small Bowel Obstruction
    3. Reduced with patient lying supine in Trendelenburg position
      1. Examiner holds gentle pressure on the Herniated bulge for up to 15 minutes
      2. Stop and obtain immediate surgical Consultation for strangulation if pain before or during the procedure
  2. Strangulated Hernia
    1. Surgical emergency with vascular compromise and high risk of infarcted bowel
  • References
  1. Degowin (1987) Diagnostic Examination, p. 489-96
  2. Goroll (2000) Primary Care Medicine, p. 431-4
  3. Stevens (2013) Crit Dec Emerg Med 27(9): 2
  4. Bax (2001) Am Fam Physician 59(4):143-56 [PubMed]
  5. LeBlanc (2013) Am Fam Physician 87(12): 844-8 [PubMed]