Inguinal Hernia

Aka: Inguinal Hernia, Groin Hernia, Scrotal Hernia, Indirect Inguinal Hernia, Indirect Hernia, Direct Inguinal Hernia

1. See Also
   1. Inguinal Hernia in Children
   2. Abdominal Hernia
   3. Femoral Hernia
   4. Sports Hernia
2. 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
3. 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
4. Types
   1. Indirect Inguinal Hernia (most common)
      1. Course
         1. Hernia sac passes outside Hasselbach's Triangle
         2. Herniates via Inguinal Canal
            1. Enters through Internal Inguinal Ring
            2. Lateral to inferior epigastrics
            3. See Inguinal Canal for anatomic course
         3. May result in Scrotal Hernia in males
      2. Pathophysiology
         1. Nonobliterated processus vaginalis (congenital)
         2. Internal abdominal ring weakened fascia
   2. Direct Inguinal Hernia
      1. Hernia sac passes within Hasselbach's Triangle
      2. Breaches posterior inguinal wall
      3. Passes medial to inferior epigastrics
      4. Pathophysiology
         1. Usually occurs in males
         2. Acquired deficiency in transversus abdominis muscle
5. 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
6. 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
7. 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
8. 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
9. Imaging: Inguinal Ultrasound
   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
10. Management
    1. Small, first, incidental or minimally symptomatic hernia
       1. Observation is reasonable
    2. Large or recurrent hernias
       1. See Herniorrhaphy
       2. Repair is recommended within one month of diagnosis
11. 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
12. References
    1. Goroll (2000) Primary Care Medicine, p. 431-4
    2. Degowin (1987) Diagnostic Examination, p. 489-96
    3. Bax (2001) Am Fam Physician 59(4):143-56
    4. LeBlanc (2013) Am Fam Physician 87(12): 844-8