What are the different types of hernias?

Types of Hernias

Hernias are broadly classified into two main categories: congenital diaphragmatic hernias (CDHs) and acquired diaphragmatic hernias (ADHs), with various subtypes within each category based on anatomical location and etiology. 1

Congenital Diaphragmatic Hernias (CDHs)

• Bochdalek hernia: Most common CDH (95%), occurring predominantly on the posterior left side of the diaphragm (85% left-sided vs. 15% right-sided). Results from incomplete development of the diaphragm during gestation. 1

• Morgagni hernia: Rare congenital defect (approximately 3% of surgically treated diaphragmatic hernias) occurring in the anterior aspect of the diaphragm between the costal and sternal portions. 2

Acquired Diaphragmatic Hernias (ADHs)

ADHs typically occur in adulthood and can be categorized into three main types:

1. Hiatal Hernias

Hiatal hernias are classified into four types:

• Type I (Sliding hiatal hernia): Most common type (90%) where the gastroesophageal junction and gastric cardia herniate through the esophageal hiatus into the thoracic cavity. 1

• Type II (Paraesophageal hiatal hernia): Accounts for 10% of hiatal hernias. The gastroesophageal junction remains in normal position, but the gastric fundus herniates through a defect in the phrenoesophageal membrane. 1

• Type III: Combination of Types I and II - paraesophageal hernia with superiorly displaced gastroesophageal junction. 1

• Type IV: Large diaphragmatic hernia that can accommodate additional viscera including stomach, colon, and spleen. 1

2. Traumatic Diaphragmatic Hernias

Result from blunt or penetrating trauma to the diaphragm, allowing abdominal contents to herniate into the thoracic cavity.

3. Iatrogenic Hernias

Occur as complications of surgical procedures involving the diaphragm.

Abdominal Wall Hernias

The current relative frequency of different abdominal wall hernia types (in decreasing order) is:

1. Inguinal hernias: Most common overall, especially in men 3, 4
2. Umbilical hernias 4
3. Epigastric hernias 4
4. Incisional hernias: Occur at sites of previous surgical incisions 4
5. Para-umbilical hernias 4
6. Femoral hernias: More common in women, now the fifth most common hernia type 3, 4
7. Other types: Including Spigelian hernias 4

Diagnostic Approaches

• CT scan with IV contrast: Most effective diagnostic modality for confirming diaphragmatic hernias, particularly Morgagni hernias 2
• Ultrasonography: Useful for diagnosing groin hernias in women and when complications are suspected 3
• MRI: Higher sensitivity and specificity than ultrasonography, useful for diagnosing occult hernias when clinical suspicion is high despite negative ultrasound findings 3

Clinical Significance and Management

• Emergency presentation of hernias is associated with higher complication rates and longer hospital stays 5
• Surgical repair is the definitive treatment, with laparoscopic approaches generally associated with shorter recovery times, less pain, and lower recurrence rates than open repair 3
• Watchful waiting may be reasonable for men with asymptomatic or minimally symptomatic inguinal hernias, but is not recommended for symptomatic hernias or in nonpregnant women 3

Complications of Hernias

• Incarceration (trapping of hernia contents)
• Strangulation (compromised blood supply to herniated contents)
• Bowel obstruction
• Perforation

Early diagnosis and appropriate management of hernias are crucial to prevent these potentially life-threatening complications, with elective repair generally carrying lower risks than emergency surgery 5.