Hiatal Hernia Classification and Epidemiology

Overall Classification

Type I – Sliding Hiatal Hernia

Type II – Paraesophageal Hiatal Hernia

Type III – Mixed (Combined) Hiatal Hernia

Type IV – Giant Hiatal Hernia

Hiatal Hernia Causes and Classification

Types and Classification

• The American College of Surgeons acknowledges that hiatal hernias are categorized as acquired diaphragmatic hernias (ADH) and can be classified into four main types, with Type I (Sliding Hiatal Hernia) being the most common type (90%) where the esophageal hiatus widens, allowing herniation of the gastric cardia and migration of the gastroesophageal junction above the diaphragm 3, 4
• The Society of American Gastrointestinal and Endoscopic Surgeons recognizes Type II (Paraesophageal Hiatal Hernia) as accounting for 10% of hiatal hernias, involving a defect in the phrenoesophageal membrane that allows herniation of the gastric fundus while the gastroesophageal junction remains in normal position 3
• The European Hernia Society notes that Type III is a combination of Type I and II, with both herniation of gastric fundus and displacement of the gastroesophageal junction 3, 5
• The American Hernia Society states that Type IV is a large diaphragmatic hernia that can accommodate herniation of additional viscera including stomach, colon, and spleen 3, 6

Primary Causative Factors

Anatomical Factors

• Defects in the phrenoesophageal membrane, particularly important in paraesophageal hernias (Type II), contribute to hiatal hernia development 3