What is a giant hiatal hernia ?

According to Harrison's 18th ed Types II, III, and IV hiatal hernias are all subtypes of paraesophageal hernia in which the herniation into the mediastinum includes a visceral structure other than the gastric cardia. In type II the gastro esophageal junction remains fixed. With type IV hiatal hernias, viscera other than the stomach herniate into the mediastinum, most commonly the colon. Both Harrison and sabiston state that large hiatal hernias can occur in type III, however they don't mention the term giant. According to "THE ESOPHAGUS BY JOEL. RITCHER" and "FUNDAMENTALS OF SURGICAL PRACTICE BY ANDREW'S KINGSNOH" A giant hiatal hernia is usually a paraesophageal hernia of type III or IV in which more than 50% of the abdominal organ (stomach) has crossed the hiatal defect and causes symptom.