Classification and Assessment of Esophagogastric Junction and Hiatus Hernia
The presence of a hiatus hernia should be documented and measured during upper endoscopy, with classification based on anatomical type (Types I-IV) and measurement of axial displacement, while the esophagogastric junction should be assessed using the Prague classification for Barrett's esophagus and Hill classification for the gastroesophageal flap valve. 1
Anatomical Classification of Hiatus Hernia
Four-Type Classification System
The most widely used classification divides hiatus hernias into four distinct types 2, 3:
Type I (Sliding Hiatus Hernia): Accounts for 90% of cases, characterized by widening of the esophageal hiatus allowing herniation of the gastric cardia with migration of the gastroesophagogastric junction above the diaphragm 2
Type II (Paraesophageal Hernia): Represents 10% of cases, involving a defect in the phrenoesophageal membrane that allows herniation of the gastric fundus while the gastroesophageal junction remains in normal anatomical position 2
Type III (Combined): A combination of Types I and II, with both herniation of gastric fundus and displacement of the gastroesophageal junction 2
Type IV (Complex): A large diaphragmatic hernia that accommodates herniation of additional viscera including stomach, colon, and spleen 2
Critical Caveat on "True" Paraesophageal Hernias
Most massive hiatus hernias represent advanced degrees of sliding hernias rather than true paraesophageal hernias. In one surgical series, 91 of 94 patients (97%) with presumed paraesophageal hernias had the esophagogastric junction above the diaphragmatic hiatus at endoscopy, indicating a sliding component 4. True paraesophageal hernia with the esophagogastric junction in normal abdominal location appears rare 4.
Endoscopic Assessment Protocol
Essential Anatomical Landmarks
During upper endoscopy, systematically identify and document 1:
- Diaphragmatic hiatus location: The crural impression marking the diaphragmatic pinch
- Gastroesophageal junction (GEJ): The proximal extent of gastric folds, best examined after gastric decompression 1
- Squamocolumnar junction (Z-line): The transition between squamous and columnar epithelium
- Axial separation: Measure the distance between the diaphragmatic hiatus and the GEJ to quantify hernia size 1
Hill Classification of Gastroesophageal Flap Valve
Use the Hill classification to assess the competency of the gastroesophageal flap valve 1:
- Grade 1: Prominent fold of cardia along lesser curve, closely apposed to endoscope
- Grade 2: Flap valve present but transiently opens and closes with respiration
- Grade 3: Flap valve barely visible, failure to close around endoscope
- Grade 4: Flap valve absent, GE junction continuously open; hiatal hernia always present 1
Measurement and Documentation
Measure and document the axial length of any hiatus hernia present 1. The British Society of Gastroenterology mandates that the presence of a hiatus hernia should be documented and measured, with photo-documentation required 1.
For hernias greater than 2 cm in axial span, diagnosis is readily accomplished by barium swallow radiography, endoscopy, or manometry 5. However, subtle disruptions with less than 2 cm separation require high-resolution manometry for reliable detection 5.
Assessment of Esophagogastric Junction in Barrett's Esophagus
Prague Classification
When Barrett's esophagus is present, use the Prague classification to standardize reporting 1:
- C value: Circumferential extent of Barrett's mucosa (distance in cm from GEJ to proximal extent of circumferential Barrett's)
- M value: Maximal extent of Barrett's mucosa (distance in cm from GEJ to most proximal island of Barrett's)
The diagnosis requires salmon-colored mucosa extending a minimum of 1 cm above the proximal extent of gastric folds 1. Do not routinely biopsy a normal or irregular Z-line 1.
Diagnostic Modalities Beyond Endoscopy
Barium Esophagography
Fluoroscopy with biphasic esophagram or upper GI series is the most useful test for diagnosing hiatus hernia and determining its size 6. Barium swallow should be part of the work-up, particularly when clinical and endoscopic findings suggest axial irreducibility of the esophagogastric junction 7.
High-Resolution Manometry
For detecting lesser degrees of axial separation between the lower esophageal sphincter and crural diaphragm, high-resolution manometry is the only reliable technique 5. This permits real-time localization of esophagogastric junction components without swallow or distention-related artifact 5.
Manometric findings in hiatus hernia patients demonstrate 4:
- Hypotensive lower esophageal sphincter in 51% of cases
- Diminished amplitude of distal esophageal peristalsis in 59% of cases
- Shortened esophageal length (average 15.4 cm vs. normal 20.4 cm, p < 0.0001)
Clinical Significance and Associated Findings
Gastroesophageal Reflux Disease Association
Sliding hiatus hernia with a reducible esophagogastric junction does not necessarily influence the severity of GERD 7. However, an irreducible esophagogastric junction is associated with long-standing severe GERD and esophagitis in 80% of cases 7.
Symptomatic reflux (present or remote) occurs in 83% of patients with massive hiatus hernias 4. Gross endoscopic peptic esophagitis is observed in 36% of these patients, including ulcerative esophagitis in 22% and peptic stricture in 14% 4.
Functional Assessment
The lower esophageal sphincter in hiatus hernia patients demonstrates lower pressure (47.7 vs. 61.4 mm Hg at 50-mL distension) and increased distensibility compared to controls 8. The crural diaphragm shows even lower pressure (29.6 vs. 47.7 mm Hg) and greater distensibility than the lower esophageal sphincter 8.
Classification of Esophagogastric Junction Tumors
For oncologic purposes, the Siewert classification defines adenocarcinomas of the esophagogastric junction based on tumor epicenter location 1:
- Type I (AEG I): Epicenter >1 cm above the anatomic EGJ
- Type II (AEG II): Epicenter within 1 cm proximal and 2 cm distal to the anatomic EGJ
- Type III (AEG III): Epicenter >2 cm below the anatomic EGJ
The revised AJCC staging system classifies tumors whose midpoint is in the lower thoracic esophagus, EGJ, or within the proximal 5 cm of the stomach that extends into the EGJ or esophagus as adenocarcinoma of the esophagus 1.