Reminiscences on the antireflux mechanism

Area of Science:

• Gastroenterology
• Physiology

Background:

• The lower esophageal sphincter (LES) is commonly considered the primary antireflux mechanism.
• Radiology, surgical outcomes, and manometric studies suggest other factors are important.
• The role of the LES, hiatus size, and sphincter position in reflux control is debated.

Purpose of the Study:

• To review the evolution of thought on antireflux mechanisms.
• To propose a unifying hypothesis integrating the roles of the LES and hiatus.
• To differentiate between physiologic and pathologic reflux based on pressure resistance.

Main Methods:

• Review of existing literature and concepts.
• Analysis of radiological and surgical findings.
• Interpretation of manometric studies.

Main Results:

• The LES is vital for resisting intragastric pressure during stomach contractions.
• Hiatus size and sphincter position are critical for resisting intra-abdominal pressure.
• Failure of the anatomic component (hiatus/position) leads to pathologic reflux.

Conclusions:

• A dual-component model explains reflux control: LES for intragastric pressure, hiatus/position for intra-abdominal pressure.
• Physiologic reflux occurs when the LES is challenged by stomach pressure.
• Pathologic reflux results from failure of the anatomic antireflux barriers against abdominal pressure.