Lower Esophageal Sphincter Assessment

Introduction to LES Evaluation

The British Society of Gastroenterology recommends oesophageal manometry as the preferred method to localize and characterize the Lower Esophageal Sphincter (LES) 1
High-resolution manometry (HRM) is the definitive test for evaluating LES function, measuring basal LES pressure, integrated relaxation pressure during swallowing, and residual pressure 2

Resting pressure dynamics cannot be assessed from a static image, requiring functional assessment through manometry for accurate diagnosis 1
Relaxation patterns during swallowing require real-time measurement, which cannot be determined by standard endoscopy 2
Residual pressure after relaxation correlates with clinical symptoms but is invisible to the eye, highlighting the need for manometry 1
The American Gastroenterological Association confirms that HRM remains the gold standard for defining LES dysfunction 2

Standard endoscopy can visualize the gastroesophageal junction but cannot determine sphincter tone or function, as the appearance of the GE junction does not reliably correlate with LES pressure or competence 3, 4
Endoscopy cannot assess LES resting tone or pressure, appropriateness of LES relaxation, or presence of transient LES relaxations (the primary mechanism of reflux) 3

The British Society of Gastroenterology and the American Gastroenterological Association recommend manometry for evaluating LES function and diagnosing dysfunction 1, 2
If LES dysfunction is suspected, manometry should be ordered, particularly before antireflux surgery, as it provides critical functional information 1, 2
A timed barium esophagram can be used as an adjunct to demonstrate functional outflow obstruction 2

There is a discordance between endoscopic appearance and manometric findings in 58% of patients, highlighting the importance of manometry in diagnosing LES dysfunction 1
A lax LES with significant reflux can exist despite normal endoscopic appearance, and conversely, an endoscopically abnormal junction may have adequate sphincter function 1, 3