Many of our members and visitors to our website send us excellent questions that can help others suffering from GERD. Many questions, like this one, are about diagnostic tests to either determine if GERD exists or to evaluate the progression of the disease. Examining the LES is critical, since a damaged or weak LES can causes many of the problems for GERD sufferers.
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Is it possible to observe the LES directly with a scope to determine its physical condition?
We’ve discussed the lower esophageal sphincter (LES) previously; however, diagnostic testing on the LES is a very interesting subject, and we appreciate this question. First, let’s discuss the entire anatomy from the mouth to the stomach to highlight the location and function of the LES. The esophagus is a tube of muscles that connects the mouth to the stomach. Sphincters are located at both ends termed for their location; the upper and the lower esophageal sphincters. Food, liquids, and saliva move from the mouth to stomach via a coordinated series of events triggering muscles along the route. The image below, courtesy of the National Institute of Health, Patient Information on Acid Reflux, illustrates the lower esophageal sphincter and its location relative to the diaphragm and the stomach.
Most specialists typically begin with an endoscopic examination that provides a visual examination of the esophagus. It is a very important exam since a specialist can see any injury to the esophagus such as strictures, a hiatal hernia, or even evidence of Barrett’s esophagus and cancer. If Barrett’s or cancer is suspected, the endoscope also permits the specialist to take cell samples for further diagnosis by a pathologist. The LES itself is a muscular ring that surrounds the gastro-esophageal junction, which is the junction between the esophagus and the stomach. Since this muscle band is outside of the esophagus, it can’t technically be viewed.
The most important issue concerning the LES is how effective it performs as a barrier between the stomach and the esophagus. As a LES loses its effectiveness, it gets shorter and weaker. Dr. DeMeester MD FACS, our senior medical expert, has measured the length of the LES as well as its strength as part of his extensive research on acid reflux disease. However, a 24-hour pH test is the most common means to evaluate the overall condition of the LES. This testing was also pioneered by Dr. DeMeester and the scoring of this test also bears his name, the DeMeester Score.
A barium swallow is another test performed which provides more information on the functioning of the esophagus and the sphincter. Patients swallow a liquid contrast agent, barium, which can be viewed using a special X-ray video camera. This test is performed by a radiologist and provides a visual record of the coordinated muscle contractions from the mouth to stomach. The radiologist can also test the effectiveness of the LES at rest as a barrier since the barium should only flow from the esophagus into the stomach. However, a weak LES will allow this agent to flow back into the esophagus, suggesting a damaged or weak LES. Again, this test does not permit the LES to be viewed, but rather its effectiveness can be tested.
Manometry is an excellent diagnostic to test the muscles in the esophagus, as well as the sphincters. Using a thin tube with pressure transducers, this test effectively measures how well the entire esophagus is working to pass food and liquids from the mouth to the stomach. A GERD expert can also determine many important characteristics about the LES including it length, which correlates to the resting pressure of the LES, a key factor in keeping food from returning from the stomach to the esophagus. Again, it is not possible with manometry to “view” the LES, but this test can determine the effectiveness of the LES to perform its function as a barrier between the stomach and esophagus and provide important data on the LES itself.