An esophageal motility study, sometimes known as esophageal manometry, is a procedure used to measure the strength and movement of muscles in the esophagus, the tube which carries food to the stomach. The test may be used to investigate problems such as gastroesophageal reflux disorder, or GERD, where acid moves up from the stomach into the esophagus. It can also be useful to assess swallowing difficulties or to investigate pain in the chest which may be caused by esophageal spasms. During an esophageal motility study, a tube is passed through the nose, down the esophagus and into the stomach. The tube measures muscle pressures along the length of the esophagus, and a graph is produced that illustrates the strength and pattern of muscle movement.
Medical tests such as esophageal manometry are part of what is known as diagnostic gastroenterology. In diagnostic gastroenterology, a variety of techniques are used to investigate and diagnose diseases of the digestive system. An esophageal motility study normally takes less than an hour and is carried out without sedation, so the patient is fully awake.
It is important to fast in the hours leading up to the test, which is performed with the patient lying on one side. Anesthetic may be used to numb the nose and throat before a tube is inserted through one nostril. As the patient swallows, the tube is passed down the full length of the esophagus until it reaches the stomach. During the esophageal motility study, the tube is moved into different positions to record the pressure of muscles inside the walls of the esophagus. Pressures are also recorded while swallowing, and the patient may need to sip water while these measurements are taken.
At the top and bottom of the esophagus there are specialized rings of muscle, known as sphincters, which act as valves. A lower esophageal sphincter test may reveal one of the causes of GERD, as weakness of the lower sphincter can lead to acid passing up from the stomach. It can also be useful in diagnosing a condition known as achalasia, where the lower sphincter fails to open properly, causing swallowing difficulties. An upper esophageal sphincter test may be used to evaluate the sphincter at the top of the esophagus, which normally prevents regurgitation from the esophagus up into the throat.
The main length of the esophagus is referred to as the esophageal body. An esophageal motility study may be used to carry out an esophageal body test, which can show whether all the muscles are working in a coordinated manner. A lack of coordination can lead to painful muscle spasms, resembling a heart problem, or it could prevent normal swallowing. Disorders of esophageal motility and GERD may be treated using diet and lifestyle changes, drugs, surgery, and, in the case of achalasia, by dilating the esophagus using a special kind of balloon.