How does the nissen fundoplication reduce the symptoms of gerd?

Reinforce LES: The lower esophageal sphincter (les) is a high pressure zone at the junction of where the esophagus meets the stomach. In reflux disease the les is weakened, allowing stomach acid to reflux back into the esophagus, causing symptoms of gerd. The nissen procedure restores the pressure of the les by wrapping a portion of the stomach around the junction.

Tightening wrap: Gerd (gastroesophageal reflux disease) occurs typically when the lower esophageal sphincter (les) is lax. This allows for stomach acid to splash up into the end of the esophagus creating the burning sensation. The fundoplication is a surgical procedure that wraps the top of the stomach around the base of the esophagus in order to tighten the sphincter to prevent this backwash.

Multiple Ways: A nissen is wraping the loose upper portion of the stomach around the lower esophagus to reinforce the valve that is located there to prevent reflux from the stomach into the esophagus. It also works by bringing the lower esophagus into the abdominal cavity where pressure is greater, furthing reinforcing the valve. Also an hiatel hernia found at the time is repaired.

Preventing reflux: Fundoplication prevents reflux of stomach contents into the esophagus and thus reduces or eliminates symptoms.