The hiatus is the natural orifice in the diaphragm were the esophagus goes through and meets the stomach. If this orifice widens the stomach will work his way into the chest causing a hiatal or paraesophageal hernia. Small hernias are usually asymptomatic, but larger hernias can cause reflux, difficulty swallowing, regurgitation of undigested food and/or abdominal/chest pain.
For symptomatic hernias a laparoscopic repair can be indicated. In many occasions a fundoplication is also performed.