Gastro-intestinal Physiology After Anti-Reflux Procedures

Gastro-oesophageal reflux disease (GORD) affects 1 in 4 adults and is a condition where stomach acid leaks back up into the oesophagus (gullet). It can cause an uncomfortable burning feeling in the chest and even lead to problems such as cancer of the oesophagus. Thankfully most people feel better by changing their diet or taking medications, but for others it can be severe, and they may need to consider having surgery to tighten the internal muscles and stop acid leaking back up. The most common operation is the "laparoscopic fundoplication", which is a keyhole procedure where the top of the stomach is wrapped around the lower oesophagus. Alternatively, the "LINX device" is a keyhole procedure where a magnetic bracelet is placed around the lower oesophagus. The "Stretta procedure" is a non-surgical option, where a probe is placed in the mouth to the oesophagus, where heat energy is applied to strengthen the muscles. All three procedures have been shown to be effective at helping people feel better, but less is known about how exactly they do this and there are not many studies that have been done to compare these procedures. This study will perform tests on adult patients at St George's University Hospitals NHS Foundation Trust before and again 6 months after their surgery (laparoscopic fundoplication, LINX device or Stretta procedure). The tests are safe and are mostly performed in routine care. The tests will analyse how surgery affects: * the strength of the oesophagus muscles * the amount of acid leaking up * how sensitive the oesophagus is to acid * symptoms This should help lead to a better understanding of what changes are important to make people feel better from GORD and help inform treatment decisions with patients in future.