5-429.p1:

A ring of small magnets has been surgically implanted around your oesophagus.

The oesophagus or gullet connects the mouth with the stomach. It is a muscular tube. The muscles in the oesophagus move food into the stomach. The oesophagus is usually closed by a sphincter muscle at the junction to the stomach. This is meant to prevent the stomach contents and gastric acid being regurgitated into the oesophagus. Only during swallowing does the oesophagus briefly open its sphincter muscle to the stomach.

The aim of the ring of magnets is to prevent gastric acid from flowing into your oesophagus. You have had surgery involving a laparoscopy. A laparoscopy first involves making a small incision in the abdomen. A tube with a camera is pushed through this incision into the abdomen. This camera sends pictures of the inside of the abdomen to a screen. Tools such as forceps and scissors can be inserted through other small incisions in the abdomen.