A sterile, hand-held manual surgical instrument intended to be inserted through an orogastric (or nasogastric) tube to mechanically divert the oesophagus away from the site of surgery during electrical treatments of the heart (e.g., cardiac ablation), to facilitate surgical site access and to help prevent injury to the oesophagus. It is in the form of a metal wire made of memory alloy which curls at body temperature to an S-shape when in place in the oesophagus; typically there is a handle to assist insertion. This is a single-use device.