P.O. Box 21-096,
Edgeware,
Christchurch, 8143
A tiny camera attached to a long tube is inserted into your mouth and passed down through your pharynx into your oesophagus. This allows the surgeon to make a diagnosis either by seeing directly what is causing the problem or by taking a small tissue sample (biopsy).
https://www.healthpoint.co.nz/private/ent-head-neck-surgery/southern-cross-christchurch-hospital-otolaryngology/