1 Department of Upper GI Surgery, Northwick Park and St Mark's Hospitals, Watford Road, Harrow, London, HA1 3UJ, UK. lalin.navaratne@doctors.org.uk.
2 Department of Upper GI Surgery, Hospital Clínico Universitario de Santiago de Compostela (CHUS), Travesía de Choupana, s/n, 15706, Santiago de Compostela, La Coruña, Spain.
3 Department of Upper GI Surgery, Northwick Park and St Mark's Hospitals, Watford Road, Harrow, London, HA1 3UJ, UK.