1. University of Padova; Meta-Analysis Unit, Department of Surgery, Oncology and Gastroenterology; Via Giustiniani 2 Padova Veneto Italy 35128
2. John Radcliffe Hospital; Nuffield Department of Surgery; 6th floor Headington Oxford UK OX3 9DU
3. University of Liverpool; Academic Department; Liverpool UK
4. Hospital de Clinicas; Department of Digestive Surgery; Rua Manuel da Nobrega, 1564 Sao Paulo Sao Paulo Brazil 04001005
5. McMaster University; Department of Medicine, Division of Gastroenterology; 1280 Main Street West Room HSC 4N50 Hamilton ON Canada L8S 4K1
6. University of Padova; Clinica Chirurgica II; Via Giustiniani 2 Padova Italy 35128