R Madani1,2, M Al-Hashmi1, R Bliss1, T W J Lennard3. 1. Department of Surgery, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, Tyne and Wear, NE1 4LP, UK. 2. Department of Surgery, Whittington Hospital, Magdale Ave, London, UK. 3. Department of Surgery, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, Tyne and Wear, NE1 4LP, UK. t.w.j.lennard@ncl.ac.uk.