1 Department of Colorectal Surgery, Queen's Medical Centre, University Hospitals Nottingham NHS Trust, Nottingham NG7 2UH, UK; Department of Colorectal Surgery, Sherwood Forest Hospitals NHS Foundation Trust, Mansfield, UK; Department of Colorectal Surgery, Royal Derby Hospitals NHS Trust, Derby, UK. Electronic address: anil.george1@nhs.net.
2 Department of Colorectal Surgery, Sherwood Forest Hospitals NHS Foundation Trust, Mansfield, UK.
3 BCSP Eastern Hub, Queen's Medical Centre, Nottingham, UK.
4 Department of Medical Statistics, University Hospital of South Manchester NHS Foundation Trust, Manchester, UK.