1 Department of Colorectal Surgery, Concord Hospital and the Discipline of Surgery, Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia.
2 Department of Anatomy, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
3 Department of Colorectal Surgery, Liverpool Hospital and School of Medicine, Western Sydney University, Sydney, New South Wales, Australia.