[1] Univ Aberdeen, Inst Appl Hlth Sci, Aberdeen, Scotland
[2] Nottingham Univ Hosp, Dept Urol, Nottingham, England
[3] Nanyang Technol Univ, Lee Kong Chian Sch Med, Med Educ Res & Scholarship Unit, Singapore, Singapore
[4] Univ Aberdeen, Inst Appl Hlth Sci, Med Stat Team, Aberdeen, Scotland
[5] Aberdeen Royal Infirm, Dept Colorectal Surg, Aberdeen, Scotland
[6] Queen Alexandra Hosp, Dept Maxillofacial Surg, Portsmouth, Hants, England