[1] Glostrup Univ Hosp, Dept Surg D, Glostrup, Denmark
[2] Univ London Imperial Coll Sci Technol & Med, Dept Biosurg & Surg Technol, London W2 1NY, England
[3] Aarhus Univ Hosp, Dept Surg L, DK-8000 Aarhus, Denmark
[4] St Michaels Hosp, Div Gen Surg, Toronto, ON M5B 1W8, Canada