[1] Univ Insubria Varese, Dept Surg Sci, Multimed Santa Maria Hosp, I-21053 Castellanza, Varese, Italy
[2] Hosp Univ 12 Octubre, Madrid, Spain
[3] Univ Copenhagen, Herlev Hosp, Dept Surg, DK-2730 Herlev, Denmark
[4] CH Jean Verdier, Bondy, France
[5] Derriford Hosp, Peninsula Med Sch, Plymouth PL6 8DH, Devon, England
[6] Univ Hosp Gasthuisberg, Dept Abdominal Surg, B-3000 Louvain, Belgium