[1] Univ Seville, Hosp Univ Virgen del Rocio, Unidad Cirugia Colorrectal, CSIC,IBiS,Serv Cirugia Gen & Aparato Digest, Seville, Spain
[2] Hosp Juaneda Miramar, Serv Cirugia Gen & Aparato Digest, Palma de Mallorca, Spain
[3] Hosp Salnes, Serv Cirugia Gen & Aparato Digest, Villagarcia, Pontevedra, Spain
[4] Hosp Valle De Hebron, Serv Cirugia Gen & Aparato Digest, Unidad Coloproctol, Barcelona, Spain
[5] Hosp Bellvitge Princeps Espanya, Serv Cirugia Gen & Aparato Digest, Unidad Coloproctol, Barcelona, Spain
[6] Hosp Donostia, Serv Cirugia Gen & Aparato Digest, Unidad Coloproctol, San Sebastian, Spain
[7] Hosp Josep Trueta, Serv Cirugia Gen & Aparato Digest, Unidad Coloproctol, Girona, Spain