1. Department of Surgery, Fundación Jiménez Díaz University Hospital, Avda. Reyes Católicos, 2, 28040 Madrid, Spain
2. Department of Surgery, Universidad Autónoma de Madrid, C/Arzobispo Morcillo s/n, 28034 Madrid, Spain
3. Department of Surgery, General University Hospital of Ciudad Real, C/Obispo Rafael Torija, s/n, 13005 Ciudad Real, Spain
4. Department of Mathematics, University of Castilla-La Mancha, Camino de Moledores, s/n, 13071 Ciudad Real, Spain
5. Department of Gynaecology, General University Hospital of Ciudad Real, C/Obispo Rafael Torija, s/n, 13005 Ciudad Real, Spain
6. Department of Surgery, General University Hospital of Jaén, 23007 Jaén, Spain
7. Department of Anaesthesia, General University Hospital of Ciudad Real, C/Obispo Rafael Torija, s/n, 13005 Ciudad Real, Spain