1. Colorectal Surgery Department, Santa Elena Clinic, Madrid, Spain;
2. Department of General Surgery, Hospital Comarcal de Melilla, Melilla, Spain;
3. Department of Geriatrics and Gerontology, Hospital Clinico San Carlos, Madrid, Spain;
4. Clinical Research and Methodology Unit, Hospital Clínico San Carlos, Medical School, Universidad Complutense, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain;
5. Colorectal Surgery Department, Fundación Jiménez Díaz, Madrid, Spain