1. Department of General Surgery, Digestive Surgery, School of Medicine, Andrés Bello University, Chile
2. Department of General Surgery, Digestive Surgery, University of Chile, Chile
3. Department of Clinical Coloproctology, INDISA Clinic, Faculty of Medicine, Andrés Bello University, Chile
4. Department of Coloproctology, INDISA Clinic, Faculty of Medicine, University of Chile, Chile