Received: 21 December 2016
Accepted: 9 February 2018
First Online: 21 February 2018
: The authors declare that they have no competing interests.
: The patients, surgeons and trainees in the study participated voluntarily, after signing an informed consent. The study protocol was approved by the Bioethics and Research Committee of the Faculty of Medicine at the Universidad Austral de Chile (N° 2014/11/03).
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.