Text and Data Mining valid from 2018-03-06
Received: 11 October 2017
Accepted: 23 February 2018
First Online: 6 March 2018
Compliance with ethical standards
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: All patients consented to their procedures.
: For this type of study, formal (research participation) consent is not required.
: The authors declare that they have no conflict of interest.