Text and Data Mining valid from 2017-08-22
Received: 29 May 2017
Accepted: 11 August 2017
First Online: 22 August 2017
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: The authors have no disclosure of any personal or financial support for this multicenter study.
: 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. For this type of study formal consent is not required.
: Informed consent was obtained from all individual participants includedin the study.