Text and Data Mining valid from 2018-04-17
First Online: 17 April 2018
Compliance with ethical standards
: No funding was received for this 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.
: Retrospective study, hence no informed consents were obtained.