Text and Data Mining valid from 2018-12-21
Received: 22 October 2018
Accepted: 12 December 2018
First Online: 21 December 2018
Compliance with ethical standards
: All authors declare that there is no conflict of interest.
: 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. This is a retrospective study that was approved by the local ethical committee (530/2018BO2).