Text and Data Mining valid from 2019-01-14
Received: 21 May 2018
Accepted: 3 January 2019
First Online: 14 January 2019
Compliance with ethical standards
: No funding was received for this study.
: The authors declare that they have no conflict of interest.
: All procedures performed in the 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 retrospective study formal consent is not required and all patient data was anonymized.