Text and Data Mining valid from 2019-01-26
Received: 26 October 2018
Revised: 7 January 2019
Accepted: 17 January 2019
First Online: 26 January 2019
Compliance with ethical standards
: The authors declare that they have 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.
: Given the retrospective nature of the study and the use of anonymized patient data, formal consent is not required.