Text and Data Mining valid from 2018-10-11
Received: 31 July 2018
Revised: 2 October 2018
Accepted: 3 October 2018
First Online: 11 October 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: The study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki. Since we analysed only anonymised patient data that were obtained during clinical routine no informed consent had to be provided and consultation of the institutional review board was not required.