Text and Data Mining valid from 2018-08-04
Received: 4 April 2018
Accepted: 26 July 2018
First Online: 4 August 2018
Compliance with ethical standards
: All authors declare that they do not have conflicts of interest regarding the work covered by this manuscript.
: All procedures involving human participants were in accordance with the 1964 Declaration of Helsinki and its later amendments.
: The local ethics committee approved the studies (ethics committee of the University of Erlangen-Nürnberg; reference numbers 243 12 B and 60 14 B), and all patients gave their written informed consent.