Received: 23 January 2019
Accepted: 24 June 2019
First Online: 1 July 2019
Ethics approval and consent to participate
: This retrospective study was approved by the concerned local ethics committee (Heinrich-Heine-University, Duesseldorf, Germany; study-no.: 2018–229-RetroDEuA). Individual consent was not necessary according to local ethical regulations in a retrospective investigation based on the hospital data management system as performed here.
: Not applicable.
: The authors declare that they have no competing interests.