Received: 13 April 2020
Accepted: 15 June 2020
First Online: 24 June 2020
Ethics approval and consent to participate
: The need for ethics approval and consent was waived by the Institutional Review Board of the RWTH Aachen University due to the retrospective nature of the study (EK 341/19).
: Not applicable.
: All authors report no conflict for interest for this research paper.