Received: 4 August 2020
Accepted: 23 November 2020
First Online: 7 January 2021
Ethics approval and consent to participate
: The study was approved by the local ethics committee, the need for informed consent was waived (ethics committee of the State Chamber of Physicians of Baden-Wuerttemberg, Germany, file number F-2019-096).
: Not applicable.
: AG and CN have disclosed that they do not have any conflicts of interest.