Received: 19 July 2020
Accepted: 24 November 2020
First Online: 18 December 2020
Ethics approval and consent to participate
: This study adheres to the ethical principles of the Declaration of Helsinki. It was approved by the Ethics Committee of Ulm University (No.399/17). For the presented retrospective data, the requirement to obtain informed consent was waived in accordance with the vote of the Ethics Committee.
: Not applicable.
: The authors declare that they have no competing interests.