Article History
Received: 4 July 2019
Accepted: 10 November 2019
First Online: 23 November 2019
Compliance with ethical standards
:
: All authors declare that they have no conflicts of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the local ethics committee of the University of Freiburg (vote no. 432/16) and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was not needed due to the retrospective nature of the study.