Funding for this research was provided by:
Received: 28 August 2021
Revised: 21 March 2022
Accepted: 6 April 2022
First Online: 18 April 2022
: The authors declare that there is no conflict of interest regarding the publication of this article.
: As it is retrospective study the need of an informed consent was waived by the ethical committee of the University of Regensburg.
: All authors give their consent to publish this article in the ESJ.
: The study was approved by the local ethics committee (20-1821-104) of the University of Regensburg. All methods were carried out in accordance with the ethical standards of the Declaration of Helsinki 1975.