Böhm, F.
Schildgen, O.
Brockmann, M.
Schildgen, V.
Article History
Received: 29 January 2019
Revised: 14 March 2019
Accepted: 11 July 2019
First Online: 3 June 2021
COMPLIANCE WITH ETHICAL STANDARDS
: <i>Conflict of interests</i>. The authors declare that they have no conflicts of interest.
: <i>Statement of compliance with standards of research involving humans as subjects</i>. All procedures were in agreement with the declaration of Helsinki in its present form and a vote from the local ethical committee of the Private University of Witten Herdecke (vote no. 73/2012). Due to the retrospective and epidemiological character of the study no written informed consent was required as confirmed by the local ethical committee.