Ostendorf, J.
Vassiliu, P.
Kühling, K.
Massalis, I.
Luedi, M. M.
Doll, D. http://orcid.org/0000-0001-9832-4545
Article History
First Online: 20 November 2020
Compliance with ethical guidelines
:
: J. Ostendorf, P. Vassiliu, K. Kühling, I. Massalis, M.M. Luedi, and D. Doll declare that they have no conflict of interest. There are no other relevant or minor financial relationships between authors, their relatives or next of kin, and external companies.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1975 Helsinki declaration and its later amendments or comparable ethical standards. The Helsinki Declaration, last updated Oct 2008, declares that ethical approval for all interventional studies is required. This retrospective study does not influece any intervention, and documents world wide well known long term established treatment results. Thus formal Committee application is not required.