Text and Data Mining valid from 2019-03-07
Received: 17 August 2018
Accepted: 4 February 2019
First Online: 7 March 2019
Compliance with ethical standards
: Elias Tappeiner, Samuel Pröll, Markus Hönig, Patrick F. Raudaschl, Paolo Zaffino, Maria F. Spadea, Gregory C. Sharp, Rainer Schubert, Karl Fritscher declare to have no conflict of interest.
: 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 1964 Helsinki declaration and its later amendments or comparable ethical standards.