Received: 7 April 2017
Accepted: 21 March 2018
First Online: 19 April 2018
Ethics approval and consent to participate
: Approval for performing the study was given by the institutional ethics committees of the respective universities (approval numbers: 266/2010 (Ethics Committee Medical University of Vienna) and UN4144 (Ethics Committee Medical University of Innsbruck)). Due to the study’s retrospective design informed consent was not requested by the respective ethics committees.
: Not applicable
: The authors declare that they have no competing interests.
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