Received: 27 April 2019
Accepted: 26 June 2019
First Online: 11 July 2019
Ethics approval and consent to participate
: The study was approved by the Clinical Ethics Committee of the University of Tübingen (Project number: 336/2017BO2).
: All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.