Received: 31 August 2017
Accepted: 2 October 2017
First Online: 12 October 2017
Compliance with ethical standards
: The authors declare that they have no financial or non-financial competing interests.
: 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. This article does not contain any studies with animals performed by any of the authors. This study was approved by the local ethics committee (No. 2016–585-f-S, Ethikkommission der Ärztekammer Westfalen-Lippe und der Westfälischen Wilhelms-Universität Münster).