Text and Data Mining valid from 2020-01-09
First Online: 9 January 2020
Compliance with ethical guidelines
: A. Barg, T.L. Kahn, G. Dekeyser, Y. Sripanich and V. Valderrabano declare that they have no competing interests.
: This retrospective study was approved by the institutional review board (University of Basel) with a waiver of informed consent. For this article no studies with human participants or animals were performed by any of the authors. All studies performed were in accordance with the ethical standards indicated in each case.