Text and Data Mining valid from 2020-01-14
Received: 28 August 2019
Accepted: 8 January 2020
First Online: 14 January 2020
Ethics approval and consent to participate
: The study was approved by the local ethics committee (Ethikkommission II der Medizinischen Fakultät Mannheim, University of Heidelberg, reference number 2013-813R-MA) and has therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. Patient consent was not required by our local ethics committee due to the retrospective nature of the study and the lack of patient interaction.
: Not applicable.
: The authors declare that they have no competing interests.