Received: 30 April 2020
Accepted: 7 September 2020
First Online: 27 September 2020
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: 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. For this type of retrospective study, formal consent is not required. The ethics committee of the University Hospitals Leuven approved the study.