Received: 4 February 2019
Accepted: 19 May 2019
First Online: 7 June 2019
Ethics approval and consent to participate
: The local medical ethical review board (MEC OLVG) approved the study and waived informed consent due to its retrospective design in accordance with the Dutch and European legislation (study no. WO 13.063).
: Not needed as stated by the ethical review board.
: The authors declare that they have no competing interests.