Received: 19 July 2019
Accepted: 6 September 2019
First Online: 21 October 2019
Ethics approval and consent to participate
: This study was approved by the ethics committee of the Hannover Medical School (no. 8471_BO_K_2019).
: Not applicable (No individual details such as images or videos are included).
: The authors declare that they have no competing interests.