Received: 16 October 2018
Accepted: 27 May 2019
First Online: 30 May 2019
Ethics approval and consent to participate
: This study was approved by the institutional ethics committee of the University of Leipzig (Az.: 309/16-ek). Informed written consent was obtained from each patient before surgery. The authors declare that all experiments have been conducted according to the principles of the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.