Received: 24 July 2017
Accepted: 15 January 2018
First Online: 19 January 2018
Ethics approval and consent to participate
: This retrospective study was conducted by approval of the local ethical board (Ludwig Maximilians University, Munich (LMU) #232–11), participants gave their written content during follow-up.
: Not applicable
: The authors declare that they have no competing interests.
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