Binkert, L
Medinger, M
Halter, J P
Heim, D
Gerull, S
Holbro, A
Lengerke, C
Weisser, M
Passweg, J R
Article History
Received: 23 March 2015
Revised: 30 April 2015
Accepted: 15 May 2015
First Online: 29 June 2015
Competing interests
: The authors declare no conflict of interest.