Article History
Received: 28 August 2017
Accepted: 15 January 2018
First Online: 1 February 2018
Ethics approval and consent to participate
: The Helsinki University Hospital approved the study plan. No Ethics committee approval was required.
: Not applicable, not individual patient data presented.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.