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Article History

Received: 27 October 2017

Accepted: 14 February 2018

First Online: 2 March 2018

Compliance with ethical standards

: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

: The authors declare that they have no conflict of interest.

: For this retrospective type of study formal consent is not required.

: For this retrospective type of study informed consent was not obtained from every participant.