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Article History

Received: 22 May 2018

Accepted: 31 July 2018

First Online: 13 August 2018

Ethics approval and consent to participate

: Not required; as part as routine care, 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.

: Not applicable. As a retrospective study, no consent was required.

: The authors declare that they have no competing interests.

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