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Article History

Received: 20 February 2018

Accepted: 30 April 2018

First Online: 7 May 2018

Ethics approval and consent to participate

: This retrospective study was approved by the ethical review committee, Pusan National University Yangsan Hospital (05–2017-028). Written informed consent was obtained from participants for research studies and presented data.

: The authors declare that they have no competing interests.

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