Article History
Received: 25 April 2018
Accepted: 24 January 2019
First Online: 18 February 2019
Ethics approval and consent to participate
: 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. As the following study was performed in retrospectively, formal consent was not required. This research protocol is reviewed and approved by the Jeju National University Hospital (JNUH) IRB.
: Not applicable.
: The authors declare that they have no competing interests.
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