Text and Data Mining valid from 2019-04-27
Received: 31 December 2017
Accepted: 8 April 2019
First Online: 27 April 2019
Ethics approval and consent to participate
: The study protocol was approved by the Ethical Review Committee of Jeju National University Hospital (IRB number 2017–04-005). Informed consent was waived because of the retrospective nature of the study.
: Not applicable.
: The authors declare that they have no competing interests.
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