Received: 28 September 2018
Accepted: 24 January 2019
First Online: 4 February 2019
Ethics approval and consent to participate
: This research was approved by the institutional IRB (IRB of Yonsei University Hospital, IRB No. 2017-3510-001).Informed written consent was waived owing to the study’s retrospective nature.
: Not applicable
: The authors declare that they have no competing interests.
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