Received: 2 October 2017
Accepted: 16 October 2018
First Online: 26 October 2018
Ethics approval and consent to participate
: This study protocol was approved by the institutional review board of Ewha Womans University Mokdong Hospital (IRB number: 2017–08-010). All methods were used in accordance with the relevant guidelines and regulations. Informed consent was waived by the IRB because of the study’s retrospective nature.
: Not applicable.
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