Received: 10 June 2018
Accepted: 10 August 2018
First Online: 20 August 2018
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of the Yeungnam University Hospital, South Korea (file no. YUMC 2017–07-014), and complied with the principles outlined in the Declaration of Helsinki. Institutional Review Board of our institution allowed us “waiver of informed consent” because it is determined that obtaining consent from a human subject of research is impracticable in the course of research and the risk to a human subject of research is very low even if the project is exempted from consent, as per the Bioethics and Safety Act of the Republic of Korea (Chapter 3, Article 16, Paragraph 3, Act No. 14839. Enforcement Date 26. Jul, 2017.).
: Not applicable.
: The authors declare that they have no competing interests.
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