Chang, Hyung Seok http://orcid.org/0000-0003-3071-0890
Kim, Soo Jeong http://orcid.org/0000-0002-8514-7102
Kim, Young Hwan http://orcid.org/0000-0002-6513-3846
Article History
Received: 28 July 2020
Revised: 10 September 2020
Accepted: 28 September 2020
First Online: 7 October 2020
Compliance with Ethical Standards
:
: Hyung Seok Chang, Soo Jeong Kim, and Young Hwan Kim declare that they have no conflict of interest.
: 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.For this type of study, formal consent is not required.
: The institutional review board of our institute approved this retrospective study, and the requirement to obtain informed consent was waived.