Article History
Received: 13 January 2021
Revised: 26 March 2021
Accepted: 13 April 2021
First Online: 27 April 2021
Declarations
:
: Soo Jin Kwon, Joo Hyun O, and Ie Ryung Yoo declare 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 Helsinki declaration as revised in 2013 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 (KC20RASI0078), and the requirement to obtain informed consent was waved.