Article History
Received: 12 November 2019
Revised: 1 December 2019
Accepted: 3 December 2019
First Online: 13 December 2019
Compliance with Ethical Standards
:
: Jiyoung Wang, Dongwoo Kim, Won Jun Kang, and Hojin Cho 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.
: The institutional review board of our institute approved this retrospective study, and the requirement to obtain informed consent was waived.