Received: 15 November 2019
Accepted: 12 October 2020
First Online: 11 January 2021
Ethics approval and consent to participate
: This study was approved by the Gachon University Gil Medical Center Institutional Review Board (IRB No: GAIRB2017–349). Written informed consent was waived by the Board in this retrospective study.
: Not applicable
: The authors declare that they have no competing interests.