Received: 31 August 2019
Accepted: 12 June 2020
First Online: 17 June 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Chungnam National University Hospital (IRB number; CNUH 2019–02-024), and the requirement for obtaining written consent was waived because of the retrospective design of the study. 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.
: Not applicable.
: The authors have no conflicts of interest to declare.