Received: 1 April 2020
Accepted: 26 July 2020
First Online: 29 July 2020
Ethics approval and consent to participate
: The study was approved by the Instituitional Research Ethics Committee of the Severance hospital in Yonsei university (3–2018-0194). All procedures performed in the studies involving human participants were in accordance with the ethical standards of our Institutional Review Board with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. In this retrospective study, the requirement for informed consent was waived. Patient data was de-identified data upon data collection.
: Not applicable.
: The authors declare that they have no conflict of interest.