Article History
Received: 29 October 2019
Accepted: 24 April 2020
First Online: 15 May 2020
Compliance with Ethical Standards
:
: The authors 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 and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: The requirement for informed consent was waived by the institutional review boards of Dokkyo Medical University Saitama Medical Center, Japan, and the NTT Medical Center Tokyo, Japan.