Article History
Received: 26 December 2019
Revised: 28 February 2020
Accepted: 21 March 2020
First Online: 4 April 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 Sapporo City General Hospital and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.