Received: 22 May 2020
Accepted: 7 October 2020
First Online: 14 October 2020
Ethics approval and consent to participate
: The institutional review board of Tokyo Metropolitan Bokutoh Hospital approved the study (institutional approval reference number 02–003), which complied with the tenets of the Declaration of Helsinki. The requirement for informed consent was waived owing to the retrospective design of the study.
: Not applicable.
: The authors declare that they have no competing interests.