Received: 26 January 2021
Accepted: 19 April 2021
First Online: 30 June 2021
: Not applicable
: Consent to publish was obtained from all applicable parties.
: Akira Komuro, Yoichi Yamada, Satoshi Uesugi, Hiroaki Terashima, Masashi Kimura, Hiroto Kishimoto, Tsutomu Iida, Katsuya Sakamoto, Kenichi Okuda, Takashi Sakamoto, and Shunsuke Baba state that there are no conflicts of interests.