Conflict of interest

Ikuo Misumi, Hiroto Kishi, Koji Sato, Akihisa Tabira, Hiroki Usuku, Kenichi Tsujita declare that they have no conflict of interest.

Informed consent

Informed consent was obtained from the patient.

Human and rights statements

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1964 and later versions.