Conflict of interest

Hiroshi Takahashi, Katsutoshi Sugimoto, Naohisa Kamiyama, Tatsuya Kakegawa, Takuya Wada, Hirohito Takeuchi, and Takao Itoi declare that they have no conflicts of interest.

Human rights statement and informed consent

All procedures followed were in accordance with the ethical standards of the committee responsible for human experimentation (institutional and national) and with Helsinki Declaration of 1964 and later versions. Informed consent was obtained from the patient for being included in the study.