Text and Data Mining valid from 2018-07-26
Received: 20 December 2017
Accepted: 23 April 2018
First Online: 26 July 2018
Ethics approval and consent to participate
: All procedures followed were in accordance with the ethical standards of the responsible committees on human experimentation (institutional and national) and with the Helsinki Declaration of 1964 and later versions. The study was approved by an institutional review board of our university (approval No. D2016-061). The requirement for informed consent from each patient was waived in this retrospective study, which was also approved by our institutional review board.
: Hiroko Ishii, Akemi Tetsumura, Yoshikazu Nomura, Shin Nakamura, Masako Akiyama, and Tohru Kurabayashi declare that they have no competing interests.
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