Text and Data Mining valid from 2018-03-23
Received: 26 November 2017
Accepted: 20 January 2018
First Online: 23 March 2018
Compliance with ethical standards
: Kyohei Abe, Hiroaki Shiba, Junichi Shimada, Shinji Onda, Taro Sakamoto and Katsuhiko Yanaga declare that they have no conflict of interest.
: All procedures followed have been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments.
: Informed consent was obtained from all patients for being included in the study.