Funding for this research was provided by:
JA Kyosai Research Institute
Text and Data Mining valid from 2019-01-28
Received: 6 July 2018
Accepted: 17 January 2019
First Online: 28 January 2019
Ethics approval and consent to participate
: All cadavers were donated to Tokyo Medical and Dental University. All of the donors had voluntarily declared that their remains were to be donated as materials for education and study. This voluntary donor system of cadavers is in place throughout Japan, and our study completely complies with the current Japanese laws.
: The authors declare that they have no competing interests.
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