Received: 25 March 2019
Accepted: 29 August 2019
First Online: 5 September 2019
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the Committee on Ethics and the Institutional Review Board of Tokai University School of Medicine (18R-315), the House Clinical Study Committee, and Profit Reciprocity Committee. Because this study was retrospective, the requirement for informed consent was not deemed necessary.
: Not applicable.
: The authors declare that they have no competing interests.