Article History
Received: 13 January 2020
Accepted: 27 January 2020
First Online: 5 February 2020
Ethics approval and consent to participate
: This retrospective observational study was approved by the Institutional Review Board of Nara Medical University (Kashihara, Nara, Japan; Chairperson Prof. M. Yoshizumi; approval no. 2964; December 17, 2018). The requirement of informed consent was waived because of the retrospective nature of this study.
: Not applicable
: The authors declare that they have no competing interests.