Received: 8 January 2020
Accepted: 23 January 2020
First Online: 30 January 2020
Ethics approval and consent to participate
: This study on humans was conducted according to guidelines of the Declaration of Helsinki and approved by the Ethics Committee of the Medical Research, Saitama Red Cross Hospital, Japan (approval no. 18-AE). Informed consent was waived because of the retrospective nature of the study.
: Not applicable.
: The authors declare no conflicts of interest in association with this article.