Received: 29 October 2019
Accepted: 30 March 2020
First Online: 22 April 2020
Ethics approval and consent to participate
: This study was conducted in accordance with the guidelines of the 1975 Declaration of Helsinki. The need for informed patient consent was waived because of the retrospective nature of the study. All procedures used in this research were approved by the Ethical Committee of Japanese Red Cross Narita Hospital.
: Not applicable
: The authors declare that they had no funding source for this study.