Received: 16 June 2020
Accepted: 30 December 2020
First Online: 13 January 2021
Ethics approval and consent to participate
: All procedures including review of patient record used in this research were approved by the institutional review board of Tsukuba University Hospital Mito Clinical Education and Training Center/ Mito Kyodo General Hospital (No.17 − 01). Verbal informed consents were obtained from all patients and their parent to participate in this study. An IRB approve the study and the procedure outlined for the verbal consent obtainment.
: Written informed consent for publication was obtained from the patients included in this study.
: The authors declare that there are no relevant competing interest.