Received: 11 June 2020
Accepted: 2 September 2020
First Online: 7 September 2020
Ethics approval and consent to participate
: This study was approved by the institutional review board of Ewha Womans University Mokdong Hospital. In the case of TTM patients, the patient’s own consent cannot be obtained. Written informed consent was obtained from legal guardians of the patients before enrollment in the study.
: Not applicable.
: The authors declare that they have no competing interests.