Funding for this research was provided by:
Program for Liaoning Innovative Talents in University (XLYC1807131)
the Natural Science Foundation of Liaoning Province (20170540294)
Teaching reform research project of Dalian Medical University (DYLX19010)
Received: 31 January 2020
Accepted: 13 May 2020
First Online: 24 May 2020
Ethics approval and consent to participate
: This research was approved by the ethics committee of the First Affiliated Hospital of Dalian Medical University. And agreement to participate was given by the participants. Because of the retrospective nature of the study, informed consent was waived.
: Written informed consent for publication of their clinical details and/or clinical images was obtained from the patient/parent/guardian/relative of the patient.
: The authors declare that they have no competing interests.