Received: 18 June 2019
Accepted: 7 September 2020
First Online: 15 September 2020
Ethics approval and consent to participate
: This was a retrospective study approved by the Affiliated Hospital of Xuzhou Medical University review board (NO.XYFY2019-KL032–01). Informed consent was waived.
: The data do not contain any information that could identify the patient, therefore consent for publication was waived.
: The authors declare that they have no competing interests.