Text and Data Mining valid from 2019-11-16
Received: 12 June 2019
Accepted: 23 October 2019
First Online: 16 November 2019
Ethics approval and consent to participate
: Due to the retrospective nature of this study, informed consent was waived. But the study was approved by the ethics committee of our hospital.
: Consent was obtained from all patients for the publication of the present study。.
: The authors declare that they have no competing interests.