Funding for this research was provided by:
Natural science foundation of Shandong Province (ZR2019MH130)
Received: 21 July 2021
Accepted: 30 September 2021
First Online: 18 October 2021
: This study was approved by our institutional review board. The need for informed consent was waived, because our study was performed retrospectively.
: All authors have read and agreed to the published version of the manuscript.
: The authors declare no competing interests.