Article History
Received: 5 March 2020
Accepted: 28 April 2020
First Online: 16 May 2020
Compliance with ethical standards
:
: The authors declare that they have no competing interests.
: Ethical approval was obtained from the Ethics Committee of the Second Hospital of Shandong University. All procedures performed in studies involving human participants were in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. All patients signed the informed consent.
: Informed consent was obtained from all individual participants included in the study.