Received: 9 April 2020
Accepted: 18 June 2020
First Online: 23 June 2020
Ethics approval and consent to participate
: This retrospective study involving human participants was in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The Human Investigation Committee (IRB) of Deyang People’s Hospital approved this study.
: Not Applicable.
: The authors declare that they have no competing interests.