Article History
First Online: 8 December 2018
Compliance with Ethical Standards
:
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
: Since this is a retrospective study, formal consent is not required for this type of study.
: The authors declare that they have no conflicts of interest.