Document is current

Article History

Received: 15 January 2018

Accepted: 16 March 2018

First Online: 27 March 2018

Ethics approval and consent to participate

: The Ethics Committee of Xinhua Hospital approved the study. The informed consent was waived because this is a retrospective study.

: The written consent is available for review by the chief editor.

: The authors declare that they have no competing interests.

: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.