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Article History

Received: 9 February 2018

Accepted: 30 August 2018

First Online: 3 September 2018

Ethics approval and consent to participate

: Ethical approval was obtained from the Xiamen Xianyue Hospital Ethical Committee. Permission to access patients’ records was also sought from the Management of Xiamen Xianyue Hospital. Informed consent was not necessary for this retrospective study.

: No patient identifiable information has been reported.

: The authors declare that they have no competing interests.

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