Funding for this research was provided by:
Guangzhou Science and Technology Key Project (No. 323201508020261)
Guangdong Provincial Science and Technology Planning Project 324 (No.2014A020212676)
Received: 13 March 2019
Accepted: 21 April 2019
First Online: 15 May 2019
: Not applicable.
: We further confirm that any aspect of the data collection covered in this manuscript that has involved our patients has been conducted with the ethical approval of all relevant bodies and that such approvals are acknowledged within the manuscript.
: We guarantees that the contribution to the work has not been previously published elsewhere, or that if it has been published in whole or in part, any permission necessary to publish it in the work has been obtained.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.