Received: 27 March 2019
Accepted: 9 September 2019
First Online: 7 October 2019
Ethics approval and consent to participate
: This study was conducted in accordance with the declaration of Helsinki. This study was approved by the Ethics Committee of Central Hospital of Zao Zhuang Mineral Group. Written informed consent was obtained from all participants.
: We have obtained consent to publish from the participants (or legal parent or guardian) to report their individual patient data.
: The authors declare that they have no competing interests.