Received: 6 August 2017
Accepted: 10 January 2018
First Online: 23 January 2018
Ethics approval and consent to participate
: This retrospective study has been approved by the ethics committee at West China Hospital of Sichuan University. Meanwhile, every patient had signed a consent about the treatment and study.
: Written consent for the publication of images used in the manuscript was obtained from the patients.
: The authors declare that they have no competing interests.
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