Received: 6 May 2019
Accepted: 21 August 2019
First Online: 2 September 2019
Ethics approval and consent to participate
: All patients provided informed consent to participate in the study after the study protocol. The present study was retrospectively registered at the University Hospital Medical Information Network (UMIN no. 000041762). This study was designed in accordance with the Declaration of Helsinki.
: Not applicable
: The authors declare that they have no competing interests.