Text and Data Mining valid from 2019-02-04
Received: 3 December 2018
Accepted: 21 January 2019
First Online: 4 February 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This type of study does not require formal ethical approval.
: All patients having this procedure sign an informed consent form before having the procedure. No patient data or characteristics were used for this study.