Text and Data Mining valid from 2018-09-24
Received: 5 June 2018
Accepted: 10 September 2018
First Online: 24 September 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: For this type of study formal consent is not required.
: This article does not contain any studies with human participants or animals performed by any of the authors.
: No individual participants were included in this study. Data from this study was obtained retrospectively from a database without patient identifiers.