Text and Data Mining valid from 2019-09-07
Received: 24 April 2019
Accepted: 27 August 2019
First Online: 7 September 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This is a retrospective study and does not contain any studies with animals performed by any of the authors.
: Informed consent was not required as the study is a retrospective study.