Text and Data Mining valid from 2019-01-30
Received: 10 December 2018
Revised: 20 January 2019
Accepted: 22 January 2019
First Online: 30 January 2019
Compliance with ethical standards
: JCT discloses support for counselling and travel grants by Brainlab.
: The study has been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. Informed consent was obtained from all patients.