Received: 26 May 2019
Accepted: 2 August 2019
First Online: 16 August 2019
Conflicts of interest
: Dr. James Porter: Speaker for Intuitive Surgical, Consultant for Ceevra, C-SATS advisory board. The other authors declare that they have no competing interest.
: This was a retrospective study on human participants. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (include name of committee + reference number) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.