Article History
Received: 13 September 2018
Revised: 13 November 2018
Accepted: 6 December 2018
First Online: 5 January 2019
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: This study was approved by the Institutional Review Board of Samsung Medical Center (Seoul, South Korea). This study was conducted in accordance with the tenets of the Declaration of Helsinki.
: Informed consent was not obtained in this study. Identifying information about participants was not presented in this study.