Article History
Received: 19 April 2018
Accepted: 6 June 2018
First Online: 15 June 2018
Compliance with ethical standards
: The study was approved by the Mahidol University Institutional Review Board of Human Rights Related to Research Involving Human Subjects, Mahidol University (Protocol number 086006). The study protocol complied with the guidelines of the declaration of Helsinki. Information on the study procedures, benefits, and potential side effects were given to the patients before enrolling the study. Written informed consent was obtained from each patient before study initiation
: None.
: The authors declare that they have no conflict of interest.