1 Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Bei-Hu Branch, National Taiwan University College of Medicine, Taipei, Taiwan; Center for Regional Anesthesia and Pain Medicine, Wang-Fang Hospital, Taipei, Medical University, Taipei, Taiwan. Electronic address: kvchang011@gmail.com.
2 Center for Regional Anesthesia and Pain Medicine, Wang-Fang Hospital, Taipei, Medical University, Taipei, Taiwan.