Chad Brummett is Clinical Lecturer and Director of Pain Research, Dept of Anesthesiology, Back and Pain Center, University of Michigan School of Medicine, Ann Arbor, Michigan, USA. Steven Cohen is Associate Professor of Anesthesiology and Critical Care Medicine, Director of Medical Education, Pain Management Division, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA, and Associate Professor of Anesthesiology and Director of Pain Pain Research, Walter Reed Army Medical Center, Uniformed Services University of Health Sciences, Bethesda, Maryland, USA