Principles and practice of pain medicine / editors, Zahid H. Bajwa, MD, Director, Boston Headache Institute, Director, Clinical Research at Boston PainCare, Tufts University School of Medicine, Boston, Massachusetts, R. Joshua Wootton, MDiv, PhD, Director of Pain Psychology, Arnold-Warfield Pain Center, Beth Israel Deaconess Medical Center, Brookline, Massachusetts, Assistant Professor, Department of Anesthesia, Harvard Medical School, Boston, Massachusetts, Carol A. Warfield, MD, Lowenstein Distinguished Professor of Anesthesia, Harvard Medical School, Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts.