[1] Stanford Univ, Dept Anesthesiol Perioperat & Pain Med, Div Pain Med, Stanford, CA 94305 USA
[2] Harvard Med Sch, Brigham & Womens Hosp, Dept Anesthesiol, Boston, MA USA
[3] Stanford Univ, Dept Neurosurg, Stanford, CA 94305 USA
[4] Stanford Univ, Dept Orthopaed Surg, Stanford, CA 94305 USA
[5] Stanford Univ, Div Hand & Plast Surg, Dept Orthopaed Surg, Stanford, CA 94305 USA
[6] Stanford Univ, Dept Anesthesiol Perioperat & Pain Med, Stanford, CA 94305 USA
[7] Stanford Univ, Dept Hlth Res & Policy, Stanford, CA 94305 USA