[1] Univ Texas, MD Anderson Canc Ctr, Dept Neurosurg, Houston, TX 77030 USA
[2] Med Coll Penn & Hahnemann Univ, Dept Neurol, Philadelphia, PA 19102 USA
[3] Ctr Pain Relief, Clarksburg, WV USA
[4] Oregon Hlth & Sci Univ, Dept Neurol Surg, Portland, OR 97201 USA
[5] Hop Zone Morges, Anesthesia & Pain Management Serv, Morges, Switzerland
[6] Trinity Pain Med Assoc PA, Ft Worth, TX USA
[7] Ctr Pain Relief, Charleston, WV USA
[8] Swedish Med Ctr, Dept Anesthesia, Seattle, WA USA
[9] Univ Penn Hlth Syst, Pain Med Ctr, Philadelphia, PA USA
[10] Texas Tech Univ, Hlth Sci Ctr, Dept Anesthesiol, Lubbock, TX 79430 USA
[11] AZ St Lucas, Ghent, Belgium
[12] Mt Sinai Med Ctr, Dept Neurosurg, New York, NY 10029 USA
[13] Beth Israel Deaconess Med Ctr, Dept Pain Med & Palliat Care, New York, NY 10003 USA
[14] Wake Forest Univ, Baptist Med Ctr, Pain Control Ctr, Winston Salem, NC 27109 USA
[15] Alabama Pain Ctr, Huntsville, AL USA
[16] Univ Calif San Diego, Dept Anesthesiol, San Diego, CA 92103 USA