[1] Harvard Med Sch, Massachusetts Gen Hosp, Dept Orthopaed Surg, 55 Fruit St, Boston, MA 02114 USA
[2] Harvard Med Sch, Brigham & Womens Hosp, Dept Neurosurg, Boston, MA 02114 USA
[3] Harvard Med Sch, Brigham & Womens Hosp, Dept Orthopaed Surg, Boston, MA 02114 USA
[4] Harvard Med Sch, Massachusetts Gen Hosp, Divison Pain Med, Boston, MA 02114 USA