[1] Univ Florida, Lillian S Wells Dept Neurol Surg, Box 100265, Gainesville, FL 32610 USA
[2] Weill Cornell Med Coll, Dept Orthopaed Surg, New York, NY USA
[3] Univ Wisconsin, Dept Orthoped & Rehabil, Madison, WI USA
[4] Univ Kansas, Sch Med, Dept Neurosurg, Kansas City, KS USA
[5] Harvard Med Sch, Brigham & Womens Hosp, Dept Neurosurg, Boston, MA 02115 USA
[6] Univ Utah, Dept Neurosurg, Salt Lake City, UT USA
[7] Univ Calif San Francisco, Dept Neurol Surg, San Francisco, CA USA
[8] St Louis Minimally Invas Spine Ctr, St Louis, MO USA
[9] Thomas Jefferson Univ, Dept Neurol Surg, Philadelphia, PA 19107 USA
[10] Thomas Jefferson Univ, Dept Orthoped Surg, Philadelphia, PA 19107 USA
[11] Rush Univ, Med Ctr, John H Stroger Jr Hosp Cook Cty, Div Neurosurg, Chicago, IL 60612 USA
[12] Rush Univ, Med Ctr, Dept Neurol Surg, Chicago, IL 60612 USA
[13] Columbia Univ, Dept Neurosurg, New York, NY USA