[1] Case Western Reserve Univ, Cleveland Clin, Lerner Coll Med, Cleveland, OH 44106 USA
[2] Case Western Reserve Univ, Sch Med, Cleveland, OH USA
[3] Cleveland Clin, Dept Neurosurg, Cleveland, OH 44106 USA
[4] Cleveland Clin, Dept Radiat Oncol, Cleveland, OH 44106 USA