[1] Univ Cattolica Sacro Cuore, Sch Med, Rome, Italy
[2] Univ Texas Austin, Dell Med Sch, Austin, TX 78712 USA
[3] Univ Zurich, Univ Hosp Zurich, Clin Neurosci Ctr, Dept Neurosurg, Zurich, Switzerland
[4] Fdn Policlin Univ Agostino Gemelli IRCCS, Ist Neurochirurg, Rome, Italy