[1] Bern Univ Hosp, Dept Neurosurg, Inselspital, Bern, Switzerland
[2] Kantonsspital St Gallen, Dept Neurosurg, St Gallen, Switzerland
[3] Univ Bern, CTU Bern, Bern, Switzerland
[4] Kantonspital Aarau, Dept Neurosurg, Aarau, Switzerland
[5] Univ Hosp Zurich, Clin Neurosci Ctr, Dept Neurosurg, Zurich, Switzerland
[6] Univ Zurich, Zurich, Switzerland
[7] Hosp Univ Penn, Penn Med, Dept Neurosurg, Philadelphia, PA USA
[8] Univ Basel, Univ Hosp Basel, Dept Neurosurg, Basel, Switzerland
[9] Maimonides Hosp, Dept Surg Neurol & Radiol, Brooklyn, NY USA
[10] Swiss Med Network, Clin Genolier, Genolier, Switzerland
[11] Univ Hosp Lausanne, Dept Neurosurg, Lausanne, Switzerland
[12] Bern Univ Hosp, Inselspital, Dept Neurosurg, Freiburgstr, CH-3010 Bern, Switzerland
[13] Univ Freiburg, Med Ctr, Dept Neurosurg, Breisacher Str 64, D-79106 Freiburg, Germany