[1] Univ Gottingen, Univ Med Gottingen Georg August, Dept Neurosurg, Gottingen, Germany
[2] Hosp Tech Univ Munich, Dept Neurosurg, Munich, Germany
[3] Univ Hosp Geneva, Fac Med, Dept Neurosurg, Geneva, Switzerland
[4] Univ Hosp Cologne, Dept Neurosurg, Cologne, Germany
[5] Univ Hosp Augsburg, Dept Neurosurg, Augsburg, Germany