1. Department of Neurosurgery, Kantonsspital Aarau, Kantonsspital Aarau, Aarau, Switzerland
2. Cerebrovascular Research Group, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
3. Department of Neurosurgery, University Hospital Zurich, Zurich, Switzerland
4. Department of Neurosurgery, Kantonsspital Aarau, University of Bern, Switzerland