1. Department of Neurosurgery, Heidelberg University Hospital, 69120 Heidelberg, Germany
2. Department of Cardiac Surgery, Heidelberg University Hospital, 69120 Heidelberg, Germany
3. Department of Otorhinolaryngology, Heidelberg University Hospital, 69120 Heidelberg, Germany
4. Department of Neuroradiology, Heidelberg University Hospital, 69120 Heidelberg, Germany