1. Department of Medical Engineering, Fraunhofer Institute for Machine Tools and Forming Technology, Dresden, Germany, and the Department of Neurosurgery, University of Leipzig Faculty of Medicine, Leipzig, Germany
2. Department of Biomedical Engineering, West Saxon University of Applied Sciences, Zwickau, Germany
3. Department of Neurological Surgery, University of Pittsburgh Medical Center (UPMC), Pittsburgh
4. Cranial Base Surgery, UPMC Presbyterian Hospital, Pittsburgh