1. Department of Neurosurgery, Academic Hospital of University of Muenster, St. Marien Hospital Luenen, 44532 Luenen, Germany
2. Medical School, Westfaelische Wilhelms University of Muenster, 48149 Muenster, Germany
3. Medical School, University of Nicosia, Nicosia 2408, Cyprus
4. Institute of Pathology, Ruhr University Bochum, 44789 Bochum, Germany
5. Biostatistics and Medical Biometry, Medical School OWL, Bielefeld University, 33615 Bielefeld, Germany
6. MVZ Dr. Eberhard & Partner Dortmund, 44137 Dortmund, Germany