Intracranial Hypertension and the Importance of Cerebral Venous Drainage Variability: A Case Report of Headache as the Initial Clinical Presentation of an Intraspinal Paraganglioma - Freimann, F. B.; Kroppenstedt, S.; Vajkoczy, P.; Sprung, C. (Journal of Neurological Surgery Part A: Central European Neurosurgery, 2013)