His clinical special fields of interest are Neurovascular Surgery (Aneurysms, Bypass Surgery, AVMs), Skull Base Surgery (Pituitary Surgery, Posterior Fossa), Neuro-oncology (Complex Glioma Surgery) and Minimally Invasive Spine Surgery. His research fields are the pathogenesis and therapy of subarachnoid hemorrhage, the prevention and therapy of vasospasm, novel concepts of multimodality monitoring of neurocrtically ill patients, artrteriogenesis following vessel occlusion, cellular and molecular mechanisms of brain tumor angiogenesis, mechanisms of brain tumor cell migration and invasion, relevance of neuronal guidance molecules for brain tumor biology, as well as homing and recruitment of immune/hematopoietic cells to the nervous system.