Teaching Course Arteriovenous Malformations Neurosurgical Treatment of Cerebral Arteriovenous Malformations

Th e prevalence is calculated 0.2-0.5%/100.000 although lower numbers are discussed (0.01%) Men are slightly more aff ected than women (1.4:1) [1]. Most patients present with the neurological sequelae of intracranial haemorrhage caused by the AVM (50%), which is a major cause of intracerebral bleeding in younger adults. In 25% patients present with epileptic seizures and in 25% with other symptoms including neurological defi cits not related to haemorrhage, headaches and neuropsychological disturbances including e.g. memory defi cits and learning disabilities. Th e annual risk of spontaneous intracerebral bleeding of an AVM has been reported to be 2-4% per year leading to a mortality of 10-15% and a permanent morbidity of 30-50%. Th e risk of rebleeding is increased up to 18% within the fi rst year after the fi rst bleeding then declining again [4]. AVMs with a high intranidal pressure (highfl ow feeder or obstructed veins), only one draining vein or AVM associated aneurysms have a higher risk of bleeding. Whether small deep seated AVMs carry also a higher risk is still a matter of debate. AVMs are generally categorized using the Spetzler-Martin grading scale which is built on size oft he nidus, the location oft he aneurysm and the type of venous drainage [7].