Dural arteriovenous malformations of the skull base.

Dural arteriovenous malformations (AVMs) are interesting lesions, which can present as diagnostic and therapeutic challenges. Such AVMs were initially described as located solely in the dural venous sinuses, but during the last decade researchers have discovered them in other locations such as the tentorium and foramen magnum. It is understandable that they can develop in other locations because numerous arteriovenous shunts normally occur all over the dura. Early reports emphasize that they are congenital; however, some investigators have proposed that they are acquired lesions arising after sinus thrombosis and trauma. They also have variable clinical features. From 1975 to 2000 we treated 400 AVMs, of which 46 were dural. Of these 46 dural AVMs, 18 could be classified as skull base AVMs. We restricted the designation of skull base AVMs to those AVMs located in the tentorium or adjacent to bones of the skull base. Two of these AVMs actually had their vascular nidus located in the bone. The common dural sinus AVMs were excluded from this category. The presenting clinical features of these skull base AVMs ranged from headache and pulsatile tinnitus to intracranial hemorrhage. They were treated by a combination of endovascular and microsurgical treatment. The majority of patients had a good clinical outcome. Skull base dural AVMs are an interesting clinical entity. Their clinical course, treatment and final outcome are variable depending on their location. They should be managed by a multidisciplinary approach.