Intradural Perimedullary Arteriovenous Malformations: Vascular Structure and Surgical Treatment

Intradural Perimedullary Arteriovenous Malformations: Vascular Structure and Surgical Treatment

The current classification system of spinal arteriovenous malformations (AVM) comprises 4 types based on the angiographic features and pathophysiology of the lesions. Type I spinal AVMs are the dural AVMs in which the radicular arterial feeder forms a fistula in the dural root sleeve. Type II spinal AVMs are the glomus lesions and consist of a compact, intramedullary nidus. Type III spinal AVMs are also known as juvenile type and are mostly intramedullar lesions that may also have an extramedullary and even an extraspinal extension. Intradural perimedullary AVMs (type IV), the most poorly investigated lesions, are localized on the surface of a spinal cord and they do not penetrate the spinal cord and do not fall outside the limits of dura. Type IV AVMs are traditionally considered as true arteriovenous fistulas. These AVMs often happen to be a challenge to neurosurgeons due to complicated varieties of blood supply including feeding and draining spinal vessels with high blood flow. So far the results of the surgical treatment remain unsatisfactory.