Vascular malformations of the spinal cord type IV

This type is an intradural arteriovenous fistula of the spinal cord. The lesion is essentially an arteriovenous fistula supplied directly from the anterior spinal artery in the dura. The arteriovenous fistula and its return vein are located outside the spinal cord, and the lesion does not spread into the spinal cord. This type is divided into three subtypes: IVA, IVB and IVC. These lesions consist of a direct anastomosis between the intramedullary artery (or occasionally the posterior spinal artery) and the intradural reflux vein.