Arteriovenous fistulae of the filum terminale

Abstract

Filum terminale arteriovenous fistulae are a rare type of arteriovenous shunt generally characterized by a single direct communication between the artery of the filum terminale and a single draining vein. These intradural arteriovenous shunts are three times more common in men than women (mean age 55 years). Symptoms are related to venous congestion, vascular hypertension, and a putative chronic steal phenomenon which result in spinal cord ischemia and myelopathy. Interestingly, hemorrhage has never been reported as a mode of presentation. MRI demonstrates increased flow voids and T2 changes involving the conus and the lower spinal cord, and these findings are not dissimilar from those seen with the more common type 1 spinal dural arteriovenous fistulae. Thus conventional spinal angiography is necessary for a definitive diagnosis and to localize exactly the site of the fistula. Both surgical interruption of the fistula and endovascular embolization are safe and effective therapeutic modalities. However, because of the very small caliber of the feeding artery, endovascular therapy is often not feasible; and thus, surgery remains the method more commonly utilized for their treatment. Definitive treatment consists of obliteration of the direct arteriovenous shunt. In this review, we describe the anatomy, pathophysiology, clinical presentation, imaging, and treatment options of these less common intradural arteriovenous shunts.

Dilated Vein of the Filum Terminale on MRI: A Marker for Deep Lumbar and Sacral Dural and Epidural Arteriovenous Fistulas

“…A fistula of the filum terminale will, by definition, have a dilated VFT. 21 Thus, there is the potential for an overreliance on this sign to cause clinicians to miss such a lesion. However, these lesions are also characterized by a markedly enlarged anterior spinal artery.…”

Spinal arteriovenous fistulas of the filum terminale: Case report and literature review

“…[27] Interestingly, hemorrhage has never been reported as a mode of presentation in association with this subtype of spinal vascular malformation. [6]…”

“…Furthermore, we recommend surgical treatment considering the low morbidity and the high occlusion rates. [6]…”

Spinal arteriovenous fistula located in the filum terminale externa: A case report and review of the literature

“…5 FTAVF presents as progressive myelopathy and conus medullaris syndrome caused by spinal cord venous congestion. 3,6 Most reported FTAVFs are intradural spinal AVFs that developed in the FTI and present with perimedullary drainage. 3,[5][6][7][8][9] The FTAVF angioarchitecture is typically simple and comprises focal or single hole fistulas located below the conus medullaris supplied by the artery of the FT (AFT) with perimedullary venous drainage through the vein of the FT (VFT).…”

“…3,6 Most reported FTAVFs are intradural spinal AVFs that developed in the FTI and present with perimedullary drainage. 3,[5][6][7][8][9] The FTAVF angioarchitecture is typically simple and comprises focal or single hole fistulas located below the conus medullaris supplied by the artery of the FT (AFT) with perimedullary venous drainage through the vein of the FT (VFT). 3,6,10 However, the FTE has not received much attention because it is an extradural component of the FT.…”