Angiographic and Clinical Characteristics of Thoracolumbar Spinal Epidural and Dural Arteriovenous Fistulas

Abstract

Background and purpose: The purpose of this study is to compare the angiographic and clinical characteristics of spinal epidural arteriovenous fistulas (SEAVFs) and spinal dural arteriovenous fistulas (SDAVFs) of the thoracolumbar spine.

Methods: A total of 168 cases diagnosed as spinal dural or extradural arteriovenous fistulas of the thoracolumbar spine were collected from 31 centers. Angiography and clinical findings, including symptoms, sex, and history of spinal surgery/trauma, were retrospectively reviewed. Angiographic images were evaluated, with a special interest in spinal levels, feeders, shunt points, a shunted epidural pouch and its location, and drainage pattern, by 6 readers to reach a consensus.

Results: The consensus diagnoses by the 6 readers were SDAVFs in 108 cases, SEAVFs in 59 cases, and paravertebral arteriovenous fistulas in 1 case. Twenty-nine of 59 cases (49%) of SEAVFs were incorrectly diagnosed as SDAVFs at the individual centers. The thoracic spine was involved in SDAVFs (87%) more often than SEAVFs (17%). Both types of arteriovenous fistulas were predominant in men (82% and 73%) and frequently showed progressive myelopathy (97% and 92%). A history of spinal injury/surgery was more frequently found in SEAVFs (36%) than in SDAVFs (12%; P=0.001). The shunt points of SDAVFs were medial to the medial interpedicle line in 77%, suggesting that SDAVFs commonly shunt to the bridging vein. All SEAVFs formed an epidural shunted pouch, which was frequently located in the ventral epidural space (88%) and drained into the perimedullary vein (75%), the paravertebral veins (10%), or both (15%).

Conclusions: SDAVFs and SEAVFs showed similar symptoms and male predominance. SDAVFs frequently involve the thoracic spine and shunt into the bridging vein. SEAVFs frequently involve the lumbar spine and form a shunted pouch in the ventral epidural space draining into the perimedullary vein.

Keywords: angiography; arteriovenous malformations; drainage; male; spinal injuries.

Figure 1.

Relationship of the medial interpedicle line with the location of the shunt point in spinal dural arteriovenous fistulas. A, Schematic drawing of the medial interpedicle line (red line) and its relation to the location of the shunt point (star) of the spinal dural arteriovenous fistulas (SDAVFs). The SDAVF shunts to the bridging vein on the dura mater of the spinal cord when the shunt point is medial to the medial interpedicle line (right side). The SDAVF shunts to the radiculomedullary vein (RMV) on the dura mater of the spinal nerve root sleeve when the shunt point is lateral to the medial interpedicle line (left side). B, Superselective angiography of the radiculomeningeal artery (RMA) in a patient with SDAVF during an embolization procedure. The red line represents the medial interpedicle line. The shunt point (arrow) of the SDAVF is medial to the medial interpedicle line, suggesting that the SDAVF shunts to the bridging vein on the dura mater of the spinal cord. Lateral muscular artery (arrowhead) and the dorsal somatic branch (double with arrows) are embolized with coils. PLA indicates prelaminar artery.

Figure 2.

Typical angiographic features of spinal dural arteriovenous fistulas (SDAVFs) in a 63-year-old man who presented with progressive myelopathy. A, Anterior view of the left subcostal angiography shows an SDAVF fed by multiple meningeal branches. The meningeal branches mainly originate from the radiculomeningeal artery (RMA) and turn longitudinally to gather and join the single vein (arrow) that continues to the perimedullary vein. B–D, Coronal maximum intensity projection images reconstructed from rotational angiography of the sub To Reviewer #1: 3costal artery and schematic drawing of the angioarchitecture (D). Multiple meningeal branches originating from the RMA and the prelaminar artery (PLA) join and continue to the bridging vein on the dura mater of the spinal cord (white arrow). Longitudinal meningeal arterial feeders and a drainage vein form horizontal T sign (yellow color in D). The dorsal somatic branch (DSB) does not feed the SDAVF. dors SA indicates dorsal spinal artery; and SCB, subcostal branch.

Figure 3.

Typical angiographic features of spinal epidural arteriovenous fistulas in a 69-year-old man who presented with progressive myelopathy. A–C, Anteroposterior view (A) and coronal (B) and axial (C) maximum intensity projection images of the right fourth lumbar angiography shows an epidural arteriovenous fistula with an epidural venous pouch (VP) fed by the right dorsal somatic branch (arrows) and the left dorsal somatic branch (open arrows). The arteriovenous fistula drains into the perimedullary vein (white arrowheads). Axial maximum intensity projection image (C) shows that the ventral somatic branches (VSBs) and the dorsal somatic branch shunt to the VP located in the ventral epidural space. D, Anteroposterior view of the left fourth lumbar angiography shows that the left dorsal somatic branch (arrows) also shunts to the epidural VP. dors SA indicates dorsal spinal artery; and LMB, lateral muscular branch.

Figure 4.

Spinal epidural arteriovenous fistulas located in the lateral epidural space in a 76-year-old man who presented with progressive myelopathy. A, Anteroposterior view of the left second lumbar angiography shows that multiple feeding arteries from the radiculomeningeal artery (RMA) and the prelaminar artery (PLA) converge on a venous pouch (VP), which continued to the perimedullary vein. B–D, Axial reformatted images of the rotational angiography of the left second lumbar artery show multiple feeding arteries arising from the PLA, the dorsal somatic branch (DSB), and the RMA converge on a VP, which were located in the lateral epidural space and partially in the vertebral arch. The VP continues to an intradural vein (bridging vein [BV]). A slit-like stricture (arrowhead) is seen at the junction of the epidural VP and the BV.

Figure 5.

Spinal epidural arteriovenous fistula with perimedullary and paravertebral venous drainage in a 53-year-old man presented with progressive myelopathy. A and B, Anteroposterior view of the left third lumbar angiography at early arterial phase (A) and late arterial phase (B) show epidural arteriovenous fistulas fed by multiple feeding arteries mainly from the dorsal somatic branch (DSB). Numerous feeders from ventral somatic branches (VSBs) also converge on an epidural venous pouch (VP). The AVF drains via the epidural venous plexus (EDV) into the paravertebral vein, the third lumbar vein (LV), and the ascending LV (ALV). Perimedullary venous drainage via the left L4 radiculomedullary vein (arrows) is also noted.