Spinal ventral epidural arteriovenous fistulas of the lumbar spine: angioarchitecture and endovascular treatment

Abstract

Introduction: Spinal ventral epidural arteriovenous fistulas (EDAVFs) are relatively rare spinal vascular lesions. We investigated the angioarchitecture of spinal ventral EDAVFs and show the results of endovascular treatment.

Methods: We reviewed six consecutive patients (four males and two females; mean age, 67.3 years) with spinal ventral EDAVFs treated at our institutions from May 2011 to October 2012. All patients presented with progressive myelopathy. The findings of angiography, including 3D/2D reformatted images, treatments, and outcomes, were investigated. A literature review focused on the angioarchitecture and treatment of spinal ventral EDAVFs is also presented.

Results: The EDAVFs were located in the ventral epidural space at the L1-L5 levels. All EDAVFs were supplied by the dorsal somatic branches from multiple segmental arteries. The ventral somatic branches and the radiculomeningeal arteries also supplied the AVFs in two patients. The AVFs drained via an epidural venous pouch into the perimedullary vein in four patients and into both the perimedullary vein and paravertebral veins in two patients. Four cases without paravertebral drainage were treated by transarterial embolization with diluted glue, and two cases with perimedullary and paravertebral drainages were treated by transvenous embolization alone or in combination with transarterial embolization. An angiographic cure was obtained in all patients. Clinical symptoms resolved in two patients, markedly improved in three patients, and minimally improved in one patient.

Conclusion: In our limited experience, spinal ventral EDAVFs were primarily fed by somatic branches. EDAVFs can be successfully treated by endovascular techniques selected based on the drainage type of the AVF.

Fig. 1

Schematic drawing of the spinal vascular anatomy relevant to ventral epidural arteriovenous fistula. VSBs, ventral somatic branches; DSBs, dorsal somatic branches; RMen A, radiculomeningeal artery; RMed A, radiculomedullary artery; RC anast, retrocorporal anastomosis; VE, ventral epidural venous plexus; paraVV, paravertebral vein; REV, radiculoemissary vein; PMV, perimedullary vein

Fig. 2

Case2: a, b Sagittal T2-weighted MR images of the spine show a hyperintensity at the conus medullaris and dilated vessels at the posterior surface of the spinal cord (white arrowheads in a). A signal void (white arrow in b) suggesting a shunted pouch is seen in the ventral epidural space at L3. c, d Selective angiography of the left (c) and right (R) third lumbar arteries shows epidural AVFs fed by dorsal somatic branches (white arrows). The ventral somatic branch (arrowheads in d) of the right third lumbar artery also feeds the AVF. The AVFs drain into an epidural venous pouch, then into the ascending lumber vein and the left radiculomedullary vein to the perimedullary vein (arrows). e Axial reformatted images of rotational angiography of the right third lumbar artery demonstrates the AVF with a shunted venous pouch (S) fed by the ventral somatic branch (white arrowheads) and dorsal somatic branch (large white arrows). The shunted venous pouch is located at the mid-portion of the ventral epidural space and runs leftward laterally then continues to the radiculomedullary–perimedullary vein (small white arrows) and runs inferiorly to the ascending lumbar vein. f Selective angiography of the left third lumbar artery during selective transvenous embolization shows coils placed into the shunted venous pouch. g Selective angiography of the left third lumbar artery after embolization shows disappearance of the AVFs

Fig. 3

Case 4: a Selective angiography of the left iliolumbar artery shows epidural AVFs fed by the dorsal somatic branches (arrows). The AVFs drain into an epidural venous pouch, then into the left radiculomedullary vein and to the perimedullary vein (arrowheads). b Selective angiography with simultaneous injection of contrast media via the two microcatheters placed into the bilateral dorsal somatic branches clearly shows the bilateral dorsal somatic branches (arrows) feed the AVF with a shunted venous pouch (S) at the midline. The AVF drains into the radiculomedullary-perimedullary vein (arrowheads). c Selective angiography with contrast injection via a microcatheter placed closed to the fistulous point from the right iliolumbar artery. A diluted glue (20 % NBCA-lipiodol mixture) was injected via the microcatheter with simultaneous injection of 20 % glucose via another microcatheter placed at the left dorsal somatic branch of the left iliolumbar artery. d Fluoroscopic image immediately after embolization shows sufficient filling of the glue cast (arrows) in the shunted pouch and the proximal portion of the radicullomedullary vein. e Selective angiography of the right iliolumbar artery after embolization shows disappearance of the AVFs. f CT after embolization shows glue cast in the ventral epidural pouch

Fig. 4

Case 5: a Sagittal T2-weighted MR images of the spine show a hyperintensity in the spinal cord and dilated vessels at the medullary surface (white arrowheads). A signal void (white arrow) suggesting a shunted pouch is seen in the ventral epidural space at L5. b Selective angiography of the dorsal somatic branch of the right (R) fourth lumbar artery shows epidural AVFs with an epidural venous pouch (S) draining into the left radiculomedullary/perimedullary vein (arrowheads). Retrograde filling of an additional feeder of the dorsal somatic branch of the right iliolumbar artery is also noted. Arrows indicate anastomosis of the dorsal somatic branches of the L4 and iliolumbar arteries. c Selective angiography of the left fourth lumber artery shows the epidural AVFs fed by a dorsal somatic branch (small arrow) and the radiculomeningeal artery (large arrow). These feeders shunted into the same venous pouch with multiple shunting points, and the AVFs drain into the left radiculomedullary/perimedullary vein (arrowheads). d Axial MIP image of the rotational angiography of the right fourth lumber artery demonstrates the AVF with a shunted venous pouch (S) fed by the dorsal somatic branch (white arrows). The shunted venous pouch is located at the ventral epidural space and runs laterally towards the left and then continues to the radiculomedullary-perimedullary vein (arrowheads). e Axial MIP image from rotational angiography of the left fourth lumber artery shows AVFs fed by the dorsal somatic branch (white arrow) and the radiculomeningeal artery (white arrowheads) with multiple shunted points. S: shunted venous pouch. f The dorsal somatic branch of the right fourth lumber artery was embolized with coils (arrowhead) just proximal to the retrocorporal anastomosis, and then a microcatheter (arrow) was advanced close to the fistulous portion via the right iliolumbar artery. A diluted glue (20 % NBCA-lipiodol mixture) was injected via the microcatheter with simultaneous injection of 20 % glucose via another microcatheter placed at the left dorsal somatic branch of the left fourth lumbar artery. g Selective angiography of the right fourth lumber artery after embolization shows disappearance of the AVFs