PMC6357538_01
Computed tomography (CT) shows subarachnoid hemorrhage (SAH)
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On head CT, subarachnoid hemorrhage (SAH) was observed [Figure 1].
(a): Digital subtraction angiography (DSA) (Anterior-Posterior view) reveals arteriovenous fistula at craniocervical junction. VA: Vertebral Artery, RA: Radicular Artery, ASV: Anterior Spinal Vein (b): Schematic illustration shows detail flows feeding artery to draining vein. (c): Cone beam CT (CBCT) demonstrates the vascular anatomy and clearer definition of the relationships to bone structure. (d and e): Radiculospinal vein is on the back side of anterior radicular vein (d: posterior-anterior view, e: 180 degrees rotated Figure 2d) (*) Epidural Venous Plexus (EVP), (1) Radicular artery, (2) Radicular artery flows into EVP, ( ) Fistulous site (purple arrowhead), (3) Radiculospinal vein (red arrow), (4) Anterior radicular vein (green arrow), (5) Anterior spinal medullary vein (blue arrow), ( ) Coronal Venous Plexus (CVP), (6) Anterior spinal vein, FM: Foramen Magnum, VA: Vertebral Artery, RA: Radicular Artery, ASV: Anterior Spinal Vein
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C1/Foramen magnum [Figure 2a]. CBCT was performed using an Allura Xper FD20/10  angiography device (Philips Electronics Japan). Once it penetrated the dura mater, it was found that there were two veins derived from the radiculospinal vein; one was the anterior radicular vein descending toward the dorsal side (the shallow layer of the surgical field) and another was the anterior spinal medullary vein ascending toward the ventral side (the deep layer of the surgical field) and flowing out to the anterior spinal vein at the level of foramen magnum while forming the coronal venous plexus [Figure 2b-e].
Intraoperative view. (a): Anterior radicular vein exhibits red vein (green arrow). (b): Anterior radicular vein exhibits arterial flow by injecting ICG (green arrow). (c): Radiculospinal vein is on the back side of anterior radicular vein and collapsing by suction tube (red arrow). (d): Digital subtraction angiography (DSA) (lateral view) reveals disappearance of venous drainage route and two temporary clips are reflected (black arrows). (1) spinal cord, (2) C1 nerve root, (3) dura matter
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The anterior radicular vein was observed dorsal to the site where the vertebral artery penetrated the dura mater [Figure 3a]. It was confirmed that the anterior radicular vein was depicted in the arterial phase [Figure 3b]. Furthermore, the radiculospinal vein bifurcating to the anterior spinal medullary vein in the deep surgical field was identified [Figure 3c]. This was also temporarily blocked using a temporary clip, and it was confirmed that the draining vein was not observed on the intraoperative DSA performed for the second time [Figure 3d].