PMC7538799_01
Preoperative axial magnetic resonance imaging. (a) Diffusion-weighted image (DWI), (b) fluid attenuated inversion recovery (FLAIR), and (c) gadolinium (Gd)-enhanced T1-weighted images showing a lesion in the medulla oblongata. The lesion is hypointense on DWI hyperintense on FLAIR and shows moderate enhancement on Gd administration.
SNI-11-287-g001.jpg
PMC7538799_01_SNI-11-287-g001.jpg
F1
Gadolinium (Gd) administration showed moderate enhancement mainly within the medulla oblongata [Figure 1].
Gadolinium (Gd)-enhanced T1-weighted MRI (a: axial and b: sagittal) clearly showing abnormal dilated veins around the brain stem and in front of the cervical spinal cord (white arrow). T2-weighted sagittal image showing hyperintensity of the medulla and an abnormal signal flow void extending to the cervical portion of the spinal cord (white dashed arrow) (c).
SNI-11-287-g002.jpg
PMC7538799_01_SNI-11-287-g002.jpg
F2
T2-weighted imaging (T2-WI) in the medulla, with an abnormal signal flow void extending to the cervical portion of the spinal cord [Figure 2c]. This characteristic radiological finding suggested the possibility of a vascular malformation due to a DAVF, and cerebral angiography was thus performed.
Left vertebral artery angiographic findings. (a) Anteroposterior view and (b) lateral view showing a spinal dural arteriovenous fistula (red arrowhead) supplied by the C5 radicular artery arising from the left vertebral artery draining into the spinal perimedullary veins (black bald arrow) reaching the cortical vein localized along the left aspect of the medulla oblongata. Computed tomography three-dimensional fusion digital subtraction angiography demonstrating the exact location of the arterio-venous shunt point (red arrowhead). (c) Axial view, (d) coronal view, and (e) reconstruction fusion model (red blood vessels are arteries and blue are draining veins)
SNI-11-287-g003.jpg
PMC7538799_01_SNI-11-287-g003.jpg
F3
The draining vein was single, and it drained into the cortical vein localized retrograde along the left aspect of the medulla oblongata through spinal perimedullary veins [Figure 3].
Intraoperative views (opening of the dura mater, left side), showing the shunt location and the single draining vein (white arrow) (a and b), which is disconnected with bipolar coagulation (black arrow: disconnected vein) (c). The draining vein is degenerated with shunt disconnection (black dashed arrow) (d).
SNI-11-287-g004.jpg
PMC7538799_01_SNI-11-287-g004.jpg
F4
Therefore, the surgical disconnection of the spinal DAVF by a posterior approach was performed [Figure 4].
Left vertebral artery angiographic findings. (a) Anteroposterior view and (b) lateral view demonstrating complete disappearance of the dural arteriovenous fistula. Postoperative MRI shows marked reductions of the hyperintense sign of the medulla oblongata on fluid- attenuated inversion recovery (c) and the disappearance of the atypical perimedullary vein on gadolinium-enhanced T1-WI (d).
SNI-11-287-g005.jpg
PMC7538799_01_SNI-11-287-g005.jpg
F5
Cerebral angiography 2 weeks after surgery showed complete disappearance of the spinal DAVF [Figure 5a and b], resulting in marked reductions of the hyperintense sign of the medulla oblongata on FLAIR and disappearance of the atypical perimedullary vein on Gd- enhanced T1-WI on MRI [Figure 5c and d].