PMC8035593_01
On magnetic resonance imaging, there is compression of the spinal cord at the level of C1 (a) with the flow void of intradural vertebral artery (yellow arrow) seen on the right side (b). On computed tomographic, there was increased atlanto-dental interval with narrowing of the foramen magnum (c). There was anterior dislocation of the right C1 lateral mass/ occipital condyle on C2 (d). On computed tomographic angiography, bilateral vertebral artery were equal in calibre with abnormal course, computed tomographic angiography shows that the anomalous side vertebral artery is coursing below the isthmus (which represents the C2/3 foramen) and the contralateral side is normal route. Postoperative computed tomographic images showed the canal decompression, spacer placed at right C1/2 joint and the occipito cervical construct (e and f)
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F2
Axial MRI sections at the same level revealed an intradural, lateral location of the right VA [Figure 2a and b]. C2/3 congenital fusion and rotatory atlanto-axial dislocation (AAD) with right-sided neck tilt [Figure 2c and d]. CT angiography (CTA) revealed bilaterally symmetrical VAs, with the anomalous course. The basilar artery (BA), bilateral posterior inferior cerebellar artery, and posterior cerebral arteries were normal [Figure 2e and f].
PMC8035593_02
On computed tomographic angio, the left vertebral artery was hypoplastic and C2 segmental type while the dominant right sided vertebral artery was C3 type (a). On magnetic resonance imaging, there is cord intensity change at the level of C2 with intradural vertebral artery at the same level (b). There was associated hypoplasia of the right C2 hemilamina and poor visualization of the distal BA. Sagittal computed tomography of second patient show anterior atlanto-axial dislocation with mild basilar invagination (c). Postoperatively, there was total correction of the dislocation on postoperative computed tomographic with well-placed screws (d)
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F3
C2 vertebra revealed an intradural location of the right VA with a hypoplastic left VA coursing normally through the bony foramen [Figure 3a-c]. CT imaging of the CVJ area revealed an abnormally increased anterior atlanto-dental interval suggesting an anterior AAD. There was no gross injury to the VA [Figure 3d].