PMC8492420_01
Magnetic resonance imaging on admission. (a) Fluid-attenuated inversion recovery imaging reveals no abnormal changes. (b) Cervical and intracranial magnetic resonance angiography show hypoplasia of the right vertebral artery (white arrow).
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The MR fluid-attenuated inversion recovery study was normal [Figure 1a and b].
Preoperative dynamic digital subtraction angiography (a-1: neutral head position, a-2: head rotation to the right side) and three-dimensional computed tomography angiography (b-1: neutral head position, b-2: head rotation to the right side). When the head is rotated to the right side, near-complete occlusion of the left vertebral artery is observed at the C1-C2 level (white and black arrow). Cervical X-ray (lateral view) and dynamic X-ray images. Lateral view in the neutral position shows an atlantodental interval of 3.2 mm (c-1) and in the flexed position shows an atlantodental interval of 2.4 mm (c-2).
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C1-C2 level [Figure 2a and b]. Cervical X-rays were unremarkable [Figure 2c].
Operative imaging for C1-C2 posterior fusion using O-arm navigation systems. (a) C1 lateral mass screws are placed using the Goel-Harms technique. (b and c) For C2 screw placement, a pedicle screw is inserted on the right side (b). However, intraoperative real-time planning using the O-arm navigation system shows a risk of left vertebral artery injury during tapping the tract for left pedicle screw insertion (white arrow: transverse foramen; yellow arrowhead: trajectory on the navigation system) (c). (d) We switch to performing a translaminar technique for left-side fixation of C2 and the laminar screws are inserted.
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C1-C2 posterior fusion using O-arm navigation. C1 lateral mass screws were placed using the Goel-Harms technique [Figure 3a]. However, the O-arm documented that a C2 pedicle screw should not be inserted; rather a translaminar left-C2 screw was placed, while a routine pedicle screw was placed on the right [Figure 3b-d]; The C1-C2 rods were finally applied and the fusion was completed without incident; postoperative cervical X-rays and 3D-CT studies confirmed good fixation [Figure 4].
Postoperative cervical X-ray and three-dimensional computed tomography (3D-CT) show good fixation. (a) Lateral view cervical X-ray in the neutral position. (b and c) Axial-view 3DCT imaging (b: C1 portion; c: C2 portion).
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However, the O-arm documented that a C2 pedicle screw should not be inserted; rather a translaminar left-C2 screw was placed, while a routine pedicle screw was placed on the right [Figure 3b-d]; The C1-C2 rods were finally applied and the fusion was completed without incident; postoperative cervical X-rays and 3D-CT studies confirmed good fixation [Figure 4].