PMC3190430_01
Displaced comminuted odontoid fracture is seen in sagittally reconstructed (a) and axial (b) cervical spinal computed tomography
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F1
Three-dimensional (3D) cervical spinal computed tomography revealed that the oblique odontoid fracture extending to the apex of the corpus was comminuted sagittal image [Figure 1a] and axial image [Figure 1b].
The fracture with oblique extension is seen to narrow the spinal canal in sagittal T1-weighted magnetic resonance images
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F2
Magnetic resonance imaging arose the suspicion of posterior longitudinal ligament rupture [Figure 2], and showed that the atlantoaxial interval was about 6 mm.
The entry point is drilled at a point 2-mm lateral and 1-mm inferior compared to the first one in the cadaveric specimen (a), and illustrated figure (b)
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F3
The dominant VA being on the right side with a fracture at the corpus extending mediolaterally, posterior longitudinal ligament rupture and anterior dislocation of the odontoid necessitated a left C1-2 transarticular screw placement followed by contralateral odontoid fixation by posterior transodontoid screw placement with a supplementary screw directed medially [Figure 3a] and toward the apex [Figure 3b]. Then, contralateral entry point is drilled at a point 2-mm lateral and 1-mm inferior compared with the first one [Figure 3].
Both entry points on the axis are seen in the axial (a) and coronally reconstructed (b) cervical spinal computed tomography images. 2 mm anterior to the first coronally reconstructed image, the screws are seen entering the pedicle (c). At this level, the screw can be seen in the coronal reconstructed images, too (d). The position of the screws after passing through the pedicles is seen (e). The axial (f) and sagittally (g) and coronally (h) reconstructed cervical spinal computed tomography images show the screws passing from the corpus to the broken odontoid
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F4
All these are shown tomographically and as drawings in Figure 4(a-h).
Note the direction of the right supplementary screw from the base of the odontoid to the apex in the illustrated image (a). Lastly, left transarticular screw is seen penetrating or fixating the lateral mass and the right supplementary screw is seen into the pedicle, (opened the roof) fixating the odontoid process in compression (b), the tip of the screw is in the apex of the odontoid process (cadaveric study)
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F5
Both illustration and cadaver studies are presented in Figures 5 a and b.
The fusion was observed in coronal (a) and sagittal (b) CT at the postoperative 6 month
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F6
Fusion can be seen at the follow-up time in 6 months [Figure 6].