PMC8645510_01
(a-b) Flexion and extension X-ray of patient 1 film showing no evidence of instability and (c) C-spine magnetic resonance imaging of patient 1 showing pannus formation at C1 and (d) sagittal upright X-ray of patient 1 at 1-year follow-up demonstrating secure screw placement and stability of C-spine.
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F3
Despite lack of obvious movement on flexion and extension lateral X-rays [Figure 3a and b], the presence of pannus suggested chronic instability which can be worsened by removing the lamina of C1 and interruption of the posterior ligamentous complex [Figure 3c]. The patient continued to do well at one-year follow-up, and upright X-ray film showed secure screw placement and no hardware failure [Figure 3d].
PMC8645510_02
(a-b) Flexion and extension X-ray of patient 2 showing signs of instability and (c) C-spine magnetic resonance imaging of patient 2 showing pannus formation at behind dens of C2 and (d) sagittal upright X-ray of patient 2 at 1-year follow-up demonstrating secure screw placement and stability of C-spine.
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F4
Further workup revealed a small amount of pannus formation behind the dens [Figure 4a], and dynamic X-rays showed 4 mm of motion at the C1-C2 level between flexion and extension [Figure 4b and c]. She continues to do well at 1-year follow-up with upright X-ray film showing secure screw placement and no hardware failure [Figure 4d].