PMC9852344_01
Preoperative x-ray revealing atlantoaxial instability.
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F1
Cervical flexion and extension radiographs suggested atlantoaxial instability (Figure 1), and a cervical computed tomography (CT) scan demonstrated the existence of a bony continuity that had not been displaced within the odontoid process (Figure 2).
Sagittal CT view showing os odontoideum ( ).
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F2
Cervical flexion and extension radiographs suggested atlantoaxial instability (Figure 1), and a cervical computed tomography (CT) scan demonstrated the existence of a bony continuity that had not been displaced within the odontoid process (Figure 2).
Sagittal and axial preoperative magnetic resonance imaging showing os odontoideum ( ) and a compressive retro-odontoid cyst (arrows) with a hyperintense medullary signal.
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F3
T2 hyperintensity and T1 hypointensity. The cyst was exerting pressure on the spinal cord, and the intramedullary T2 hyperintensity signified a spinal cord disorder (Figure 3).
Preoperative carotid CTA indicated the presence of a high left carotid artery span in the patient.
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F4
Figure 4 indicates the presence of a high left carotid artery span in the patient.
Postoperative lateral x-ray of cervical spine.
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F5
It was decided to perform a C1-C3 fixation (Figure 5), and, two days after the operation, the MRI results showed that the retro-odontoid cyst was still present and had not changed significantly compared with the preoperative MRI results (Figure 6).
Sagittal and axial immediate postoperative magnetic resonance imaging showing the continued presence of the retro-odontoid cyst.
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F6
It was decided to perform a C1-C3 fixation (Figure 5), and, two days after the operation, the MRI results showed that the retro-odontoid cyst was still present and had not changed significantly compared with the preoperative MRI results (Figure 6).
Sagittal and axial 3-month postoperative magnetic resonance imaging showing the complete disappearance of the retro-odontoid cyst.
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F7
The follow-up MRI also showed the complete disappearance of the retro-odontoid cyst and no signs of persistent spinal cord involvement (Figure 7).