Morphometric characteristics of the C2 vertebra and high-riding vertebral artery at the craniovertebral junction in rheumatoid arthritis.

INTRODUCTION

To compare axial and sagittal C2 pedicle-related morphometric parameters between patients with rheumatoid arthritis (RA) and healthy controls, with specific emphasis on the prevalence of a high-riding vertebral artery (HRVA).

MATERIALS AND

METHODS

This retrospective cross-sectional study analyzed cervical computed tomography (CT) scans of 30 patients with RA and 194 healthy individuals. Bilateral axial and sagittal C2 pedicle-related parameters, including pedicle width, length, angulation, isthmus height, and internal height, were measured. HRVA was defined as an isthmus height of ≤ 5 mm and/or an internal height of ≤ 2 mm. Morphometric parameters and HRVA prevalence were compared between the groups.

RESULTS

No significant differences were observed between the groups regarding pedicle angles, lengths, or widths. However, patients with RA demonstrated significantly reduced right-sided isthmus height and internal height compared with controls. In addition, the prevalence of HRVA was significantly higher in the RA group on both sides.

CONCLUSION

RA is associated with distinct C2 morphometric alterations, particularly reduced right-sided isthmus and internal heights and a higher prevalence of HRVA. These findings have important implications for posterior cervical fixation, underscoring the need for meticulous preoperative CT-based morphometric assessment to optimize surgical planning and enhance neurovascular safety.