Comparison of Cervical Sagittal Alignment Between EOS and Conventional Standing Radiographs: Agreement, Variability,...

Area of Science:

• Spine surgery and imaging analysis.
• Radiological assessment of spinal alignment.

Background:

• Accurate cervical spine alignment is crucial for surgical planning.
• Conventional cervical radiographs (cXR) are standard, but EOS imaging offers full-body, low-radiation scans.
• Direct comparison of EOS and cXR for cervical alignment is lacking.

Purpose of the Study:

• To compare cervical alignment measurements between EOS imaging and cXR.
• To identify factors influencing discrepancies in measurements.
• To assess the interchangeability of EOS and cXR for cervical alignment evaluation.

Main Methods:

• Retrospective cohort study of 171 patients with both EOS and cXR.
• Measured cervical parameters: C0-C2 Cobb, C2-C7 Cobb, C2-C7 sagittal vertical axis (SVA), T1 slope.
• Used Bland-Altman analysis for agreement and multiple linear regression for predictors of difference.

Main Results:

• EOS and cXR showed significant differences in C0-C2 Cobb, C2-C7 SVA, and T1 slope.
• No significant difference for C2-C7 Cobb.
• Bland-Altman analysis revealed variability in C2-C7 SVA.
• Humerus angle, height, and baseline C2-C7 SVA predicted measurement differences.

Conclusions:

• EOS and cXR are largely interchangeable for assessing cervical alignment.
• C2-C7 SVA measurements require cautious interpretation due to variability.
• Humerus angle and patient height are key factors influencing C2-C7 SVA discrepancies.