Unveiling and Validating a Modified Method to Assess Cervical Sagittal Alignment as an Effective Substitute for...

Area of Science:

• Orthopedics
• Radiology
• Spine Surgery

Background:

• Cervical sagittal alignment is crucial for spinal health.
• Assessing alignment often relies on the C2-C7 Cobb method, which can be limited by C7 endplate visibility.
• A modified parameter, the SYS-G angle, was developed to address these limitations.

Purpose of the Study:

• To validate the SYS-G angle as a substitute for the C2-C7 Cobb method in assessing cervical sagittal alignment.
• To determine the reference range of the SYS-G angle in a large cohort of asymptomatic Chinese adults.

Main Methods:

• Retrospective analysis of lateral cervical spine X-rays from 825 asymptomatic Chinese adults.
• Comparison of C7 lower endplate visibility with other landmarks.
• Measurement of C2-6 Cobb angle, SYS-G angle, and C2-7 Cobb angle.
• Assessment of intra- and interobserver reliability and efficacy of the SYS-G angle.
• Analysis of factors affecting C7 endplate visibility and correlation with SYS-G angle.

Main Results:

• C7 lower endplate visibility was significantly reduced compared to C6 and C7 upper endplates.
• Age, weight, BMI, and male sex negatively impacted C7 lower endplate visibility.
• The SYS-G angle demonstrated strong correlation with the C2-7 Cobb angle and excellent efficacy in evaluating cervical lordosis.
• Reference ranges for the SYS-G angle were established, showing positive correlation with age and higher values in men.

Conclusions:

• The SYS-G angle is a reliable alternative for cervical sagittal morphology assessment, especially when C7 endplate visibility is compromised.
• Established reference ranges provide valuable data for clinical guidance in managing cervical spine disorders.
• The study highlights the influence of demographic factors on C7 endplate visibility and SYS-G angle values.