How does cervical and cervicothoracic alignment impact horizontal gaze?

Area of Science:

• Orthopedics
• Radiology
• Biomechanical Engineering

Background:

• Cervical sagittal alignment is crucial for maintaining horizontal gaze and supporting skull axial load.
• Limited research exists on cervical sagittal alignment and its correlation chains within the Indian population.
• Understanding these alignments is vital for assessing horizontal gaze and cervicothoracic mechanics.

Purpose of the Study:

• To investigate the correlation chain between cervical and cervicothoracic sagittal alignment parameters and horizontal gaze in an Indian adult population.
• To identify key parameters influencing the relationship between spinal alignment and head posture.
• To contribute novel data on cervical alignment specific to Indian ethnicity.

Main Methods:

• A retrospective cross-sectional study of 104 asymptomatic Indian adults (18-50 years).
• Lateral cervical X-rays were analyzed for parameters including McGregor slope (McGS), C0-C2 angle, C1-C2 angle, C2 slope, Cervical Lordosis (CL) C2-C7, C7 slope, and T1 slope (T1S).
• Pearson's correlation coefficient was used to analyze relationships between alignment parameters and horizontal gaze.

Main Results:

• A significant correlation chain was observed between upper cervical, lower cervical, and cervicothoracic alignment parameters, impacting horizontal gaze (McGS).
• The C7 Slope strongly correlated with T1 Slope (r=0.675), initiating a chain involving CL, C0-C2, C1-C2 angles, and McGS.
• The C2 Slope showed the highest correlation with the T1S-CL mismatch (r=-0.946), highlighting its critical role.

Conclusions:

• A statistically significant correlation chain exists between cervical and cervicothoracic sagittal alignment and horizontal gaze in the Indian population.
• T1 Slope and C7 Slope serve as foundational elements in this correlation chain.
• The C2 Slope plays a significant role in maintaining cervical sagittal alignment and horizontal gaze.