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Impact of Cervical Sagittal Alignment Parameters on Neck Disability
Sravisht Iyer1, Venu M Nemani, Joseph Nguyen
1*Hospital for Special Surgery, New York City, NY †Spinal Surgery and UCSF Spine Center, Spinal Biomechanics Laboratory, San Francisco, CA ‡Hospital for Special Surgery, Weill Cornell Medical College, New York City, NY.
Pre-operative cervical alignment, including C2-C7 angle (CL), T1 slope (TS), and TS minus CL (TS-CL), correlates with neck disability index (NDI) scores. Low TS-CL and high C2-C7 SVA independently predict higher pre-operative NDI.
Area of Science:
- Orthopedics
- Spine Surgery
- Radiology
Background:
- Growing interest exists in the link between cervical sagittal alignment and clinical outcomes.
- Previous studies indicate C2-C7 sagittal vertical axis (SVA) correlates with worse NDI in post-operative patients.
- This study is the first to investigate the impact of cervical sagittal parameters on pre-operative disability.
Purpose of the Study:
- To determine if pre-operative cervical alignment independently predicts pre-operative disability.
- To assess the relationship between various cervical sagittal parameters and the Neck Disability Index (NDI).
Main Methods:
- Retrospective cross-sectional study of 90 patients with pre-operative cervical radiographs and NDI scores.
- Measured parameters included Occiput-C2 angle, C1-C2 angle, C2-C7 angle (CL), T1 slope (TS), TS-CL, C2-C7 SVA, and C1-C7 SVA.
- Intra- and inter-observer reliability was assessed, and multivariate linear regression was performed.
Main Results:
- Increasing CL, TS, and TS-CL correlated with decreasing NDI scores (P < 0.011).
- Multivariate regression revealed TS-CL (P=0.040) and C2-C7 SVA (P=0.015) as independent predictors of NDI.
- Good to excellent intra- and inter-observer reliability (ICC > 0.8) was achieved.
Conclusions:
- Pre-operative cervical alignment parameters, specifically CL, TS, and TS-CL, are associated with pre-operative NDI.
- Low TS-CL and high C2-C7 SVA are identified as independent predictors of higher pre-operative disability.
- These findings highlight the importance of cervical sagittal alignment in pre-operative patient assessment.
