The effect of C2–3 disc angle on postoperative adverse events in cervical spondylotic myelopathy

Presented at the 2018 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

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Complete radiographic and clinical evaluations are essential in the surgical treatment of cervical spondylotic myelopathy (CSM). Prior studies have correlated cervical sagittal imbalance and kyphosis with disability and worse health-related quality of life. However, little is known about C2–3 disc angle and its correlation with postoperative outcomes. The present study is the first to consider C2–3 disc angle as an additional radiographic predictor of postoperative adverse events.


A retrospective chart review was performed to identify patients with CSM who underwent surgeries from 2010 to 2014. Data collected included demographics, baseline presenting factors, and postoperative outcomes. Cervical sagittal alignment variables were measured using the preoperative and postoperative radiographs. Univariable logistic regression analyses were used to explore the association between dependent and independent variables, and a multivariable logistic regression model was created using stepwise variable selection.


The authors identified 171 patients who had complete preoperative and postoperative radiographic and outcomes data. The overall rate of postoperative adverse events was 33% (57/171), and postoperative C2–3 disc angle, C2–7 sagittal vertical axis, and C2–7 Cobb angle were found to be significantly associated with adverse events. Inclusion of postoperative C2–3 disc angle in the analysis led to the best prediction of adverse events. The mean postoperative C2–3 disc angle for patients with any postoperative adverse event was 32.3° ± 17.2°, and the mean for those without any adverse event was 22.4° ± 11.1° (p < 0.0001).


In the present retrospective analysis of postoperative adverse events in patients with CSM, the authors found a significant association between C2–3 disc angle and postoperative adverse events. They propose that C2–3 disc angle be used as an additional parameter of cervical spinal sagittal alignment and predictor for operative outcomes.

ABBREVIATIONS AUC = area under the curve; CSM = cervical spondylotic myelopathy; HRQOL = health-related quality of life; ROC = receiver operating characteristic; SVA = sagittal vertical axis.

Article Information

Correspondence Bryan S. Lee: Cleveland Clinic, Cleveland, OH.

INCLUDE WHEN CITING Published online October 12, 2018; DOI: 10.3171/2018.6.SPINE1862.

B.S.L. and K.M.W. share first authorship of this work.

Disclosures Dr. Steinmetz reports being a consultant for Globus and Intellirod, receiving clinical or research support for the described study from Globus, and receiving royalties from Zimmer Biomet and Elsevier. Dr. Mroz reports being a consultant for Stryker.

© AANS, except where prohibited by US copyright law.



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    Illustrative representation of the measurement of C2–3 disc angle in a degenerative spine (left) and after surgical deformity correction with decompression and instrumented fusion (right). Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2017–2018. All rights reserved. Figure is available in color online only.

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    ROC curve for a custom algorithm, including postoperative C2–3 disc angle, C2–7 SVA, C2–7 Cobb angle, age, sex, and antiinflammatory drug use.

  • View in gallery

    Lateral cervical radiographs of a patient before surgery (A) and at 1 year follow-up (B), showing mild kyphosis and anterolisthesis at C2–3. Lateral radiograph demonstrating progressive anterolisthesis of C2 on C3 at the last follow-up (C), ultimately requiring reoperation and extension of the fusion construct. Figure is available in color online only.





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