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A Clinical Prediction Model to Determine Outcomes in Patients with Cervical Spondylotic Myelopathy Undergoing Surgical TreatmentData from the Prospective, Multi-Center AOSpine North America Study
Lindsay A. Tetreault, BSc1; Branko Kopjar, MD, PhD2; Alexander Vaccaro, MD, PhD3; Sangwook Tim Yoon, MD, PhD4; Paul M. Arnold, MD5; Eric M. Massicotte, MD, MSc, FRCSC1; Michael G. Fehlings, MD, PhD, FRCSC1
1 Toronto Western Hospital, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada. E-mail address for M.G. Fehlings: Michael.Fehlings@uhn.on.ca
2 Department of Health Sciences, University of Washington, 4333 Brooklyn Avenue N.E., Suite 1400/#315, Seattle, WA 98195
3 Thomas Jefferson University, 925 Chestnut Street, Philadelphia, PA 19107-4216
4 Emory Orthopaedics & Spine Center, Emory University, 59 Executive Park South, Suite 3000, Atlanta, GA 30329
5 Department of Neurosurgery, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 3021, Kansas City, KS 66160
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Investigation performed at the University Health Network, University of Toronto, Toronto, Ontario, Canada

Disclosure: One or more of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of an aspect of this work. In addition, one or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.

Copyright © 2013 by The Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2013 Sep 18;95(18):1659-1666. doi: 10.2106/JBJS.L.01323
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Cervical spondylotic myelopathy is a progressive spine disease and the most common cause of spinal cord dysfunction worldwide. The objective of this study was to develop a prediction model, based on data from a prospective multi-center study, relating a combination of clinical and imaging variables to surgical outcome in patients with cervical spondylotic myelopathy.


Two hundred and seventy-eight patients diagnosed with cervical spondylotic myelopathy treated surgically were enrolled at twelve different sites in the multi-center AOSpine North America study. Univariate analyses were performed to evaluate the relationship between outcome, assessed with the modified Japanese Orthopaedic Association (mJOA) score, and various clinical and imaging predictors. A set of important candidate variables for the final model was selected on the basis of author consensus, literature support, and statistical findings. Logistic regression was used to formulate the final model.


Univariate analyses demonstrated that the odds of a successful outcome decreased with a longer duration of symptoms (odds ratio [OR] = 0.80, 95% confidence interval [CI] = 0.65 to 0.98, p = 0.030); a lower baseline mJOA score (OR = 0.74, 95% CI = 0.65 to 0.84, p < 0.0001); the presence of psychological comorbidities (OR = 0.51, 95% CI = 0.29 to 0.92, p = 0.024); the presence of broad-based, unstable gait (OR = 2.72, 95% CI = 1.47 to 5.06, p = 0.0018) or other gait impairment (OR = 3.56, 95% CI = 1.75 to 7.22, p = 0.0005); and older age (OR = 0.96, 95% CI = 0.93 to 0.98, p = 0.0004). The dependent variable, the mJOA score at one year, was dichotomized for logistic regression: a “successful” outcome was defined as a final score of ≥16 and a “failed” outcome was a score of <16. The final model included age (OR = 0.97, 95% CI = 0.94 to 0.99, p = 0.0017), duration of symptoms (OR = 0.78, 95% CI = 0.61 to 0.997, p = 0.048), smoking status (OR = 0.46, 95% CI = 0.21 to 0.98, p = 0.043), impairment of gait (OR = 2.66, 95% CI = 1.17 to 6.06, p = 0.020), psychological comorbidities (OR = 0.33, 95% CI = 0.15 to 0.69, p = 0.0035), baseline mJOA score (OR = 1.22, 95% CI = 1.05 to 1.41, p = 0.0084), and baseline transverse area of the cord on magnetic resonance imaging (OR = 1.02, 95% CI = 0.99 to 1.05, p = 0.19). The area under the receiver operator characteristic curve was 0.79, indicating good model prediction.


On the basis of the results of the AOSpine North America study, we identified a list of the most important predictors of surgical outcome for cervical spondylotic myelopathy.

Level of Evidence: 

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

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    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
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