Cervical Radiographical Alignment: Comprehensive Assessment Techniques and Potential Importance in Cervical Myelopathy

Ames, Christopher P. MD*; Blondel, Benjamin MD†,‡; Scheer, Justin K. BS§; Schwab, Frank J. MD; Le Huec, Jean-Charles MD, PhD; Massicotte, Eric M. MD, MSc, FRCS(C); Patel, Alpesh A. MD, FACS**; Traynelis, Vincent C. MD††; Kim, Han Jo MD‡‡; Shaffrey, Christopher I. MD§§; Smith, Justin S. MD, PhD§§; Lafage, Virginie PhD

doi: 10.1097/BRS.0b013e3182a7f449
Influence of Spinal Deformity on Management and Outcome of Cervical Spondylotic Myelopathy

Study Design. Narrative review.

Objective. To provide a comprehensive narrative review of cervical alignment parameters, the methods for quantifying cervical alignment, normal cervical alignment values, and how alignment is associated with cervical deformity and myelopathy with discussions of health-related quality of life.

Summary of Background Data. Indications for surgery to correct cervical alignment are not well-defined and there is no set standard to address the amount of correction to be achieved. In addition, classifications of cervical deformity have yet to be fully established and treatment options defined and clarified.

Methods. A survey of the cervical spine literature was conducted.

Results. New normative cervical alignment values from an asymptomatic volunteer population are introduced, updated methods for quantifying cervical alignment are discussed, and describing the relationship between cervical alignment, disability, and myelopathy are outlined. Specifically, methods used to quantify cervical alignment include cervical lordosis, cervical sagittal vertical axis, and horizontal gaze with the chin-brow vertical angle. Updated methods include T1 slope. Evidence from a few recent studies suggests correlations between radiographical parameters in the cervical spine and health-related quality of life. Analysis of the cervical regional alignment with respect to overall spinal pelvic alignment is emerging and critical. Cervical myelopthay and sagittal alignment of the cervical spine are closely related as cervical deformity can lead to spinal cord compression and tension.

Conclusion. Cervical deformity correction should take on a comprehensive approach in assessing global cervical-pelvic relationships and the radiographical parameters that effect health-related quality of life scores are not well-defined. Cervical alignment may be important in assessment and treatment of cervical myelopathy. Future work should concentrate on correlation of cervical alignment parameters to disability scores and myelopathy outcomes.

Summary Statements.

Statement 1: Cervical sagittal alignment (cervical SVA and kyphosis) is related to thoracolumbar spinal pelvic alignment and to T1 slope.

Statement 2: When significant deformity is clinically or radiographically suspected, regional cervical and relative global spinal alignment should be evaluated preoperatively via standing 3-foot scoliosis X-rays for appropriate operative planning.

Statement 3: Cervical sagittal alignment (C2-C7 SVA) is correlated to regional disability, general health scores and to myelopathy severity.

Statement 4: When performing decompressive surgery for CSM, consideration should be given to correction of cervical kyphosis and cervical sagittal imbalance (C2-C7 SVA) when present.

Cervical deformity is disruption of normal cervical alignment. This review focuses on normal cervical alignment, methods for quantifying alignment, and how alignment is associated with cervical deformity, myelopathy. Included are discussions of health-related-quality of life, surgical considerations, and the future direction of cervical alignment assessment.

*Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA

Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY

Université Aix-Marseille, Marseille, France

§University of California, San Diego, School of Medicine, La Jolla, CA

Spine Unit 2, Bordeaux University Hospital, Bordeaux, France

Division of Neurosurgery, University of Toronto, Toronto, Ontario Canada

**Department of Orthopaedic Surgery, Loyola University, Chicago, IL

††Department of Neurosurgery, Rush University, Chicago, IL

‡‡Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY; and

§§Department of Neurosurgery, University of Virginia Health System, Charlottesville, VA.

Address correspondence and reprint requests to Christopher P. Ames, MD, Department of Neurosurgery, University of California, San Francisco, Medical Center, 400 Parnassus Ave, A850, San Francisco, CA; E-mail: amesc@neurosurg.ucsf.edu

Acknowledgment date: March 7, 2013. First revision date: June 8, 2013. Second revision date: July 15, 2013. Acceptance date: July 25, 2013.

The manuscript submitted does not contain information about medical device(s)/drug(s).

Supported by AOSpine North America, Inc. Analytic support for this work was provided by Spectrum Research, Inc., with funding from the AOSpine North America.

Relevant financial activities outside the submitted work: board membership, payment for lectures, consultancy, grants/grants pending, patents, royalties, support for travel, provision of writing assistance, medicines, equipment, or administrative support, expert testimony, grant, consulting fee or honorarium, travel/accommodations/meeting expenses, and stock/stock options.

© 2013 by Lippincott Williams & Wilkins